Global warning

Species from birds to butterflies are doing strange things, and a new report blames the behavior on the Earth's rising temperature.

By Dawn MacKeen

Mar 2, 2001 | For the last 20 years, on average, the red-chested cardinal has made its singing debut at the Leopold Memorial Reserve in Baraboo, Wisc., on Feb. 8. This year biologists recorded its first song more than a month early. And the hepatica, a flower from the buttercup family, has pushed its blooming date up by about two and a half weeks. In fact, researchers report that more than a third of the 300 species found on this 1,400 acre piece of land are coming in early.

And the cause? They say temperature changes.

According to a report issued last week by the United Nations Intergovernmental Panel on Climate Change (IPCC), the strange things going on at the Leopold Reserve are not isolated. Researchers found that more than 80 percent of the 500 species studied -- including birds, amphibians, mammals, reptiles, plants, mollusks, insects and other invertebrates -- are changing in response to rising temperatures. Some birds are migrating up to three weeks earlier now; other animals are migrating outside their natural habitat, edging closer to the poles and living at higher altitudes.

"There's no doubt there will be extinction," says Terry Root, the University of Michigan professor who led the research. "Because you have species that have small ranges, a lot of them won't be able to move quickly [enough] since the temperature is rising so fast."

The researchers who conducted the analysis of more than 44 studies on the topic say this can create a slew of problems since not all birds, for example, are changing their migration pattern. Some birds, previously thought to migrate in response to day length -- the hours of light in a given day -- are now believed to cue to temperature instead. Root says the ones still responding to day length may end up arriving at a habitat where other bird species have already set up shop. This could make it difficult for them to find a spot to nest, possibly setting off a whole set of other complications.

In January the IPCC released the first installment of its study, which focused on the science of global warming and predicted that the earth's atmosphere could warm up by 10.4 degrees Fahrenheit during the next 100 years. But this latest report devotes many of its 1,000 pages to a hard look at the damage that global warming has already caused. For example, as ice packs break up, polar bears will have a more difficult time stalking their prey and feeding, since seals will no longer need breathing holes to get air. It also forecasts that, as temperatures rise, there will be more deaths from heat stress, as well as an increase in the number of people exposed to vector- and water-borne diseases like malaria and cholera. The report also predicts decreased water for those living in the subtropics, and more flooding in many low-lying areas, like Bangladesh, as sea levels continue to rise.

"What we're seeing is movement into uncharted territory, into a warmer state that we have not known for the last 450,000 or perhaps up to a million years," says James McCarthy, professor of oceanography at Harvard University and co-chairman of the IPCC panel that issued the report. "So it will take many organisms into a condition they haven't been in."

Researchers say that we can learn a lot about our own fate by studying global warming's effect on different animal and plant species.

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