+

THE PHILADELPHIA INQUIRER, January 20, 2003

Change in climate, and nature?

Two studies attributed more-northward migration and earlier breeding to the Earth’s warming.

By Usha Lee McFarling

LOS ANGELES TIMES

Gradual warming over the last century has forced a global movement of animals and plants northward, and it has sped up such perennial spring activities as flowering and egg hatching around the globe - two signals that the Earth and its denizens are dramatically re­sponding to a minute shift in temperature, according to two recent studies.

One study shows that animals have shifted north an average of nearly four miles per decade. Another shows that animals are migrating, hatching eggs and bearing young an average of five days sooner than they did decades ago, when the average global temperature was 1de­gree cooler.

In some cases, the shifts have been dramatic. The common murre, an Arctic seabird, breeds 24 days earlier than it did decades ago. And some checker-spot butterflies shifted their range northward by near­ly 60 miles in the last century.

Although many individual shifts in timing and range have been reported by field biolo­gists, the studies published in the Jan. 2 issue of Nature are the first to establish that a vari­ety of organisms in myriad habi­tats are responding in similar ways to climatic change.

“There is a consistent signal,” said Terry L. Root, a biologist at Stanford University and lead au­thor of one report. “Animals and plants are being strongly affected by the warming of the globe.”

Root said she was surprised that the two Nature studies were able to detect the effect. She said she thought the in­creased temperature was too small to cause widespread change. Root also said she ex­pected that any damaging ef­fects of climatic change would be unnoticeable amid the enor­mous habitat destruction in modem times caused by devel­opment, pollution and other hu­man activities.

“It was really quite a shock, given such a small temperature change,” she said.

Many scientists have debated whether plants and wildlife have been widely affected by climatic change. Some scientists have argued that no widespread response has occurred and that a few examples of animals changing the timing of their mi­gration or reproduction have been used by environmental groups to overstate the dangers of global warming.

The new studies attempt to override such criticism by ana­lyzing thousands of reports of biological change in animals and plants and correlating them with climatic change.

“People said there wasn’t a quantitative analysis and it was just storytelling,” said Camille Parmesan, a biologist at the Uni­versity of Texas, who led the oth­er Nature study. “This is the first hard-core, quantitative analysis.”

The changes are not necessar­ily bad for all species. The earli­er hatching of eggs gives some bird species a chance to lay two clutches of eggs per summer in­stead of one, Root said. Many plants have a longer growing season.

But the scientists are con­cerned that warming will harm some species, particularly those already at risk. The extinction of the golden toad from the cloud forests of Costa Rica has been linked by some scientists to heat stress, Root said. And chicks of the jewel-colored quetzal bird in the same forest are now being preyed upon by toucans that moved to higher elevations in the forest as tem­peratures warmed, she said.

Ecosystems could also be at risk, she added, if insects ma­ture too late to pollinate plants that now flower earlier. The ear­lier migration of wood warblers is leaving behind spruce trees full of spruce budworm caterpil­lars, which devastate the trees and leave the timber damaged.

“If we’ve had so much change with just 1 degree, think of how much we will have with 10 de­grees,” she said, referring to pro­jections by the Intergovernmen­tal Panel on Climate Change on how high temperatures could rise in the next century. “In my opinion, we’re sitting at the edge of a mass extinction.”

Such worst-case scenarios un­derestimate the ability of biologi­cal entities to adapt, some ex­perts say. In a report written for the George C. Marshall Institute, Lenny Bernstein, an expert on the social and economic effect of climatic change, said some “mar­ginal species” would become ex­tinct. He added, however, that plants and animals have always faced climatic changes and that they often have survived.