Tag Archives: Ice melt

Ice melt dilutes Arctic sea’s CO2 clean-up role

Cutting edge: climate scientist Dorte Haubjerg Søgaard studies the sea ice in Greenland Image: Søren Rysgaard,  Arctic Research Centre, Aarhus University
Cutting edge: climate scientist Dorte Haubjerg Søgaard studies the sea ice in Greenland
Image: Søren Rysgaard, Arctic Research Centre, Aarhus University

By Tim Radford

New scientific research confirms that global warming is melting increasingly larger areas of Arctic sea ice − and reducing its vital function of removing CO2 from the atmosphere.

LONDON, 26 September, 2014 − The Arctic ice cap has just passed its summer minimum – and it’s the sixth lowest measure of sea ice recorded since 1978, according to scientists at the US space agency NASA.

For three decades, the shrinking Arctic ice – and the growing area of clear blue water exposed each summer – has been a cause of increasing alarm to climate scientists.

Polar seasonal changes are measured annually by NASA, but reliable satellite data goes back only to 1978, For much of the 20th century, the Arctic was part of the Cold War zone, so only Soviet naval icebreakers and US nuclear submarines took consistent measurements − and neither side published the data.

But studies of 17th and 18th century whaling ships’ logbooks and other records make it clear that the ice once stretched much further south each summer than it does today.

Steady decline

In the last 30 years, the thickness and the area of the ice have both been in steady decline, with predictions that in a few decades the Arctic Ocean could be virtually ice free by September, opening up new sea routes between Asia and Europe.

This year could have been worse, although the area of ice fell to little more than 5 million square kilometres − significantly below the 1981-2010 average of 6.22 million sq km.

“The summer started off relatively cool, and lacked the big storms or persistent winds that can break up ice and increase melting,” said Walter Meier, a research scientists at NASA’s Goddard Space Flight Centre. “Even with a relatively cool year, the ice is so much thinner than it used to be. It is more susceptible to melting.”

Warming in the Arctic is likely to affect climate patterns in the temperate zones, and the state of the polar ice has become of such concern that researchers are using ground-based and sea-based monitors to explore the physics of the phenomenon.

But there is another reason for the attention: as polar ice diminishes, so does the planet’s albedo − its ability to reflect sunlight back into space.

So, as the ice shrinks, the seas warm, making it more difficult for new ice to form. And greater exposure to sunlight increases the probability that permafrost will thaw, releasing even more greenhouse gases locked in the frozen soils.

Now researchers have found another and unexpected example of climate feedback that could affect the cycle of warming. Climate scientist Dorte Haubjerg Søgaard, of the Greenland Institute of Natural Resources and the University of Southern Denmark, and research colleagues have discovered that sea ice itself is an agency that removes carbon dioxide from the atmosphere.

That the oceans absorb the stuff, and tuck it away as calcium carbonate or other marine minerals, is old news.

“But we also thought that this did not apply to ocean areas covered by ice, because the ice was considered impenetrable,” Søgaard said. “However, new research shows that sea ice in the Arctic draws large amounts of CO2 from the atmosphere into the ocean.”

The research is published in four journals, Polar Biology, The Cryosphere, The Journal of Geophysical Research: Atmospheres and Marine Ecology Progress Series.

Two-stage pattern

The Danish research team observed a complex, two-stage pattern of gas exchange as ice floes formed off southern Greenland. They measured the role of atmospheric carbon dioxide in the formation and release of calcium carbonate crystals form in the sea ice, and kept a tally during a 71-day cycle of the carbon dioxide budget.

In the course of this complicated bit of natural cryo-chemistry, they found that some CO2 was carried deep into the ocean with dense, heavy brines, as the ice froze and some was captured by algae in the thawing ice.

They also identified a third factor: the “frost flowers” that formed on the new ice had an unexpectedly high concentration of calcium carbonate.

The profit-and-loss accounting meant that every square metre of ice effectively removed 56 milligrams of carbon from the atmosphere during the 71-day cycle. Over an area of 5 million sq km, this would represent a significant uptake.

