The Great London:
Climate Change

Few Americans may be aware of it, but in 1952 a killer fog that contained pollutants covered London for five days, causing breathing problems and killing thousands of residents. The exact cause and nature of the fog has remained mostly unknown for decades, but an international team of scientists that includes several Texas A&M University-affiliated researchers believes that the mystery has been solved and that the same air chemistry also happens in China and other locales.

Texas A&M researcher Renyi Zhang, University Distinguished Professor and the Harold J. Haynes Chair of Atmospheric Sciences and Professor of Chemistry, along with graduate students Yun Lin, Wilmarie Marrero-Ortiz, Jeremiah Secrest, Yixin Li, Jiaxi Hu and Bowen Pan and researchers from China, Florida, California Israel and the UK have had their work published in the current issue of >Proceedings of the National Academy of Sciences.

In December of 1952, the fog enveloped all of London and residents at first gave it little notice because it appeared to be no different from the familiar natural fogs that have swept over Great Britain for thousands of years.

But over the next few days, conditions deteriorated, and the sky literally became dark. Visibility was reduced to only three feet in many parts of the city, all transportation was shut down and tens of thousands of people had trouble breathing. By the time the fog had lifted on Dec. 9, at least 4,000 people had died and more than 150,000 had been hospitalized. Thousands of animals in the area were also killed.

Recent British studies now say that the death count was likely far higher -- more than 12,000 people of all ages died from the killer fog. It has long been known that many of those deaths were likely caused by emissions from coal burning, but the exact chemical processes that led to the deadly mix of fog and pollution have not been fully understood over the past 60 years.

The 1952 killer fog led to the passage of the Clean Air Act in 1956 by the British Parliament and is still considered the worst air pollution event in the European history.

Through laboratory experiments and atmospheric measurements in China, the team has come up with the answers.

"People have known that sulfate was a big contributor to the fog, and sulfuric acid particles were formed from sulfur dioxide released by coal burning for residential use and power plants, and other means," Zhang says.

"But how sulfur dioxide was turned into sulfuric acid was unclear. Our results showed that this process was facilitated by nitrogen dioxide, another co-product of coal burning, and occurred initially on natural fog. Another key aspect in the conversion of sulfur dioxide to sulfate is that it produces acidic particles, which subsequently inhibits this process. Natural fog contained larger particles of several tens of micrometers in size, and the acid formed was sufficiently diluted. Evaporation of those fog particles then left smaller acidic haze particles that covered the city."

The study shows that similar chemistry occurs frequently in China, which has battled air pollution for decades. Of the 20 most polluted cities in the world, China is home to 16 of them, and Beijing often exceeds by many times the acceptable air standards set by the U.S. Environmental Protection Agency.

"The difference in China is that the haze starts from much smaller nanoparticles, and the sulfate formation process is only possible with ammonia to neutralize the particles," Zhang adds.

"In China, sulfur dioxide is mainly emitted by power plants, nitrogen dioxide is from power plants and automobiles, and ammonia comes from fertilizer use and automobiles. Again, the right chemical processes have to interplay for the deadly haze to occur in China. Interestingly, while the London fog was highly acidic, contemporary Chinese haze is basically neutral."

Zhang says China has been working diligently over the past decade to lessen its air pollution problems, but persistent poor air quality often requires people to wear breathing masks during much of the day. China's explosive industrial and manufacturing growth and urbanization over the past 25 years have contributed to the problem. "A better understanding of the air chemistry holds the key for development of effective regulatory actions in China," he adds.

"The government has pledged to do all it can to reduce emissions going forward, but it will take time," he notes. "We think we have helped solve the 1952 London fog mystery and also have given China some ideas of how to improve its air quality. Reduction in emissions for nitrogen oxides and ammonia is likely effective in disrupting this sulfate formation process."

Source: Texas A&M University [November 15, 2016]

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]

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]

Beneath the Aurora Borealis an oil tanker glides through the night past the Coast Guard ice breaker Amundsen and vanishes into the maze of shoals and straits of the Northwest Passage, navigating waters that for millennia were frozen over this time of year.

Warming has forced a retreat of the polar ice cap, opening up a sea route through the Canadian Arctic Archipelago and connecting the Atlantic and Pacific Oceans for several months of the year.

