The forecast is warmer and weirder 

 

Justin Gillis and Joanna M. Foster

April 1, 2012

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Crazy climate ... does science have a clue what is going on? Photo: Nick Moir

Melting Arctic sea ice is the focus of research into increasingly erratic weather patterns.
Some people call what has been happening across the northern hemisphere in the past few years ''weather weirding'' and March turned out to be a fine example. As a surreal heatwave was peaking across much of the US last week, pools and beaches drew crowds, some farmers planted their crops six weeks early and trees burst into bloom.
''The trees said, 'Aha! Let's get going!''' says Peter Purinton, a maple syrup producer in Vermont. ''Spring is here!''
Now a cold snap in the northern states has brought some of the lowest temperatures of the season, with damage to tree crops alone likely to be in the millions of dollars.

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Lurching from one weather extreme to another seems to have become routine. Parts of the US may be shivering but Scotland is setting heat records. Across Europe, hundreds of people died during a severe cold wave in the first half of February but a week later revellers in Paris were strolling on the Champs-Elysees in shirt sleeves.
Does science have a clue what is going on? The short answer appears to be: not quite.
The longer answer is that researchers are developing theories that, should they withstand scrutiny, may tie at least some of the erratic weather to global warming. Suspicion is focused on the drastic decline of Arctic sea ice, believed to be a direct consequence of the human release of greenhouse gases.
''The question really is not whether the loss of the sea ice can be affecting the atmospheric circulation on a large scale,'' says Jennifer Francis, a Rutgers University climate researcher. ''The question is, how can it not be and what are the mechanisms?''
As the planet warms, many scientists say, more energy and water vapour enter the atmosphere and are driving weather systems.
''The reason you have a clothes dryer that heats the air is that warm air can evaporate water more easily,'' says Thomas C. Peterson, a researcher with the National Oceanic and Atmospheric Administration. A report released last week by the Intergovernmental Panel on Climate Change, the UN body that issues periodic updates on climate science, confirmed a strong body of evidence links global warming to an increase in heatwaves, heavy rainfall and other precipitation and more frequent coastal flooding.
''A changing climate leads to changes in the frequency, intensity, spatial extent, duration and timing of extreme weather and climate events, and can result in unprecedented extreme weather and climate events,'' it says.
US government scientists recently reported that February was the 324th consecutive month in which global temperatures exceeded their long-term average for a given month; the last month with below-average temperatures was February 1985. In the US, many more record highs are being set at weather stations than record lows, a bellwether indicator of warming.
So far this year, the US has set 17 daily highs for every daily low, according to an analysis performed by the New Jersey research group Climate Central. Last year the country set nearly three highs for every low. But, while the link between heatwaves and global warming may be clear, the evidence is much thinner regarding types of weather extremes.
Scientists studying tornadoes are plagued by poor statistics that could be hiding significant trends but so far they are not seeing a long-term rise in the most damaging twisters.
And researchers studying specific events such as the Russian heatwave of 2010 have often come to conflicting conclusions about whether to blame climate change.
Scientists who dispute the importance of global warming have long ridiculed attempts to link greenhouse gases to weather extremes. John Christy, a climate scientist at the University of Alabama in Huntsville, told the US Congress last year ''weather is very dynamic, especially at local scales, so that extreme events of one type or another will occur somewhere on the planet every year''.
Yet mainstream scientists are determined to figure out which climate extremes are being influenced by human activity and their attention is increasingly drawn to the Arctic sea ice.
Because greenhouse gases are causing the Arctic to warm more rapidly than the rest of the planet, the sea ice cap has shrunk about 40 per cent since the early 1980s: an area of the Arctic Ocean the size of Europe has become dark, open water in the summer instead of reflective ice, absorbing extra heat and releasing it to the atmosphere in autumn and early winter.
Francis, of Rutgers, has presented evidence that this is affecting the jet stream, the huge river of air that circles the northern hemisphere in a meandering fashion. Her research suggests the declining temperature contrast between the Arctic and the middle latitudes is causing kinks in the jet stream to move from west to east more slowly and that those kinks have everything to do with the weather in a particular spot.
''This means that whatever weather you have today - be it wet, hot, dry or snowy - is more likely to last longer than it used to,'' says Francis, who recently published a paper on her theory. ''If conditions hang around long enough, the chances increase for an extreme heatwave, drought or cold spell to occur.'' But the weather can change rapidly once the kink moves along.
Not all of her colleagues buy that explanation. Martin Hoerling, a National Oceanic and Atmospheric Administration researcher, agrees that global warming should be taken seriously but contends some researchers are in too much of a rush to attribute specific weather events to human causes. Hoerling says he has run computer analyses that failed to confirm a widespread effect outside the Arctic from declining
sea ice. ''What's happening in the Arctic is mostly staying in the Arctic,'' he says and suspects that future analyses will find the magnitude of this month's heatwave to have resulted mostly from natural causes but concedes, ''It's been a stunning March.''
That's certainly what farmers have thought. Purinton has been tapping maple trees for 46 years. This year he tapped the trees two weeks earlier than usual, a consequence of the warm winter.
But when the heatwave hit the trees budded early, which tends to ruin the syrup's taste. That forced him to stop four weeks earlier and halved his typical production.
''Is it climate change? I really don't know,'' he says. ''This was just one year out of my 46 but I have never seen anything like it.''

