New Study Projects Collapse of West Antarctic Ice Sheet by 3000
12.01.2011 - Atmosphere & Space, Water & Oceans, Ice & Snow, Bi-polar
Based on various emission and climate scenarios depending on whether carbon dioxide emissions stopped being produced in 2010 or 2100, a new study led by Nathan Gillett of the Canadian Centre for Climate Modelling and Analysis and his colleagues suggests that the West Antarctic Ice Sheet might collapse by the year 3000, causing average global sea level to rise by nearly four metres. The study, published in the journal Nature Geoscience, suggests that the impact of rising CO2 levels in the Earth's atmosphere is likely to have a significant impact on the climate for at least the next 1000 years.
Exploring various scenarios, the researchers found that the Northern Hemisphere would fare better than the Southern Hemisphere, with differences of 1 to 4°C, and patterns of climate change possibly reversing within a thousand years in places such as Canada, depending on when the world stopped producing greenhouse gas emissions. However, at the same time, parts of North Africa are likely to experience increased desertification, while the warming of the ocean around Antarctica could trigger the collapse of the West Antarctic Ice Sheet.
There are multiple reasons behind the variability in projected changes, the scientists say. One could be the slow movement of ocean water from the North Atlantic to the South Atlantic. Because of the inertia of intermediate and deep ocean currents flowing into the Southern Atlantic, these oceans are only now beginning to warm as a result of CO2 emissions from the 20th century. According to the simulation, warming will continue rather than stop or reverse on a 1000-year time scale.
Wind currents in the Southern Hemisphere could also have an impact, as they tend to strengthen and stay strong without reversing. This increases the mixing in the ocean, drawing more heat down from the atmosphere, and warming the ocean.
