Climate change on the fast track? (News from the World of Trees).

Global climate change could occur abruptly, pushing temperatures up as much as 18 degrees F, according to a new National Academy of Sciences report on the threat of rapid climatic shifts. The NAS report, released in December, warns that "gradual global warming coupled with other human impacts on the environment could 'trip the switch' for sudden climate change," Reuters reports.

If you have a very large, abrupt change, a lot of people and a lot of ecosystems are going to notice," Richard Alley, a Penn State University climate expert and lead author of the report, said. "The bigger and faster it is, the harder it will be to deal with."

Should a sudden warm-up occur, most immediate dangers would include droughts and floods that could affect water supply and agriculture across the planet, the report warned. Gelogical evidence has shown frequent instances of rapid climate change, resulting in drastic temperature changes in the space of a few decades.

Researchers used ice cores drilled from glaciers and other ice sheets to create a model showing world temperatures that have spiked and dipped over the past 110,000 years. Among the rapid changes: the fast-paced warming of the North Atlantic from 1920 to 1930 and the devastating Dust Bowl drought of the 1930s.

Many researchers have linked the greenhouse gases emitted by fossil fuels to a rise in global temperatures.