The Great London [Search results for Climate Change] 

A new and more dangerous phase of impacts on the world's remaining tropical forests is emerging, threatening to simplify the world's most diverse ecosystem including mass species loss, according to new UCL-led research published today in Science.

The impact of humans on these areas has been increasing for millennia and today more than three-quarters of the world's remaining tropical forests have been degraded by human actions.

The scientists identified three prior phases of expanding impacts, the first when hunter-gatherers moved into tropical forests and the second following the emergence of tropical agriculture, some 6,000 years ago. Under both, the overall health of tropical forests was maintained.

Today, we live in the third phase, marked by much greater impacts, with distant decision-makers directing how land is used, including permanent intensive agriculture, often for soybeans or palm oil, frontier industrial logging for timber export, cross-continental species invasions, and early climate change impacts. The scientists term this phase the era of 'Global Integration', affecting even the most remote areas.

Lead author, tropical forest expert Dr Simon Lewis (UCL Geography and University of Leeds) said: "Earth has lost 100 million hectares of tropical forest over the last 30 years, mostly to agricultural developments. Few people think about how intertwined with tropical forests we all are. Many foodstuffs include palm oil which comes from once pristine Asian tropical forest, while remaining intact forests are buffering the rate of climate change by absorbing about a billion tonnes of carbon each year."

Current trends look set to intensify without major policy changes, as global food demand is projected to double, over 25 million kilometres of road are predicted to be built by 2050, and climate change intensifies, ushering in a new phase of human dominance of tropical forests.

Dr Lewis added: "I fear a global simplification of the world's most complex forests. Deforestation, logging and road building all create fragmented patches of forest. However, as the climate rapidly changes the plants and animals living in the rainforest will need to move to continue to live within their ecological tolerances. How will they move? This is a recipe for the mass extinction of tropical forest species this century.

"What is needed are unbroken areas of forest that link today's core tropical regions with forest areas about 4 degrees cooler, so as temperatures rise and rainfall patterns change species have a better chance of surviving rapid 21st century climate change. We need to bring conservation in line with the reality of climate change."

The authors note that while deforestation and degradation continue, more optimistically, logged forest retains many environmental benefits, and marginal agricultural lands are being abandoned, which can return back to forest.

Dr David Edwards (University of Sheffield), co-author of the study, said: "Much biodiversity still remains in selectively logged forests, and can recover in secondary forests that grow on abandoned farmland. There is abundant potential to incorporate these forests into global plans to make tropical biodiversity climate change ready.

"Despite their value for biodiversity, logged-over and old secondary forests are frequently threatened by conversion to species-poor agricultural plantations. We urgently need to protect these human-impacted forests, especially in regions such as Southeast Asia where almost nowhere is left undegraded."

A suite of policy measures can help tropical forests survive, including giving forest dwellers formal collective legal rights over their land, which previous studies have shown is one of the best ways of preserving forests. A study of 292 protected areas in Amazonia showed that indigenous reserves were the most effective at avoiding deforestation in high pressure areas.

Most of the financial benefits of logging and plantation agriculture, such as palm oil, flow out of the forests. Ensuring local people have collective long-term rights over their lands would mean that benefits flowing from forest lands accrue to local people. This can provide the beginnings of programs of 'development without destruction', tackling poverty while maintaining forests. This, the authors argue, provides human rights and conservation win-wins.

Dr Lewis added: "With long-term certainty of tenure people can plan, maintaining forests while investing in improving agricultural productivity without expanding into forested lands. Forest dwellers won't be perfect managers of forests, but they won't look for a quick profit and then move on, as big businesses often do.

"This is a pivotal year for the global environment. There are some good signs for the world's tropical forests, with the UN New York Declaration on Forests agreeing to not only halt deforestation, but also restore 150 million hectares of forest. However, there are ominous signs too, with the palm oil industry having driven the world's highest deforestation rates in South East Asia now gearing up to repeat this process across Africa.

"The Paris climate change talks in December are doubly important for forests and forest communities. The levels of emission cuts will be a critical factor in determining how many tropical forest plants and animals go extinct over the coming decades and centuries. The agreements on reducing deforestation, including durable finance, will be pivotal. The final test will be whether some funds for adaptation will include land-use planning to retain forest connectivity as the climate rapidly changes."

Source: University College London [August 24, 2015]

The appearance of infectious diseases in new places and new hosts, such as West Nile virus and Ebola, is a predictable result of climate change, says a noted zoologist affiliated with the Harold W. Manter Laboratory of Parasitology at the University of Nebraska-Lincoln.

In an article published online today in conjunction with a special issue of the Philosophical Transactions of the Royal Society B, Daniel Brooks warns that humans can expect more such illnesses to emerge in the future, as climate change shifts habitats and brings wildlife, crops, livestock, and humans into contact with pathogens to which they are susceptible but to which they have never been exposed before.

"It's not that there's going to be one 'Andromeda Strain' that will wipe everybody out on the planet," Brooks said, referring to the 1971 science fiction film about a deadly pathogen. "There are going to be a lot of localized outbreaks putting pressure on medical and veterinary health systems. It will be the death of a thousand cuts."

Brooks and his co-author, Eric Hoberg, a zoologist with the U.S. National Parasite Collection of the USDA's Agricultural Research Service, have personally observed how climate change has affected very different ecosystems. During his career, Brooks has focused primarily on parasites in the tropics, while Hoberg has worked primarily in Arctic regions.

Each has observed the arrival of species that hadn't previously lived in that area and the departure of others, Brooks said.

"Over the last 30 years, the places we've been working have been heavily impacted by climate change," Brooks said in an interview last week. "Even though I was in the tropics and he was in the Arctic, we could see something was happening." Changes in habitat mean animals are exposed to new parasites and pathogens.

For example, Brooks said, after humans hunted capuchin and spider monkeys out of existence in some regions of Costa Rica, their parasites immediately switched to howler monkeys, where they persist today. Some lungworms in recent years have moved northward and shifted hosts from caribou to muskoxen in the Canadian Arctic.

But for more than 100 years, scientists have assumed parasites don't quickly jump from one species to another because of the way parasites and hosts co-evolve.

Brooks calls it the "parasite paradox." Over time, hosts and pathogens become more tightly adapted to one another. According to previous theories, this should make emerging diseases rare, because they have to wait for the right random mutation to occur.

However, such jumps happen more quickly than anticipated. Even pathogens that are highly adapted to one host are able to shift to new ones under the right circumstances.

Brooks and Hoberg call for a "fundamental conceptual shift" recognizing that pathogens retain ancestral genetic capabilities allowing them to acquire new hosts quickly.

"Even though a parasite might have a very specialized relationship with one particular host in one particular place, there are other hosts that may be as susceptible," Brooks said.

In fact, the new hosts are more susceptible to infection and get sicker from it, Brooks said, because they haven't yet developed resistance.

Though resistance can evolve fairly rapidly, this only changes the emergent pathogen from an acute to a chronic disease problem, Brooks adds.

"West Nile Virus is a good example - no longer an acute problem for humans or wildlife in North America, it nonetheless is hhere to stay," he said.

The answer, Brooks said, is for greater collaboration between the public and veterinary health communities and the "museum" community - the biologists who study and classify life forms and how they evolve.

In addition to treating human cases of an emerging disease and developing a vaccine for it, he said, scientists need to learn which non-human species carry the pathogen.

Knowing the geographic distribution and the behavior of the non-human reservoirs of the pathogen could lead to public health strategies based on reducing risk of infection by minimizing human contact with infected animals, much likethose that reduced the incidence of malaria and yellow fever by reducing human contact with mosquitos.

Museum scientists versed in understanding the evolutionary relationships among species could use this knowledge to anticipate the risk of the pathogen becoming established outside of its native range.

Brooks, who earned his bachelor's and master's degrees from the University of Nebraska-Lincoln, was a zoology professor at the University of Toronto for 30 years until he retired early in 2011 to devote more time to his study of emerging infectious disease. In addition to being a senior research fellow with UNL's Manter Laboratory, he is a visiting senior fellow at the Universidade Federal do Parana, Brazil, funded by the Ciencias sem Fronteiras (Sciences without Borders) of the Brazilian government, and a visiting scholar with Debrecen University in Hungary.

Brooks' and Hoberg's article, "Evolution in action: climate change, biodiversity dynamics and emerging infectious disease," is part of a Philosophical Transactions of the Royal Society B issue on "Climate change and vector-borne diseases of humans," edited by Paul Parham, a specialist in infectious disease epidemiology at Imperial College in London.

"We have to admit we're not winning the war against emerging diseases," Brooks said. "We're not anticipating them. We're not paying attention to their basic biology, where they might come from and the potential for new pathogens to be introduced."

Source: University of Nebraska-Lincoln [February 16, 2015]

A multidisciplinary research team including University of Granada (UGR) researchers has analyzed two sea bed loggings retrieved from the Alboran Sea's basin at very high resolution and reconstructed climate and oceanographic conditions over the last millennium, including the anthropogenic influence in the westernmost region of the Mediterranean Sea.

Global warming, climate change and their effects on health and safety are probably the worst threats in mankind's history. Recent reports from the Intergovernmental Panel on Climate Change (IPCC 2007, 2014) have accumulated scientific evidence that the observed rise in mean ground temperature all over the world from the beginning of the 20th century is probably due to anthropogenic influence.