Commander Alain Lacerte is at the helm as the vessel navigates the Queen Maud Gulf, poring over charts that date from the 1950s and making course corrections with the help of GPS.

"Where it's white (on the chart), it means the area hasn't been surveyed," he explains -- leaning over a map that is mostly white. "Most of the far north hasn't been surveyed, so our maps are unreliable."

The crew constantly take radar and multi-beam sonar measurements and check their position.

"We don't want any shoals named after us," says the old sea dog from behind his spectacles.

Almost the size of the European Union, the Canadian Arctic seabed remains largely uncharted. The waters are also shallow and navigating unknown parts can be deadly -- even when the north is ice-free.

Today, taking this route cuts 7,000 kilometers (4,350 miles) off a trip from London to Tokyo, saving time and fuel.

'Never imagined this'

Since the 15th century there have been a dozen expeditions seeking a faster shipping route from Europe to Asia through the north.

The Norwegian explorer Roald Amundsen was the first to cross the Northwest Passage, on board the Gjoa, in an expedition that took three years, finishing in 1906.

Afterward interest in the waterway waned. An average of one ship per year attempted to make the crossing over the past century.

But thawing of the polar ice promises Arctic nations new opportunities to open ocean trade routes and offshore oil fields.

In the summer months the Amundsen is used by Canadian government scientists -- among them Roger Provost, a Canadian Ice Service meteorologist -- as well as a network of scientists led by the ArcticNet organization.

Provost looked with amazement from the wheelhouse at the lack of any ice cover around the coast guard ship.

"Anyone who still denies climate change is real has their head in the ground, they're blind," he said.

In 37 years of Arctic exploration, he said he "never imagined ever seeing this," pointing to satellite images showing a clear path through the Queen Maud Gulf and the M'Clintock Channel, where the Amundsen is headed.

Almost 112 years ago to the day, the explorer Amundsen got stuck in the pack ice here. And in 1979, Provost recalls, another Canadian Coast Guard ice-breaker had to cut short its inaugural journey, unable to push beyond this point through thick ice.

Over the past five years the number of cargo and cruise ships, tankers and others crossing the Passage climbed to 117.

In 2010, Canada imposed shipping regulations on seafarers going through the Passage, but the United States and the European Union do not recognize Canada's ownership of the waterway, considering it international waters.

'Completely disappear'

The ice cover has steadily retreated over the past decade, with this year set to be the hottest on record, according to the US National Oceanic and Atmospheric Administration.

The previous year saw average global temperatures rise one degree Celsius -- but by three degrees in the Arctic.

What most worries Provost is the loss of "multi-year ice," formed over centuries. "In a few years it will completely disappear," he forecast.

"It's a tragedy for all humanity what is happening."

Glaciologist Lauren Candlish said: "We're now in the transition phase, from having multi-year ice through the entire summer, to a seasonally ice free Arctic."

Poring over data on her computer in a nook of the ship the University of Manitoba researcher says: "It's a different Arctic now. Less predictable, with more fluctuations."

The last such melting occurred "before the last ice age," from AD 100,000 to AD 10,000, she noted.

Most aboard the ship doubt we are headed for an Arctic shipping boom predicted by many, as the weather remains unpredictable and harsh. But there is sure to be an increase, which raises concerns for the environment.

"When it was covered in ice, this ecosystem was not threatened," says Provost. The Arctic is a unique and diverse ecosystem that is home to whales, seals, polar bears, walruses and several bird species.

"A massive oil spill like the one in the Gulf of Mexico in 2010 must never happen in the Arctic," he said. "The consequences would be much more serious."

Author: Clement Sabourin | Source: AFP [October 20, 2015]

The human-dominated geological epoch known as the Anthropocene probably began around the year 1610, with an unusual drop in atmospheric carbon dioxide and the irreversible exchange of species between the New and Old Worlds, according to new research published today in Nature.

Previous epochs began and ended due to factors including meteorite strikes, sustained volcanic eruptions and the shifting of the continents. Human actions are now changing the planet, but are we really a geological force of nature driving Earth into a new epoch that will last millions of years?

Scientists at UCL have concluded that humans have become a geological power and suggest that human actions have produced a new geological epoch.

