> > > > Until recently, much of the climate debate has centered on > > whether global warming is occurring at all. Most climate models > > had assumed a slow, steady increase in temperature and forecast > > gradual changes with gradual effects. But newer, more > > sophisticated models suggest that the Earth's climate system is > > "nonlinear" -- in other words, small changes can have large > > effects on everything from ocean and land temperatures to drought > > and monsoon patterns, icecaps and tropical rain forests. > > > > Though loath to cry wolf, more and more experts are beginning to > > publicly discuss--and personally fear--changes that are far > > more dramatic, and potentially faster, than those at the center > > of discussion so far. Some events could permanently alter life on > > Earth. > > > > For example, one projection is that melting Arctic ice could > > cause a flow of fresh water into the North Atlantic that would > > shut down the Gulf Stream this century. That warm current > > moderates the European climate, and turning it off would make a > > swath of land from London to Stockholm miserable. > > > > > > Anisimov said the increased flow of Siberian rivers also provides > > evidence that Arctic waters are freshening. Thawing permafrost in > > the region, he said, could also fuel warming by allowing > > decomposing material to emit greenhouse gases now trapped in > > frozen soil. > > I've read a number of things recently that suggest climate changes in the past have not been gradual, but sudden and catastrophic, with very major changes in the habitability of ecosystems occurring in a very short period, like a few decades. I've done a lot of travel in the Canadian Arctic, winter and summer, during the past forty years. This February, on a trip to Iqaluit, I saw an enormous open lead of water just south of Baffin Island. I had never seen anything quite like it. We need to take climate change seriously. It's here. Ed Weick