Moreover, global mean concentration of carbon dioxide in the atmosphere has risen since the industrial revolution due to human activities. This concentration has surpassed that found in ice cores over the last 800 000 years. In January 2016, NASA and the U.S. National Oceanic and Atmospheric Administration (NOAA) revealed that global mean temperature in 2015 was the highest since 1880, when records began.

Reconstructions of the global ground temperature in the Northern Hemisphere over the last millennium show hotter conditions during the so called Medieval Climatic Anomaly (800-1300 A.C.) and cooler temperatures during the Little Ice Age (1300-1850 A.C.).

Natural climate variability

Climate models give us a coherent explanation of the progressive cooling over the last millennium due to a natural climate variability (solar cycle changes and volcanic eruptions). However, we can see that this global tendency has reverted during the 20th century. Climate models are not capable of simulating the fast warming observed during the last century without including human impact along with natural mechanisms of climate forcing.

With this in mind, a multidisciplinary team of researchers has conducted a study reconstructing climate and oceanographic conditions in the westernmost region of the Mediterranean Sea. For that purpose, they have used marine sediments retrieved from the Alboran Sea's basin.

As a semi-closed basin located in a latitude affected by several climate types, it's especially sensitive and vulnerable to anthropogenic and climate forcing. Several organic and inorganic geochemical indicators have been integrated in the model for this research, thus deducing climate variables such as sea surface temperature, humidity, changes in vegetation cover, changes in sea currents, and human impact.

These indicators have shown consistent climate signals in the two sea bed loggings—essentially hot and dry climate conditions during the Medieval Climatic Anomaly, which switched to mostly cold and wet conditions during the Little Ice Age. The industrial period showed wetter conditions than during the Little Ice Age, and the second half of the 20th century has been characterized by an increasing aridity.

Climate variability in the Mediterranean region seems to be driven by variations in solar irradiation and changes in the North Atlantic Oscillation (NAO) during the last millennium. The NAO alternates a positive phase with a negative one. The positive phase is characterized by western winds, which are more intense and move storms towards northern Europe, which resulted in dry winters in the Mediterranean region and the north of Africa during the Medieval Climatic Anomaly and the second half of the 20th century.

In contrast, the negative phase is associated with opposite conditions during the Little Ice Age and the industrial period. Our records show that during NAO prolonged negative phases (1450 and 1950 A.C.), there occurred a weakening of the thermohaline circulation and a reduction of "upwelling" events (emergence of colder, more nutrient-rich waters). Anthropogenic influence shows up in the unprecedented increase of temperature, progressive aridification and soil erosion, and an increase of polluting elements since the industrial period. On a broad scale, atmospheric circulation patterns, oceanic circulation patterns (the NAO and the Atlantic meridional overturning circulation), and variations in solar irradiance seem to have played a key role during the last millennium.

Results show that recent climate records in the westernmost region of the Mediterranean Sea are caused by natural forcing and anthropogenic influence. The main conclusions derived from this research have been published in a special volume of the >Journal of the Geological Society of London about climate change during the Holocene.

Source: University of Granada [October 12, 2016]

Habitat degradation poses a greater risk to the survival of turtles and tortoises than rising global temperatures, according to new research.

More than 60 per cent of the group are listed by the International Union for Conservation of Nature (IUCN) as vulnerable, endangered, or critically endangered, because they are being traded, collected for food and medicine and their habitats are being degraded. Understanding the additional impact of global warming and changes in rainfall patterns on their diversity and distributions is therefore paramount to their conservation.

The team of researchers set out to test if long-term climate change poses a threat or opportunity to turtles and tortoises and how they might respond to increased global temperatures.

As turtles live such long lives, it is impossible to conduct experiments to test for the impact of warming over several generations. The group used a novel combination of state of the art climate models and the deep time fossil record of turtles during warmer times.

The Late Cretaceous fossil record (66-72 million years ago), dating from the time just before the demise of the dinosaurs, was investigated as a natural experiment to quantify differences between the ecology of living turtles and tortoises and those living in an earlier, warmer greenhouse world.

The results of this study, funded by the Natural Environment Research Council (NERC) with support from The Royal Society, show that during periods with much warmer climates, turtles and tortoises were able to stand the heat in the warmer tropics -- as long as there was enough water to support those species living in rivers and lakes.

Amy Waterson, PhD student and lead author from the University of Bristol, said: "Some groups of turtles have maintained similar niches over millions of years. They have withstood warmer climates in the past and their ability to adapt to the rate of environmental change happening today will be an important factor in their resilience to future climate change."

Turtles and tortoises are highly sensitive to changes in temperature and rainfall, hence concerns about the impact of climate change on their distribution. Alongside overexploitation and habitat loss, climate change is a significant threat to their conservation status with growth, abundance and geographical ranges all predicted to decline under future climate change projections.

In many species, temperature determines if the egg will develop into a male or female showing a direct impact of warming. As the group lives in ponds, rivers, on land and in the sea climate change can impact them via changes in temperature, rainfall, and major ocean currents.

However, Professor Daniela Schmidt, an expert in palaeobiology from the University of Bristol's School of Earth Sciences, explained that the bigger question for the conservation of the group is not how warm it will be in the near future but how fast that warming will be: "The largest difference between the warm Cretaceous and today is that this earlier warming happened over tens of thousands of years, giving these animals a chance to adapt to these conditions, not in a century."

Professor Paul Barrett from the Natural History Museum, London added: "Other conservation threats, such as humanmade habitat degradation and barriers to movement, might be as important in determining the fates of turtles in a warming world as the warming itself."

The study is published in the >Royal Society of Proceedings B.

Source: University of Bristol [September 22, 2016]

The erosion rates of cliffs along the Sussex coast have rapidly sped up in the last 200 years, a new study has found.

The research shows that the erosion rates along Beachy Head and Seaford Head in Sussex had remained relatively stable, at around two to six centimetres each year, for thousands of years. However, around 200 to 600 years ago the rates rapidly accelerated, increasing to between 22 and 32 centimetres each year.

The authors suggest that rising sea levels and increasingly severe storms have rapidly eroded the Beachy Head and Seaford Head shorelines. The loss of beach means that the cliffs are exposed to the eroding wave action forces, which is causing them to collapse into the sea. The researchers suggest this erosion process is probably happening along other coastlines in the UK and elsewhere around the world, with implications for how coasts will respond to climate change and what we can do to manage the impact on important coastal infrastructure.

Dr Dylan Rood, co-author from the Department of Earth Science and Engineering at Imperial College London, said: "The coast is clearly eroding, and Britain has retreated fast. Our study on British coasts leaves no question that coastal cliff retreat accelerated in the recent past. A nearly ten-fold increase in retreat rates over a very short timescale, in geological terms, is remarkable. The UK cannot leave the issue of cliff erosion unresolved in the face of a warming world and rising sea levels. Cliff erosion is irreversible; once the cliffs retreat, they are gone for good."

The scientists used a process called cosmogenic dating to learn how the chalk cliffs at Beachy Head and Seaford Head have eroded. Cosmogenic dating allows scientists to analyse the build-up of a rare isotope of beryllium (beryllium-10). This isotope is created when cosmic radiation reacts with oxygen atoms in the exposed flint rock, so by measuring its accumulation, it acts as a kind of 'rock clock' to show the rate of rock erosion.

Since the rate of accumulation has previously been relatively constant, measuring rock samples from across the shore platforms allowed researchers to build a record of how coastal erosion has proceeded over the last 7000 years or so.

Dr Rood added: "Cosmogenic isotopes including beryllium-10 are advancing the science of retreating coastlines in Great Britain and worldwide. These new tools provide a rare insight into how dramatically environmental change and human impact affected sensitive coastal landscapes. We still need to better understand how other rocky coastlines have responded in the past, and cosmogenic isotopes are the key to unlocking this mystery."

The researchers now hope to use their observations to create a more accurate predictive model of how climate change will affect coastal erosion in the future, which could help authorities make more informed decisions about coastal management.

The research was published in the >Proceedings of the National Academy of Sciences.

Author: Caroline Brogan | Source: Imperial College London [November 16, 2016]

The first annual State of the World's Plants report, which involved more than 80 scientists and took a year to produce, is a baseline assessment of current knowledge on the diversity of plants on earth, the global threats these plants currently face, as well as the policies in place and their effectiveness in dealing with threats.

"This is the first ever global assessment on the state of the world's plants. We already have a 'State of the World's ...birds, sea-turtles, forests, cities, mothers, fathers, children even antibiotics' but not plants. I find this remarkable given the importance of plants to all of our lives- from food, medicines, clothing, building materials and biofuels, to climate regulation. This report therefore provides the first step in filling this critical knowledge gap." said Professor Kathy Willis, Director of Science at the Royal Botanic Gardens, Kew at the report launch on Monday.

"But to have effect, the findings must serve to galvanise the international scientific, conservation, business and governmental communities to work together to fill the knowledge gaps we've highlighted and expand international collaboration, partnerships and frameworks for plant conservation and use," she added.

The status of plants outlined in the report is based on the most up to date knowledge from around the world as of 2016 and is divided into three sections; describing the world's plants, global threats to plants and policies and international trade.

