In the next 50 years, even the lower limit of impending climate change–an additional global mean warming of 1°C above the last decade–is far beyond the range of climate variability experienced during the past thousand years and poses global problems in planning for and adapting to it. Warming greater than 2°C above 19th century levels is projected to be disruptive, reducing global agricultural productivity, causing widespread loss of biodiversity, and–if sustained over centuries–melting much of the Greenland ice sheet with ensuing rise in sea level of several meters. If this 2°C warming is to be avoided, then our net annual emissions of CO2 must be reduced by more than 50 percent within this century. With such projections, there are many sources of scientific uncertainty, but none are known that could make the impact of climate change inconsequential. Given the uncertainty in climate projections, there can be surprises that may cause more dramatic disruptions than anticipated from the most probable model projections.
Precisely. In short, the time to act is now.
While this is a strong statement by itself, its true strength comes when you consider that this statement is just one of a spate of similar statements by other expert organizations: the American Meteorological Association, the American Association for the Advancement of Science, the U.S. National Academy of Sciences (PDF), as well as several others….
Whom should we believe? Jim Inhofe or virtually all of the world’s experts? That’s a tough one….