Antarctica’s melting is accelerating faster

Scientists have just completed the most detailed mass observation of the southern continent so far. The news is ominous: Antarctica’s melting is speeding up.

LONDON, 14 June, 2018 – The speed of Antarctica’s melting has begun to gather pace. Between 1992 and 2017, the rate of loss of ice from West Antarctica has risen threefold, from 59 billion metric tons per year to 159bn. The West Antarctic peninsula, one of the fastest warming places on Earth, has seen ice loss soar from 7bn to 33bn tonnes a year in that timespan, as ice shelves have collapsed.

Altogether, in those 25 years, Antarctica has lost more than a trillion tonnes of ice. Since the southern continent is the biggest store of freshwater on the planet – if it all melted, the sea levels would rise by 58 metres – the news is ominous. It means that melting in Antarctica alone has raised global sea levels by 8mm, as global average temperatures rise, in response to ever-higher levels of carbon dioxide in the atmosphere.

And if the world’s economies go on burning the fossil fuels that have driven rising levels of greenhouse gases, then by 2070 global sea levels will rise even faster – by a metre, with one fourth of that from Antarctic meltwater – and ever more ice will be lost from the Southern Ocean.

This in turn will drive big changes in the marine ecosystems of the Antarctic and for the first time permit invasive pests to colonise what was once a pristine, unspoiled landscape.

“If we aren’t already alert to the dangers posed by climate change, this should be an enormous wake-up call”

But such an outcome is not inevitable. “The future of Antarctica is tied to that of the rest of the planet and human society,” said Steve Rintoul, of the Centre for Southern Hemisphere Oceans Research in Hobart, Tasmania, and one of the research team.

Actions can be taken now that will slow the rate of environmental change, increase the resilience of Antarctica, and reduce the risk that we commit to irreversible changes with widespread impact.”

A series of research papers in the journal Nature tells a story of ice loss and global concern. A team of 84 scientists from 44 international organisations have amalgamated 24 satellite surveys of change in the farthest south with greater precision that any other study so far.

“According to our analysis, there has been a steep increase in ice losses from Antarctica during the last decade, and the continent is causing sea levels to rise faster today than at any time in the past 25 years,” said Andrew Shepherd of the University of Leeds, UK, who led the assessment. “This has to be a concern for the governments we trust to protect our coastal cities and communities.”

None of this is a surprise: what is new about the latest research is the confidence with which the researchers speak. Human exploration of Antarctica began little more than a century ago, and systematic scientific observation began only in the mid-20th century.

Diminishing argument

Antarctic ice has retreated and advanced and retreated again many times over the millennia: there has always been argument about how much of the change is because of natural cycles, how much because of human-induced climate change. In the last few years, the contribution of warmer oceans and warmer atmosphere has begun to become obvious.

Researchers have warned that warmer seas make faster melting inevitable and that by 2050 the rate of loss could double.

Using both direct observation and remote sensing, they have watched fresh water running off the polar surface in the summer and recorded the first signs of invasive plants on rocks that were once all but barren.

And now data from satellites launched by the European Space Agency, Japan, Canada, NASA, Italy and Germany has been combined into something known as the Ice Sheet Mass Balance Inter-comparison Exercise, or IMBIE for short. And it has settled one of the great uncertainties.

Continent-wide picture

While the western Antarctica ice sheet has been steadily melting, there has been evidence that East Antarctica itself was stable, or even growing. The latest study settles an old argument: the combined evidence suggests that East Antarctica is more or less stable, gaining if anything 5bn tonnes a year on average, perhaps because of greater snowfall.

Overall, though, the continent is losing the mass of its ice, and if the world continues to warm, this loss can only accelerate.

“Unfortunately, we appear to be on a pathway to substantial ice-sheet loss in the decades ahead, with longer-term consequences for enhanced sea-level rise; something that has been predicted in models for some time.

“If we aren’t already alert to the dangers posed by climate change, this should be an enormous wake-up call,” said Martin Siegert, of the Grantham Institute at Imperial College London, and one of the authors.

“Antarctica is being affected by global warming, and unless we curtail our CO2 emissions within the next decade, and have a zero carbon economy within a few decades, we will be locked into substantial global changes, including those in Antarctica and the Southern Ocean.” – Climate News Network

UK and US scientists tackle Antarctic glacier

British and American scientists are joining forces to research the melting of an Antarctic glacier in what they are calling a race against time. 