Naming and Counting

The first section focuses on the diversity of plants on earth, noting that there are now an estimated 391,000 vascular plants known to science of which 369,000 are flowering plants -- with around 2,000 new vascular plant species described annually. Some of the most exciting were found during fieldwork while many others were detected only after they have already been preserved and filed as herbarium specimens and a few have been discovered in the glasshouses at Kew.

One of the largest carnivorous plants known (1.5m in height), a new insect-eating plant of the sundew genus called Drosera magnifica was even first discovered on Facebook. Eighteen new species of the genus Ipomoea in the morning glory family, were described from Bolivia last year, among them a close relative of the sweet potato, Ipomoea batatas, offering exciting options for the future of this crop.

"But there are still large parts of the world where very little is known about plants. Identification of these important plant areas is now critical." said Steve Bachman, strategic output leader for the State of the World´s Plants report, RBG Kew. "Similarly, we still only know a fraction of the genetic diversity of plants and whole-genome sequences are currently available for just 139 species of vascular plants. Activity in this area needs to speed up," he added.

Useful plants

In terms of the uses of plants, the report collates data from multiple data sources to reveal that at least 31,000 plant species have a documented use for medicines, food, materials and so on. The majority (17,810 plants) of those now documented have a medicinal use.

Aside from the plants that are currently in use, the report looks at where collection efforts should focus to include plants that will be useful in the future. One set of plant species of critical importance to global food security are the wild relatives of crops, a pool of genetic variation that can help to drive the improvement of our crops into the future. A recent inventory has revealed that there are currently 3,546 prioritised global plant taxa identified as 'crop wild relatives' and Kew's Millennium Seed Bank (MSB) includes 688 crop wild relatives among its over 78,000 accessions, but there are still substantial gaps.

Research in this sector has found that the traits that have been bred into crops over years of domestication are not necessarily the same ones that will provide the greatest climate resilience. Given that many of the wild populations of these species are under considerable threat due to land-use and climate change there is an urgent need to conserve those species not adequately represented in current collections. More seed banking will help preserve a wider range of alternatives to the crops on which the world over relies today (report pages 20-23).

Climate change

The report also explores current knowledge around the impact of climate change on plants and finds that while there is a good understanding for some regions of the world, there are still large areas for which little or no research exists. In those areas where good data is available, clear impacts are visible, including changes in flowering times, turnover in plant communities and movement of species with changing climates.

Research referenced in the report shows that all but one of the world's biomes have experienced more than 10% change in land-cover type in the past decade due to the combined impacts of land-use and climate change.

This research, led by teams at the International Center for Tropical Agriculture in Colombia is also the first of its kind to allocate timeframes for the changes in policy and practice needed to maintain food production and security in Africa. It identifies that up to 30% of areas growing maize and bananas, and up to 60% of those growing beans, are likely to become unviable by the end of the century. But it also highlights some crops like cassava and yams that are showing much greater resilience and could worth focusing on in years to come (report pages 36-39).

"Having proof that root crops like cassava and yams are among the climate-smart crops of the future for sub Saharan Africa is vital for informing policy and planning today," added Professor Willis.

Further research into building a climate resilient coffee economy in Ethiopia published in this report highlights how coffee production is likely to be drastically affected by climate change, but claims that this could be offset if there were interventions now to develop new areas for coffee plantations, which may even lead to gains in coffee production.

Important plant areas

1,771 important plant areas have been identified globally but very few currently have conservation protection. In the UK alone, 165 such sites have been recognised, including parts of the Atlantic woodlands and the Celtic rainforests which are considered to be globally important. These sites include the Lizard in Cornwall, the Brecklands in East Anglia and parts of the west coast of Scotland. Important plant areas have also been identified in several of the UK Overseas Territories including the Falkland Islands and plans are underway to extend this programme to the Caribbean UK Overseas Territories.

Invasive species

A large movement of invasive alien plant species is also occurring. Nearly 5000 plant species are now documented as invasive in global surveys. These plants are causing large declines in native plants, damaging natural ecosystems, transforming land-cover and often causing huge economic losses. In the UK, this includes the highly invasive Japanese knotweed (Reynoutria japonica), introduced as an ornamental plant to Britain in the mid-19th century and costing Great Britain more than £165 million annually to control (report pages 48-51).

The report calls for closer collaboration between institutions and organisations working with invasive species to enable the establishment of a single global list that documents taxonomy, threat, distribution, control and other relevant information. Stricter enforcement of legislation and increased implementation of quarantine procedures would minimise the risk of further.

Plant diseases

There are many emerging threats also occurring with plant diseases, and research effort into these diseases is skewed towards countries with a wealthier research infrastructure.

Threats and extinction

Best estimates lead us to believe that 21% of the world's plants are currently threatened with extinction and ongoing monitoring will allow us to determine whether the trend is of plants slipping closer towards extinction or becoming less threatened.

Plants and policies

Although trade in plants supports livelihoods worldwide, illegal or unsustainable trade is causing additional pressure on wild biodiversity and strict enforcement of international legislation is crucial. Adoption and implementation of policies such as CITES (Convention on International Trade in Endangered Species) have had demonstrable benefits and there is cause for optimism that the Nagoya Protocol will enhance the effectiveness with which countries conserve and utilise their biodiversity.

One of the main plant groups that are still widely traded are orchids, a fact confirmed by data from the UK borderforce. Of all plants plants seized at Heathrow airport in 2015 over 42% were wild orchids.

"This is the most significant horizon-scanning document to be released by Kew in recent decades and I hope as many people as possible will access the findings," said Richard Deverell, Director of the Royal Botanic Gardens, Kew.

"Plants represent one of the most important constituents of biodiversity, the foundation of most of the world's ecosystems and hold the potential to tackle many of the world's present and future challenges. We are uniquely placed to unlock their importance and are proud to have both the catalogue of over 250 years of collections and active scientific field work globally that allows us to interpret the data so it will have multiple uses for generations to come," he added.

Read the report >here.

Source: Royal Botanic Gardens Kew [May 11, 2016]

Typically ignored, the millions of microorganisms that we tread upon daily play a major role in the decomposition of soil matter -- one that is of far greater significance than that of the whales and pandas that tend to steal our attention. A group of researchers has just shown that there is an enormous diversity among a group of bacteria-eating microorganisms known as Cercozoa. In four small soil samples, each consisting of a half gram of soil, they discovered more than 1000 different species per sample. The research suggests that a drier climate in the years ahead due to climate change will contribute to a shift in the number of soil microorganisms, and thus, a shift in the decomposition of soil matter, with as of yet to be known consequences.

A team led by researchers from the Section for Terrestrial Ecology (Flemming Ekelund, Christopher B. Harder and Regin Ronn, at the Department of Biology, University of Copenhagen) has just published an article in the >ISME Journal. The group's studies show that there is enormous species diversity among an oft-overlooked group of organisms known as Cercozoa. In four small soil samples, each consisting of just a half gram of soil, the researchers discovered more than 1000 different species per sample. The research was conducted in collaboration with Section for Microbiology staff (Department of Biology, University of Copenhagen) and the eminent British scientist, David Bass (Natural History Museum, London), and is supported by national research councils and the Carlsberg Foundation.

Associate Professor Flemming Ekelund of the Department of Biology explains, "Cercozoa are small bacteria-eating microorganisms that play a prominent role in soil ecology. Serious interest in these organisms began about 25-30 years ago, as people began to wonder what caused bacteria to disappear from soil. As interest took root, the number of known species increased sharply."

The name Cercozoa is derived from the Greek word, kerkos (tail), as some of the species within the group have a tail like end, and zoon (animal), as these organisms were previously thought to be a type of animal.

A single teaspoon of soil (a couple of grams) contains millions of microorganisms, so it is hopeless to create a species list by studying organisms one by one. Furthermore, many of these organisms belong to species unknown to science.

"We took small soil samples (½-1 gram), from which we analysed DNA strands (genetic material) from hundreds of thousands of organisms" (deep sequencing), explains Christoffer Bugge Harder. "However, it's difficult to catalogue and systematise this huge amount of data. To do so, we used the Section of Microbiology's capacity to deploy specialized statistics tools. Our British colleague, David Bass, contributed precise DNA references for the species in the group that have already been thoroughly catalogued. For now, this remains at just under 1000."

The studies were conducted in correlation with a climate experiment (Climate) that investigates the consequences of climate change in Denmark, as many climate researchers expect it to present itself, by 2075. Besides being able to report an enormous number of species in these samples, the research also demonstrated that a more arid climate, as expected in 2075, will probably lend to a shift in the occurrence of microorganism species; particularly within a group referred to as testate amoebae.

Researchers already know that climate change will result in significant shifts in plant and animal frequency. But it can also lead to changed frequencies among microorganisms, which means that climate change could have an impact on the ecological processes at work in soil. More studies are needed for researchers to specify the impact of an offset and the amount of microorganisms found in soil as a result of global warming.

Source: Faculty of Science - University of Copenhagen [June 21, 2016]

When the Black Death swept through Europe in 1347, it was one of the deadliest disease outbreaks in human history, eventually killing between a third and half of Europeans.

Prior work by investigators has traced the cause to plague-carrying fleas borne by rats that jumped ship in trading ports. In addition, historical researchers believe that famine in northern Europe before the plague came ashore may have weakened the population there and set the stage for its devastation.

