Arctic thaw would cost half of world’s annual earnings

Arctic thaw would cost half of world's annual earnings

If Arctic soils melt and release frozen carbon, the impact would cost almost half the world’s annual gross domestic product, researchers say.

LONDON, 22 September, 2015 – The melting permafrost in the Arctic could cost the world dearly. New research calculates that the economic damage that would flow from loss of permafrost and the increased emissions of greenhouse gases (GHGs) would add up to US$43 trillion

This is very nearly the estimated combined gross domestic product last year of the US, China, Japan, Germany, the UK, France, and Brazil.

And, British and US scientists say, this would be in addition to at least $300 tn of economic damage linked to other consequences of climate change.

The attempt to put a cumulative economic value on natural changes in climate that have yet to happen is part of the bid to get governments to take climate change seriously. In the latest attempt to cost the impact of rising carbon dioxide levels in the atmosphere, and the continuous rise in global average temperatures, all as a consequence of fossil fuel combustion and other human action, the economist Chris Hope of the University of Cambridge and the polar expert Kevin Schaefer of the University of Colorado have turned their sights on the Arctic.

The Arctic is the fastest-warming region of the planet. It was once much warmer, and its now-frozen soils are home to huge quantities of vegetation that never had a chance to decompose.

Increased risk

The two scientists report in Nature Climate Change that if emissions of greenhouse gases continue to rise as they are doing now, the thaw of the permafrost and the loss of the ice caps could release 1,700 billion metric tons of carbon now locked in as frozen organic matter.

What would follow would include a higher chance of catastrophic floods, wind storms, heat waves and drought, the accelerated melting of the Greenland (and West Antarctic) ice sheets, rising sea levels, the loss of agricultural land and rising energy demand as more and more people began to depend on air conditioning.

So the total cost of permafrost thaw would be $43 tn, which is about half the annual global domestic product of the planet right now. The predicted total cost of climate change by 2200 could reach $369 tn, an increase of 13% on all calculations so far.

Governments – and industry – have tended to resist steps such as a switch to renewable resources and greater care for the remaining forests, on the grounds that change on such a scale imposes economic costs. So estimates of the economic costs of climate change are part of an attempt to persuade nations that to do nothing would be far more expensive. 

Researchers have tried to derive the true social costs of, for instance, fossil fuels and the economic setbacks associated with specific climate events such as heat waves in single countries, or even the possible costs in lives and income of multiple impacts across a continent

Expensive inaction

Their conclusion: an extra $43 tn bill for inaction. An aggressive strategy to limit thaw in the permafrost, on the other hand, could save the world $37 tn.

The two scientists used a computer model to simulate the impacts of what is now known as the business-as-usual-scenario, in which the world goes on burning more and more fossil fuels, until the concentrations in the atmosphere of carbon dioxide reach 700 parts per million.

Right now, the concentration has just tipped 400 ppm. For most of human history, it has hovered around 270ppm.

“We want to use these models to help us make better decisions – linking scientific and economic models together is a way to help us do that,” said Dr Hope. “We need to estimate how much it will cost if we do nothing, how much it will cost if we do something, and how much we need to spend to cut back greenhouse gases.” – Climate News Network

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Ecuador’s plants head uphill to escape warmth

Ecuador's plants head uphill to escape warmth

In just two centuries many plant species have scrambled 500 metres up the Andes in search of cooler temperatures, Danish scientists say.

LONDON, 20 September, 2015 – In 1802, the great explorer Alexander von Humboldt went up a mountain in Ecuador, and made a note of every plant and its elevation as he climbed.

In 2012, Danish researchers retraced his footsteps. They found that, in response to global warming, the plants Humboldt recorded had moved more than 500 metres uphill.

When Humboldt, whose “physical tableau” became one of the oldest plant data sets in the world, climbed the 6,268-metre Chimborazo volcano the highest plant was at 4,600 m. Naia Morueta-Holme  of Aarhus University and colleagues report in the Proceedings of the National Academy of Sciences that they found that the vegetation had gone up in the world.

“Right up at 5,185 m, we found the last trace of vegetation, a defiant little plant belonging to the sunflower family and half-covered in snow – in full flower in spite of the cold conditions, the thin air and the harsh wind,” she said.

