John Roach, National Geographic News 14 May 08;
Human-induced climate warming is already having a dramatic effect on Earth's plumbing, plants, and animals, according to an exhaustive analysis of data from around the world.
The report's individual findings are familiar and widely cited, such as cannibalistic polar bears, melting glaciers, and earlier-blooming plants.
But this is the first time the data have been compiled in a single study and directly linked to human activity, the report authors say.
The results underscore and extend the conclusions of a 2007 report by the UN's Intergovernmental Panel on Climate Change that found human-induced warming was "likely" to have effects on a wide array of Earth's systems.
Outside experts call the new paper a sweeping portrait of the consequences of anthropogenic warming, noting that it could further spur political advocacy.
In telephone interviews, two of the study's authors expressed particular concern at the amount of change that has occurred with just 1 degree Fahrenheit (0.6 degree Celsius) of average warming.
Global average temperatures are expected to rise between 4 and 11 degrees Fahrenheit (2 and 6 degrees Celsius) before the climate stabilizes over the next century, according to the IPCC.
Study co-author Terry Root, a biologist at Stanford University in California, said the new report is similar to findings presented by the IPCC since 2001—only now the alarm bell is ringing louder.
"We need to start paying attention to the bell," she said, "because if we don't there's going to be a lot of extinctions, I'm afraid."
Strong Links
The researchers analyzed published data on 829 physical systems—such as melting glaciers and warming waters—and 28,800 living plant and animal systems stretching back to 1970.
All of the systems have shown documented changes over the past few decades.
In 95 percent of the physical systems and 90 percent of the living systems, the changes are consistent with the predicted effects of a warming climate, according to the researchers.
The team then used statistical analyses to compare the trends to global and continental temperature changes and found a strong link.
"It is very unlikely for there to be any other reason for those linkages, other than the human influence on the temperature," said Cynthia Rosenzweig, a scientist at the NASA Goddard Institute for Space Studies in New York and lead author of the study.
At the continental scale, the link was strongest in North America, Asia, and Europe. Central and South America, Africa, and Australia lack sufficient data for a robust correlation, she noted.
Rosenzweig, Root, and colleagues from nine other institutions report their findings in tomorrow's issue of the journal Nature.
David Inouye is a biologist at the University of Maryland in College Park who has worked at the Rocky Mountain Research Laboratory in Colorado to document the earlier arrival of spring.
He was not involved with the new paper, which he said is a "major contribution" to making a connection between human-induced warming and observed changes.
Inouye has not yet made a direct link in his own work, but based on the findings of other researchers, he said, "I can assume there is a link there."
Call for Action?
Roger Pielke, Jr., is a political scientist and professor of environmental studies at the University of Colorado at Boulder.
He said via email that the new study would likely be "used promotionally to advocate for a greater pace of action of mitigation and/or adaptation" to climate change.
But whether such a strategy is effective, he added, is debatable.
"I would probably lean toward thinking that such use of these studies can have a numbing effect on the public."
Root, the Stanford University study co-author, said the message from the analysis is more of the same but worth noting because it highlights the need for adaptation to a warming world.
"Any time we can get people to notice that global warming is affecting us right now is good," she said.
"What we're doing is finding a lot more instances of it."
New study amplifies warning on climate change
Yahoo News 14 May 08;
A wide-scale study published Wednesday has strengthened warnings, spelt out last year by UN scientists, that climate change is already on the march.
The paper, published in Nature, goes beyond the scope taken by a landmark report issued by the UN's Intergovernmental Panel on Climate Change (IPCC) in February 2007.
In that document, the IPCC said man-made global warming was "likely" -- within a probability of 66-90 percent -- to have had a "discernible" effect on many physical and biological systems.
The new study, published in the British journal Nature, is written by many of the people who wrote the so-called Working Group I report, the first of a trio of major assessments released last year by the IPCC.
Its approach widens the net of data for making a fresh analysis.
It concludes "significant changes" are already occurring among natural systems on all continents, with the exception of Antarctica, and in most oceans.
"Humans are influencing climate through increasing greenhouse gas emissions," said lead author Cynthia Rosenzweig of the NASA Goddard Institute for Space Studies and the Columbia Center for Climate Systems Research.
"The warming world is causing impacts on physical and biological systems attributable at the global scale."
The analysis is based on a trawl of hundreds of papers published in peer-reviewed journals, on data stretching back to 1970s.
These investigations covered phenomena as varied as the earlier leafing of trees and plants; the movement of species to higher latitudes and altitudes in the northern hemisphere in response to warmer weather; the shrinkage of glaciers and melting of permafrost; and changes of bird migrations in Europe, North America and Australia.
Critics of the IPCC report have variously argued that the perceptible warming that has occurred over the last three decades is due to natural causes, such as volcanic eruptions or changes in solar radiation, or to the effect of deforestation and other changes in land use.
The new paper rejects this, saying the changes in Earth's natural systems cannot be explained by such factors, and only man-made warming could be the culprit.
The Working Group I report forecast likely warming of 1.8-4.0 degrees Celsius (3.2-7.2 degrees Fahrenheit) by 2100 and a rise in sea levels of at least 18 centimetres (7.2 inches). Hunger, homelessness and water-borne disease are among the many risks that would be amplified as a result of climate change.
In a commentary, also published by Nature, climatologists Francis Zwiers and Gabriele Hegerl picked over the big dispute as to whether climate impacts could be pinned on human interference.
They placed a question mark over the shortness of the records put forward by Rosenzweig's team. Evidence stretching back far longer than a few decades was needed to get a solid perspective, they said.
But, they added, these objections are outweighed by "the sheer number of changes" that the paper lists.