Now, new research using a unique combination of ice-core data and written historical records indicates that the cool, wet weather blamed for the northern European famine actually affected a much wider area over a much longer period. The work, which researchers say is preliminary, paints a picture of a deep, prolonged food shortage in the years leading to the Black Death.

“The evidence indicates that the famine was a broader phenomenon, geographically and chronologically,” said Alexander More, a postdoctoral fellow in the Harvard History Department and a lecturer in the History of Science Department.

A widespread famine that weakened the population over decades could help explain the Black Death’s particularly high mortality. Over four or five years after arriving in Europe in 1347, the pandemic surged through the continent in waves that killed millions.

The ice-core data is part of a unique program linking traditional historical research with scientific data-collecting techniques. The program, called the Initiative for the Science of the Human Past at Harvard (SoHP), is headed by Michael McCormick, the Francis Goelet Professor of Medieval History. SoHP’s ice-core project is being conducted in collaboration with the University of Maine’s Climate Change Institute and researchers at Heidelberg University. The project’s approach puts it at the juncture of environmental science, archaeology, and history. It is supported by the Arcadia Fund of London.

More presented his findings at a conference in November arranged to discuss the project. Joining him was Harvard junior Matthew Luongo, an Earth sciences and environmental engineering concentrator from Dunster House, who discussed the discovery of volcanic tephra in the ice core. Tephra, microscopic airborne volcanic particles, are generally believed absent from cores in European glaciers, make Luongo’s assumption-puncturing discovery potentially significant.

Luongo spent several days at the Climate Change Institute last summer performing chemical analyses and examining the volcanic bits through a scanning electron microscope. Each volcanic eruption has a slightly different chemical fingerprint, so he was able to trace the tephra to the 1875 Askja eruption in Iceland, one of the largest eruptions there in history.

Since many eruptions were written about contemporaneously, the ice core’s volcanic traces can be used to align ice-core data with written records, providing greater certainty in dating other chemical traces in the ice, such as those from human activities like lead from Roman-era smelting.

“I think it was a really important project,” Luongo said.

McCormick said that the advanced technologies scientists used to understand areas like the human genome and climate change are increasingly being applied to the humanities, and opening new avenues of investigation.

McCormick was part of a team that in 2011 used tree-ring data to reconstruct European climate over the last 2,500 years, showing that the period before the fall of the Roman Empire was marked by wide climactic variability. In November, McCormick summed up the use of climate data in historical research as reading history “from the environment itself.”

“All these things are happening in the sciences and spilling over into the humanities,” McCormick said. “Twenty years ago, if you’d have told me that climate could have caused the collapse of the Roman Empire and that we would have the means to test that, I wouldn’t have believed you.”

The new data emerging from the ice core could be the first of a flood of information about the last millennium and beyond. McCormick’s University of Maine colleagues, led by Paul Mayewski, have developed a laser-based method of ice analysis. It requires far smaller samples of ice and can take 50,000 samples in a one-meter ice core, compared with just 100 in the previous method. The new technology allows much higher resolution analysis of even very thin ice layers — to the specific year and potentially to individual storms — and can go back farther than the 1500 A.D. limit of this glacier with previous techniques.

The ice core was the first ever taken specifically for historical research, McCormick said, and was drilled in 2013 from the Colle Gnifetti glacier, high in the Alps near the Swiss-Italian border. It was divided between partner organizations, with the portion allocated to the Initiative for the Science of the Human Past and the Climate Change Institute being held at the University of Maine.

The findings about the period preceding the Black Death described by More continue to fill in an emerging and newly complex picture of a key period in human history. Recent research has traced the genesis of the European plague to animal groups in Asia and climate-related outbreaks that traveled along Silk Road trade routes.

McCormick said this application of scientific methods opens new avenues of inquiry, akin to discovering colossal collections of historical records, whether read directly from the DNA of ancient people, from the trees that grew at the time, or from the ice deposited in ancient storms.

“It’s a gigantic set of archives that document the least-documented part of [history],” McCormick said. “It’s kind of a renaissance of history.”

Author: Alvin Powell | Source: Harvard University [January 07, 2016]

Researchers from Royal Holloway, Birkbeck and Kings College, University of London used satellite images to map abandoned shore lines around Palaeolake Mega-Chad, and analysed sediments to calculate the age of these shore lines, producing a lake level history spanning the last 15,000 years.

At its peak around 6,000 years ago, Palaeolake Mega-Chad was the largest freshwater lake on Earth, with an area of 360,000 km2. Now today's Lake Chad is reduced to a fraction of that size, at only 355 km2. The drying of Lake Mega-Chad reveals a story of dramatic climate change in the southern Sahara, with a rapid change from a giant lake to desert dunes and dust, due to changes in rainfall from the West African Monsoon. The research, published in the journal Proceedings of the National Academy of Sciences confirms earlier suggestions that the climate change was abrupt, with the southern Sahara drying in just a few hundred years.

Part of the Palaeolake Mega-Chad basin that has dried completely is the Bodele depression, which lies in remote northern Chad. The Bodele depression is the World's single greatest source of atmospheric dust, with dust being blown across the Atlantic to South America, where it is believed to be helping to maintain the fertility of tropical rainforests. However, the University of London team's research shows that a small lake persisted in the Bodele depression until about 1,000 years ago. This lake covered the parts of the Bodele depression which currently produce most dust, limiting the dust potential until recent times.

"The Amazon tropical forest is like a giant hanging basket," explains Dr Simon Armitage from the Department of Geography at Royal Holloway. "In a hanging basket, daily watering quickly washes soluble nutrients out of the soil, and these need to be replaced using fertiliser if the plants are to survive. Similarly, heavy washout of soluble minerals from the Amazon basin means that an external source of nutrients must be maintaining soil fertility. As the World's most vigorous dust source, the Bodele depression has often been cited as a likely source of these nutrients, but our findings indicate that this can only be true for the last 1,000 years," he added.

Source: University of Royal Holloway London [June 29, 2015]

For each ton of carbon dioxide (CO2) that any person on our planet emits, 3 m² of Arctic summer sea ice disappear. This is the finding of a new study that has been published in the journal Science this week by Dr. Dirk Notz, leader of Max Planck research group "Sea Ice in the Earth System" at the Max Planck Institute for Metorology (MPI-M) and by Prof. Julienne Stroeve from the National Snow and Ice Data Centre in Boulder, Colorado, and the University College London, UK. These numbers allow one for the first time to grasp the individual contribution to global climate change. The study also explains why climate models usually simulate a lower sensitivity - and concludes that the 2 °C global warming target will not allow Arctic summer sea ice to survive.

The rapid retreat of Arctic sea ice is one of the most direct indicators of the ongoing climate change on our planet. Over the past forty years, the ice cover in summer has shrunk by more than half, with climate model simulations predicting that the remaining half might be gone by mid century unless greenhouse gas emissions are reduced rapidly. However, a number of studies have indicated that climate models underestimate the loss of Arctic sea ice, which is why the models might not be the most suitable tools to quantify the future evolution of the ice cover.

To address this issue, a new study in the >journal Science now derives the future evolution of Arctic summer sea ice directly from the observational record. To do so, the authors examine the link between carbon-dioxide emissions and the area of Arctic summer sea ice, and find that both are linearly related. "The observed numbers are very simple", explains lead author Dirk Notz. "For each ton of carbon dioxide that a person emits anywhere on this planet, 3 m² of Arctic summer sea ice disappear." And his co-author Julienne Stroeve from adds: "So far, climate change has often felt like a rather abstract notion. Our results allow us to overcome this perception. For example, it is now straight-forward to calculate that the carbon dioxide emissions for each seat on a return flight from, say, London to San Francisco causes about 5 m² of Arctic sea ice to disappear."

The study also explains the linear relationship between carbon-dioxide emissions and sea-ice loss. "Put simply, for each ton of carbon dioxide emission, the climate warms a little bit. To compensate for this warming, the sea-ice edge moves northward to a region with less incoming solar radiation. This then causes the sea-ice area to shrink. Simple geometric reasons cause these processes to combine to the observed linearity", explains Notz.

Climate models also simulate the observed linear relationship between sea-ice area and CO2 emissions. However, they usually have a much lower sensitivity of the ice cover than has been observed. The Science study finds that this is most likely because the models underestimate the atmospheric warming in the Arctic that is induced by a given carbon-dioxide emission. "It seems that it's not primarily the sea-ice models that are responsible for the mismatch. The ice just melts too slow in the models because their Arctic warming is too weak", says Stroeve.

Regarding the future evolution of Arctic sea ice, the new study finds that the internationally agreed 2 °C global warming target is not sufficient to allow Arctic summer sea ice to survive. Given the observed sensitivity of the ice cover, the sea ice is gone throughout September once another 1000 gigatons of carbon dioxide have been emitted. This amount of emissions is usually taken as a rough estimate of the allowable emissions to reach the 2 °C global-warming target. Only for the much lower emissions that would allow one to keep global warming below 1.5 °C, as called for by the Paris agreement, Arctic summer sea ice has a realistic chance of long-term survival, the study concludes. 