Wholesale change

The scientists found changes all the way up the mountain. Individual species have moved up 500 m in the last 210 years. Glaciers are in retreat, the snow cover is lighter, and the lower parts of the mountain are now cultivated.

Humboldt’s tableau provides an insight into potential response to climate change as a consequence of rising carbon dioxide levels in the atmosphere, driven by fossil fuel combustion by human society.

“Even though the plants have kept up on average until now, we see many individual species that are lagging behind, while others – especially common species that are good at spreading and living under many different conditions – are moving upslope.

“We can thus expect even more drastic changes in the vegetation in the future, and there are concerns about how the rare and specialised species will survive, particularly in the tropics, where most of them grow,” Dr Morueta-Holme, now at the University of California at Berkeley, said.

Airborne menace

And according to a new study in the Proceedings of the Royal Society B, in the far north the Arctic mosquitoes are hatching earlier and growing faster. Lauren Culler of Dartmouth College in the US and colleagues made computer models of mosquito populations as a consequence of climate change and predict that, as Arctic temperatures rise by 2°C, the probability of mosquito survival and emergence from the tundra snowmelt would increase by half.

Since Arctic mosquitoes have a reputation for being more than usually ferocious, this could be uncomfortable for the caribou and any other potential donors of a blood meal. And since mosquitoes are also pollinators of tundra plants, and prey for Arctic birds, the overall impact on Arctic ecology could be significant.

The scientists used laboratory studies and fieldwork in western Greenland to follow the changing life cycle of the mosquito: warmer spring temperatures caused the creatures to emerge two weeks early and their larval and pupal stages were shortened by 10% for every 1°C increase in temperature.

Diving beetles consumed more of the immature mosquitoes, but they were at risk for shorter periods, so overall their chance of survival was greater. At 2°C, the chance of survival increased 53%. And as the insects increased in abundance, and moved further north, Dr Culler predicted “negative consequences for the health and reproduction of caribou.” – Climate News Network

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Clean energy plans may increase toxins in plankton

Clean energy plans may increase toxins in plankton

Environmental assessment of a proposed hydroelectric dam in Canada sheds new light on the cause of high levels of a potent neurotoxin in Arctic marine life.

LONDON, 10 September, 2015 – Scientists in the US think they may now have the explanation to a conundrum that has puzzled them for a long time − why there are high levels of methylmercury, which can damage the nervous system, in Arctic marine life.

The answer, they report, appears to be one of those examples of worsening a problem by trying to solve it: human attempts to mitigate climate change have inadvertently altered the eating habits of Arctic plankton.

Researchers from the Harvard John A.Paulson School of Engineering and Applied Science and Harvard T.H. Chan School of Public Health suggest in the Proceedings of the National Academy of Sciences that the high levels of methylmercury, a potent neurotoxin, are a byproduct of global warming and the melting of sea ice in Arctic and sub-Arctic regions.

To tackle global warming, many governments are turning to hydro-electric power to replace fossil fuels.

Impact review

This latest research was part of a review of the environmental impact assessment for the Muskrat Falls hydroelectric dam in Labrador, Canada, which in 2017 will flood a large region upstream from an estuarine fjord called Lake Melville. The communities along the shores of Lake Melville are predominantly indigenous and rely on the lake for much of their food.

The researchers spent 10 days criss-crossing the lake to measure baseline methylmercury levels. They found that concentrations in the plankton peaked between one and 10 metres below the surface, closely matching findings from the central Arctic Ocean.

When fresh and salt water meet – in estuaries, or when sea ice melts in the ocean – salinity increases as water deepens, allowing organic matter − which typically sinks to the bottom − to reach a neutral buoyancy so that it cannot float either up or down in the water.

“Scientists have a responsibility to understand and explain how environmental systems
will react before they are modified”

This layer collects other small pieces of debris and concentrates them into a feeding zone for marine plankton. The bacteria stuck in this zone then complete a complex chemical process that turns naturally-occurring mercury into dangerous and readily-accumulated methylmercury.

Plankton in the Arctic and sub-Arctic are not choosy eaters: once in the debris layer, they go on a feeding frenzy that can last several weeks. The methylmercury they produce accumulates in other organisms and magnifies as it works its way up the food chain.