Defining an epoch requires two main criteria to be met. Long-lasting changes to the Earth must be documented. Scientists must also pinpoint and date a global environmental change that has been captured in natural material, such as rocks, ancient ice or sediment from the ocean floor. Such a marker -- like the chemical signature left by the meteorite strike that wiped out the dinosaurs -- is called a golden spike.

The study authors systematically compared the major environmental impacts of human activity over the past 50,000 years against these two formal requirements. Just two dates met the criteria: 1610, when the collision of the New and Old Worlds a century earlier was first felt globally; and 1964, associated with the fallout from nuclear weapons tests. The researchers conclude that 1610 is the stronger candidate.

The scientists say the 1492 arrival of Europeans in the Americas, and subsequent global trade, moved species to new continents and oceans, resulting in a global re-ordering of life on Earth. This rapid, repeated, cross-ocean exchange of species is without precedent in Earth's history.

They argue that the joining of the two hemispheres is an unambiguous event after which the impacts of human activity became global and set Earth on a new trajectory. The first fossil pollen of maize, a Latin American species, appears in marine sediment in Europe in 1600, becoming common over subsequent centuries. This irreversible exchange of species satisfies the first criteria for dating an epoch -- long-term changes to Earth.

The Anthropocene probably began when species jumped continents, starting when the Old World met the New. We humans are now a geological power in our own right -- as Earth-changing as a meteorite strike

The researchers also found a golden spike that can be dated to the same time: a pronounced dip in atmospheric carbon dioxide centred on 1610 and captured in Antarctic ice-core records. The drop occurred as a direct result of the arrival of Europeans in the Americas. Colonisation of the New World led to the deaths of about 50 million indigenous people, most within a few decades of the 16th century due to smallpox. The abrupt near-cessation of farming across the continent and the subsequent re-growth of Latin American forests and other vegetation removed enough carbon dioxide from the atmosphere to produce a drop in CO2. Thus, the second requirement of a golden spike marker is met.

The researchers have named the 1610 dip in carbon dioxide the 'Orbis Spike'. They chose the Latin word for 'world' because this golden spike was caused by once-disconnected peoples becoming globally linked.

Lead author, Dr Simon Lewis (UCL Geography and University of Leeds), said: "In a hundred thousand years scientists will look at the environmental record and know something remarkable happened in the second half of the second millennium. They will be in no doubt that these global changes to Earth were caused by their own species. Today we can say when those changes began and why. The Anthropocene probably began when species jumped continents, starting when the Old World met the New. We humans are now a geological power in our own right -- as Earth-changing as a meteorite strike."

He added: "Historically, the collision of the Old and New Worlds marks the beginning of the modern world. Many historians regard agricultural imports into Europe from the vast new lands of the Americas, alongside the availability of coal, as the two essential precursors of the Industrial Revolution, which in turn unleashed further waves of global environmental changes. Geologically, this boundary also marks Earth's last globally synchronous cool moment before the onset of the long-term global warmth of the Anthropocene."

The authors also considered the merits of dating the Anthropocene to 1964, which saw a peak in radioactive fallout following nuclear weapons testing. This marker is seen in many geological deposits, and by the 1960s human impact on the Earth was large. However, the researchers note that while nuclear war could dramatically alter Earth, so far it has not. While the fallout from nuclear bomb tests is a very good marker, the testing of nuclear weapons has not been -- in geological terms -- an Earth-changing event.

The beginning of the Industrial Revolution, in the late 18th century, has most commonly been suggested as the start of the Anthropocene. This linked a clear turning point in human history, and the rise of atmospheric carbon dioxide from fossil fuel use is a long-term global environmental change of critical importance. However, the researchers did not find a golden spike at that time because most effects were local, while the global exponential rise in carbon dioxide was too smooth an increase to form a precisely dated marker.

The authors' new paper ends by highlighting some implications of formally defining the Anthropocene.

Co-author, geologist Professor Mark Maslin (UCL Geography) said: "A more wide-spread recognition that human actions are driving far-reaching changes to the life-supporting infrastructure of Earth will have implications for our philosophical, social, economic and political views of our environment. But we should not despair, because the power that humans wield is unlike any other force of nature, it is reflexive and therefore can be used, withdrawn or modified. The first stage of solving our damaging relationship with our environment is recognising it."