Source: Max Planck Society [November 04, 2016]

While searching through historical archives to find out more about the 15th-century climate of what is now Belgium, northern France, Luxembourg, and the Netherlands, Chantal Camenisch noticed something odd. "I realised that there was something extraordinary going on regarding the climate during the 1430s," says the historian from the University of Bern in Switzerland.

Compared with other decades of the last millennium, many of the 1430s' winters and some springs were extremely cold in the Low Countries, as well as in other parts of Europe. In the winter of 1432-33, people in Scotland had to use fire to melt wine in bottles before drinking it. In central Europe, many rivers and lakes froze over. In the usually mild regions of southern France, northern and central Italy, some winters lasted until April, often with late frosts. This affected food production and food prices in many parts of Europe. "For the people, it meant that they were suffering from hunger, they were sick and many of them died," says Camenisch.

She joined forces with Kathrin Keller, a climate modeller at the Oeschger Centre for Climate Change Research in Bern, and other researchers, to find out more about the 1430s climate and how it impacted societies in northwestern and central Europe. Their results are published in >Climate of the Past, a journal of the European Geosciences Union.

They looked into climate archives, data such as tree rings, ice cores, lake sediments and historical documents, to reconstruct the climate of the time. "The reconstructions show that the climatic conditions during the 1430s were very special. With its very cold winters and normal to warm summers, this decade is a one of a kind in the 400 years of data we were investigating, from 1300 to 1700 CE," says Keller. "What cannot be answered by the reconstructions alone, however, is its origin -- was the anomalous climate forced by external influences, such as volcanism or changes in solar activity, or was it simply the random result of natural variability inherent to the climate system?"

There have been other cold periods in Europe's history. In 1815, the volcano Mount Tambora spewed large quantities of ash and particles into the atmosphere, blocking enough sunlight to significantly reduce temperatures in Europe and other parts of the world. But the 1430s were different, not only in what caused the cooling but also because they hadn't been studied in detail until now.

The climate simulations ran by Keller and her team showed that, while there were some volcanic eruptions and changes in solar activity around that time, these could not explain the climate pattern of the 1430s. The climate models showed instead that these conditions were due to natural variations in the climate system, a combination of natural factors that occurred by chance and meant Europe had very cold winters and normal to warm summers.

Regardless of the underlying causes of the odd climate, the 1430s were "a cruel period" for those who lived through those years, says Camenisch. "Due to this cluster of extremely cold winters with low temperatures lasting until April and May, the growing grain was damaged, as well as the vineyards and other agricultural production. Therefore, there were considerable harvest failures in many places in northwestern and central Europe. These harvest failures led to rising food prices and consequently subsistence crisis and famine.

Furthermore, epidemic diseases raged in many places. Famine and epidemics led to an increase of the mortality rate." In the paper, the authors also mention other impacts: "In the context of the crisis, minorities were blamed for harsh climatic conditions, rising food prices, famine and plague." However, in some cities, such as Basel, Strasbourg, Cologne or London, societies adapted more constructively to the crisis by building communal granaries that made them more resilient to future food shortages.

Keller says another decade of very cold winters could happen again. "However, such temperature variations have to be seen in the context of the state of the climate system. Compared to the 15th century we live in a distinctly warmer world. As a consequence, we are affected by climate extremes in a different way -- cold extremes are less cold, hot extremes are even hotter."

The team says their Climate of the Past study could help people today by showing how societies can be affected by extreme climate conditions, and how they should take precautions to make themselves less vulnerable to them. In the 1430s, people had not been exposed to such extreme conditions before and were unprepared to deal with the consequences.

"Our example of a climate-induced challenge to society shows the need to prepare for extreme climate conditions that might be coming sooner or later," says Camenisch. "It also shows that, to avoid similar or even larger crises to that of the 1430s, societies today need to take measures to avoid dangerous anthropogenic climate interference."

Source: European Geosciences Union [December 01, 2016]

A relationship that has lasted for 100 million years is at serious risk of ending, due to the effects of environmental and climate change. A species of spiny crayfish native to Australia and the tiny flatworms that depend on them are both at risk of extinction, according to researchers from the UK and Australia.

Look closely into one of the cool, freshwater streams of eastern Australia and you might find a colourful mountain spiny crayfish, from the genus Euastacus. Look even closer and you could see small tentacled flatworms, called temnocephalans, each only a few millimetres long. Temnocephalans live as specialised symbionts on the surface of the crayfish, where they catch tiny food items, or inside the crayfish's gill chamber where they can remove parasites. This is an ancient partnership, but the temnocephalans are now at risk of coextinction with their endangered hosts. Coextinction is the loss of one species, when another that it depends upon goes extinct.

In a new study, researchers from the UK and Australia reconstructed the evolutionary and ecological history of the mountain spiny crayfish and their temnocephalan symbionts to assess their coextinction risk. This study was based on DNA sequences from crayfish and temnocephalans across eastern Australia, sampled by researchers at James Cook University, sequenced at the Natural History Museum, London and Queensland Museum, and analysed at the University of Sydney and the University of Cambridge. The results are published in the >Proceedings of the Royal Society B.

"We've now got a picture of how these two species have evolved together through time," said Dr Jennifer Hoyal Cuthill from Cambridge's Department of Earth Sciences, the paper's lead author. "The extinction risk to the crayfish has been measured, but this is the first time we've quantified the risk to the temnocephalans as well -- and it looks like this ancient partnership could end with the extinction of both species."

Mountain spiny crayfish species diversified across eastern Australia over at least 80 million years, with 37 living species included in this study. Reconstructing the ages of the temnocephalans using a 'molecular clock' analysis showed that the tiny worms are as ancient as their crayfish hosts and have evolved alongside them since the Cretaceous Period.

>A symbiotic relationship that has existed since the time of the dinosaurs is at risk of ending,> as habitat loss and environmental change mean that a species of Australian crayfish >and the tiny worms that depend on them are both at serious risk of extinction >[Credit: David Blair/James Cook University]
Today, many species of mountain spiny crayfish have small geographic ranges. This is especially true in Queensland, where mountain spiny crayfish are restricted to cool, high-altitude streams in small pockets of rainforest. This habitat was reduced and fragmented by long-term climate warming and drying, as the continent of Australia drifted northwards over the last 165 million years. As a consequence, mountain spiny crayfish are severely threatened by ongoing climate change and the International Union for the Conservation of Nature (IUCN) has assessed 75% of these species as endangered or critically endangered.

"In Australia, freshwater crayfish are large, diverse and active 'managers', recycling all sorts of organic material and working the sediments," said Professor David Blair of James Cook University in Australia, the paper's senior author. "The temnocephalan worms associated only with these crayfish are also diverse, reflecting a long, shared history and offering a unique window on ancient symbioses. We now risk extinction of many of these partnerships, which will lead to degradation of their previous habitats and leave science the poorer."

The crayfish tend to have the smallest ranges in the north of Australia, where the climate is the hottest and all of the northern species are endangered or critically endangered. By studying the phylogenies (evolutionary trees) of the species, the researchers found that northern crayfish also tended to be the most evolutionarily distinctive. This also applies to the temnocephalans of genus Temnosewellia, which are symbionts of spiny mountain crayfish across their geographic range. "This means that the most evolutionarily distinctive lineages are also those most at risk of extinction," said Hoyal Cuthill.

The researchers then used computer simulations to predict the extent of coextinction. This showed that if all the mountain spiny crayfish that are currently endangered were to go extinct, 60% of their temnocephalan symbionts would also be lost to coextinction. The temnocephalan lineages that were predicted to be at the greatest risk of coextinction also tended to be the most evolutionarily distinctive. These lineages represent a long history of symbiosis and coevolution of up to 100 million years. However they are the most likely to suffer coextinction if these species and their habitats are not protected from ongoing environmental and climate change.

"The intimate relationship between hosts and their symbionts and parasites is often unique and long lived, not just during the lifespan of the individual organisms themselves but during the evolutionary history of the species involved in the association," said study co-author Dr Tim Littlewood of the Natural History Museum. "This study exemplifies how understanding and untangling such an intimate relationship across space and time can yield deep insights into past climates and environments, as well as highlighting current threats to biodiversity."

Source: University of Cambridge [May 24, 2016]

Molecular-based moisture indicators, remains of midges and climate simulations have provided climate scientists with the final piece to one of the most enduring puzzles of the last Ice Age.

For years, researchers have struggled to reconcile climate models of the Earth, 13,000 years ago, with the prevailing theory that a catastrophic freshwater flood from the melting North American ice sheets plunged the planet into a sudden and final cold snap, just before entering the present warm interglacial.

Now, an international team of scientists, led by Swedish researchers from Stockholm University and in partnership with UK researchers from the Natural History Museum (NHM) London, and Plymouth University, has found evidence in the sediments of an ancient Swedish lake that it was the melting of the Scandinavian ice sheet that provides the missing link to what occurred at the end of the last Ice Age. The study, published in Nature Communications, today, examined moisture and temperature records for the region and compared these with climate model simulations.

Francesco Muschitiello, a PhD researcher at Stockholm University and lead author of the study, said: "Moisture-sensitive molecules extracted from the lake's sediments show that climate conditions in Northern Europe became much drier around 13,000 years ago."