CAMBRIDGE, UK, 30 April, 2018 – An international team of scientists is mounting an ambitious research programme to find how soon a vast Antarctic glacier may collapse, with implications for sea levels worldwide.

The Thwaites Glacier in West Antarctica could significantly affect global sea levels. It already drains an area roughly the size of Britain or the US state of Florida, accounting for around 4% of global sea-level rise, an amount that has doubled since the mid-1990s. Its collapse would destabilise other parts of the ice sheet.

If – or more likely when – Thwaites and its neighbour, the Pine Island glacier, ultimately lose all their ice, one estimate suggests that could raise global sea levels by about 3.4m, enough to affect every coastal city on Earth.

Fastest-moving

Satellites have shown for more than a decade that the Thwaites region is an area of massive change and rapid ice loss as the global climate warms in response to rising greenhouse gas emissions from humans’ profligate use of fossil fuels. The two glaciers are among the fastest-moving in the Antarctic.

One of the scientists involved in the research is David Vaughan, director of science at the Cambridge-based British Antarctic Survey (BAS). He says he and his colleagues are involved in “a race against time”.

Professor Vaughan told the Climate News Network: “Understanding sea level rise is the front line of climate change, and sea level rise doesn’t happen overnight. [What’s happening to Thwaites] is not an emergency this year, but I’m very glad we’re doing the research this decade, because we can’t wait too long.”

Understanding collapse

As part of a new £20 million (roughly US$27.5m) research collaboration, the UK Natural Environment Research Council and the US National Science Foundation are about to send a team of scientists to Antarctica to gather the data needed to understand when the collapse of the Thwaites glacier could begin – in centuries, or in the next few decades.

NERC and NSF are jointly funding eight large-scale projects that will bring together leading polar scientists in the International Thwaites Glacier Collaboration (ITGC), the largest joint project undertaken by the two nations in Antarctica for more than 70 years. The ITGC involves around 100 scientists from leading research institutes in both countries with researchers from South Korea, Germany, Sweden, New Zealand and Finland.

There are signs that the process of Thwaites’ collapse has already begun. Antarctica’s glaciers add to sea-level rise when they lose more ice to the ocean than they gain from snowfall. To fully understand the causes of changes in ice flow requires research on the ice itself, the nearby ocean, and the Antarctic climate.

“Sea level rise doesn’t happen overnight. [It’s] not an emergency this year, but I’m very glad we’re doing the research this decade, because we can’t wait too long”

The Collaboration will use drills that can make access holes 1,500 metres into the ice with jets of hot water, as well as other state-of-the-art techniques and equipment, such as autonomous submarines like the Autosub Long Range, the first of whose fleet is named Boaty McBoatface.

While NERC is funding the UK’s share of the project, it is being co-ordinated by BAS, whose total annual budget is around £50m. The agency co-ordinating the US share is the National Snow & Ice Data Center.

As well as the cost of the research itself, the physical problems of mounting a scientific campaign in one of the most remote places in Antarctica could cost as much again in logistical support. The nearest permanently occupied research station to the Thwaites glacier is more than 1,600km away, so even getting the scientists to where they need to be will be demanding.

Collaboration welcome

Researchers on the ice will rely on aircraft support from UK and US research stations, but oceanographers and geophysicists will approach the glacier from the sea in British and American research icebreakers.

The UK’s science minister, Sam Gyimah, said: “Rising sea levels are a globally important issue which cannot be tackled by one country alone. The Thwaites glacier already contributes to rising sea levels, and understanding its likely collapse in the coming century is vitally important.”

The five-year programme begins in October this year and continues to 2023. Its data will be archived and freely shared when it ends. – Climate News Network

Plastic particles now infest the Arctic

Tiny plastic particles have been found in every sample collected of Arctic sea ice. But the ice can only hold these indestructible pollutants for so long.

LONDON, 27 April, 2018 – Plastic particles have colonised one of the last  once-pristine oceans. German scientists sampled sea ice from five locations within the Arctic Circle and counted up to 12,000 microscopic particles per litre of ice.

They have even been able to identify the sources and piece together the journey to the icy fastness. Some tiny lumps of plastic detritus have made their way north from what has become known as the Great Pacific Garbage Patch, a swirling assembly of an estimated 80,000 tons of plastic floating in the ocean across a stretch of water bigger than France.

Other fragments, that began as paint and nylon, date from the invasion of increasingly ice-free Arctic summer waters by more freight ships, and more fishing vessels, the scientists report in the journal Nature Communications.