But the real importance of the discovery is that scientists have identified yet another way in which the ice – while it is there – helps keep the Arctic cold, and yet another way in which carbon dioxide is absorbed by the oceans.

“If our results are representative, then the sea ice plays a greater role than expected, and we should take account of this in future global CO2 budgets,” Søgaard said. – Climate News Network

Fresh water causes Antarctic seas to rise faster

Meltwater from Antarctic glaciers is causing sea levels to rise Image Jason Auch via Wikimedia Commons
Glacial meltwater is a key factor in the sea level rise in Antarctica
Image Jason Auch via Wikimedia Commons

By Tim Radford

Researchers in the UK have established that billions of tonnes of fresh water from melting glaciers are causing Antarctic sea levels to rise much higher and faster than the global average.

LONDON, 7 September, 2014 − Sea levels around Antarctica are rising faster than anywhere else in the southern ocean. The global average rise in ocean heights in the last 19 years has been 6cms, but the rise in seas around Antarctica is 2cms higher.

This seemingly counter-intuitive finding is certainly a consequence of melting ice in the Southern Ocean, but the connection with global warming is, for the moment, tenuous. The agency that is behind the rising sea levels is simply an excess of fresh water from melting glaciers − about 350 billion tonnes of it.

“Fresh water is less dense than salt water, and so in regions where an excess of fresh water has accumulated we expect a localised rise in sea level,” says Craig Rye, an oceanography researcher at of the University of Southampton in the UK, who, with colleagues, has published the findings in Nature Geoscience.

Partly because the oceans are warmer and are therefore expanding, and partly because the terrestrial glaciers are in retreat, global sea levels on average have crept up by about 3 millimetres a year. Waters off the Antarctic shelf seem to be gaining an additional 2mm a year.

Less saline

The scientists studied satellite scans of a region of more than a million square kilometres to make their finding, and used ship-based studies of the Antarctic sea water to confirm that is has become less saline.

The melting of the Antarctic ice sheet – German scientists recently calculated that around 125 cubic kilometres of meltwater is running off the continent each year − and the thinning of the floating ice shelves is enough to explain the unexpected rise.

Computer model studies confirm the interpretation that the rise is happening because the southern seas have just got fresher. The consequences in the longer term are uncertain.

Rye, a postgraduate researcher, said: “The interaction between air, sea and ice in these seas is central to the stability of the Antarctic ice sheet and global sea levels, as well as other environmental processes, such as the generation of Antarctic bottom water, which cools and ventilates much of the global ocean abyss.” – Climate News Network

Sun sheds light on Arctic carbon puzzle

Sun reflects through ice crystals on the Arctic Ocean Image: Mike Dunn/NOAA Climate Program via Wikimedia Commons
The sun reflects from ice crystals on the Arctic Ocean
Image: Mike Dunn/NOAA Climate Program via Wikimedia Commons

By Tim Radford

Scientists discover that, as the Arctic continues to warm, sunlight will be the major cause of CO2 escaping into the atmosphere from vegetation preserved in frozen soil.

LONDON, 4 September, 2014 − One of the puzzles of the permafrost has been solved by scientists in the US. The key to the carbon cycle in the Arctic north is not the microbe population − it’s the sunlight.

Such a discovery is not, strictly speaking, concerned with climate change, but with the more detailed question of how the world works – specifically, how the carbon that was once plant material gets back into the atmosphere.

However, since the Arctic permafrost is home to half of all the organic carbon trapped in the soils of the entire Earth, the finding is ominous.

The Arctic is one of the fastest warming regions on the planet. As it warms, more and more carbon dioxide is likely to escape from the half-decayed tundra vegetation preserved in the frozen soil and will find its way into the atmosphere, to accelerate still further warming.

For the moment, the study is another piece fitted into place in a wider understanding of the carbon cycle.

Organic carbon

Rose Cory, of the University of Michigan, US, reports with colleagues, in the journal Science, that they measured the speeds at which bacteria and sunlight converted dissolved organic carbon in the lakes and rivers of Alaska.