Natural changes pinned to warming
Richard Black, BBC News 14 May 08;
Major changes in the Earth's natural systems are being driven by global warming, according to a vast analysis.
Glacier and permafrost melting, earlier spring-time, coastal erosion and animal migrations are among the observations laid at the door of man-made warming.
The research, in the journal Nature, involves many scientists who took part in last year's Intergovernmental Panel on Climate Change (IPCC) report.
It links warming and natural impacts on a tighter regional scale.
Changes in the Earth's physical and biological systems since at least 1970 are seen in regions which are known to be warming, it concludes.
The researchers assembled a database including more than 29,500 records that documented changes seen across a wide range of natural phenomena, such as:
* the earlier arrival of migratory birds in Australia
* declining krill stocks around Antarctica
* earlier break-up of river ice in Mongolia
* genetic shift in the pitcher plant mosquito in North America
* declining productivity of Lake Tanganyika
* melting Patagonian ice-fields
"Since 1970, there's been about 0.5C, 0.6C of warming - that's the global average," said Cynthia Rosenzweig from Nasa's Goddard Institute for Space Studies (Giss) in New York.
"And look at all the effects this relatively low amount of warming has had.
"It reveals the sensitivity to relatively low amounts of warming in many physical and biological systems," she told BBC News.
Deeper look
Dr Rosenzweig was one of the scientists who played a leading role in compiling the section of last year's IPCC report dealing with climate impacts.
This analysis uses more sets of data, and different techniques for attributing the root cause of the observed changes.
Francis Zwiers from Environment Canada and Gabriele Hegerl from the University of Edinburgh, who reviewed the work for Nature, commented: "(This) is the first (study) to formally link observed global changes in physical and biological systems to human-induced climate change, predominantly from increasing greenhouse gases".
About 90% of the changes documented were consistent with rising temperatures at regional scales, the researchers found.
And in virtually all cases, global warming was the primary driver of change, as opposed to natural variability or other human impacts such as deforestation or water pollution.
Not all of the changes observed in nature are damaging to all creatures - for example, last week researchers showed that some British birds are able to handle the earlier arrival of spring pretty well.
But others, such as the loss of Arctic sea ice, will clearly have a detrimental effect on parts of the living world.
And phenomena such as the melting of mountain glaciers are likely to have major impacts on societies that depend on them for drinking water.
"This provides up-to-the-minute impetus that climate change is changing how the world works," said Dr Rosenzweig.
"We need to get our act together, both for adaptation to these changes that are happening now, and for mitigation to reduce long-term risk."
Giant study pinpoints changes from climate warming
Deborah Zabarenko, Reuters 14 May 08;
WASHINGTON (Reuters) - Human-generated climate change made flowers bloom sooner and autumn leaves fall later, turned some polar bears into cannibals and some birds into early breeders, a vast global study reported on Wednesday.
Hundreds of previous studies have noted these specific changes and most suggested a link to so-called anthropogenic global warming, but a new analysis published in the journal Nature correlated these earlier studies with changes in temperature, the study's lead author said.
There was a close relationship between temperature shifts between 1970 and 2004 and changes in plants, animals and the physical world, such as the retreat of glaciers and the water level in desert lakes, the study found.
"When you look at all of the glaciers and all of the snowpack and all of the birds laying eggs earlier and all of the plants having spring earlier across a continent, then we see we can detect anthropogenic signals," said Cynthia Rosenzweig of NASA's Goddard Institute for Space Studies.
They worked to rule out observed changes that could have been caused by other factors besides anthropogenic climate change.
Building on research done to support findings reported in 2007 by the U.N.'s Intergovernmental Panel on Climate Change, Rosenzweig and her co-authors brought together nearly 30,000 sets of data about biological and physical changes around the world, and then matched that up with a detailed database of global temperature change.
PENGUINS, POLAR BEARS AND POLLEN
"We overlay those two global datasets and then we do a spatial pattern analysis globally about the co-location of significant temperature trends and observed changes consistent with warming," Rosenzweig said in a telephone interview. "We see that those are strongly co-located."
The link between human-caused global warming -- generated by industrial and vehicle emissions of carbon dioxide to produce a temperature-boosting greenhouse effect -- and observed biological and physical changes is very strong, she said.
On a global scale, the correlation is more than 99 percent between the two factors; on a continental scale, she said, the correlation if very likely between 90 and 99 percent.
Going continent by continent, here are some observed changes in the natural world attributable to climate change, according to the study:
-- NORTH AMERICA: Earlier plant flowering of 89 species from American holly to sassafras; intraspecific predation, cannibalism and declining population of polar bears; earlier breeding and arrival dates of birds including robins and Canada geese.
-- EUROPE: Glacier melting in the Alps; changes in 19 countries of leaf-unfolding and flowering of such plants as hazel, lilac, apple, linden and birch; early pollen release in the Netherlands; long-term changes in fish communities in Upper Rhone River.
-- ASIA: Greater growth of Siberian pines in Mongolia; earlier break-up and thinning of river and lake ice in Mongolia; change in freeze depth of permafrost in Russia; earlier flowering of gingko in Japan.
-- SOUTH AMERICA: Glacier wastage in Peru; melting Patagonia ice fields contributing to sea-level rise.
-- AFRICA: Decreasing aquatic ecosystem productivity of Lake Tanganyika.
-- AUSTRALIA: Early arrival of migratory birds including flycatchers and fantails; declining water levels in Western Victoria.
-- ANTARCTICA: 50 percent decline in population of emperor penguins on Antarctic Peninsula; retreating glaciers.
(Editing by David Wiessler)
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