“During our work, we realised that more than half of the microplastic particles trapped in the ice were less than a twentieth of a millimetre wide, which means they could easily be ingested by Arctic micro-organisms like ciliates, but also by copepods,” said Ilka Peeken, a biologist with the Alfred Wegener Institute.

“Microplastics are now ubiquitous within the surface waters of the world’s oceans.  Nowhere is immune”

“No one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately also for human beings.”

The researchers gathered their samples during three expeditions to the Arctic aboard the icebreaker Polarstern in the spring of 2014 and the summer of 2015, following an ice movement called the Transpolar Drift from Siberia as far as the Fram Strait where warm Atlantic water enters the polar ocean. The Transpolar Drift was first identified by the Norwegian explorer Fridtjof Nansen aboard the Fram, late in the 19th century.

Microplastic particles are defined as 5mm or smaller, and many are measured in millionths of a metre. These are formed by the deterioration of larger pieces of plastic dumped into landfills in billions of tonnes, or released into the waterways and thus into the ocean.

Man-made synthetic polymers are effectively indestructible, and now represent a major source of marine pollution and a constant hazard to wildlife.

More than two-thirds of the particles measured 50 millionths of a metre or smaller. Some were as small as 11 micrometres – one sixth of the diameter of a human hair.

Multiple sources

The researchers identified 17 different types of plastic in the sea ice: from paints, nylon, polyester, cellulose acetate – used in cigarette filters – and the packaging materials polyethylene and polypropylene.

The guess is that the plastics endure in the sea ice for between two and 11 years before melting from their icy packaging in the Fram Strait, to begin sinking in deeper waters. One study recently found 6,500 bits of microplastic per kilogram sampled from the sea floor.

“This is an important finding because it means that they were always present in the water under the ice as it was growing, and drifting, within the Arctic Ocean,” said Jeremy Wilkinson, a sea ice physicist with the British Antarctic Survey, commenting on the study.

“Sea ice grows from the freezing of seawater directly onto the bottom of the ice (i.e. it grows vertically downwards), thus it was incorporating microplastic particles as it grew. It suggests that microplastics are now ubiquitous within the surface waters of the world’s oceans.  Nowhere is immune.” – Climate News Network

High Arctic species respond to climate warming

The northern ocean is abuzz with life, but the composition of those high Arctic species is changing as the world gets warmer.

LONDON, 23 April, 2018 – Global warming is beginning to change the high Arctic species which make up the region’s most numerous occupants. Scientists who have been collecting spiders, mites, ticks, bugs, bees, wasps, ants, moths and springtails in the northeast of Greenland report that the arthropod population is starting to respond to the changing seasons.

Arthropods make up the largest variety of animals on the planet: this is a phylum of jointy-legged things with exoskeletons that includes spiders as well as flies, bees and butterflies as well as mites. In the tundra, the mass of arthropods is greater than that of birds or mammals.

Danish and US scientists report in the Royal Society journal Open Science that between 1996 and 2014, researchers collected 593,788 specimens of different arthropod groups around the Zackenberg research station and noted the way the species composition of a population changed with time and with the pattern of summer rainfall.

In this region, the winter temperatures fall to minus 30°C and average annual temperature is minus 9°C. The ground is more or less permanently frozen. But in the brief Arctic summer, temperatures can soar to between 3°C and 7°C and the Arctic fens, heaths and arid zones effervesce with life.

”We often don’t pay much attention to these small animals, but there could be real consequences to their changing abundances”

Compared with the past, the population is changing. There are more herbivores and creatures that parasitise other animals, but the detritivores – the creatures that consume carrion, excrement and decomposing plants – seem to be on the way down, with, the scientists say, potential implications for key ecosystem processes such as decomposition, nutrient cycling and primary productivity.

Change varied according to habitat: the changes in the composition of the community of arthropods were up to five times more extreme in the drier ecosystems. The implication of such research is that study of shorter-lived, tinier creatures may provide more information about adaptation and loss in the rapidly warming Arctic than, for instance, study of seals and polar bears.

And the insects do respond, even to subtle change: researchers four years ago noted that around 80 species of moth inside Finland’s Arctic seemed to be coping with warmer summers.

“Twenty years may not be long enough to detect changes in abundances of longer-lived species, like some mammals, but because of their short life spans, it’s a pretty long time for arthropods. Still, the fact that we can detect changes over 20 years in some of these animal groups at such a coarse taxonomic resolution is remarkable,” said Amanda Koltz, of Washington University in St Louis, who led the study.