Amina Schartup, a biogeochemist at Harvard and lead author of the paper, says: “This system is incredibly efficient at accumulating methylmercury.” She adds that the same system is mirrored in the Arctic, where fresh water from melting ice mixes with salt water.

To find out what happens when methylmercury levels increase because of reservoir flooding upstream, the researchers collected soil cores from the inland areas due to be flooded in 2017 for the hydro-electric plant.

Simulated flooding

The team simulated flooding by covering the cores with river water. And, within five days, mercury levels in the water covering the cores increased 14-fold.

One of the communities along the shores of Lake Melville – and two-thirds of the lake itself – is part of Nunatsiavut, the first autonomous region in Canada governed by Inuit.

“Any kind of contamination is going to disrupt how we live as Inuit and impact our health and lifestyle,” says Sarah Leo, president of the Nunatsiavut government.

“We need more research to understand the downstream effects, and we need to develop strategies to mitigate those effects. How are we, as a community, going to adjust our lifestyle if we can no longer live off the land? These are all questions we need answered before flooding.”

Schartup says: “Scientists have a responsibility to understand and explain how environmental systems will react before they are modified, because once the damage is done, you can’t take it back.” – Climate News Network

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Shell swims against oil price tide

Shell swims against oil price tide

As the giant Shell oil company begins highly controversial exploration drilling in the Arctic, the price of crude continues to slide.

LONDON, 30 August, 2015 – It’s a gamble – some would say a giant gamble. Before even one litre of oil has been found, the Anglo-Dutch Shell group is believed to have spent more than US$7 billion – just making preparations for its latest Arctic venture.

Shell is betting on finding the oil industry’s Holy Grail: according to 2008 estimates by the US Geological Survey, the Arctic contains more than 20% of the world’s remaining hydrocarbon resources – including at least 90 billion barrels of oil.

If Shell does strike oil in big quantities maybe its gamble will pay off – and its anxious shareholders can look forward to handsome payouts.

But the whole venture is a high-risk business. The decision by the US administration to allow Shell to start drilling in the Chukchi Sea, off the coast of Alaska, is highly controversial.

Environmentalists and scientists say any further exploitation of fossil fuels must be halted in order to limit the rise in average global temperatures to within 2°C of pre-industrial levels and avert serious climate change.

Possible catastrophe

Drilling conditions in the Arctic can be treacherous: in 2012 a Shell rig which had been drilling for oil in the Beaufort Sea off Alaska ran aground in a storm and had to scrapped. Any oil spill in the ecologically rich waters of the Arctic could be catastrophic.

Hillary Clinton, President Obama’s former secretary of state and now a presidential contender, criticises Washington for allowing Shell to drill.

“The Arctic is a unique treasure”, she says. “Given what we know, it’s not worth the risk of drilling.”

Shell says its operations meet the highest standards. “We owe it to the Arctic, its inhabitants, and the world to work with great care as we search for oil and gas resources and develop those at the request of governments across the region”, the company says.

The financial rationale of Shell’s move is also being questioned. Drilling in the Arctic is an expensive business and involves complex logistical challenges.

Stubbornly low

Analysts say so-called unconventional oil – crude recovered from difficult environments such as the Arctic – needs to command a price of between US$70 and US$100 a barrel to make its recovery economical.

At present, though oil demand is strong, there are deep uncertainties about future economic growth, particularly in China. Oil is staying stubbornly below US$50 per barrel. The big oil producers such as Saudi Arabia have not, as in the past, lowered output in order to shore up prices.

A tentative agreement between western nations and Iran on nuclear issues is likely to mean new supplies of Iranian crude hitting the international market, putting further downward pressure on prices. Despite continue bombing and communal strife, Iraq is gearing up its oil production.

One of the major factors influencing the downward movement of oil prices over recent years has been the development of the US fracking industry, with vast amounts of oil and gas recovered from shale deposits deep underground.

Perhaps Shell – and big producer countries like Saudi Arabia – foresee an end to the fracking boom.

Fracking slows

As recovery from shale deposits becomes more difficult and prices remain low, fracking is not enjoying the explosive growth it saw a few years ago.

Some drilling sites in the US states of Texas and North Dakota are being abandoned. Several of the smaller fracking companies – which borrowed large amounts during the good times to finance their operations – have gone bust.

