"Most terrifying of all, [James] Hansen thinks that all of this could happen with just a 2 °C rise in temperature – the supposedly safe limit.The consequences, of course, would be catastrophic. “It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilisation,” the paper states."
https://www.newscientist.com/article/dn27957-leading-climate-scientist-future-is-bleaker-than-we-thought/ http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015.pdf Hansen starts by arguing that the ice melting on and around Greenland and Antarctica will cause rises in sea level that are much faster than mainstream predictions, meaning that we are likely to see several metres of sea level rise this century. It is an argument he has been making for a long time: for instance in his 2007 feature for New Scientist.Even more startling are the consequences that Hansen thinks will result from this rapid melt. Because fresh water is less dense than saltwater, the cold, fresh meltwater will pool around the coasts of Greenland and Antarctica.Water blanketAround Antarctica, this surface layer will act as a blanket, floating on top of warmer, saltier water and preventing it from losing heat to the air. Instead, this heat will go into melting the underside of ice shelves and glaciers. Hansen argues that the growth in sea ice around Antarctica is a sign that this is starting to happen already, with freshening surface water forming sea ice more readily.This freshwater layer will also shut down the ocean currents that carry heat from the tropics to the poles, so the tropics will warm fast while high latitudes cool down because of the cold surface waters. This resulting temperature difference, Hansen claims, will power superstorms of a size and fury unlike anything we have ever seen.Such superstorms occurred towards the end of the last interglacial period 120,000 years ago, the paper claims. It details several lines of evidence suggesting that the islands of the Bahamas were frequently pounded by massive waves at this time. For instance, there are wave-formed ridges many kilometres long on the islands, and wave deposits up to 40 metres above current sea level, including massive boulders weighing thousands of tonnes.Most terrifying of all, Hansen thinks that all of this could happen with just a 2 °C rise in temperature – the supposedly safe limit.The consequences, of course, would be catastrophic. “It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilisation,” the paper states. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
