By Luis Otero
The usual projections of the future on climate change calculate what will happen in the next two centuries, in which the temperature and the sea level will rise significantly, but they do not usually venture about what will happen in the longer term.
A study published in Nature Climate Change makes a projection for the next 10,000 years and the conclusions are grim: the negative impact of another three centuries of carbon pollution will continue to influence the environment several millennia after the cessation of carbon dioxide emissions . One of the authors Shaun Marcott, professor of Earth Sciences at the University of Wisconsin-Madison, predicts a rise in sea level for thousands of years into the future.
"We thought that studies that only look at a period of two or three centuries do not cover the full long-term effect of sending between one and five trillion tons of carbon dioxide into the atmosphere over the next three centuries. Whereas most of research analyzes the last 150 years of data and compares it with projections for the next several centuries, we look back 20,000 years with recently collected data on carbon dioxide, global temperature and sea level measurements that cover the latest ice age. Then we have compared past data with model results stretching 10,000 years into the future, "explains Marcott.
Climate - the result of the interaction between land, ocean and atmosphere - has a long-term memory. "Many people believe that temperatures and sea levels, which rise as we continue to burn fossil fuels, will drop again once we stop burning them. However, it will take thousands of years for the excess carbon dioxide completely leaves the atmosphere and goes back into storage in the ocean.
The study was based on four possible levels of carbon pollution between 2000 and 2300 and their effects, based on an analysis designed by Michael Eby, from the University of Victoria and Simon Frase University, in Canada. "Even if we stop burning carbon in the relatively near future, the system will continue to react because an equilibrium has not been reached. If you boil water and turn off the fire, the water stays hot because the heat remains in it," says Marcott.
A similar but more complex phenomenon occurs with the entire climate system. New data on the relationship between carbon dioxide, sea level and temperature over the past 20,000 years was the basis for looking into the next 10,000 years. Current emissions of the carbon contained in total carbon dioxide are about 10 million tons per year, but that figure is growing 2.5% a year, more than twice as fast as in the 1990s. it has released about 580 million tons of carbon dioxide into the atmosphere.
The researchers analyzed the effect of the release of between 1,280 to 5,120 million tons between 2000 and 2300 and found that even if the entry of carbon dioxide ends in 300 years, the impact will last another 10,000 years. The increase in temperature could reach 7ºC by the year 2300, and would drop only slightly, to about 6ºC, after 10,000 years. In addition, the thaw in Greenland and Antarctica "will translate into a rise in sea level of between 24.8 and 51.8 meters", according to Jack Williams, professor of geography and expert in climate history at the University of Wisconsin. Madison.