But there is still a global glut of oil: the International Energy Agency says there is unlikely to be a rebound in oil prices any time soon.

The drilling season in the Arctic is brief: the days shorten quickly and the ice begins to form. Shell – and its shareholders – will be hoping for quick returns.

International negotiators preparing for the climate summit in Paris later this year are calling for urgent action to head off global warming. There are many who hope Shell’s exploration activities will not succeed – and that the Arctic hydrocarbons stay where they are, thousands of feet below the seabed. – Climate News Network

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Arctic’s melting ice shrinks shipping routes

Arctic’s melting ice shrinks shipping routes

The opening up of waters north of Siberia as Arctic ice melts will change world trade patterns by cutting a third off distances between north-west Europe and the Far East.

LONDON, 4 August, 2015 – The disappearing Arctic ice cap will boost trade between north-west Europe and countries such as China, Japan and South Korea by making the sea routes far shorter, according to economic analysts.

The new sea route will alter world trade, making northern countries richer, but causing serious problems for Egypt, which will lose a large chunk of revenue currently gained from ships coming through the Suez Canal.

One advantage to the environment − according to a discussion paper from the Netherlands Bureau for Economic Policy Analysis − is that ships will burn far less fossil fuel to reach their destination.

However, this gain will be offset when the volume of trade increases because of the shorter sea route, making climate change slightly worse.

Open all year

The northern sea route is already open in the summer months, but the paper predicts that it will be available all year round by 2030, or possibly sooner. It says that Arctic ice is melting faster than predicted by scientists.

To police the new route, the Russian government has already formed a federal state institution and is building 10 “relief ports” along the Siberian coastline for ships that might need repairs or supplies. China has signed a free trade agreement with Iceland in anticipation of regularly using the route.

The paper estimates that trade between north-west Europe and China, Japan and Korea will increase by 10% as a result of the opening of the route, but that this will happen gradually.

The northern route will become one of the busiest shipping lanes in the world, increasing the economic and political importance of the Arctic

Since 90% of world trade by volume is carried by ship, the distance between ports is a vital consideration. The northern route reduces the distance from Japan to north European countries by 37%, from South Korea by 31%, China 23%, and Taiwan 17%.

The advantage of shorter distances applies only to countries in northern East Asia. For countries south of the equator, such as Singapore and Indonesia, the southern route via Suez is still shorter.

Similarly, southern European countries do not gain because they remain roughly the same distance away from their trading partners whichever route they use.

The countries in Europe that will gain most from the new sea route are those with access to ports on the North Sea and the Baltic. These include Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, Germany, Ireland, Latvia, the Netherlands, Poland, Slovakia, Sweden, the UK and Norway.

Drop in trade

Some countries in eastern and southern Europe would experience a drop in trade because of the comparatively longer distances their exports and imports would need to travel, according to the report. These include Bulgaria, Croatia, Hungary, Italy, Romania and Slovenia.

The report says that roughly 8% of world trade goes through the Suez Canal, and that two-thirds of this volume will go via the shorter Arctic route. The northern route will become one of the busiest shipping lanes in the world, increasing the economic and political importance of the Arctic.

At the same time, it will put huge economic pressure on Egypt and Singapore, who rely heavily on shipping using the southern route.

Over time, the opening of the Arctic route will have knock-on effects on jobs and prosperity in all the countries concerned, but it is predicted that this will be a gradual rather than sudden process. – Climate News Network

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Half of climate safety level has gone

Half of climate safety level has gone

Global temperatures have risen by 1°C in the past 150 years, and one scientist says doubling that level could unleash catastrophic sea level rise this century.

LONDON, 2 August, 2015 – The world is now halfway towards the internationally-agreed safety limit of a maximum 2°C rise in global average temperatures, researchers say.

That limit seeks to prevent the global warming caused by the burning of fossil fuels exceeding 2°C above the pre-industrial global temperature. The UN’s Paris climate summit later this year aims to ensure that it is not breached.

It appears that the human race has taken roughly 250 years to stoke global warming by 1°C. On present trends, we look likely to add the next 1°C far more quickly – across much of the world, many climate scientists believe, by the middle of this century.

The research is published in the journal New Scientist, which commissioned it. As so often with climate projections, it needs qualifying and teasing apart.