An official decision on whether to formally recognise the Anthropocene, including when it began, will be initiated by a recommendation of the Anthropocene Working Group of the Subcommission of Quaternary Stratigraphy, due in 2016.

Source: University College London [March 11, 2015]

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]

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]

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 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]

With scientists forecasting sea levels to rise by anywhere from several inches to several feet by 2100, historic structures and coastal heritage sites around the world are under threat. Some sites and artifacts could become submerged.

Scientists, historic preservationists, architects and public officials are meeting this week in Newport, Rhode Island—one of the threatened areas—to discuss the problem, how to adapt to rising seas and preserve historic structures.

"Any coastal town that has significant historic properties is going to be facing the challenge of protecting those properties from increased water and storm activity," said Margot Nishimura, of the Newport Restoration Foundation, the nonprofit group hosting the conference.

Federal authorities have encouraged people to elevate structures in low-lying areas, but that poses challenges in dense neighborhoods of centuries-old homes built around central brick chimneys, Nishimura said, especially ones where preservationists are trying to keep the character intact.

Many of the most threatened sites in North America lie along the East Coast between Cape Hatteras, North Carolina, and southern Maine, where the rate of sea level rise is among the fastest in the world, said Adam Markham, of the Union of Concerned Scientists, a speaker at the conference.

"We're actually not going to be able to save everything," he said.

A look at some of the historic areas and cultural sites that are under threat from rising sea levels:

Statue of Liberty and Ellis Island

Situated in New York Harbor, the Statue of Liberty and Ellis Island are some of New York's most important tourist attractions.

In 2012, Superstorm Sandy submerged most of the low-elevation Liberty and Ellis islands. After the storm, the Statue of Liberty, a gift from the people of France in 1886, was closed for eight months. Ellis Island, the entry point for about 12 million immigrants to the United States from 1892 to 1954, remained closed for nearly a year.

A report by the National Park Service looked at how several parks would be threatened by 1 meter, or around 3 feet, of sea level rise. It found $1.51 billion worth of assets at the Statue of Liberty National Monument were highly exposed to sea level rise.

Much of historic Boston is along the water and is at risk due to sea level rise, including Faneuil Hall, the market building known as the "Cradle of Liberty," and parts of the Freedom Trail, a walking trail that links historic sites around the city.

Boston has seen a growing number of flooding events in recent years, up from two annually in the 1970s to an average of 11 annually between 2009 and 2013, according to a 2014 report by the Union of Concerned Scientists. If sea levels rise by 5 inches, the group reported, the number of floods is projected to grow to 31 annually. If seas rise by 11 inches, the number of flooding events is projected to rise to 72 per year.

Newport

The Point neighborhood in the Rhode Island resort town has one of the highest concentrations of Colonial houses in the United States, and it sits 4 feet above mean sea level. Tidal flooding is already occurring in the neighborhood, and that is expected to increase as sea levels rise, Nishimura said. The smell of sea water already permeates the basement of some homes.

Annapolis

Maryland's capital, on Chesapeake Bay, boasts the nation's largest concentration of 18th-century brick buildings. The city briefly served as the nation's capital in the post-Revolutionary War period, and the Treaty of Paris, which formally ended the war, was ratified there. The city is also home to the U.S. Naval Academy.

The city already sees tidal flooding dozens of times a year, and scientists have predicted number could rise to hundreds annually in the next 30 years.

Jamestown

Established in 1607, it is the first permanent English colony in North America. It sits along the tidal James River in Virginia, and most of the settlement is less than 3 feet above sea level. A large part of the settlement has already eroded because of wave action, Markham said. Storms have also damaged the site, including Hurricane Isabel in 2003, which flooded nearly 1 million artifacts. A rising water table at the site also poses a threat to archaeological remains, Markham said.

He called the loss of archaeological artifacts "an urgent problem" along the U.S. coastline.

Hawaii

Reports by the National Park Service and others have found that rising sea level rises threaten archaeological sites at various historic places in Hawaii. Those include ancient fish ponds at Pu'ukohola Heiau National Historic Site and a "Great Wall" at a sacred site in Pu'uhonua o Honaunau National Historical Park. It is considered the best-preserved such wall in Hawaii.

