Global warming affecting climate change

The red fox is spreading northward in response to a warmer climate, scientists say. Credit: USFWS

The planet is warming, humans are mostly to blame and plants and animals are going to dramatic lengths to cope. That's the consensus of a number of recent studies that used wildlife to gauge the extent of global warming and its effects.

While the topic of climate change is contentious - including whether the planet is actually heating up - a growing number of documented shifts in traits and behaviors in the wild kingdom is leading many scientists to conclude the world is changing in unnatural ways.

• Marmots end their hibernations about three weeks earlier now compared to 30 years ago.

• Polar bears today are thinner and less healthy than those of 20 years ago.

• Many fish species are moving northward in search of cooler waters.

• A fruitfly gene normally associated with hot, dry conditions has spread to populations living in traditionally cooler southern regions.

While we argue ...

Over the past century, Earth's average temperature has risen by about 1 degree Fahrenheit and many scientists believe greenhouse gases and carbon dioxide emissions from human activities are to blame. Left unattended, they warn, temperatures may rise by an additional 2-10 degrees by the end of the century. In the leading computer models, it follows that polar ice will melt and seas would rise drastically, threatening coastal communities around the globe.

A handful of scientists dispute the data. Others say humans aren't to blame.

Terry Root, an environmental science and policy professor at Stanford University, says that as humans argue about thermometer readings, animals are providing evidence that should be figured in to scientific and political decisions.

Animals are "just reacting to what's going on out there, " Root says. "And if their behavior is very similar to what we expect with what's going on with global warming - if they're shifting and they're moving, if they're changing their breeding time by 5 days in 10 years - we can use that information to support what the thermometers are also showing."

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