CHICAGO, Feb. 14 (Xinhua) -- Global warming is likely to worsen faster and cause more environmental damage than scientists have predicted, top scientists warned Saturday.

    Unless aggressive measures are taken, the greenhouse gases will accumulate faster than expected in the Earth's atmosphere, increasing the danger of irreversible climate change by the end of the century, Chris Field, a leading climate scientist of the Intergovernmental Panel on Climate Change (IPCC), said at a meeting here.

    At the five-day annual meeting of the American Association for the Advancement of Science, the Nobel Prize-winning organization presented its newest assessment on global climate change and sea rise.

    "This will impact most likely much worse than predicted in the fourth IPCC report," Field said.

    Just a year ago, the IPCC, one of the world's leading climate change study centers, published their landmark fourth assessment report "Climate Change 2007," warning of severe global climate change and its disastrous impact, such as flood, forest fire and desertification.

    But fresh data showed the report was too optimistic, he said, citing an average annual increase of 3.5 percent in greenhouse gas emissions from 2000 to 2007.

    The panel also urges different regions to mitigate global warming via multiple approaches, as the climate has been affected by the ecosystems.

    "Reductions in desertification rates reduce the likelihood of drought in arid zones; reductions in greenhouse-gas emissions will be particularly effective in industrialized nations, the IPCC assessment said.