Climate Change In Antarctica? Blame The Atlantic Ocean’s Warming Waters
A team of scientists have found that distant regional conditions are impacting Antarctic climate change. A group of New York University scientists studied over three decades of atmospheric data to conclude that the climate change in Antarctica is influenced by the gradual warming of the North and Tropical Atlantic Ocean. The study is published in the journal Nature.
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The findings identified "a previously unknown and surprising force behind climate change," said Xichen Li, a doctoral student in NYU's Courant Institute of Mathematical Sciences and the study's lead author, in a press release. "Moreover, the study offers further confirmation that warming in one region can have far reaching effects in another," said Li.
Antarctica has experienced some of the strongest changes in temperature over the last few decades, compared to other region on the planet. The climatic changes in Antarctica summer have been partially explained by increased greenhouse gas emissions and ozone loss. However, the forces responsible for climate change that operate in the winter of Antarctica are not quite clear especially because of the complex nature of these changes during the cold season.
Past research has shown that the climate of the distant Pacific Ocean impacts the Antarctica climate, but to these point scientists have only understood short term forces (such as El Nino). But at the same time, scientists did now that there were non-seasonal, long-term impacts to the area, including warming along the Antarctic Peninsula and several decades of sea-ice-redistribution in the southern hemisphere's winter.
The scientists wondered if the Atlantic Ocean, overlooked as the source of climate change in Antarctic, could be the possible source of long-term impact. They focused their study on the last three decades of data on the North and Tropical Atlantic's Sea Surface Temperature (SST) variability. The changes in the ocean's surface temperature could offer them a possible insight into the issue.
The scientists found changes in the North and Tropical Atlantic's SST and changes in Antarctic climate highly correlated on a time-series analysis. More specifically, the data revealed that changes in sea-level pressure in the Amundsen Sea and warming of Atlantic waters followed each other. Additionally, redistribution of sea-ice between Antarctic's Ross and Amundsen-Bellingshausen-Weddell Seas followed warming patterns.
The study used both observational data and computer modeling. The observational data revealed a correlation between Atlantic and Antarctic data sets, which only demonstrates a simultaneous occurrence rather than their causal link. However, the second part of the study, which used a state-of-the-art, computer-generated global atmospheric model showed a distinct causal link between North Atlantic warming and Antarctic climate change.
"While our data analysis showed a correlation, it was the use of a state-of-the-art computer model that allowed us to see that North Atlantic warming was causing Antarctic climate change and not vice versa," said to David Holland, coauthor of the study, a professor at NYU's Courant Institute and past director of NYU's Center for Atmospheric Ocean Science, in the press statement.
The study has raised some deeper issues. For example, the researchers now wonder if there is any difference between changes in Arctic and Antarctic sea-ice. While there is distinct sea-ice decline in the Arctic, the Antarctic sea ice, in contrast, has redistributed rather than declined, according to Holland. "From this study, we are learning just how Antarctic sea-ice redistributes itself, and also finding that the underlying mechanisms controlling Antarctic sea ice are completely distinct from those in the Arctic," he said.
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