Steve Brooks, Researcher at the NHM, added: "The remains of midges, contained in the lake sediments, reveal a great deal about the past climate. The assemblage of species, when compared with modern records, enable us to track how, after an initial warming of up to 4° Centigrade at the end of the last Ice Age, summer temperatures plummeted by 5°C over the next 400 years."

Dr Nicola Whitehouse, Associate Professor in Physical Geography at Plymouth University, explained: "The onset of much drier, cooler summer temperatures, was probably a consequence of drier air masses driven by more persistent summer sea-ice in the Nordic Seas."

According to Francesco Muschitiello the observed colder and drier climate conditions were likely driven by increasingly stronger melting of the Scandinavian ice sheet in response to warming at the end of the last Ice Age; this led to an expansion of summer sea ice and to changes in sea-ice distribution in the eastern region of the North Atlantic, causing abrupt climate change. Francesco Muschitiello added: "The melting of the Scandinavian ice sheet is the missing link to understanding current inconsistencies between climate models and reconstructions, and our understanding of the response of the North Atlantic system to climate change."

Dr Francesco Pausata, postdoctoral researcher at Stockholm University, explained: "When forcing climate models with freshwater from the Scandinavian Ice Sheet, the associated climate shifts are consistent with our climate reconstructions."

The project leader, Professor Barbara Wohlfarth from Stockholm University, concluded: "The Scandinavian ice sheet definitely played a much more significant role in the onset of this final cold period than previously thought. Our teamwork highlights the importance of paleoclimate studies, not least in respect to the ongoing global warming debate."

Source: University of Plymouth [November 17, 2015]

Arctic sea ice has reached its lowest winter point since satellite observations began in the late 1970s, raising concerns about faster ice melt and rising seas due to global warming, US officials said Thursday.

The maximum extent of sea ice observed was 5.6 million square miles (14.5 million square kilometers) on February 25, earlier than scientists had expected, said the report by the National Snow and Ice Data Center.

"It is also the lowest in the satellite record," the NSIDC said.

Below-average ice conditions were observed everywhere except in the Labrador Sea and Davis Strait.

The sea ice was about 425,000 square miles below the average from 1981 to 2010, a loss equal to more than twice the size of Sweden.

It was also 50,200 square miles below the previous lowest maximum that occurred in 2011.

Environmentalists said the report offered more evidence of worsening global warming, and urged action to curb the burning of fossil fuels that send greenhouse gases into the atmosphere.

"This is further evidence that global warming and its impacts have not stopped despite the inaccurate and misleading claims of climate change 'skeptics,'" said Bob Ward of the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science.

"The gradual disappearance of ice is having profound consequences for people, animals and plants in the polar regions, as well as around the world, through sea level rise."

The World Wildlife Fund said the loss of sea ice means trouble for a vast web of life that depends on it, from polar bears to marine creatures.

"Today's chilling news from the Arctic should be a wakeup call for all of us," said Samantha Smith, leader of the WWF Global Climate and Energy Initiative.

"Climate change won't stop at the Arctic Circle. Unless we make dramatic cuts in polluting gases, we will end up with a climate that is unrecognizable, unpredictable and damaging for natural systems and people."

The NSIDC said much of the ice loss could be attributed to an unusually warm February in parts of Russia and Alaska, and that it was still possible that a late-season surge of ice growth could occur.

A detailed analysis of the winter sea ice from 2014 to 2015 is due to be released in early April.

Source: AFP [March 19, 2015]

The ice sheet covering Greenland is four times bigger than California -- and holds enough water to raise global sea-level more than twenty feet if most of it were to melt. Today, sea levels are rising and the melting of Greenland is a major contributor. Understanding how fast this melting might proceed is a pressing question for policymakers and coastal communities.

To make predictions about the future of the ice sheet, scientists have tried to understand its past, hoping to glean what the ice was doing millions of years ago when the Earth was three or more degrees Fahrenheit warmer than it is now. But our understanding of the ice sheet's complex behavior before about 125,000 years ago has been fragmentary at best.

Now, two first-of-their-kind studies provide new insight into the deep history of the Greenland Ice Sheet, looking back millions of years farther than previous techniques allowed. However, the two studies present some strongly contrasting evidence about how Greenland's ice sheet may have responded to past climate change -- bringing new urgency to the need to understand if and how the giant ice sheet might dramatically accelerate its melt-off in the near future.

The two new studies were published in the journal Nature, including one led by University of Vermont geologist Paul Bierman.

Ice On the East

In >the first study Bierman and four colleagues -- from UVM, Boston College, Lawrence Livermore Laboratory, and Imperial College London -- examined deep cores of ocean-bottom mud containing bits of bedrock that eroded off of the east side of Greenland. Their results show that East Greenland has been actively scoured by glacial ice for much of the last 7.5 million years -- and indicate that the ice sheet on this eastern flank of the island has not completely melted for long, if at all, in the past several million years. This result is consistent with existing computer models.

Their field-based data also suggest that during major climate cool-downs in the past several million years, the ice sheet expanded into previously ice-free areas, "showing that the ice sheet in East Greenland responds to and tracks global climate change," Bierman says. "The melting we are seeing today may be out of the bounds of how the Greenland ice sheet has behaved for many millions of years."

Since the data the team collected only came from samples off the east side of Greenland, their results don't provide a definitive picture of the whole Greenland ice sheet. But their research, with support from the National Science Foundation, provides strong evidence that "an ice sheet has been in East Greenland pretty much continuously for seven million years," says Jeremy Shakun, a geologist at Boston College who co-led the new study. "It's been bouncing around and dynamic -- but it's been there nearly all the time."

Contrasting Results

The >other study in Nature -- led by Joerg Schaefer of Lamont-Doherty Earth Observatory and Columbia University, and colleagues -- looked at a small sample of bedrock from one location beneath the middle of the existing ice sheet and came to what appears to be a different conclusion: Greenland was nearly ice-free for at least 280,000 years during the middle Pleistocene -- about 1.1 million years ago. This possibility is in contrast to existing computer models.

"These results appear to be contradictory -- but they may not be," UVM's Bierman says. He notes that both studies have "some blurriness," he says, in what they are able to resolve about short-term changes and the size of the ancient ice sheet. "Their study is a bit like one needle in a haystack," he says, "and ours is like having the whole haystack, but not being sure how big it is."

That's because Schaefer and colleagues' data comes from a single point in the middle of Greenland, pointing to a range of possible scenarios of what happened in the past, including several that challenge the image of Greenland being continuously covered by an extensive ice sheet during the Pleistocene. In contrast, Bierman and colleagues' data provides a record of continuous ice sheet activity over eastern Greenland but can't distinguish whether this was because there was a remnant in East Greenland or whether the ice sheet remained over the whole island, fluctuating in size as the climate warmed and cooled over millions of years.

"It's quite possible that both of these records are right for different places," Bierman says. "Both of these studies apply a similar innovative technique and let us look much farther into the past than we have been able to before."

New Method

Both teams of scientists used, "a powerful new tool for Earth scientists," says Dylan Rood, a scientist at Imperial College London and a co-author on the Bierman-led study: isotopes within grains of quartz, produced when bedrock is bombarded by cosmic rays from space. The isotopes come into being when rock is at or near Earth's surface -- but not when it's buried under an overlying ice sheet. By looking at the ratio of two of these cosmic-ray-made elements -- aluminum-26 and beryllium-10 caught in crystals of quartz, and measured in an accelerator mass spectrometer -- the scientists were able to calculate how long the rocks in their samples had been exposed to the sky versus covered by ice.

>Paul Bierman, a geologist at the University of Vermont and his colleagues --f rom UVM, Boston College, 
>Lawrence Livermore Laboratory, and Imperial College London--wanted to develop a better understanding 
>of the ancient history of the huge ice sheet that covers Greenland, like this portion of the ice sheet shown from 
>a helicopter on a Bierman-led expedition there. The team studied deep cores of ocean-bottom mud containing 
>bits of bedrock that eroded off of the east side of Greenland. Their results show that East Greenland has been 
>actively scoured by glacial ice for much of the last 7.5 million years--and indicate that the ice sheet on the 
>eastern flank of the island has not completely melted for long, if at all, in the past several million years. Their 
>field-based data also suggest that during major climate cool-downs in the past several million years, the ice sheet 
>expanded into previously ice-free areas, "showing that the ice sheet in East Greenland responds to and tracks
> global climate change," Bierman says. "The melting we are seeing today may be out of the bounds of how 
>the Greenland ice sheet has behaved for many millions of years." [Credit: Joshua Brown/UVM]
This isotope technique has been used for several decades for measuring land-based erosion, but this is its first application to ocean core samples, said Lee Corbett, a postdoctoral researcher at UVM and co-author with Bierman. "This has never been attempted with marine sediments," she says. Their results overcome a basic problem of trying to discern the deep history of ice from bedrock: every time an ice sheet retreats and then grows back, it scours away the bedrock and the isotope record of its own past. "It's hard to discern an ice sheet's cycles on land because it destroys the evidence," she says, "but it dumps that evidence in the oceans, archived in layers on the bottom."

Now Corbett, Shakun, and others are applying this isotope technique to additional cores taken from around the coast of Greenland to get a more complete and in-focus picture of the whole ice sheet's long history. And they have already applied the new isotope technique far beyond Greenland -- particularly in exploring the much larger, more mysterious ice sheets covering Antarctica.