“We often don’t pay much attention to these small animals, but there could be real consequences to their changing abundances.” – Climate News Network

North Atlantic ocean currents are slowing

The North Atlantic currents which help to warm north-west Europe have slowed significantly since the last century, scientists confirm.

LONDON, 12 April, 2018 – The Gulf Stream is slowing, the North Atlantic is cooling. An international scientific study has found new and harder evidence that one of the planet’s key heat pumps, the currents which exchange warmth between the tropics and the Arctic, are weaker today than at any time in the last thousand years.

The currents, known as the Atlantic overturning – its scientific name is the Atlantic Meridional Overturning Circulation, the AMOC – bring warm water north from the tropics and return south with cold water.

Earlier studies suggested strongly that any weakening of the AMOC would speed sea level rise on the US east coast and cool north-west Europe by up to 5°C.

Those studies made use of computer simulations. But the latest research is radically different. It is based on direct observation of what is happening in the ocean. And it is, in non-scientific language, hard evidence that the Gulf Stream is slowing down.

”The specific trend pattern we found in measurements looks exactly like what is predicted by the computer simulations as a result of a slowdown in the Gulf Stream system”

A team from Germany’s Potsdam Institute for Climate Impact Research (PIK) and the US National Oceanic and Atmospheric Administration has found evidence which it says not only supports the earlier predictions, but makes them hard to dispute.

In a study published in the journal Nature the researchers say analysis of sea surface temperature data shows that the AMOC has slowed down by roughly 15% since the middle of the 20th century, with human-made climate change a prime suspect.

“We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coast – which is highly characteristic for a slowdown of the Atlantic overturning, also called the Gulf Stream system,” said the lead author, Levke Caesar from PIK. “It is practically like a fingerprint of a weakening of these ocean currents.”

For decades computer simulations have generally predicted that the AMOC will weaken in response to human-caused global warming. But whether this is already happening has until now been unclear, because of a lack of long-term direct current measurements.

Most robust

Not any more, though. “The evidence we’re now able to provide is the most robust to date,” says Stefan Rahmstorf of the Potsdam Institute, who conceived the study. “We’ve analysed all the available sea surface temperature data sets, comprising data from the late 19th century until the present.”

“The specific trend pattern we found in measurements looks exactly like what is predicted by the computer simulations as a result of a slowdown in the Gulf Stream system, and I see no other plausible explanation for it.”

The Atlantic overturning is driven by the differences in the density of the ocean water: when the warm, lighter water flows from south to north it becomes colder, denser and heavier, making it sink deeper and flow back southwards.

Global warming is not the only influence on the AMOC. Increased rainfall and meltwater from the Arctic sea ice and Greenland ice sheet are also diluting the waters of the northern Atlantic, reducing the salinity. Less saline water is less dense and so less heavy, making it harder for the water to sink from the surface to the ocean depths.

Second study

There have been long debates about whether the AMOC could collapse, which would constitute a tipping element in the Earth system. The PIK study does not consider the AMOC’s future, instead analysing how it has changed over the past century.

A second study, by a team including David Thornalley, from University College London,  in the same issue of Nature, looks into the Earth’s past climate to reconstruct Atlantic overturning changes over the past 1,600 years.

It provides independent confirmation for earlier conclusions that the weakness of the circulation today is unprecedented for more than a millennium at least.

“Several lines of evidence are coming together to a consistent picture now, all pointing at the same weakening since the 1950s,” says Professor Rahmstorf: “[They include] sub-polar Atlantic cooling, the warming inshore of the Gulf Stream, Thornalley’s proxy data for subsurface Atlantic temperatures, and earlier proxy data from deep sea corals showing water mass changes in the Gulf of Maine.” – Climate News Network

Polar ice is melting fast in north and south

In the high latitudes in both hemispheres, the polar ice is in retreat. Two studies support fears for the ice caps, north and south.

LONDON, 10 April, 2018 – New studies have confirmed, once again, the rapid melting of the polar ice in both hemispheres.

A British team has used satellite data to reveal that the retreat of the all-important grounding line of many Antarctic glaciers has accelerated to five times the historic level. And US scientists have confirmed that in Arctic waters the West Greenland ice sheet is now melting faster than at any time in the last 450 years.

Both studies deliver ominous evidence of the long-term consequences of climate change due to profligate human use of fossil fuels. The Greenland icecap holds enough water to raise global sea levels by seven metres. The West Antarctic ice sheet – where the latest study has identified most of the change – holds enough water to raise sea levels by up to five metres.