In the standard domestic garden compost heap, the hard work of turning such things as decaying cabbage stalks, potato peelings and grass cuttings back into carbon dioxide and methane is performed by microbes.

But visible and ultraviolet light beams also pack a punch. They too can oxidise organic carbon and turn it back into gas molecules.

In 2013, Dr Cory and colleagues established that levels of dissolved organic carbon in a region that was once permanently frozen were rising, giving microbes and other conversion processes a chance to get to work.

The researchers took samples of flowing and still water from 135 lakes and 73 rivers on Alaska’s North Slope over a three-year period, and then incubated them under differing conditions of light.

More efficient

They found that sunlight was 19 times more efficient than microbes at processing the carbon, and could account for between 70% and 95% of all the carbon released from Alaskan water.

“We’re likely to see more carbon dioxide released from thawing permafrost than people had previously believed,” Dr Cory said. “We are able to say that because we now know that sunlight plays a key role and that carbon released from thawing permafrost is readily converted to carbon dioxide once it is exposed to sunlight.”

Microbes are less efficient in low temperatures. And the sunlight works more efficiently because it can directly degrade the dissolved organic carbon, and can also convert it into a condition that makes it more accessible for the microbes.

“This is because most of the fresh water in the Arctic is shallow, meaning sunlight can reach the bottom of any river – and most lakes – so that no dissolved organic carbon is kept in the dark,” said Byron Crump, a microbial ecologist at Oregon State University, and a co-author of the report. “Also there is little shading of rivers and lakes in the Arctic because there are no trees.” – Climate News Network

Plan to make renewables cheaper than coal within 10 years

 

Solar power in India: Could renewables answer the world's energy needs? Image: Bkwcreator via Wikimedia Commons

Solar power in India: Could renewables answer the world’s energy needs?
Image: Bkwcreator via Wikimedia Commons

By Alex Kirby

Three weeks before the UN Secretary-General’s extraordinary meeting of world leaders in New York to tackle climate change, a leading British scientist unveils plans for a global low-carbon fund on a par with the Apollo Moon programme.

LONDON, 2 September 2014 – There are prospects of significant progress in the response of world governments to climate change, according to a former UK Government chief scientist, Sir David King.

“There are signs that a leadership role is beginning to emerge”, he told a conference in London held by the Green Economy Coalition.

Sir David also announced that he and a colleague are working with governments to raise funds to help all countries, including developing countries,  to switch to renewable energy. Their scheme hopes to raise nearly as much as the cost of the Apollo programme, NASA’s moon-landing project.

“President Obama is getting ready to commit the US to action, and last week the Chinese Prime Minister, Li Kichiang, announced that his country’s emissions had fallen by 5% in a year”, he said.

“The US and China are positioning themselves for an agreement. And that’s not all. The first speech by the new leader of India, Narendra Modi, spoke of his determination ‘to solarise’ the economy.

Ice in retreat

“Brazil’s emissions, including from deforestation, have fallen from 16.5 tonnes per person to 6.5 tonnes since 2005. Across the Andes in Peru, where the UN climate convention negotiations will take place in December, they know well enough about climate change.

“From Lima they can see the ice retreating up the mountains. At its lowest point it is now 1,000 metres above where it reached to 30 years ago..”

Sir David praised the UK’s commitment to cut greenhouse emissions by 80% by 2050, compared with their 1990 levels. He said the target – matched by Mexico – was likely to be met. The biggest climate challenge confronting the UK, he said, was from rising sea levels.

Some critics say, despite this, that the UK Government is dragging its feet, especially on supporting renewable energy. With a colleague, the economist Professor Lord Richard Layard, Sir David is working on a scheme to raise money to address this.

“It’s called the Global Apollo Programme”, he explained. “We are urging all governments to form a Commission to spend 0.02% of their GDP, which should raise US$10-20 bn p a over 10 years,  to fund RD&D for low-carbon technology.

“We are encouraging governments to launch the Programme at the UN during Ban Ki-moon’s Climate Summit on 23 September. The objective is that by 2020 renewable power should be cheaper than coal in all sunny parts of the world, and by 2025 in all parts of the world.”

