Tropical forests may dry out and become vulnerable to devastating wildfires as global warming accelerates over the coming decades, a senior scientist has warned.

    Soaring greenhouse gas emissions, driven by a surge in coal use in countries such as China and India, are threatening temperature rises that will turn damp and humid forests into parched tinderboxes, said Dr Chris Field, co-chair of the UN's Nobel prize-winning Intergovernmental Panel on Climate Change (IPCC).

    Higher temperatures could see wildfires raging through the tropics and a large scale melting of the Arctic tundra, releasing billions of tonnes of carbon into the atmosphere that will accelerate warming even further, he said.

    Field, director of global ecology at the Carnegie Institute, told the American Association for the Advancement of Science meeting in Chicago at the weekend that the IPCC's last report on climate change in 2007 had substantially underestimated the severity of global warming over the rest of the century.

    The report concluded that the Earth's temperature is likely to rise between 1.1C and 6.4C by 2100, depending on future global carbon emissions. "We now have data showing that from 2000 to 2007, greenhouse gas emissions increased far more rapidly than we expected, primarily because developing countries, like China and India, saw a huge upsurge in electric power generation, almost all of it based on coal," Field said. The next report, which Field will oversee, is due in 2014 and will now include future scenarios where global warming is far more serious than previous reports have suggested, he said.

    Field said that if the tropics became dry enough for fires to break out, tropical forests would pass a "tipping point" from absorbing carbon dioxide from the atmosphere to releasing it.

    Chicago - The pace of global warming is likely to be much faster than recent predictions, because industrial greenhouse gas emissions have increased more quickly than expected and higher temperatures are triggering self-reinforcing feedback mechanisms in global ecosystems, scientists said Saturday.

    "We are basically looking now at a future climate that's beyond anything we've considered seriously in climate model simulations," Christopher Field, founding director of the Carnegie Institution's Department of Global Ecology at Stanford University, said at the annual meeting of the American Association for the Advancement of Science.

    Field, a member of the United Nations' Intergovernmental Panel on Climate Change, said emissions from burning fossil fuels since 2000 have largely outpaced the estimates used in the U.N. panel's 2007 reports. The higher emissions are largely the result of the increased burning of coal in developing countries, he said.

    Unexpectedly large amounts of carbon dioxide are being released into the atmosphere as the result of "feedback loops" that are speeding up natural processes. Prominent among these, evidence indicates, is a cycle in which higher temperatures are beginning to melt the arctic permafrost, which could release hundreds of billions of tons of carbon dioxide and methane into the atmosphere, said several scientists on a panel at the meeting.

    The permafrost holds 1 trillion tons of carbon, and as much as 10 percent of that could be released this century, Field said. Along with carbon dioxide melting permafrost releases methane, which is 25 times more potent a greenhouse gas than carbon dioxide.

    "It's a vicious cycle of feedback where warming causes the release of carbon from permafrost, which causes more warming, which causes more release from permafrost," Field said.

    Study: Many North American species spending winters farther north.

    Washington - When it comes to global warming, the canary in the coal mine isn't a canary at all. It's a purple finch.

    As the temperature across the U.S. has gotten warmer, the purple finch has been spending its winters more than 400 miles farther north than it used to.

    And it's not alone.

    An Audubon Society study released Tuesday found that more than half of 305 birds species in North America, a hodgepodge that includes robins, gulls, chickadees and owls, are spending the winter about 35 miles farther north than they did 40 years ago.

    The purple finch was the biggest northward mover. Its wintering grounds are now more along the latitude of Milwaukee, Wis., instead of Springfield, Mo.

    Bird ranges can expand and shift for many reasons, among them urban sprawl, deforestation and the supplemental diet provided by backyard feeders. But researchers say the only explanation for why so many birds over such a broad area are wintering in more northern locales is global warming.

    Over the 40 years covered by the study, the average January temperature in the United States climbed by about 5 degrees Fahrenheit. That warming was most pronounced in northern states, which have already recorded an influx of more southern species and could see some northern species retreat into Canada as ranges shift.

    With arctic sea ice melting like ice cubes in soda, scientists want to protect a region they say will someday be the sole remaining frozen bastion of a disappearing world.

    Spanning the northern Canadian archipelago and western Greenland, it would be the first area formally protected in response to climate change, and a last-ditch effort to save polar bears and other animals.

    "All the indications are of huge change, and a huge response is needed if you want to have polar bears beyond 2050," said Peter Ewins, the World Wildlife Fund's Director of Species Conservation.

    National Parks have proven to be one of the most important ways to protect and preserve natural areas and wildlife. First established in the United States in 1872, national parks have since been adopted internationally. But protecting an area outside of a single country's borders could prove to be difficult.

    The arctic sea ice is composed of vast plains of three- to nine-foot-thick ice that cover the top of the northern hemisphere. Though some of the ice melts each summer, much of it remains frozen year-round - or, at least, it used to.

    Summer melts are accelerating, and winter re-freezing can no longer make up the difference. Every summer now seems to be accompanied by news of unprecedented ice loss and more waters open for the first time in known history.

    "When the (Ice Age) glaciers retreated, there was ice left in different spots around the world. Those isolated pockets of biodiversity were called refugia," said Stephanie Pfirman, an environmental science professor at Barnard College. "The same is likely to happen in the Arctic."

    If current greenhouse gas emission trends continue, the proposed protected region will be the only area with year-round ice, according to the Intergovernmental Panel on Climate Change.