Some scientists, for example, warn that there’s uncertainty about just what the pre-industrial global temperature was. The New Scientist research is careful to be specific: it says global surface temperature is now passing 1°C of warming relative to the second half of the 19th century.

Farewell, hiatus

And one of the four main trackers of temperature thinks that milestone will be passed only if there is a strong El Niño, the cyclic Pacific weather phenomenon that periodically brings widespread chaos in its wake.

However, the research looks likely finally to lay to rest the argument that global warming is slowing and stuttering to a virtual halt, the so-called hiatus theory. Kevin Trenberth, of the US National Center for Atmospheric Research in Boulder, Colorado, told New Scientist: There’s a good chance the hiatus is over.”

The hottest year since records began was by a very small margin – 2014, and this year’s El Niño could mean a temperature rise of 0.1°C this year, an increase which usually takes about a decade to develop. Dr Trenberth thinks 2015 is likely also to be a record-breaker. 

Between 1984 and 1998 the Earth warmed at 0.26°C a decade, but the Intergovernmental Panel on Climate Change (IPCC)  says the rate then fell back until 2012 to about 0.04°C, for a number of reasons, including a less active Sun, more cooling aerosols from volcanoes and Asian factories, and more heat being absorbed by the oceans. The New Scientist findings suggest that warming may soon revert to the higher rate. 

From a quite different source comes a warning not only that temperatures may soon start a marked rise, but that sea level may also accelerate far faster than most scientists think likely.

It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable”

The prospect it holds out is at odds with most mainstream climate science, and might well be discounted as alarmist and fanciful. But the lead author of the discussion paper in which it appears is the highly respected James Hansen, former director of NASA’s Goddard Institute for Space Studies.

He and his colleagues say the ice melting around Greenland and Antarctica will cause sea level rises much faster than mainstream predictions suggest, by several metres this century. This will add to a process which they say has already begun, accelerating the melting of the undersides of Antarctic glaciers and ice shelves.

Another consequence, they think, will be the shutting down of ocean currents which carry heat from the tropics to the polar regions, leaving the tropics to warm fast and the high latitudes to cool. This temperature difference, they say, will spawn superstorms unlike any seen so far.

All this, Professor Hansen and his colleagues say, could happen with a 2°C temperature rise, with devastating consequences: It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilisation.”

Professor Hansen may of course be wrong, but it would be short-sighted to assume that he is. He has a strong record of ultimately being proved right. Climate News Network

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Melting sea ice means shortage of bear necessities

Melting sea ice means shortage of bear necessities

Researchers explode theory that polar bears can use hibernation techniques to last without food as climate change reduces their summertime hunting habitat.

LONDON, 20 July, 2015 – Global warming is likely to leave the polar bear high and dry and very hungry as increasing loss of sea ice reduces the hunting grounds of the Arctic’s top predator.

Researchers have established that while Ursus maritimus can survive for months without eating during winter hibernation, in the summertime it is not much better at going without food than any other mammal.

The polar bear is capable of shutting its own metabolism down to astonishingly low levels during hibernation and, until now, zoologists have surmised that the bear could minimise energy losses by entering a hibernation-like state when deprived of food.

But John Whiteman, a doctoral student in ecology, zoology and physiology at the University of Wyoming, and colleagues report in Science journal that that theory is wrong. Once they are up and hunting, bears need food.

Energy expenditure

“We report gradual, moderate declines in activity and body temperature of both shore and ice bears in summer, resembling energy expenditures typical of fasting, non-hibernating mammals,” they write.

As carbon dioxide levels in the atmosphere creep up, as a consequence of the human combustion of fossil fuels, so Arctic temperatures have on average risen.

The loss of sea ice in the Arctic has, over the last decade, happened even faster than climate scientists predicted, which creates problems for bears that need to hunt and gorge on high-calorie diets in preparation for the winter.

The polar bear hunts on the ice, and its preferred diet is the blubber-rich flesh of seals and small whales. On shore, it must forage for scraps, berries and small mammals while waiting for the seas to freeze again.

“Polar bears appear unable to meaningfully prolong their reliance on stored energy”

But Arctic summers have stayed milder for longer, and the areas of summer sea ice have steadily dwindled. So the bears have spent increasing periods without their preferred diet.