Sir David, who for seven years was the UK Government’s chief scientist, is now its Foreign Secretary’s special representative for climate change. Asked if he were hopeful about progress to tackle climate change, he replied: “I’m in this job because I’m an optimist.”

Global reach

His hopes were echoed by another speaker, Hunter Lovins, president of the Colorado-based Natural Capitalism Solutions.  She told the Climate News Network: “We can do it. But it’s going to be tough. So will we do it?

“I don’t agree with the exponents of the idea of near-term human extinction (NTHE), who say we face total collapse by around 2030 or 2035.

‘”What we need is to find incentives for business, to get big countries behind solar+, the idea David King is working on – combining renewables and efficiency, with back-up where it’s needed.”

Professor Lovins told the conference: “Business-as-usual is going to get really ugly. What’s the narrative we can produce to compete with neo-liberalism?” – Climate News Network

Satellite mapping shows ice caps’ faster melt rate

Surface water flows into a 'moulin' shaft in Greenland's ice cap Image: NASA via Wikimedia Commons
Surface water flows down into a ‘moulin’ shaft in the Greenland ice cap
Image: NASA via Wikimedia Commons

By Tim Radford

Scientists have been able to measure more accurately than ever the thickness of the world’s major ice caps  revealing that melting is causing the loss of 500 cubic kms of ice annually.

LONDON, 1 September, 2014 − German researchers have established the height of the Greenland and Antarctic ice caps with greater precision than ever before. And the new maps they have produced show that the ice is melting at an unprecedented rate.

The maps, produced with a satellite-mounted instrument, have elevation accuracies to within a few metres. Since Greenland’s ice cap is more than 2,000 metres thick on average, and the Antarctic bedrock supports 61% of the planet’s fresh water, this means that scientists can make more accurate assessments of annual melting.

Dr Veit Helm and other glaciologists at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, report in the journal The Cryosphere that, between them, the two ice sheets are now losing ice at the unprecedented rate of 500 cubic kilometres a year.

Big picture

The measurements used to make the maps were taken by an instrument aboard the European Space Agency’s orbiting satellite CryoSat-2. The satellite gets closer to the poles − to 88° latitude − than any previous mission and traverses almost 16 million sq km of ice, adding an area of ice the size of Spain to the big picture of change and loss in the frozen world.

CryoSat-2’s radar altimeter transmitted 7.5 million measurements of Greenland and 61 million of Antarctica during 2012, enabling glaciologists to work with a set of consistent measurements from a single instrument.

Over a three-year period, the researchers collected 200 million measurements in Antarctica and more than 14 million in Greenland. They were able to study how the ice sheets changed by comparing the data with measurements made by NASA’s ICESat mission.

More complex

Greenland’s volume of ice is being reduced at the rate of 375 cubic km a year. In Antarctica, the picture is more complex as the West Antarctic ice sheet is losing ice rapidly, but is growing in volume in East Antarctica.

Overall, the southern continent − 98% of which is covered with ice and snow − is losing 125 cubic km a year. These are the highest rates observed since researchers started making satellite observations 20 years ago.

“Since 2009, the volume loss in Greenland has increased by a factor of about two, and the West Antarctic ice sheet by a factor of three,” said Angelika Humbert, one of the report’s authors. − Climate News Network

Pre-history proof of climate’s see-saw sensitivity

The woolly rhinoceros once roamed wild on the plains of Europe Image: Public Library of Science via Wikimedia Commons
The woolly rhinoceros once roamed wild on the plains of Europe
Image: Public Library of Science via Wikimedia Commons

By Tim Radford

Computer simulations reaching back deep into the last Ice Age have enabled scientists to put a historic perspective on how even small variations in the climate system can lead to dramatic temperature change.

LONDON, 24 August, 2014 − It doesn’t take much to change a planet’s climate – just a little shift in the Northern hemisphere glacial ice sheet and a bit more carbon dioxide in the atmosphere. After that, the response is rapid. The tropical rain belt moves north and the southern hemisphere cools a bit, in some sort of bipolar see-saw response.