The UK measure of Antarctic ice retreat is important because it confirms on a wider scale what individual measurements of glacier retreat have already shown: that increasingly warm southern ocean waters are melting the ice at depth.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise”

Depth in this study is critical: glaciers move slowly because the frozen rivers are “anchored” or grounded in bedrock as they flow off the continent, and then grounded again up to a kilometre deep off the continental shelf.

This applies a brake to the flow towards the open sea. The further from the coast the grounding line, the slower the glacier’s flow, the more stable the ice shelf, and the slower the consequent sea level rise.

Hannes Konrad of the University of Leeds in the UK and colleagues report in the journal Nature Geoscience that they used the European Space Agency’s satellite Cryosat-2 data to track the changes in the grounding line along 16,000 kilometres of southern polar coastline.

Around West Antarctica, more than a fifth of the ice sheet has retreated faster than the 25 metres or so a year that has been normal since the end of the last ice age. In some cases the retreat of the grounding line has been five times that rate. The retreat has been extreme in eight of the ice sheet’s 65 biggest glaciers.

Clear evidence

“Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now,” Dr Konrad said.

“This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

Far to the north, ice is also melting. Erich Osterberg of Dartmouth College in the US and colleagues report in the journal Geophysical Research Letters that they collected seven ice cores from a remote zone in the West Greenland ice sheet where meltwater trickles down into the deeper snow and then freezes again: this “new” ice in the compacted snow provides scientists with a record of melting over time.

Longer record

Researchers have been watching the apparent acceleration of the summer melting of Greenland’s ice for decades: they have monitored ever faster rates of glacier flow and tried to identify direct influences on the surface of the ice sheet that might accelerate overall melting.

But direct observation of the northern hemisphere’s largest concentration of ice began only about five decades ago. The Dartmouth cores provide a total of almost five centuries of summer melt patterns.

“The ice core record ends about 450 years ago, so the modern melt rates in these cores are the highest of the whole record that we can see. The advantage of the ice cores is that they show us just how unusual it is for Greenland to be melting this fast,” Dr Osterberg said.

“We see that West Greenland melt really started accelerating about 20 years ago. Our study shows that the rapid rise in the West Greenland melt is a combination of specific weather patterns and an additional long-term warming trend over the last century.” – Climate News Network

Arctic ice depends on half a degree of heat

Half a degree Celsius doesn’t sound like much, but for the Arctic ice it could make a world of difference.

LONDON, 3 April, 2018 – Two separate studies have calculated what it would take to keep the Arctic ice frozen through the summer months – and thus preserve the precious polar ecosystem and help contain further global warming.

It’s simple: fulfil the promises that 195 nations made in Paris in 2015, and keep global warming to “well below 2°C” and ideally at 1.5°C by the year 2100.

That extra half a degree makes a huge difference. At a maximum global average warming of 2°C above the norm for most of human history, the Arctic could become technically ice-free once every three to five years.

Reduce carbon dioxide emissions even further, take greater steps to conserve forests and keep the global temperature at the 1.5° C maximum rise, and the chances are that the Arctic seaways will open only about one summer in 40 years.

Glaciologists consider the Arctic “ice-free” when there are only a million square kilometres of floe left. It has yet to happen. But the sea ice has become noticeably thinner, and smaller in surface area, over the last 40 years.

“The good news is that the sea has a quick response time and could theoretically recover if we brought down global temperatures . . . though  other ecosystems could see permanent negative impacts from ice loss”

For more than two decades, meteorologists and oceanographers have repeatedly warned that runaway global warming, as a consequence of ever-greater combustion of fossil fuels, could bring about an ice-free polar ocean by about 2050.

Sea ice is part of the climate machine. It reflects solar radiation and keeps the ocean cool. It provides a surface on which Arctic seals can haul out, and on which polar bears can feed.

But the catch is that, although the world’s nations almost unanimously voted in Paris to contain global warming, the pledges made at the time were nowhere near ambitious enough.

Since the Paris meeting global warming has accelerated, and one group has warned that the 1.5°C limit could be exceeded by 2026. Many researchers think that the political decisions of the next decade will be vital.

Clear benefits

Researchers already know that the 1.5°C target will deliver palpable rewards: it will make a huge difference, for instance, to sea levels, grain harvests and global fish catches.

US and Canadian climate scientists set out to see what difference half a degree would make to the Arctic. They worked with different climate simulations to reach roughly the same conclusion, in two papers in the journal Nature Climate Change.

