If the world continues on a business-as-usual path, the Intergovernmental Panel on Climate Change predicts that there is a fifty-fifty chance the temperature will exceed 5 degrees by the end of this century. This increase may not sound like much, but let me remind you that during the last ice age, the world was only 6 degrees colder. During this time, most of Canada and the United States down to Ohio and Pennsylvania were covered year round by a glacier. A world 5 degrees warmer will be very different. The change will be so rapid that many species, including Humans, will have a hard time adapting. I’ve been told for example, that, in a much warmer world, insects were bigger. I wonder if this thing buzzing around is a precursor.

We also face the specter of nonlinear “tipping points” that may cause much more severe changes. An example of a tipping point is the thawing of the permafrost. The permafrost contains immense amounts of frozen organic matter that have been accumulating for millennia. If the soil melts, microbes will spring to life and cause this debris to rot. The difference in biological activity below freezing and above freezing is something we are all familiar with. Frozen food remains edible for a very long time in the freezer, but once thawed, it spoils quickly. How much methane and carbon dioxide might be released from the rotting permafrost? If even a fraction of the carbon is released, it could be greater than all the greenhouse gases we have released since the beginning of the industrial revolution. Once started, a runaway effect could occur.