Sound familiar? It does, and it doesn’t. It all happened long before the internal combustion engine, or even the new Stone Age.

Researchers from the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research, Bremerhaven, the University of Bremen, Germany, and the University of Cardiff in the UK, report in Nature journal that they have made climate simulations that agree with observations of historical climate change that date back 800,000 years.

Long before the present alarms about global warming through the emission of carbon dioxide from fossil fuels, climate researchers were puzzled by the phenomenon of the Ice Ages and the “interglacials” that punctuated those long periods when the Arctic ice extended from the North Pole to the Atlantic coast of France, and over huge tracts of North America.

Vanished species

Mysteriously, and at great speed, the temperatures would rise by up to 10°C and the vast walls of ice would retreat. Lion, hyena and rhinoceros would invade the wild plains of what is now southern England, and now-vanished species of humans would hunt big game and gather fruit and seeds in the valleys and forests of Europe and America.

Since the end 10,000 years ago of the last ice age – itself a very rapid event – was the springboard for agriculture and civilisation, and eventually an Industrial Revolution based on fossil fuels, the story of climate change plays a powerful role in human history.

So any analysis of the tiny shifts in ice cover that seemed to trigger these dramatic, bygone events can be helpful in understanding the long story of the making of the modern world.

The researchers found a tentative scenario involving weak ocean currents, and prevailing winds that shifted the sea ice and allowed the oceans and atmosphere to exchange heat, pushing warmer water into the north-east Atlantic.

These changes precipitated a dramatic warming of the northern hemisphere in just a few decades, and the retreat of the glaciers for an extended period before the ice returned to claim much of the landmass again. But, overall, such changes tended to occur when sea levels reached a certain height.

“The rapid climate changes known in the scientific world as Dansgaard-Oeschger events were limited to a period of time from 110,000 to 23,000 years before the present,” said Xu Zhang, the report’s lead author.

“The abrupt climate changes did not take place at the extreme low sea levels, corresponding to the time of maximum glaciations 20,000 years ago, or at high sea levels such as those prevailing today. They occurred during periods of intermediate ice volume and intermediate sea levels”

Climate swings

Co-author Gerrit Lohmann, who leads the Wegener Institute’s palaeoclimate dynamics group, said: “Using the simulations performed with our climate model, we were able to demonstrate that the climate system can respond to small changes with abrupt climate swings.

“At medium sea levels, powerful forces − such as the dramatic acceleration of polar ice cap melting − are not necessary to result in abrupt climate shifts and associated drastic temperature changes.”

How much this tells anybody about modern climate change is open to debate. Right now, according to this line of evidence, the planet’s climate could be in one of its more stable phases of the Earth’s history.

But while the conditions for the kind of rapid change recorded in pre-history do not exist today, Prof Lohmann warns that “sudden climate changes cannot be excluded in the future”. – Climate News Network

Antarctic warming could accelerate sea level rise

Warming would cause more Antarctic ice to break off and melt Image: PIK/R.Winkelmann
Rising concern: warming would cause more Antarctic ice to break off and melt
Image: PIK (R.Winkelmann)

By Alex Kirby

An international study says warming is affecting not only the Arctic but also the Antarctic – and that could significantly raise global sea levels much faster than previously predicted.

LONDON, 20 August, 2014 − The effect of climate change on the world’s two polar regions looks like a stark contrast: the Arctic is warming faster than most of the rest of the Earth, while most of Antarctica appears to remain reassuringly locked in a frigid embrace.

But an international scientific team says the reality is quite different. The Antarctic is warming too, it says, and the southern ice could become the main cause of global sea level rise during this century − far sooner than previously thought.

The study, led by the Potsdam Institute for Climate Impact Research (PIK) in Germany, found that ice discharge from Antarctica could contribute up to 37 centimetres to global sea levels by 2100.

Computer simulations

The study is the first comprehensive estimate of the full range of Antarctica’s potential contribution to global sea level rise based on physical computer simulations. It combines state-of-the-art climate models and observational data with various ice models.