Read more: http://www.smh.com.au/environment/weather/the-forecast-is-warmer-and-weirder-20120331-1w50o.html#ixzz1rOusUKpx

US behind China on carbon - Turnbull 

 

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''I think we are more likely to see leadership out of China than America" ... Malcolm Turnbull. Photo: Alex Ellinghausen

CHINA is more likely than the United States to provide global climate change leadership, the former Liberal leader Malcolm Turnbull believes.
The Coalition leader, Tony Abbott, cites the impact of soaring Chinese emissions as one of the ''crazy things'' about Australia's plans to reduce its emissions by 5 per cent by 2020.
In an interview with The Monthly magazine, Mr Turnbull agrees the growth in Chinese emissions is ''the big problem'' compared with the other major world emitter, the US.

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But, he says, ''the Americans are in a period of dysfunctionality on this … the Chinese are very alert to it and are introducing an emissions trading scheme. It's a trial and it's got a very small price, but the Chinese do take it seriously.
''I think we are more likely to see leadership out of China than America.'' China is trialling an emissions trading scheme in seven provinces, but was widely condemned for cruelling any chances of an international climate change deal at the 2009 United Nations meeting in Copenhagen.
Mr Turnbull said he found it astonishing that climate change denialism was now a pre-requisite for Republican presidential candidates in the US, where a ''war against science'' had been successfully waged by vested interests.
The Coalition's position is to accept the science of climate change, although Mr Abbott once famously described the idea that the scientific debate was settled as ''absolute crap''.
Mr Turnbull also said he thought there was little prospect that military action in Afghanistan would result in ''what many in the West think of as victory'', with the corruption in the Karzai government inhibiting the possibility of winning ''hearts and minds'' and any kind of peace requiring compromise with elements of the Taliban.

Read more: http://www.smh.com.au/opinion/political-news/us-behind-china-on-carbon--turnbull-20120403-1wast.html#ixzz1rOufNBwF

 

Which plants will survive droughts, climate change?

 

By Stuart Wolpert
5 April 2012

New research by UCLA life scientists could lead to predictions of which plant species will escape extinction from climate change.
Droughts are worsening around the world, posing a great challenge to plants in all ecosystems, said Lawren Sack, a UCLA professor of ecology and evolutionary biology and senior author of the research. Scientists have debated for more than a century how to predict which species are most vulnerable.
Sack and two members of his laboratory have made a fundamental discovery that resolves this debate and allows for the prediction of how diverse plant species and vegetation types worldwide will tolerate drought, which is critical given the threats posed by climate change, he said.
The research is currently available in the online edition of Ecology Letters, a prestigious ecology journal, and will be published in an upcoming print edition.
Why does a sunflower wilt and dessicate quickly when the soil dries, while the native chaparral shrubs of California survive long dry seasons with their evergreen leaves? Since there are many mechanisms involved in determining the drought tolerance of plants, there has been vigorous debate among plant scientists over which trait is most important. The UCLA team, funded by the National Science Foundation, focused on a trait called "turgor loss point, which had never before been proven to predict drought tolerance across plant species and ecosystems.
A fundamental difference between plants and animals is that plant cells are enclosed by cell walls while animal cells are not. To keep their cells functional, plants depend on "turgor pressure" — pressure produced in cells by internal salty water pushing against and holding up the cell walls. When leaves open their pores, or stomata, to capture carbon dioxide for photosynthesis, they lose a considerable amount of this water to evaporation. This dehydrates the cells, inducing a loss of pressure.
During drought, the cell's water becomes harder to replace. The turgor loss point is reached when leaf cells get to a point at which their walls become flaccid; this cell-level loss of turgor causes the leaf to become limp and wilted, and the plant cannot grow, Sack said.
"Drying soil may cause a plant's cells to reach turgor loss point, and the plant will be faced with the choice of either closing its stomata and risking starvation or photosynthesizing with wilted leaves and risking damaging its cell walls and metabolic proteins," Sack said. "To be more drought-tolerant, the plant needs to change its turgor loss point so that its cells will be able to keep their turgor even when soil is dry."
The biologists showed that within ecosystems and around the world, plants that are more drought-tolerant had lower turgor loss points; they could maintain their turgor despite drier soil.
The team also resolved additional decades-old controversies, overturning the long-held assumptions of many scientists about the traits that determine turgor loss point and drought tolerance. Two traits related to plant cells have been thought to affect plants' turgor loss point and improve drought tolerance: Plants can make their cell walls stiffer or they can make their cells saltier by loading them with dissolved solutes. Many prominent scientists have leaned toward the "stiff cell wall" explanation because plants in dry zones around the globe tend to have small, tough leaves. Stiff cell walls might allow the leaf to avoid wilting and to hold onto its water during dry times, scientists reasoned. Little had been known about the saltiness of cells for plants around the world.
The UCLA team has now demonstrated conclusively that it is the saltiness of the cell sap that explains drought tolerance across species. Their first approach was mathematical; the team revisited the fundamental equations that govern wilting behavior and solved them for the first time. Their mathematical solution pointed to the importance of saltier cell sap. Saltier cell sap in each plant cell allows the plant to maintain turgor pressure during dry times and to continue photosynthesizing and growing as drought ensues. The equation showed that thick cell walls do not contribute directly to preventing wilting, although they provide indirect benefits that can be important in some cases — protection from excessive cell shrinking and from damage due to the elements or insects and mammals. […]
This new study showed that the saltiness of cells in plant leaves can explain where plants live and the kinds of plants that dominate ecosystems around the world. The team is working with collaborators at the Xishuangbanna Tropical Botanical Gardens in Yunnan, China, to develop a new method for rapidly measuring turgor loss point across a large number of species and make possible the critical assessment of drought tolerance for thousands of species for the first time.
"We're excited to have such a powerful drought indicator that we can measure easily," Bartlett said. "We can apply this across entire ecosystems or plant families to see how plants have adapted to their environment and to develop better strategies for their conservation in the face of climate change."