The Canadian team calculated that at 2°C, ice-free conditions would happen every five years; at 1.5°C, the hazard would drop to one in 40 years; at 3°C, permanent ice-free summers would be likely. A second study from the US backed up the premise.

“I didn’t expect to find that half a degree Celsius would make a big difference, but it really does,” said Alexandra Jahn, of the University of Colorado at Boulder.

Higher costs

“At 1.5°C half the time we stay within our current summer sea ice regime, whereas if we reach two degrees of warming, the summer sea ice will always be below what we have experienced in recent decades.”

Higher levels of warming would impose higher costs: 4°C of warming would deliver a high probability of an ocean free of ice for three months every summer by 2050, and five months a year by 2100.

“The good news is that the sea has a quick response time and could theoretically recover if we brought down global temperatures at any point in the future,” Dr Jahn said.

“In the meantime, though, other ecosystems could see permanent negative impacts from ice loss, and those can’t necessarily bounce back.” – Climate News Network

Methane from permafrost melt more than thought

A key source of a powerful greenhouse gas, methane emissions from permafrost, is producing much more than realised, scientists report.

LONDON, 31 March, 2018 – Methane emissions are the source of the greenhouse gas which, after carbon dioxide, probably causes climatologists more sleepless nights than any of the other gases. And now it appears they have quite a lot more to bother them than they had realised.

Methane is reckoned to be at least 30 times more powerful than CO2 at warming the Earth, with some estimates putting its potency much higher still. The good news, research has suggested, is that there is far less methane than CO2 in the atmosphere to worry about.

The bad news, announced by an international research team, is that previous calculations may have been seriously wrong, and that thawing permafrost is likely to be producing appreciably more methane than anyone had thought.

The researchers were headed by Christian Knoblauch of the Centre for Earth System Research and Sustainability (CEN) at the University of Hamburg, Germany. Their findings, published in the journal Nature Climate Change, make it possible to predict better how much of this significant gas may be released by the thawing of the Arctic permafrost.

“Our study shows for the first time that the methane-forming micro-organisms in the thawing permafrost have significant influence on the greenhouse gas budget”

Methane and carbon dioxide are both produced in thawing permafrost as dead animal and plant remains decompose. But methane is formed only in the absence of oxygen. Until now, scientists had also thought that more greenhouse gases were formed when the ground was dry and well aerated – in other words, when oxygen was available.

So they did not expect much methane to be produced by the thawing permafrost.
What Dr Knoblauch and his colleagues have now shown is that water-saturated permafrost soils without oxygen can be twice as harmful to the climate as dry soils – which means the role of methane has been greatly underestimated.

They have, for what they say is the first time, measured in the laboratory the long-term production of methane in thawing permafrost. The team had to wait for three years before their roughly forty-thousand-year-old samples from the Siberian Arctic finally produced methane.

They observed the permafrost for a total of seven years and found that, without oxygen, equal amounts of methane and CO2 were produced.

Gigaton estimate

A co-author of their report, Susanne Liebner, from the Helmholtz Center Potsdam – GFZ German Research Center for Geosciences, said: “By combining process-based and molecular-microbiological methods, our study shows for the first time that the methane-forming micro-organisms in the thawing permafrost have significant influence on the greenhouse gas budget.”

The team used the new data to improve a computer model that estimates how much greenhouse gas is produced in permafrost in the long term – and they compiled a first forecast: the permafrost soils of northern Europe, northern Asia and North America, they say, could produce up to one gigaton (one billion tons) of methane, and 37 gigatons of carbon dioxide, by 2100.

Earlier studies have expressed concern about the interplay between permafrost and global warming, and this latest research will be exhaustively scrutinised as other teams try to corroborate, modify or contradict it. That is how science works. And there are certainly uncertainties that need resolving.

For example, how deep will the soil actually have thawed by the end of the century? Will it be wet or dry? What is certain, the team concludes, is that the new data will enable more accurate predictions to be made about the impacts of thawing permafrost on the climate. – Climate News Network

Arctic warming upsets ocean currents

Spells of Arctic warming have always come in fits and starts, but the current winter’s record-breaking extremes are puzzling scientists.

LONDON, 30 March, 2018 –There are indications from the present Arctic warming – tentative, inconclusive, but enough to arouse intense scientific interest – to suggest that the planet may now be close to one of the significant climate tipping points that could usher in drastic change.

At worst, some scientists now believe, the North Atlantic current, the northern part of the Gulf Stream, appears to be slowing. The current transports enough heat from tropical waters to the Arctic to keep north-west Europe’s temperature several degrees warmer than it would otherwise be.