The results of the study − published in the European Geosciences Union’s journal, Earth System Dynamics − reproduce Antarctica’s recent contribution to sea level rise, as observed by satellites over the last two decades.

“If greenhouse gases continue to rise as before, ice discharge from Antarctica could raise the global ocean by an additional 1 to 37 centimetres this century,” says the study’s lead author, Anders Levermann, PIK professor of dynamics of the climate system.

“Science needs to be clear about the uncertainty,
so that decision-makers can consider the potential implications . . .”

“This is a big range – which is exactly why we call it a risk. Science needs to be clear about the uncertainty, so that decision-makers on the coast and in coastal mega-cities like Shanghai or New York can consider the potential implications in their planning processes.”

The scientists analysed how rising global average temperatures resulted in a warming of the ocean around Antarctica, influencing the melting of the Antarctic ice shelves.

Antarctica currently contributes less than 10% to global sea level rise and is a relatively minor player in comparison with the impact of the oceans’ increasing thermal expansion and the melting of glaciers.

But the major contributors to future long-term sea level rise are expected to be the huge volumes of ice locked up in Greenland and the Antarctic ice sheets. The marine ice sheets in West Antarctica alone could raise sea level by several metres over a period of several centuries.

The study’s computed projections for this century’s sea level contribution are significantly higher than the upper end of the latest projections by the Intergovernmental Panel on Climate Change. These suggest a probable rise by 2100 of around 60cm, although other estimates put the figure almost twice as high.

Even if governments can agree and enforce strict climate policies limiting global warming below the international target level of a maximum 2°C increase, Antarctica’s contribution to global sea level rise is expected still to range from 0 to 23cm this century.

Critical input

A co-author of the study, Robert Bindschadler, from the NASA Goddard Space Flight Center, said: “This paper is a critical input to projections of possible future contributions of diminishing ice sheets to sea level by a rigorous consideration of uncertainty of not only the results of ice sheet models themselves but also the climate and ocean forcing driving the ice sheet models.

“Billions of dollars, euros, yuan, etc, are at stake, and wise and cost-effective decision-makers require this type of useful information from the scientific experts.”

But major modeling challenges still remain. Datasets of Antarctic bedrock topography, for instance, are still inadequate, and some physical processes of interaction between ice and ocean cannot yet be sufficiently simulated.

The team also emphasises that the study’s results are limited to this century, while all 19 of the comprehensive climate models used show that the impacts of atmospheric warming on Antarctic ice shelf cavities will hit with a time delay of several decades.

However, Levermann says: “Earlier research indicated that Antarctica would become important in the long term. But pulling together all the evidence, it seems that Antarctica could become the dominant cause of sea level rise much sooner.” − Climate News Network

Human factor speeds up glacial melting

Glaciers such as Artesonraju in the Peruvian Andes are melting at record rates Image: Edubucher via Wikimedia Commons
Glaciers such as Artesonraju in the Peruvian Andes are melting at record rates
Image: Edubucher via Wikimedia Commons

By Tim Radford

Scientists simulating changes in mountain glaciers over the last century and a half have established that rates of melting have increased greatly in recent years – and that humans are the main culprits.

LONDON, 17 August, 2014 – The impact of human activity is melting the glaciers in the world’s mountain regions, and is doing so at an accelerating rate.

Ben Marzeion, a climate scientist at the University of Innsbruck’s Institute of Meteorology and Geophysics, Austria, reports with colleagues in the journal Science that they used computer models to simulate changes in the world’s slow-flowing frozen rivers between the years 1851 and 2010. The study embraced all the world’s glaciers except those in Antarctica.

This kind of manipulation allows researchers to play with the possibilities and see, for instance, how much changes in the sunlight patterns, high-level atmospheric changes because of volcanic eruptions, or simply slow cycles of natural weather patterns might be at work in the ice record.

The answers were unequivocal about human impact on the environment. “In our data, we find unambiguous evidence of anthropogenic contribution to glacier mass loss,” Dr Marzeion says.