International Sites

Dozens of UNESCO World Heritage Sites are under threat from sea level rise, according to a 2014 report by climate scientists Ben Marzeion, of the University of Innsbruck in Austria, and Anders Levermann, of the Potsdam Institute in Germany.

Among those are: the Tower of London; Robben Island in South Africa, where Nelson Mandela was imprisoned for 27 years; Venice, Italy, and its lagoon; Mont-Saint-Michel, home to an abbey built atop a rocky islet in France; the Kasbah of Algiers, Algeria; the historic district of Old Quebec, Canada; Old Havana in Cuba; and archaeological areas of Pompeii, Italy, and Carthage in Tunisia.

The authors wrote that their findings indicate that "fundamental decisions with regard to mankind's cultural heritage are required."

Author: Michelle R. Smith | Source: The Associated Press [April 11, 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]

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]

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]

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]

Species across the world are rapidly going extinct due to human activities, but humans are also causing rapid evolution and the emergence of new species. A new study published today summarises the causes of humanmade speciation, and discusses why newly evolved species cannot simply replace extinct wild species. The study was led by the Center for Macroecology, Evolution and Climate at the University of Copenhagen.

A growing number of examples show that humans not only contribute to the extinction of species but also drive evolution, and in some cases the emergence of entirely new species. This can take place through mechanisms such as accidental introductions, domestication of animals and crops, unnatural selection due to hunting, or the emergence of novel ecosystems such as the urban environment.

Although tempting to conclude that human activities thus benefit as well as deplete global biodiversity, the authors stress that extinct wild species cannot simply be replaced with newly evolved ones, and that nature conservation remains just as urgent.

"The prospect of 'artificially' gaining novel species through human activities is unlikely to elicit the feeling that it can offset losses of 'natural' species. Indeed, many people might find the prospect of an artificially biodiverse world just as daunting as an artificially impoverished one" says lead author and Postdoc Joseph Bull from the Center for Macroecology, Evolution and Climate at the University of Copenhagen.

The study which was carried out in collaboration with the University of Queensland was published in >Proceedings of Royal Society B. It highlights numerous examples of how human activities influence species' evolution. For instance: as the common house mosquito adapted to the environment of the underground railway system in London, it established a subterranean population. Now named the 'London Underground mosquito', it can no longer interbreed with its above ground counterpart and is effectively thought to be a new species.

"We also see examples of domestication resulting in new species. According to a recent study, at least six of the world's 40 most important agricultural crops are considered entirely new" explains Joseph Bull.

Furthermore, unnatural selection due to hunting can lead to new traits emerging in animals, which can eventually lead to new species, and deliberate or accidental relocation of species can lead to hybridization with other species. Due to the latter, more new plant species in Europe have appeared than are documented to have gone extinct over the last three centuries.

Although it is not possible to quantify exactly how many speciation events have been caused through human activities, the impact is potentially considerable, the study states.

"In this context, 'number of species' becomes a deeply unsatisfactory measure of conservation trends, because it does not reflect many important aspects of biodiversity. Achieving a neutral net outcome for species numbers cannot be considered acceptable if weighing wild fauna against relatively homogenous domesticated species. However, considering speciation alongside extinction may well prove important in developing a better understanding of our impact upon global biodiversity. We call for a discussion about what we, as a society, actually want to conserve about nature" says Associate Professor Martine Maron from the University of Queensland.

Researchers do agree that current extinction rates may soon lead to a 6th period of mass extinction. Since the last Ice Age, 11.500 years ago, it is estimated that 255 mammals and 523 bird species has gone extinct, often due to human activity. In the same period, humans have relocated almost 900 known species and domesticated more than 470 animals and close to 270 plant species.

Source: Faculty of Science - University of Copenhagen [June 28, 2016]

Research published in the American Geophysical Union's journal >Global Biogeochemical Cycles shows that recent rises in levels of methane in our atmosphere is being driven by biological sources, such as swamp gas, cow burps, or rice fields, rather than fossil fuel emissions.

Atmospheric methane is a major greenhouse gas that traps heat in our atmosphere, contributing to global warming. Its levels have been growing strongly since 2007, and in 2014 the growth rate of methane in the atmosphere was double that of previous years, largely driven by biological sources as opposed to fossil fuel emissions.