"These two apparently conflicting -- but not necessarily conflicting -- studies in Nature really force the issue that we don't know enough about how ice sheets work over deep time," Bierman says. "We must recognize the importance of advancing polar science to understand how our world works. And, right now, because we're pumping huge plumes of greenhouse gases into the atmosphere, we really need to know how our world works."

The dynamics of Antarctica's giant ice sheet is full of questions and the disastrous potential. "But there's enough sea-level rise tied-up in Greenland alone to put a lot of cities and long stretches of coastline underwater," says Paul Bierman, "including Donald Trump's property in Florida."

Source: University of Vermont [December 07, 2016]

Fluctuating sea levels and global cooling caused a significant decline in the number of crocodylian species over millions of years, according to new research.

Crocodylians include present-day species of crocodiles, alligators, caimans and gavials and their extinct ancestors. Crocodylians first appeared in the Late Cretaceous period, approximately 85 million years ago, and the 250 million year fossil record of their extinct relatives reveals a diverse evolutionary history.

Extinct crocodylians and their relatives came in all shapes and sizes, including giant land-based creatures such as Sarcosuchus, which reached around 12 metres in length and weighed up to eight metric tonnes. Crocodylians also roamed the ocean -- for example, thalattosuchians were equipped with flippers and shark-like tails to make them more agile in the sea.

Many crocodylians survived the mass extinction that wiped out almost all of the dinosaurs 66 million years ago, but only 23 species survive today, six of which are classified by the International Union for Conservation of Nature as critically endangered and a further four classified as either endangered or vulnerable.

In a new study published in Nature Communications, researchers from Imperial College London, the University of Oxford, the Smithsonian Institution and the University of Birmingham compiled a dataset of the entire known fossil record of crocodylians and their extinct relatives and analysed data about Earth's ancient climate. They wanted to explore how the group responded to past shifts in climate, to better understand how the reptiles may cope in the future.

Crocodylians are ectotherms, meaning they rely on external heat sources from the environment such as the Sun. The researchers conclude that at higher latitudes in areas we now know as Europe and America, declining temperatures had a major impact on crocodylians and their relatives.

At lower latitudes the decline of crocodylians was caused by areas on many continents becoming increasingly arid. For example, in Africa around ten million years ago, the Sahara desert was forming, replacing the vast lush wetlands in which crocodylians thrived. In South America, the rise of the Andes Mountains led to the loss of a proto-Amazonian mega wetland habitat that crocodylians lived in around five million years ago.

Marine species of crocodylians were once widespread across the oceans. The team found that fluctuations in sea levels exerted the main control over the diversity of these creatures. For example, at times when the sea level was higher it created greater diversity because it increased the size of the continental shelf, providing the right conditions near the coast for them and their prey to thrive.

Interestingly, the Cretaceous-Paleogene mass extinction event, which wiped out many other creatures on Earth nearly 66 million years ago including nearly all of the dinosaurs, had positive outcomes for the crocodylians and their extinct relatives. The team found that while several groups did go extinct, the surviving groups rapidly radiated out of their usual habitats to take advantage of territories that were now uninhabited.

In the future, the team suggest that a warming world caused by global climate change may favour crocodylian diversification again, but human activity will continue to have a major impact on their habitats.

Dr Philip Mannion, joint lead author from the Department of Earth Science and Engineering at Imperial College London, said: "Crocodylians are known by some as living fossils because they've been around since the time of the dinosaurs. Millions of years ago these creatures and their now extinct relatives thrived in a range of environments that ranged from the tropics, to northern latitudes and even deep in the ocean. However, all this changed because of changes in the climate, and crocodylians retreated to the warmer parts of the world. While they have a fearsome reputation, these creatures are vulnerable and looking back in time we've been able to determine what environmental factors had the greatest impact on them. This may help us to determine how they will cope with future changes."

The next step for the researchers will be for them to look at similar patterns in other fossil groups with long histories, such as mammals and birds to determine how past climate influenced them.

Source: Imperial College London [September 24, 2015]

Some of the UK's leading nature experts have delivered a clarion call for action to help save many of the nation's native wildlife species from extinction.

A critical new report, called >State of Nature 2016 and published, delivered the clearest picture to date of the status of our native species across land and sea. Crucially, the report attributes much of the imposing threat to changing agricultural land management, climate change and sustained urban development. These threaten many of Britain's best loved species including water voles -- the fastest declining mammal.

The startling report reveals that more than half (56%) of UK species studied have declined since 1970, while more than one in ten (1,199 species) of the nearly 8000 species assessed in the UK are under threat of disappearing altogether.

The report, produced by a coalition of more than 50 leading wildlife and research organisations and specialists including Dr Fiona Mathews from the University of Exeter, demands immediate action to stave off the growing threat to Britain's unique wildlife.

Dr Mathews, an Associate Professor in Mammalian Biology at the University of Exeter and Chair of the Mammal Society, who helped write the report, said many British mammals are under pressure from house building and intensification of agriculture.

She said: "The reality is that our human population is expanding and we need urgently to work out how we can live alongside our wildlife. For example, water voles are one of our fastest declining species, and many thousands of kilometres of their habitat are affected by development every year.

"We are therefore researching ways to ensure their survival, supported by our water vole appeal fund. In the summer, we launched best-practice guidance on looking after water voles during development, and these are now being followed by industry, helping to ensure that "Ratty" survives on ponds, rivers and canals throughout the UK."

As the UK Government and devolved administrations move forward in the light of the EU Referendum result, there is an opportunity to secure world leading protection for our species and restoration of our nature. Now is the time to make ambitious decisions and significant investment in nature to ensure year-on-year improvement to the health and protection of the UK's nature and environment for future generations. The Mammal Society is currently drawing up a 'Red List' of the most threated species, to help ensure that scarce funds are directed to the animals most in need.

Dr Mathews added: "The findings emphasise that whole ecosystems, not just one or two species, are under threat.

"We are a nation of nature-lovers -- just look at the success of "Countryfile" and "Springwatch." Every week thousands of volunteers are out recording wildlife and helping with practical habitat management. We also depend on the natural environment for a huge number of goods and services, not to mention our own health and wellbeing.

"Yet successive governments have cut funding for the environment, and conservation concerns are all too often vilified as a barrier to urban development, infrastructure projects or efficient food production. This is a moment to reflect on what sort of country we want for our children -- a sustainable future for them depends on our decisions now."

The State of Nature 2016 UK report will be launched by Sir David Attenborough and UK conservation and research organisations at the Royal Society in London on Wednesday, September 14, while separate events will be held in Edinburgh, Cardiff and Belfast over the next week.

Sir David Attenborough said: "The natural world is in serious trouble and it needs our help as never before. The rallying call issued after the State of Nature report in 2013 has promoted exciting and innovative conservation projects. Landscapes are being restored, special places defended, struggling species being saved and brought back. But we need to build significantly on this progress if we are to provide a bright future for nature and for people.

"The future of nature is under threat and we must work together -- -Governments, conservationists, businesses and individuals -- -to help it. Millions of people in the UK care very passionately about nature and the environment and I believe that we can work together to turn around the fortunes of wildlife."

In order to reduce the impact we are having on our wildlife, and to help struggling species, we needed to understand what's causing these declines. Using evidence from the last 50 years, experts have identified that significant and ongoing changes in agricultural practices are having the single biggest impact on nature.

The widespread decline of nature in the UK remains a serious problem to this day. For the first time scientists have uncovered how wildlife has fared in recent years. The report reveals that since 2002 more than half (53%) of UK species studied have declined and there is little evidence to suggest that the rate of loss is slowing down.

Mark Eaton, lead author on the report, said:"Never before have we known this much about the state of UK nature and the threats it is facing. Since the 2013, the partnership and many landowners have used this knowledge to underpin some amazing scientific and conservation work. But more is needed to put nature back where it belongs -- we must continue to work to help restore our land and sea for wildlife.

"There is a real opportunity for the UK Government and devolved administrations to build on these efforts and deliver the significant investment and ambitious action needed to bring nature back from the brink.

"Of course, this report wouldn't have been possible without the army of dedicated volunteers who brave all conditions to survey the UK's wildlife. Knowledge is the most essential tool that a conservationist can have, and without their efforts, our knowledge would be significantly poorer."

Derek Crawley, Atlas Office for the Mammal Society, said "New technology now enables volunteers to share information more easily than ever before. Our MammalTracker app is freely available from the App Store, or sightings of mammals can be recorded via our website. We will also be sharing information on how to make the most of volunteer programmes at a special meeting in the autumn.

Source: University of Exeter [September 23, 2016]

Current rates of climate change could trigger instability in a major Antarctic glacier, ultimately leading to more than 2m of sea-level rise.

This is the conclusion of a new study looking at the future of Totten Glacier, a significant glacier in Antarctica. Totten Glacier drains one of the world's largest areas of ice, on the East Antarctic Ice Sheet (EAIS).

By studying the history of Totten's advances and retreats, researchers have discovered that if climate change continues unabated, the glacier could cross a critical threshold within the next century, entering an irreversible period of very rapid retreat.

This would cause it to withdraw up to 300 kilometres inland in the following centuries and release vast quantities of water, contributing up to 2.9 metres to global sea-level rise.