In retreat

That glaciers are losing mass − retreating uphill, and melting at a faster rate − is not in doubt. A year ago, one group established without any doubt that worldwide, and overall, glaciers are in retreat.

In South America, some glaciers in the Andes are melting at a record rate, while satellite measurements show that the Jakobshavn glacier in Greenland doubled its flow speed between 1997 and 2003, and has doubled it again since 2003.

In Europe, 19th-century landscape painters, pioneer photographers and mountain guides unwittingly made permanent, easily-accessible records of Alpine glacier geography. These now set a baseline for all modern measurements, and researchers have established that the melt is getting faster.

The challenge is to determine how much of this is due to natural causes, and how much to changes in human land use, and the emission of greenhouse gases.

Higher proportion

The Innsbruck team has calculated that around a quarter of all the melting between 1851 and 2010 can be put down to human activity. But that is the overall picture: the proportion gets higher with time. Between 1991 and 2010, the fraction of melting due to human activity rose to two-thirds.

“In the 19th century and first half of the 20th century we observed that glacier mass loss attributable to human activity is barely noticeable, but since then has steadily increased,” Dr Marzeion says. – Climate News Network

Arctic warming blamed for dangerous heat waves

Feeling the heat: a wildfire rages in New Mexico during the 2012 heat wave in the US Image: Kari Greer/USFS Gila National Forest via Wikimedia Commons
Feeling the heat: a wildfire rages in New Mexico during the 2012 heat wave
Image: Kari Greer/USFS Gila National Forest via Wikimedia Commons

By Paul Brown

Giant waves in the jet stream that often governs our weather are changing as the Arctic warms more rapidly − leading to long periods of soaring temperatures that pose major threats to economies and human health.

LONDON, 16 August, 2014 − Few people have heard of Rossby waves and even less understand them, but if you are sweltering in an uncomfortably long heat wave, then they could be to blame.

New discoveries about what is going on in the atmosphere are helping to explain why heat waves are lasting longer and causing serious damage to humans and the natural world. These events have doubled in frequency this century, and the cause is believed to be the warming of the Arctic.

The weather at the Earth’s surface is often governed by high winds in the atmosphere, known as jet streams. In 1939, Carl-Gustaf Arvid Rossby, a Swedish-born America meteorologist, discovered waves in the northern jet stream that were associated with the high and low pressure systems at ground level that form daily weather patterns.

Jet streams travel at up to 200 kilometres an hour, frequently wandering north and south − with cold Arctic air to the north, and warmer air to the south.

Rapid variations

When the jet stream develops Rossby waves and they swing north, they suck warm air from the tropics to Europe, Russia or the US. And when they swing south, they do the same thing with cold air from the Arctic. The waves constantly change shape, and so cause rapid variations in the weather.

But new research, published in the Proceedings of the National Academy of Sciences of the USA, has discovered a tendency for these waves in the jet stream to get much bigger and to get stuck – particularly in July and August. This causes heat waves that last not just for a few days but for weeks.

This is a serious health and economic threat. A recent example is the record heat wave in the US that hit corn farmers and worsened wildfires in 2012.

Close study of records shows that, from 1980 to 2003, there were two such heat wave events every four years on average. From 2004-07, there were three events, and between 2008-11 there were five.

Ice shrinking

Theory and the new data both suggest a link to processes in the Arctic. Since 2000, the Arctic has been warming about twice as fast as the rest of the globe. One reason for this is that ice is rapidly shrinking in the White Sea − a southern inlet of the Barents Sea on the north-west coast of Russia – and so less sunlight gets reflected back into space, while the open ocean is dark and hence warms more.

“This melting of ice and snow is actually due to our lifestyle of churning out unprecedented amounts of greenhouse gases from fossil fuels,” says Hans Joachim Schellnhuber, co-author of the study and founding director of the Potsdam Institute for Climate Impact Research.

As the Arctic warms more rapidly, the temperature difference to other regions decreases. Yet temperature differences are a major driver of the atmospheric circulation patterns that in turn rule our weather.