Source:
http://www.desdemonadespair.net/

Ice Age Next? - Bering Sea Teeming with Ice

 

Ice Age Next? - Bering Sea Teeming with Ice

Earth Observatory

© NASA image by Rob Simmon based on data from Jeff Schmaltz
Acquired March 19, 2012.

For most of the winter of 2011 - 2012, the Bering Sea has been choking with sea ice. Though ice obviously forms there every year, the cover has been unusually extensive this season. In fact, the past several months have included the second highest ice extent in the satellite record for the Bering Sea region, according to the National Snow and Ice Data Center (NSIDC).

The natural-color image above shows the Bering Sea and the coasts of Alaska and northeastern Siberia on March 19, 2012. The image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. Black lines mark the coastlines, many of which have ice shelves or frozen bays extending beyond the land borders.

NSIDC data indicate that ice extent in the Bering Sea for most of this winter has been between 20 to 30 percent above the 1979 to 2000 average. February 2012 had the highest ice extent for the area since satellite records started. As of March 16, National Weather Service forecasters noted that all of the ice cover in the Bering Sea was first year ice, much of it new and thin - which is typical in the Bering Sea

The accumulation of ice this season has largely been fueled by persistent northerly winds blowing from the Arctic Ocean across the Bering Strait. The local winter weather has been dominated by low-pressure systems - with their counterclockwise circulation - that have brought extensive moisture up from the south to coastal and interior Alaska, while sending cold winds down across the sea to the west.

Those winds pushed Arctic sea ice toward the narrow, shallow strait, where it piled up and formed an ice arch that blocked the flow. As arches fail because of wind stress, large floes of sea ice can move south into the Bering Sea. Ice also has piled up on the north side of St. Lawrence Island, near the mouth of the strait.

South of the strait and the island, those same winds push cold air and cold surface waters to lower latitudes, allowing the ice to grow farther south than usual. The widespread and persistent ice cover in the Bering Sea has posed significant problems for fisherman and for supply ships in the region. The weather driving the ice also brought extreme snowfall events to many parts of Alaska this winter.

The Bering Sea stands in stark contrast to the rest of the Arctic ice cap, where sea ice extent was below average in both January and February. Ice cover was down drastically on the Atlantic Ocean side of the Arctic, including the Kara, Barents, and Laptev Seas, where air temperatures were 4 to 8 degrees Celsius (7 to 14 degrees Fahrenheit) above the norm.

References

• NASA Earth Observatory (2012, January 22) Sea Ice off Southwestern Alaska.


• National Snow and Ice Data Center (2012, March 6) February ice extent low in the Barents Sea, high in the Bering Sea.
  Accessed March 19, 2012.


• National Weather Service, Anchorage Forecast Office Alaska Sea Ice Forecast. Accessed March 19, 2012.

Source: http://www.sott.net/articles/show/243463-Ice-Age-Next-Bering-Sea-Teeming-with-Ice