for National Geographic News
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."
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.
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