James Hansen is one of the most well-known climate scientists in the world. Hansen, who recently retired from NASA, has been involved in climate research since the 1980s and has participated in dozens of important research projects that have made clear the scope of the pressing problem
Hansen sprang to public prominence after his 1988 congressional testimony, and he is often credited as a key player in putting the global warming issue on the map. “It is time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here,” Hansen testified to Congress. After retiring from NASA in 2013, he accepted a position as an adjunct professor at Columbia University’s Earth Institute.
This time, Hansen is going public with what he says is probably the most important paper of his career. This new study, undertaken together with 16 other expert climate researchers, that outlines a scenario of a rapid rise in sea level and intense storm systems leading to major problems for coastal areas such as Miami.
The new study is published online this week in Atmospheric Chemistry and Physics Discussion, an open-access journal published by the European Geosciences Union. In the APCD format, most of the peer review process for a new paper happens in public. That is, a paper detailing a new study is uploaded, and then other scientists submit comments on the papers and the authors respond.
Details on new rising sea levels study
The study comes to the worrisome conclusion that a two degrees Celsius global warming, which is the generally accepted limit for global warming, is actually “highly dangerous.”
This new research builds on earlier studies that provided evidence of accelerating ice loss in many areas of ice sheets globally, particularly in West Antarctica. A co-author on the new paper, Eric Rignot of NASA, was the lead author of a 2014 study that said the ongoing shrinkage of West Antarctica ice could now be “irreversible.”
Hansen and his colleagues suggest in this new study that the “doubling time” for ice loss from West Antarctica could be as little as a decade. This suggests that a non-linear process is involved, meaning an up to 10 foot sea level rise in the next 50 to 200 years. Moreover, as Hansen and the other study authors note, the mainstream studies of ice loss to date have assumed a more linear process, suggesting only around a three foot rise in sea level by 2100.
The new paper concludes by describing a frightening scenario: “If the ocean continues to accumulate heat and increase melting of marine-terminating ice shelves of Antarctica and Greenland, a point will be reached at which it is impossible to avoid large scale ice sheet disintegration with sea level rise of at least several meters.”