The EAIS is currently thought to be relatively stable in the face of global warming compared with the much smaller ice sheet in West Antarctica, but Totten Glacier is bucking the trend by losing substantial amounts of ice. The new research reveals that Totten Glacier may be even more vulnerable than previously thought.

The study, by scientists from Imperial College London and institutions in Australia, the US, and New Zealand is >published in Nature. Last year, the team discovered that there is currently warm water circulating underneath a floating portion of the glacier that is causing more melting than might have been expected.

Their new research looks at the underlying geology of the glacier and reveals that if it retreats another 100-150 km, its front will be sitting on an unstable bed and this could trigger a period of rapid retreat for the glacier. This would cause it to withdraw nearly 300 km inland from its current front at the coast.

Retreating the full 300 km inland may take several hundred years, according to co-author Professor Martin Siegert, Co-Director of the Grantham Institute at Imperial College London. However, once the glacier crosses the threshold into the unstable region, the melting will be unstoppable -- at least until it has retreated to the point where the geology becomes more stable again.

"The evidence coming together is painting a picture of East Antarctica being much more vulnerable to a warming environment than we thought," he said. "This is something we should worry about. Totten Glacier is losing ice now, and the warm ocean water that is causing this loss has the potential to also push the glacier back to an unstable place."

"Totten Glacier is only one outlet for the ice of the East Antarctic Ice Sheet, but it could have a huge impact. The East Antarctic Ice Sheet is by far the largest mass of ice on Earth, so any small changes have a big influence globally."

To uncover the history of Totten Glacier's movements, the team looked at the sedimentary rocks below the glacier using airborne geophysical surveys. From the geological record, influenced by the erosion by ice above, they were able to understand the history of the glacier stretching back millions of years.

They found that the glacier has retreated more quickly over certain 'unstable' regions in the past. Based on this evidence, the scientists believe that when the glacier hits these regions again we will see the same pattern of rapid retreat.

Author: Hayley Dunning. | Source: Imperial College London [May 18, 2016]

Industrialized nations that view wildfire as the enemy have much to learn from people in some parts of the world who have learned to live compatibly with wildfire, says a team of fire research scientists.

The interdisciplinary team say there is much to be learned from these "fire-adaptive communities" and they are calling on policy makers to tap that knowledge, particularly in the wake of global warming.

Such a move is critical as climate change makes some landscapes where fire isn't the norm even more prone to fire, say the scientists in a new report published in a special issue of the >Philosophical Transactions of the Royal Society B.

"We tend to treat modern fire problems as unique, and new to our planet," said fire anthropologist Christopher Roos, Southern Methodist University, Dallas, lead author of the report. "As a result, we have missed the opportunity to recognize the successful properties of communities that have a high capacity to adapt to living in flammable landscapes—in some cases for centuries or millennia."

One such society is the ethnically Basque communities in the French Western Pyrenees, who practice fire management to maintain seasonally flammable grassland, shrub and woodland patches for forage and grazing animals. But the practice is slowly being lost as young people leave farming.

Additionally, Aboriginal people in the grasslands of Western Australia use fire as part of their traditional hunting practices. Children begin burning at a very young age, and the everyday practice is passed down. These fires improve hunting successes but also reduce the impact of drought on the size and ecological severity of lightning fires.

Social institutions support individual benefits, preserve common good

Fire-adaptive communities have social institutions in place that support individual benefits from fire-maintained landscapes while preserving the common good, said Roos, whose fire research includes long-term archaeological and ecological partnerships with the Pueblo of Jemez in New Mexico.

"These institutions have been shaped by long-histories with wildfire, appropriate fire-use, and the development of social mechanisms to adjudicate conflicts of interest," said Roos, an associate professor in the SMU Department of Anthropology. "There is a wealth of tried and tested information that should be considered in designing local fire management."

The authors note that globally, a large number of people use fire as a tool to sustain livelihoods in ways that have been handed down across many generations. These include indigenous Australians and North Americans, South Asian forest dwellers, European farmers, and also hunters, farmers and herders in tropical savannahs.

Global Warming will likely bring new fire problems, more flammable landscapes

Global Warming will likely bring new fire problems, such as making some landscapes more flammable, Roos said. More effort will be required to balance conflicting fire management practices between adjacent cultures. Currently most fire-related research tends to be undertaken by physical or biological scientists from Europe, the United States and Australia. Often the research treats fire challenges as exclusively contemporary phenomena for which history is either absent or irrelevant.

"We need national policy that recognizes these dynamic challenges and that will support local solutions and traditional fire knowledge, while providing ways to disseminate scientific information about fire," Roos said.

The authors point out that one of the greatest policy challenges of fire on a warming planet are the international consequences of smoke plumes and potential positive feedbacks on climate through carbon emissions. Most infamously, wildfire smoke plumes have had extraordinary health impacts during Southeast Asian "haze" events, which result in increased hospitalization and mortality in the region.

Not all fire is a disaster; we must learn to live with and manage fire

Carbon emissions from wildfires can be as much as 40 percent of fossil fuel emissions in any given year over the last decade. Although only deforestation fires and land conversion are a net carbon source to the atmosphere, the contribution of wildfires to global carbon emissions is non-trivial and should be a formal component of international climate dialogs.

"It is important to emphasize that not all fire is a disaster and we must learn how to both live with as well as manage fire," said co-author Andrew Scott, earth sciences professor at Royal Holloway University of London.

The report, "Living on a flammable planet: interdisciplinary, cross-scalar and varied cultural lessons, prospects and challenges," was published May 23, 2016 by The Royal Society, the U.K.'s independent scientific academy.

Authors call for holistic study of fire on Earth

The authors are from the United States, Great Britain, Canada, Australia, South Africa and Spain. The synthesis emerged from four days of international meetings sponsored by the Royal Society - the first of its kind for fire sciences.

The authors advocate for greater collaboration among researchers studying all aspects of fire.

Pyrogeography—the holistic study of fire on Earth, "may be one way to provide unity to the varied fire research programs across the globe," the authors write.

"Fire researchers across disciplines from engineering, the natural sciences, social sciences and the humanities need to develop a common language to create a holistic wildfire science," said Roos. "The magnitude of the wildfire challenges we face on a warming planet will demand greater collaboration and integration across disciplines, but our job won't be done unless we are also able to translate our research for policymakers, land managers, and the general public."

Source: Southern Methodist University [June 01, 2016]

The build-up and subsequent release of warm, stagnant water from the deep Arctic Ocean and Nordic Seas played a role in ending the last Ice Age within the Arctic region, according to new research led by a UCL scientist.

The study, published today in Science, examined how the circulation of the ocean north of Iceland -- the combined Arctic Ocean and Nordic Seas, called the Arctic Mediterranean -- changed since the end of the last Ice Age (~20,000-30,000 years ago).

Today, the ocean is cooled by the atmosphere during winter, producing large volumes of dense water that sink and flush through the deep Arctic Mediterranean. However, in contrast to the vigorous circulation of today, the research found that during the last Ice Age, the deep Arctic Mediterranean became like a giant stagnant pond, with deep waters not being replenished for up to 10,000 years.

This is thought to have been caused by the thick and extensive layer of sea ice and fresh water that covered much of the Arctic Mediterranean during the Ice Age, preventing the atmosphere from cooling and densifying the underlying ocean.

Dr David Thornalley (UCL Geography) said: "As well as being stagnant, these deep waters were also warm. Sitting around at the bottom of the ocean, they slowly accumulated geothermal heat from the seafloor, until a critical point was reached when the ocean became unstable.

"Suddenly, the heat previously stored in the deep Arctic Mediterranean was released to the upper ocean. The timing of this event coincides with the occurrence of evidence for a massive release of meltwater into the Nordic Seas. We hypothesize that this input of melt water was caused by the release of deep ocean heat, which melted icebergs, sea-ice and surrounding marine-terminating ice sheets."

This study highlights the important impact that changes in ocean circulation can have on climate, due to the ocean's capacity to redistribute vast quantities of heat around the globe. For example, scientists are currently concerned that ongoing changes in ocean circulation may result in warmer subsurface water that will cause enhanced melting and retreat of certain ice sheets in Greenland and Antarctica.

Dr Thornalley added: "To help predict the role of the ocean in future climate change, it is useful to investigate how ocean circulation changed in the past and what the associated climate effects were."

In this study, researchers from UCL, Woods Hole Oceanographic Institute and other partner institutions analysed the composition of calcite shells of small single-celled organisms (called foraminifera) that are found in ocean floor sediment. The shells of these organisms record the chemistry of the deep ocean at the time they were living, enabling the researchers to reconstruct past changes in ocean circulation.

By measuring the radiocarbon content of these shells, the research team was able to determine how rapidly deep water was being formed in the Arctic Mediterranean. A number of different techniques were then used to constrain past temperature changes, including measuring the ratio of magnesium and calcium, and the arrangement of isotopes of carbon and oxygen within the calcite shells of the foraminifera, both of which vary according to the temperature of the water in which the foraminifera grew.

A warmer, deep Arctic Mediterranean during glacial times has been suggested in previous studies, too. As summarised by co-author Dr Henning Bauch (GEOMAR/Germany) "It is good to see that new, independent proxy data would give strong support now to these former hypotheses."

Source: University College London [August 13, 2015]