The orthodoxy had been that bears, while waiting for the first freeze, had been able to enter a state called “walking hibernation”. Whiteman and his fellow researchers took a closer look.

With help from government agencies, a US coastguard icebreaker, helicopter pilots and a large number of other people, they captured two dozen polar bears, fitted satellite collars, and implanted little devices that recorded body temperature and tracked their movements on shore and on ice in the Beaufort Sea, north of Alaska and Canada, between 2008 and 2010.

Core temperature

They found that the bears could do something physiologically clever to keep warm while swimming – they could temporarily cool their outermost skin layers to insulate their inner selves and keep their core body temperatures at a healthy level, and one bear was reported to have survived a nine-day swim from shore to ice.

But they also found that the bears were not much better than other mammals at walking around on dry land, looking for food that wasn’t there.

“We found that polar bears appear unable to meaningfully prolong their reliance on stored energy, confirming their vulnerability to lost hunting opportunities on the sea ice − even as they surprised us by also exhibiting an unusual ability to minimise heat loss while swimming in Arctic waters,” Whiteman says.

The evidence, however, suggested that “walking hibernation” didn’t actually exist. The researchers conclude that the bears “are unlikely to avoid deleterious loss in body condition, and ultimately survival, that are expected with continuous ice loss and lengthening of the ice-melt period”. – Climate News Network

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Global warming threatens colder climate for Europe

Global warming threatens colder climate for Europe

New evidence that increased melting of sea ice as the Earth warms could weaken the Gulf Stream and reduce temperatures in western Europe.

LONDON, 3 July, 2015 – Scientists have yet again warned that weakening ocean circulation in the North Atlantic could deliver a climate paradox − a colder Europe as a consequence of global warming.

A study published in Nature Climate Change found that as sea ice off Iceland and Greenland retreats, the flow of cold, dense water to the bottom of the North Atlantic ocean could be reduced, and therefore weaken the warming effects of the Gulf Stream.

The great submarine current − sometimes called the Atlantic Conveyor − flows south to surface in the tropics as the Gulf Stream, which then flows north again to deliver tropic warmth to European coasts.

However, a slowdown in the natural overturning of the ocean could weaken the Gulf Stream, which in turn could cool the atmosphere over the British Isles and western Europe.

“A warm western Europe requires a cold North Atlantic, and the warming that the North Atlantic is now experiencing has the potential to result in a cooling over Western Europe,” says Kent Moore, a professor of physics at the University of Toronto Mississauga, Canada.

Calamitous change

Such a possible collapse of a natural oceanic system is predicated as one of the irreversible tipping points that could result in calamitous climate change.

Scientists have twice warned in the past six months that such change could be irreversible, unless governments jointly decide to dramatically reduce greenhouse gas emissions from the combustion of fossil fuels by switching to renewable sources of energy.

Another research group reported in March this year on how the changing salinity of the northern ocean waters − because of the increasing flow of meltwater from land-borne glaciers − threatened a weakening of the Atlantic Conveyor.

“The heat exchange is weaker – it’s like turning down the stove 20%”

In the latest study, Professor Moore and colleagues from Norway, the US and the UK looked not at changes in ocean salinity, but at the exchange of heat between sea and air.

Climate is driven by contrasts, and the flow of heat between water and wind in winter has weakened by around 20% since 1979. The Arctic is the fastest-warming region of the planet, and changes in the polar climate can have dramatic consequences for the temperate zones.

Prof Moore and his colleagues looked at wintertime data from the Iceland and Greenland Seas between 1958 and 2014, then used computer simulations to model potential changes to the Conveyor − more formally known to oceanographers and climate scientists as the Atlantic Meridional Ocean Circulation.

Cold and salty

The warm current loses its heat to the atmosphere as it moves north, and water that is both cold and salty is denser and more likely to descend.

The most effective place for such a process to happen is at the edge of the sea ice. If the sea ice retreats, then so does the region of maximum heat exchange. For the past 10,000 years or so, this heat exchange has happened at the ideal spot for surface waters to sink. Any change might not be for the better.