If the North Atlantic current changes significantly, parts of Europe would cool and sea levels would rise. Parts of West Africa could experience more drought, and the Asian monsoon might also be affected. Reports that the current may change are not new, but recent evidence from the Arctic itself has given them new urgency.

In the high Arctic it is still deep winter, with temperatures dropping to –30°C.
But across large parts of the Arctic the temperature has been above freezing, even at the North Pole itself.

One Arctic weather station, at Cape Morris Jesup, in northern Greenland, has regularly recorded temperatures above zero, and this winter it has so far experienced 61 hours above freezing. The previous record, in 1980, was 16 hours to the end of April.

“Until now, models have predicted that fresh water will threaten convection in the future. It is already affecting convection to a greater extent than we thought”

Scientists call these episodes – which are not unknown – warm intrusions, as they bring in moist, mild air. The present one is the largest on record.

The intrusions are linked to a decline in Arctic winter sea ice, which has undergone unusual melting and thinning, making it vulnerable to winter storms. The southern Arctic winds have blown this broken ice far to the north, to end in the central Arctic.

The result has been large gaps of open water in the ice pack, which in turn have released large amounts of heat into the atmosphere, melting more ice.

Scientists believe the abnormal warming of the last five Arctic winters is linked to this melting. Normally the cold winter surface water sinks towards the sea bed as it heads south out of the Arctic and is replaced by warm water which flows up from the tropics, a process called convection. But this is now being disrupted, with the warmer and less saline tropical water staying near the surface.

At the same time large quantities of fresh meltwater are pouring off the Greenland landmass, with the run-off thought to be diluting the salt water already in the sea.

Smallest extent

On 19 March NOAA reported that February’s average Arctic sea ice extent was the smallest in the 39-year record at 521,000 square miles (8.8%) below the 1981-2010 average, according to an analysis by the National Snow and Ice Data Center, using data from NOAA and NASA. The monthly extent was 62,000 sq m smaller than the previous record set just last year.

Scientists work by developing theories which, in their judgment, provide the best available explanation of the facts they observe. But observations improve, evidence from the physical world changes, and so they constantly refine and revise their theories – and sometimes replace them altogether.

That constant renewal of the current research is vigorously going ahead now in the Arctic, which is no stranger to weather and climate anomalies. There is evidence of similar interruptions to Arctic Ocean circulation in the past, but they did not persist, the journal New Scientist reports.

If newer research bears out the scientists’ findings so far, confirming that the present Arctic warming is growing stronger and happening more often, and that the interplay of wind, ice and meltwater is contributing to changes in convection, we may expect serious impacts on agriculture, weather and human wellbeing over a large part of the globe.

Marilena Oltmanns of the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, told the New Scientist: “Until now, models have predicted that fresh water will threaten convection in the future. It is already affecting convection to a greater extent than we thought.” – Climate News Network

King penguins face a shrinking realm

When an ecosystem changes, those creatures most precisely adapted become the most vulnerable – and that is bad news for king penguins.

LONDON, 28 February, 2018 – King penguins – one of the most charismatic species of the Southern Ocean – are under threat from climate change.

More than a million breeding pairs will either shift to new colonies or perish before the century’s end, as conditions in the Antarctic begin to change. The species Aptenodytes patagonicus could lose 70% of its population, according to a new study in Nature Climate Change.

The problem – increasingly familiar to conservationists and biologists – is one of mismatch engineered by climate change driven by human-induced global warming, itself a consequence of profligate combustion of fossil fuels that spill ever greater ratios of greenhouse gases into the atmosphere.

King penguins have adapted to a precise habitat range: they favour a scatter of islands in the Southern Ocean, away from the sea ice but close to an oceanic upwelling called the Antarctic Polar Front, which concentrates colossal quantities of fish into a small area.

And because of climate change, this front is in retreat. So penguin parents must swim ever further to find food for their chicks.

“There are still some islands further south where king penguins may retreat but the competition for breeding sites and for food will be harsh”

The new research predicts that – for most colonies – the distance to find fresh food will mean longer absences. At some point, the chick’s capacity to withstand starvation will be exceeded. The population will crash.

This is a reprise of an increasingly familiar story: human-induced climate change, along with other human bequests such as pollution and habitat destruction, have begun to threaten the wild things everywhere.

