On Tuesday this week, the same day as the Brussels terrorist attacks, retired NASA scientist James Hansen and his team of researches released a co-authored paper that suggested even the restricted warming agreed upon in the Paris Climate Talks will be too great to avoid some serious impacts of global warming. The foundation for the argument stems from the last time the Earth warmed comparably to the observed modern trend. During this time there is evidence that large portions of land-ice were lost and sea level rose as much as 20-30 feet. [1] The author’s also suggest these effects, as well as far more powerful storms, could begin to be felt within the next 50 years, an idea that is contended by many leading climate scientists including Penn State’s own Dr. Michael Mann.

I also have several reservations as to the proposed mechanisms for these impacts, one of which suggests that the influx of freshwater from melting glaciers can shut down the Atlantic Conveyor Belt (which has happened in recent history) and that this will exacerbate the melting of the ice sheets and lead to an amplification of global warming. However, when this happened previously it plunged Europe into the “Little Ice Age,” as warm water was prevented from reaching the North Atlantic and delivering heat to the continent. Another mechanism described in the paper, the idea that an increase in the equator-to-pole temperature gradient will cause more severe weather is contrary to all my research on the topic. Firstly, scientists have found that this temperature gradient is decreasing with global warming as the Arctic regions warm more rapidly than the rest of the planet. Furthermore, it is this decrease in temperature gradient that allows the Polar Jet Stream to wander more North to South, and set up in troughs or ridges that favor higher or lower than average precipitation in a given area, respectively. So it is actually the decrease in this gradient that is likely to cause more severe weather.

Those points of contention aside, Dr. Hansen has been one of the world’s leading scientists and activists against global warming and the fossil fuel industry, so his commitment to abating the problem cannot be denied. His colleagues simply worry whether his political leanings have begun to influence his science. Whether this is the case or not, I think Dr. Mann is correct in saying, “‘We ignore James Hansen at our own peril.'”

Source:

1. http://www.nytimes.com/2016/03/23/science/global-warming-sea-level-carbon-dioxide-emissions.html?rref=collection%2Fsectioncollection%2Fearth&action=click&contentCollection=earth&region=rank&module=package&version=highlights&contentPlacement=2&pgtype=sectionfront&_r=0