Finally on the docket in Washington

WASHINGTON: Since the current session began, lawmakers have introduced more than 10 bills addressing global warming. Several committees have scheduled hearings, including two yesterday and another today . And former vice president Al Gore, whose Oscar-nominated film "An Inconvenient Truth" has drawn millions of moviegoers, is scheduled to testify on Capitol Hill this month. After hearing from scientists and conservationists, Senator John Warner, Republican of Virginia, suggested a road trip to see the changes in the environment first hand. Though scientists have long warned about global warming, the issue had taken a back seat on the national agenda in recent years because of the Bush administration's opposition to mandatory caps on greenhouse gas emissions, which many scientists blame for the problem. But the Democratic takeover of Congress in November -- along with a disturbing report from a meeting of world-renowned scientists last week -- has given the issue new urgency among lawmakers. Although there were just five senators present and five panelists at one of the hearings yesterday, the clashes between lawmakers and specialists on the topic could be seen as a preview of the hearings that lay ahead. One prominent scientist warned of catastrophic changes, while another said he was skeptical. Senator James M. Inhofe , an Oklahoma Republican, reiterated his belief that no one really knows what is causing global warming, but Senator Barbara Boxer , a California Democrat, presented poster-sized pictures of polar bears, saying that human-generated greenhouse gas emissions must be stopped or the bears would be threatened with extinction. Yesterday's hearing was the first-ever session of the Subcommittee on Private Sector and Consumer Solutions to Global Warming and Wildlife Protection . Boxer heralded a report last week by the Intergovernmental Panel on Climate Change, in which hundreds of the world's top scientists declared that humans are almost certainly the reason behind the irrefutable warming of the planet. "If the Earth continues to warm, many animals will be forced to live in conditions that they are not well adapted" to , Boxer said. Four specialists testified that's already happening. Thomas E. Lovejoy , president of the Washington-based Heinz Center for Science, Economics and the Environment , said that climate change disrupts the timing of animal migration and flowering of plants. "Nature is on the move," he said, citing reports that showed tree swallows laying eggs nine days early by 1991 compared with 1959; lilacs in the Western United States flowering two days earlier per decade; and the Edith's Checkerspot butterfly moving its geographical range steadily northward and upslope over the past decades. Lovejoy said destructive pests like the pine bark beetle, which had been held in check by other species, are now thriving, due in part to warmer weather. That, he said, has led to the loss of wide areas of pine forests. Roger Mann , a professor at the College of William and Mary who has studied the Chesapeake Bay ecology for 30 years, said that a 3.5-degree rise in the water's temperature in 2005 killed large underwater fields of eel grass, the prime habitat for small crabs and fish. The crabs and fish have struggled to survive without it, he said. "Just a very small temperature change led to very significant losses," Mann said. But Inhofe doubted that carbon dioxide emissions, and humans, are to blame. "If a particular species is declining, it does not mean that man is at fault or that it is due to global warming," he said. "The fact is that the relationship between species and climate is not clearly understood." A. Lee Foote, an associate professor at the University of Alberta in Edmonton, Canada, said the decline in population of polar bears could be due to an increase in hunters, not global warming. Late last year, the Bush administration proposed listing polar bears as threatened on the list of the Endangered Species Act because of melting ice. If polar bears are put on the list, it would force the administration to try to do something to protect the bears' habitat. Many scientists believe that would mean forcing industries to reduce greenhouse gas emissions, something the administration has long opposed. In the middle of the debate sat Warner, 79, who recalled boyhood hunting and fishing trips taken with his father in Virginia. He said he worries that climate change is threatening the lakes, rivers, and woods he knew when he was young, and proposed a fact-finding "field trip" so senators could see any changes for themselves. One environmentalist suggested traveling to the shrinking glaciers at Glacier National Park in Montana. Another recommended exploring the "dead zones" in Chesapeake Bay . Senator Joseph I. Lieberman, a Connecticut independent who chaired the subcommittee, suggested after the meeting that another trip could be to New England. Lieberman, who stated that Warner's influence "will be very significant" when lawmakers begin considering climate change legislation, said he would like to show the senator maple trees in northern New England, where maple syrup makers are tapping trees as much as a month or more earlier than March, the usual beginning of sap runs. Globe reporter Beth Daley contributed to this report.