And even though the southern hemisphere is relatively less disturbed, and with a smaller human population, there have been signs of change. There have been separate cases of concern for Adélie and other penguins, for crested and rockhopper penguins, and even for the great survivor of the frozen south, the emperor penguin.

The entire region faces problems, in many cases driven by overfishing, and there has even been alarm about the condition of the albatross as it circles the southern ocean.

Repeated recoveries

The conclusion is based at least in part on evidence from the king penguin’s genome. The enormous string of DNA that encodes a creature’s machinery for survival is also a record of inheritance: it tells the story not just of the individual’s parentage but also of the entire species over many millennia.

And, so far at least, the king penguin DNA tells a tale of species survival: king penguin populations have crashed, and then recovered, more than once in the last 50,000 years.

But the bird faces new challenges. Humans have begun to alter the global climate, as well as to bring fishing on an industrial scale to a once isolated ocean. So hungry birds face high-technology competitors.

And faced with the choice of starve or migrate, the birds have only a limited range of potential breeding colonies. Around half of the population, on the Crozet and Prince Edward Islands, could lose their breeding colonies completely.

Poor prospects

Around a fifth of the population, based on the Kerguelen, Falkland and Tierra del Fuego Islands, will face ever greater foraging distances.

Climate change may create new opportunities for some, but overall, the outlook is bleak. “The main issue is that there is only a handful of islands in the Southern Ocean and not all of them are suitable to sustain large breeding colonies,” says Robin Cristofari, of the University of Strasbourg in France.

“There are still some islands further south where king penguins may retreat but the competition for breeding sites and for food will be harsh, especially with the other penguin species like the chinstrap, gentoo or Adélie penguins, even without the fisheries,” said his co-author Céline Le Bohec, also of the University of Strasbourg.

“It is difficult to predict the outcome, but there will surely be losses on the way. If we want to save anything, proactive and efficient conservation efforts but, above all, coordinated global action against global warming should start now.” – Climate News Network

Polar bears lose weight as climate bites

To survive, polar bears need to gain weight, not lose it. With a longer summer and less sea ice, it’s a lot harder to do that.

LONDON, 2 February, 2018 – Polar bears may be having a harder time than anybody thought. Biologists who monitored the hunting habits of the Arctic’s iconic predator found that bears have a faster metabolism – that is, they need high-energy foods more often – and are likely to lose weight just when they should be getting fat and ready for the winter.

Ursus maritimus is famous for going without food for long periods and then making up for it when the going is good. And for a polar bear, the going only gets good when there is a lot of sea ice and rich pickings among the seal population.

But US Geological Survey scientists who fitted monitors and video cameras to nine female polar bears for periods of 8 to 11 days and then tracked them on the ice of the Beaufort Sea, north of Alaska, report that five of their “volunteers” had lost weight.

Four of them had lost 10% of their body mass: that is, they could not catch seals often enough to put on weight. One had even lost muscle tissue.

The study confirms that bears are vulnerable to climate change. Sea ice minimum levels are falling at the rate of 14% a decade in the Arctic, and polar bears have been feeling the loss.

“Polar bears actually have much higher energy demands than predicted. They need to be catching a lot of seals”

But because the bear is a sit-and-wait predator, hunting ringed seals or bearded seals for preference as they haul out onto the ice, biologists had assumed that a resting bear would have a low metabolic rate. Not so, according to a new study in the journal Science.

The bears are active about one third of the time and use energy swimming and walking. The tests and observations were made during the period from April to July when bears catch most of their prey to store up the body fat they need.

In fact the instrument readings and tests of urine and blood samples told the scientists that the metabolic rate of a bear was more than 50% above previous calculations.

So a female seal out on the ice in the polar spring would need to eat one adult ringed seal, or three subadults, or 19 newborn seal pups, every 10 or 12 days just to stay as she was, at the same bodyweight.

Fall explained

But to succeed and breed in the winter, a female would ideally need to consume so much seal blubber that her fat levels matched her lean body mass. In April on the Beaufort Sea between 2014 and 2016, the bears in the test study had no great luck.

“We found that polar bears actually have much higher energy demands than predicted. They need to be catching a lot of seals,” said Anthony Pagano, a doctoral researcher from the University of California Santa Cruz, and a wildlife biologist with the US Geological Survey, who led the research.

Bear population in the Beaufort Sea has fallen by about 40% in the last decade. Now, biologists are beginning to see why.

“We now have the technology to learn how they are moving on the ice, their activity patterns and their energy needs, so we can better understand the implications of these changes we are seeing on the sea ice,” he said. – Climate News Network