Global warming is (or was) often portrayed as a moral issue concerning the well-being of our descendants and of future generations. Among those who accepted that greenhouse gases produce a greenhouse effect, there was still a widespread perception that most of the unpleasantness would be in the distant future.
Recently though, it's been getting much clearer that while future generations will still face big problems from warming, it is also very much a short term issue for those of us alive today. Particularly those of us young enough to be reading this on facebook.
In other words, not only is it a moral issue of us versus our descendants, it's also a matter of self interest to prevent global warming.
I'm bringing this up because Britain's met office just released a report which serves as a good summary of current expectations.
They predict a 4 degree rise over baseline temperatures by....2055, unless we get our act together. This danger exists because of what are called "feedback effects", which refer to natural systems which either release more greenhouse gases or cause more warming as the earth warms. Some possible feedback effects include:
1. The melting of ice replaces a white surface (ice), with a darker surface (seawater, ground, trees, etc.), which reflects less light, and hence less heat, back into space.
2. There is a lot of carbon trapped in permafrost in the north of Canada, Russia and in Alaska. As permafrost melts, this releases the gas in the form of methane, which is much more harmful than CO2.
3. Rising temperatures throw off the rain cycle, which may well destroy vulnerable ecosystems such as the amazon. As the trees go away, they release CO2 they had formerly been trapping.
4. There is methane frozen at the ocean floor in something called "methyl hydrates". As the ocean warms, these could melt, increasing warming.
There are others as well. Anyway, the met office predicts that average temperatures will rise 4 degrees. If that doesn't sound too bad, I suggest you take a closer look at that picture I included at the top. The oceans warm by less than 4 degrees, and land warms by considerably more. It averages at four, but the disruptions on land are considerably greater than it would seem at first glance.
What effects would this have?
1. Extreme disruption of ecosystems. The amazon and other forests dependent on abundant rainfall in warm regions could turn to desert. Crops dependent on certain weather conditions could stop growing.
2. The destruction of coral reefs from acidification. Some of the CO2 released dissolves in the oceans, making them more acidic. This kills coral.
3. The monsoon, vital for asian agriculture, could stop or change greatly. It's dependent on weather cycles caused by ocean temperature.
4. Sea level rise as glaciers on land melt. Not only would this impact people living on the coast, it could also spread salt onto agricultural lands, ruining them for production.
5. The disruption of water supply to regions dependent on melt water from glaciers. Notably, the Indian subcontinent and China are dependent on melt water from the Himilayas. If the glaciers appear only in winter, this could ruin regional agricultural systems.
This is pretty terrible. And, it should be noted that real world conditions have been consistently exceeding worst-case scenarios from climate models, so it could well get worse. It may in fact already be too late to stop many of these things from happening, as there is a long time lag between the time carbon is emitted to the atmosphere and when it has it's effects.
But to do nothing ( our current policy, more or less), would inevitably make the problems even worse, so we must try. This should be priority number one right now. Everything else is just a sideshow.
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