Global Warming

I’ve wanted to write something about ‘global warming’ or ‘climate change’ or whatever it is that we’re supposed to call it.  Is it a threat to human existence, or a fraudulent scheme to separate us from our industrial civilization?

Parts of the issue are beyond doubt: we, as humans, are putting more carbon dioxide in the air than natural systems can remove, leading to rising levels in the atmosphere.  And carbon dioxide functions to trap heat.

In the 1960s and early 1970s, it was thought that air pollution might cool the planet rather than heat it, chiefly through particulates and other specific forms of pollution that would reflect solar radiation back into space.  But that view was in the minority back then, although a couple of examples made it to the popular press at the time, which are waved today about by the opponents of global warming.  Moreover, the Clean Air Act and other similar law and regulation worldwide substantially limited particulates and other pollutants, although not carbon dioxide, substantially abating whatever cooling effects our industrial activities might have.

So now we have excess carbon dioxide, without particulates, and global warming.  But how much?  At this point, not very much: perhaps a fraction of a degree Celsius.  It’s still small relative to variations in climate related to solar activity, which is why the opponents of global warming have been able to seize upon a drop in temperatures in recent years as evidence that the phenomenon is not real.

But the small magnitude of the change to date doesn’t mean that it can be ignored.  As a simple example, consider a block of ice at the freezing point.  It takes a certain amount of energy to melt the ice and turn it to water, still at the freezing point.  If that same amount of energy is then applied to the liquid water, it will be heated most of the way to the boiling point.  In other words, ice must absorb a considerable amount of energy before it melts.  There are many elements in our world that work similarly to absorb the excess energy trapped in our atmosphere and limit actual warming.  But if the excess energy continues, ultimately it will have to result in warming, and the ice will melt.

So global warming is real, although the effects of it aren’t clearly apparent yet.  It is the sort of problem where government regulation is actually useful: when the effects of global warming are clearly apparent, it will be too late, so we need rules now to limit the future damage.  But what should those rules consist of?  Should we strangle our industrial civilization and go back to the 19th Century?

Probably not.  Besides the obvious impracticality and popular resistance to such a plan, there are other, longer term, reasons why such drastic measures are not necessary:

  1. The runup in carbon dioxide levels was caused by burning fossil fuels.  But these are finite, and we’ve consumed a decent fraction of them.  Eventually they will become too valuable to simply burn.
  2. It would be a stretch for 2010 technology, but still possible, to provide a technological solution to the problem by reflecting a portion of the sunlight reaching the Earth back into space.  But technology marches on, and such a solution will be practical soon enough to be relevant.

In the meantime, we should do the obvious: take practical measures to limit our consumption of fossil fuels, and develop new sources of energy.  I’d like to believe that this could be accomplished through the market, without need of government regulation, but I know that isn’t practical.  Money, alas, is lazy.

But what the government regulations should consist of is a subject for another day.

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