The Gulf Stream is the agency that makes Britain, for example, about 5°C warmer than Labrador in Canada, on the same latitude. A British government chief scientific adviser once calculated that the Gulf Stream delivered the warmth of 27,000 power stations. So if it weakens, Europe could start to feel the chill.

“The heat exchange is weaker – it’s like turning down the stove 20%,” Prof Moore says. “We believe the weakening will continue and eventually cause changes in the Atlantic Meridional Overturning Circulation and the Gulf Stream, which can impact the climate of Europe.” – Climate News Network

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Greenhouse gas-guzzlers spurn extra carbon dioxide

Greenhouse gas-guzzlers spurn extra carbon dioxide

Minutely small marine plants called diatoms mitigate climate change by consuming carbon dioxide and producing oxygen. But they may reject the rising levels of the greenhouse gas.

LONDON, 1 July, 2015 – Diatoms – those tiny ocean-dwelling photosynthesisers that produce a fifth of the planet’s oxygen each year – may not gulp down more carbon dioxide more enthusiastically as greenhouse gas levels in the atmosphere continue to rise.

Instead, they may switch off and use the gas more efficiently. If so, the consequences for the rest of the planet could be uncomfortable.

Climate scientists who try to model the machinery of the atmosphere have always banked on a “fertilisation effect” from at least some of the extra CO2 pumped into the atmosphere by the human burning of fossil fuels and the clearance of the forests. They may no longer be able to do so.

The discovery – reported in Nature Climate Change – is based on laboratory experiments with one single-celled phytoplankton species called Thalassiosira pseudonana and meticulous study of its genetic mechanisms.

Rising concentrations

It may not be a sure guide to what actually happens in the crowded, complex world of climate change later this century. But all phytoplankton are survivors of the same evolutionary history, and many of them are known to be equipped with carbon-concentrating mechanisms to make the most of the available carbon dioxide in the atmosphere. So what happens to one could be true for all.

Gwenn Hennon, an oceanographer at the University of Washington in Seattle, US, and colleagues decided to work out what happened to their laboratory diatoms in atmospheres in which carbon dioxide levels continued to rise to 800 parts per million later this century.

Right now, the concentration is almost 400 parts per million, but for most of human history until the invention of the internal combustion engine, and the exploitation of fossil fuels, it has been around 280 parts per million. A third of the emissions from factory chimneys and motor exhausts is absorbed by living things in the oceans, starting with diatoms and other phytoplankton.

The Seattle team found that while many photosynthesisers do grow faster with more CO2, the oceanic diatoms did not: they responded vigorously at first, but as long as there was a normal supply of other nutrients, over 15 generations, they slowed down.

Slow response

“There are certain genes that respond right away to a change in CO2, but the change in the metabolism doesn’t actually happen until you give the diatoms some time to acclimate,” said Hennon, a doctoral student. “Instead of using that energy from the CO2 to grow faster, they just stopped harvesting as much energy from light through photosynthesis and carried out less respiration.”

Studies like this are an illustration of the intricacy and complexity of climate science. How the living world responds to greater human emissions of carbon dioxide from fossil fuels is key to all models of future climates, but researchers in general have expected the plant world to respond by consuming more, and slowing the rate of change overall.

There is some evidence that this is happening. Half of all the anthropogenic or human-made CO2 has been gulped down in the form of more lusty growth by vegetation, but this “negative feedback” effect has been countered by other factors: more greenery in the Arctic, for instance, could accelerate global warming, and anyway, as plants grow more vigorously, so do plant predators.

And increasingly, climate scientists have begun to realise that although the responses of the forests and arid lands  are vital factors, the big players could be the creatures hardly anyone ever sees: the fungi and tiny fauna in the soil  beneath the trees, and of course the phytoplankton in the oceans.

Oxygen creators

The Seattle calculation is that the evolutionary history of the diatoms explains the carbon-concentrating mechanisms in their genetic inheritance. Microbes are life’s foundation, and single-celled creatures evolved over three billion years when CO2 levels in the atmosphere were at colossal concentrations.

The diatoms and their ancestors were the creatures that created the oxygen atmosphere in which all other complex living things evolved. An enzyme evolved to help the first microbes cope with high levels of CO2, and has survived for billions of years.

“There hasn’t been another enzyme to replace it since, so plants and algae that photosynthesise have an enzyme that functions better at a higher CO2 level than we currently have,” Hennon said.

