Nothing like a another provocative title. It is based on a comment recently made by a colleague, who noted that we are on track for another glacial period, an event made less certain because of humanity's GHG emissions. But he posited that it might be useful to determine the level of GHG emissions required to stave off another Ice Age.
That's probably not a politically expeditious thing to do.
Some have noted that global warming could actually enhance the prospects for an Ice Age.
There is nothing new about the chance that global warming could actually trigger a new Ice Age. Catastrophic melting of the Greenland ice sheet and the resulting freshening of the North Atlantic Ocean could diminish or shut down the thermohaline circulation that transfers heat from the tropics to the northern latitudes.
That is the mechanism that keeps northern Europe from having a climate like Siberia.
I posted on this prospect on 19 April 2008, including a prospect that the same could happen to the Southern Ocean because of the melting of the Antarctic ice sheet. See the diagram below.
I asked my colleague if he had calculated the level of GHG emissions needed. He replied in the negative.
"Climate change poses clear, catastrophic threats. We may not agree on the extent, but we certainly can't afford the risk of inaction." -- Rupert Murdoch
The movie "the day after tomorow" shows your theory of fresh water being dumped into the ocean, disrupting the salt/fresh mixing balence stoping the curent and reducing the amount of warm water warming the Gulf stream and north atlantic currents, freezing the world. Please watch it and reply
Posted by: Steven Healy | Friday, 26 February 2010 at 10:01 AM