Global warming has reached the point of no return, a study published in the Tuesday edition of the Proceedings of the National Academy of Sciences by a joint team of the U.S., French and Swiss researchers concludes. Even if the world reduces emissions of CO2 to the level before the industrial revolution, it will take at least 1,000 years to reverse the climate change effect that have already taken hold, AP on Sunday quoted the team as saying.
Dr. Susan Solomon of the U.S. National Oceanic and Atmospheric Administration's Earth System Research laboratory led the study. "People have imagined that if we stopped emitting carbon dioxide the climate would go back to normal in 100 years, 200 years; that's not true," she said, adding the effects are well nigh irreversible.
The reason can be found in the oceans, which slow down global warming effects by absorbing CO2 and heat. But their CO2 absorption is too slow to catch up with the excessive amounts of CO2 already in the atmosphere. Moreover, the oceans gradually release the captured heat, so once that happens global warming will accelerate, Solomon said.
If CO2 is allowed to peak at 600 parts per million from current 385, icebergs in the polar areas will quickly melt, causing sea levels to rise by 0.4 to 1 m. If it goes up to 1,000 parts per million, sea levels will rise 2 m, inundating islands and coastal towns.