“When the CO2 remains high for a long time, however, the diatoms make a more radical metabolic shift. They decrease photosynthesis and respiration to balance the cell’s energy budget. In other words, the diatoms use less energy to grow at the same rate.” – Climate News Network

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Alaska’s glaciers melt faster as climate change speeds up

Alaska's glaciers melt faster as climate change speeds up

Climate change rather than natural causes is the main cause of Alaska’s glacier loss, which is set to speed up, US scientists say.

LONDON, 30 June, 2015 – The glaciers of Alaska are melting and retreating: the chief cause is climate change and the loss of ice is unlikely to slow, according to a new study by US scientists.

They calculate that the frozen rivers of the Pacific coast of America’s northernmost state are melting fast enough to cover the whole of Alaska with 30 cms of water every seven years.

Since Alaska is enormous – it covers 1.5 million square kilometres and is the size of California, Texas and Montana put together – this adds up to a significant contribution to sea level rise.

“The Alaska region has long been considered a primary player in the global sea level budget, but the exact details of the drivers and mechanisms of Alaska glacier change have been stubbornly elusive,” said Chris Larsen, a geophysicist at the University of Alaska Fairbanks, and lead author of a study in Geophysical Research Letters.

Taxonomy of change

Scientists from the University of Alaska and the US Geological Survey analysed studies of 116 glaciers in the Alaska region over a 19-year-period to estimate the rate at which ice melted and icebergs calved.

They used airborne lidar remote sensing technology and other techniques, historical data and a global glacier inventory to establish a kind of taxonomy of glacier change.

The Columbia Glacier in Prince William Sound had retreated more than 19 kilometres because of iceberg calving and had thinned by 450 meters in height since 1980. But, unexpectedly, tidewater glaciers – those that end in the ocean – seemed to make comparatively little contribution to sea level rise.

“Instead we show that glaciers ending on land are losing mass exceptionally fast, overshadowing mass changes due to iceberg calving, and making climate-related melting the primary control on mountain glacier mass loss,” Dr Larsen said.

Big contributor

He and his colleagues calculated that Alaska is losing ice at the rate of 75 billion metric tons a year. Such research is just one more piece of careful cross-checking in the great mosaic of climate research: another systematic confirmation that overall, glaciers are not losing ice in response to some natural cycle of change of the kind that occasionally confuses the picture for climate science.

The agency at work is largely global warming as a response to the steady rise in atmospheric carbon dioxide as a consequence of the burning of fossil fuels.

Mountain glaciers represent only 1% of the total ice on the planet: the other 99% is found in Greenland – which is melting fast – and in the great frozen continent of Antarctica, where ice mass is being lost at an increasing rate.

But although the mountains of the temperate and tropic zones bear only a tiny percentage of the planet’s ice, their melting accounts for almost a third of the sea level rise currently measured by oceanographers, and this melting will go on to become a big contributor to the sea levels later this century.

“Alaska will continue to be a major driver of sea level change in the upcoming decades”

Across the border in Canada, glaciologists have warned that the country will lose a huge volume of flowing ice, and while one team has confirmed that air pollution rather than global warming long ago began to strip Europe’s Alps of their glaciers, in general mountain peaks are warming faster than the valleys and plains below them.

Geophysicists and glaciologists have established that the glaciers of the tropical Andes are at risk, and in the Himalayan mountain chain glaciers seem to be in inexorable retreat with consequences that could be devastating for the many millions in the Indian subcontinent and in China who rely on seasonal meltwater for agriculture.

Glaciers are by definition hard to study – they are high, cold and in dangerous terrain – and such research is inevitably incomplete: the scientists for instance excluded glaciers smaller than three square kilometres. But together these small patches of flowing ice account for 16% of Alaska’s glaciated landscape. The 116 glaciers in the survey together added up to only 41% of the state’s glaciated area.

But the pattern established by the Fairbanks team suggests that melting will accelerate with climate change. “Rates of loss from Alaska are unlikely to decline, since surface melt is the predominant driver, and summer temperatures are expected to increase,” said Dr Larsen.

“There is a lot of momentum in the system, and Alaska will continue to be a major driver of sea level change in the upcoming decades.” – Climate News Network

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