“The planetary waves topic illustrates how delicately interlinked components in the Earth system are,” Schellnhuber concludes: “And it shows how disproportionately the system might react to our perturbations.” – Climate News Network

Canada puts oil exploitation before forests

A plane drops a water bomb on a forest fire in Ontario, Canada Image: {Per via Wikimedia Commons
A plane drops a water bomb on a forest fire in Ontario, Canada
Image: Per via Wikimedia Commons

By Paul Brown

Having repudiated the Kyoto Protocol on reducing fossil fuel use, Canada is still exploiting tar sands for oil − despite accepting that climate change is destroying its forests.

LONDON, 9 August, 2014 − Detailed evidence that Canada’s vast natural areas are undergoing major changes because of climate change is produced in a new report by Natural Resources Canada.

The government body describes problems with disappearing glaciers, sea level rise, melting permafrost and changing snow and rainfall patterns. One of the country’s most important natural resources, the forests that cover more than 50% of its land area, is under pressure because of pests, fire and drought.

There may, the reports says, be some pluses for Canada in climate change − at least in the short term − because some staple cereal crops will also be able to be grown further north because of warmer weather, assuming that the soil is suitable.

The report, Canada in a Changing Climate, concentrates on impacts and adaptation, but does not mention the causes, or the fact that Canada is now an international pariah in the environmental community because of its exploitation of tar sands for oil.

The country does attempt, for economic reasons, to be more energy efficient, but has repudiated the Kyoto Protocol and international efforts to curb fossil fuel use. The country had accepted a target of cutting emissions on 1990 levels by 5% by 2012, but the government backed out in 2011.

Highest emissions

Average greenhouse gas emissions for oil sands extraction and upgrading are estimated to be 3.2 to 4.5 times as intensive per barrel as for conventional crude oil produced in Canada or the US. If Alberta, where the oil is produced from tar sands, was a country and not a merely a province of Canada, it would have the highest per capita greenhouse gas emissions in the world.

The only mention the report makes of tar sands extraction is the problem caused by its large use of water, and it makes the point that the industry is recycling as much as possible.

A tar sands mine at Mildred Lake, Alberta Image: TastCakes/Janitzky via Wikimedia Commons
A tar sands mine at Mildred Lake, Alberta
Image: TastyCakes/Janitzky via Wikimedia Commons

Mitigation is not on the agenda, as the country’s politicians are intent on exploiting as much of the country’s oil and gas as possible.

A study of forests says that 224,410 people are directly employed in the sector, although it makes up only 1.1% of GDP. About 5% of the forests are damaged annually because of outbreaks of pests and fire. Temperatures in the forest areas have risen far more sharply than on the rest of the planet, with far-reaching consequences for the future, the report says.

In 2009, over three million hectares of forest were destroyed by fire in a single year. The number of fires is expected to increase, with the area being burned being three to five times as much in Western Canada by the end of the century. Large fires are raging again this year, but the quantity of the damage has yet to be assessed.

Severe outbreaks

One of the pests moving north and devastating mature trees is the mountain pine beetle. The beetle is endemic, but is killed by winter temperatures below minus 35˚C, thus limiting its numbers from year to year. However, winter temperatures in many areas now fail to drop below this level, leading to larger and more severe outbreaks of the pest.

A report in 2012 concluded that 18.1 million hectares of forest dominated by mature Lodgepole pine (Pinus contorta) had been affected. Scientists conclude that productivity of the forests will decline rapidly in British Columbia, and thousands of jobs will be lost. Meanwhile, the beetle is continuing to move north and east.

One advantage of the increased temperatures in Canada is that trees can grow further north and higher up mountains than previously, and there is a longer growing season.

Trees that live 100 years cannot migrate fast enough to take advantage, so local governments are going in for assisted migration.

This involves planting the seeds of suitable species 100 to 200 metres above the existing tree line on mountains, and in some cases two degrees of latitude northwards (about 100 miles) of the existing forests into what is currently tundra or scrub. – Climate News Network