Conventional wisdom refuted

The study, led by researchers at Royal Holloway, University of London shows that methane emissions have been increasing, particularly in the tropics. Researchers discovered that biological sources, such as methane emissions from swamps, make up the majority of increase.

"Our results go against conventional thinking that the recent increase in atmospheric methane must be caused by increased emissions from natural gas, oil, and coal production. Our analysis of methane's isotopic composition clearly points to increased emissions from microbial sources, such as wetlands or agriculture" said lead author Euan Nisbet from Royal Holloway, University of London's Department of Earth Sciences.

Methane growth rate doubles

Professor Nisbet says "Atmospheric methane is one of the most potent greenhouses gases. Methane increased through most of the 20th century, driven largely by leaks from the gas and coal industries."

He continued, "At the beginning of this century it appeared that the amount of methane in the air was stabilising, but since 2007 the levels of methane have started growing again. The year 2014 was extreme, with the growth rate doubling, and large increases seen across the globe."

Tropics identified as key source

The research shows that in recent years, the increase in methane has been driven by sharp increases in the tropics, in response to changing weather patterns. It is possible that the natural processes that remove methane from the atmosphere have slowed down, but it is more likely that there's been an increase of methane emission instead, especially from the hot wet tropics.

Professor Nisbet and his team, together with the US The National Oceanic and Atmospheric Administration (NOAA), have been looking at measurements and samples of air taken from places like Alert in the Canadian Arctic; Ascension, a UK territory in the South Atlantic; Cape Point, South Africa.

International collaboration leads to new conclusions

The research has been carried out by an international team of atmospheric scientists, led by Euan Nisbet, from Royal Holloway, University of London. Ed Dlugokencky, from the NOAA, Martin Manning from Victoria University, Wellington, New Zealand and a team from the University of Colorado's Institute of Arctic and Alpine Research, led by Jim White, have been working with collaborators from the UK, France, Canada, and South Africa.

Source: University of Royal Holloway London [September 27, 2016]

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]

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]

Fossil fuel emissions could soon make it impossible for radiocarbon dating to distinguish new materials from artefacts that are hundreds of years old.

Carbon released by burning fossil fuels is diluting radioactive carbon-14 and artificially raising the radiocarbon 'age' of the atmosphere, according to a paper published in the journal PNAS.

Radiocarbon measurements have a range of uses, from analysing archaeological finds, to detecting fraudulent works of art, to identifying illegal ivory trading, to assessing the regeneration of brain cells in neurological patients.

The new study suggests that some of these current uses will be affected over this century, depending on how much fossil fuel emissions increase or decrease.

"If we reduced fossil fuel emissions, it would be good news for radiocarbon dating," said the study's author, Dr Heather Graven from the Department of Physics and the Grantham Institute -- Climate Change and Environment at Imperial College London.

Carbon-14 is a rare, but naturally occurring, radioactive type of carbon that decays over thousands of years.

Radiocarbon dating works by measuring how much the fraction of carbon-14 versus non-radioactive carbon in an object has changed and therefore how long the object has been around.

Fossil fuels like coal and oil are so old that they contain no carbon-14. When their emissions mix with the modern atmosphere, they flood it with non-radioactive carbon.

In radiocarbon dating terms this makes the atmosphere appear older, which is reflected in the tissues of plants taking in CO2 during photosynthesis, and their products such as cottons.

At the rate fossil fuel emissions are currently increasing, by 2050 a new T-shirt would have the same radiocarbon date as a robe worn by William the Conqueror a thousand years earlier.

If fossil fuel emissions were rapidly curbed, the new t-shirt would only have the same radiocarbon age as something 100 years old, according to the study.

The fraction of carbon-14 in the atmosphere decreased after the Industrial Revolution with the rise of fossil fuel combustion. But in the 1950s and 60s, nuclear weapons testing caused a sharp increase. Since then atmospheric observations show the levels have been dropping, and are now close to the pre-industrial proportions.

The new study indicates that by 2020, the fraction of carbon-14 could drop to such an extent that radiocarbon dating will start to be affected.

"We can see from atmospheric observations that radiocarbon levels are steadily decreasing. How low they go depends on changes in our fossil fuel emissions," said Dr Graven.

Author: Simon Levey | Source: Imperial College London [July 20, 2015]