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Saturday, October 15, 2005

How much global warming is due to human activity?

In a recent comment, I was asked how much global warming was due to human activity, as opposed to natural climate fluctuations, errors in measurement, and other phenomena beyond our control. (This Wikipedia article explains global warming well, with many links. It allows that there is, indeed, uncertainty over its cause.) My short answer, of course, is that I don't know, and I don't think anyone else knows for sure, either. However, it seems to me that if there is a case to be made for human acceleration of global warming, we don't need to know exactly how much we are doing, if what we are doing has bad effects. We don't know for sure if a particular smoker will die of lung cancer, but that doesn't mean that we shouldn't try to stop smoking. We do know that some smokers do die of lung cancer.

Is there any such thing as global warming at all? There is, indeed, some controversy over this, but, like some other controversies, my impression is that there shouldn't be--some people are misinformed, or are deliberately producing misinformation, and encouraging others to disbelieve global warming. For whatever reason, those who disbelieve global warming tend to be conservative Christians or Republicans. (The two are not necessarily the same!) As an example, I saw Jerry Falwell on the CBS Early Show, on October 14th, 2005. He used the phrase ". . . the myth of global warming." (Harry Smith, the moderator, was doing a segment "Is God Mad at Us?" and Falwell was one of the guests. He said that God was not mad at us. Bill Nye, the Science Guy, another guest, said that he expected more hurricanes because of global warming.)

Back to the question. Is there really global warming? I believe so. (See the New Scientist report, updated occasionally, on Climate Change. See the Wikipedia article for data going back to 1860.)

And, again, to the question that started all this. Assuming there is global warming, how much of it is due to human activity? All I can say is that some of it is, and that, if we can do so, we should take action to cut back on such human activity, by, for example, cutting down on the emission of greenhouse gases in burning, by making transportation more efficient, and the like. I don't think we want to be responsible for the melting of the polar icecaps. This would change the environment radically, to say nothing of putting many of earth's large cities, which are located at or near sea level, in jeopardy. Apparently it would lead to more hurricanes.

Would there be effects on the economy? Yes, of course. A change, such as, say, giving up gasoline-powered automobiles entirely, would cause some change, and it is understandable that it would be resisted by people who would expect to be negatively affected by such changes. Radical changes in how we do things are never easy, and care should be taken to minimize the effects on people as much as possible. However, changes are not necessarily all bad. It is almost certain that new industries, and new jobs, would arise related to any changes in how we transport ourselves, heat our homes, etc.

5 comments:

Peter LaCasse said...

I largely agree with your position, but I approach your conclusion about taking action from a different direction. A good reason to cut back on pollution is that pollution makes the environment unpleasant for us. I don't like smog, contaminated water, acid rain, or fish that are unsafe to eat. These are bad things now. If improving our environment also happens to help the climate 100 years down the line, that's great, but helping ourselves now is sufficient to justify action.

It's also a more acceptable reason, because there is uncertainty about the details of global warming. We don't understand weather or climate well enough to know if reducing our pollution would decrease or increase the rate of global warming. Taking action to achieve more immediate environmental goals is more certain, and it sidesteps the controversy and politics of global warming entirely.

Anonymous said...

I am hoping that someone can explain this to me, because obviously I have missed something. Allegedly, the Earth is around 4.5 billion years old, give or take. In all that time, the world has undergone many transformations: multiple ice ages, continental shifts, breakups, and collisions, meteor impacts that have caused the extinctions of uncountable species, the rise and fall of oceans, on and on. Nothing we can see has always been here. And nothing we see will always be here. It is all transient.
So, I guess my question is, what is all the hand wringing about? There have been many points in time when most of this continent has been under water. There have been many points in time when most of this continent was covered with ice. These events spread over thousands of years. If man alters such events by even a decade, is that really significant on a geological time scale?
So, again, what am I missing here?

Martin LaBar said...

LaCasse: That's fine with me. We should be good stewards of the environment, insofar as we know how to.

Anonymous: Well, perhaps you haven't missed anything. However, I don't think I want to be part of damaging the environment, and fouling humanity's nest, if I can help it. We couldn't help the types of changes you mention, but we can do something about some other things, and, I believe, we should, in part for our own good.

Thanks to both of you (and anyone else) for reading!

gavelect said...

Most people think it is up to the governments to stop the progress of climate change and global warming. In one hand they are correct but on the other hand it is up to ourselves to help the planet and our civilization. If we don't do it singly then we will fail our future children and grandchildren who will have the unknown forced upon them. Governments and energy companies have started the ball rolling. We are seeing a large increase in renewable energy sources here in the UK. My local energy supplier has been taken over by a larger firm - SSE - who specialize in supplying cheap gas and electric" through hydro projects, cheaper cleaner and greener. If we all work as one we will be able to make a difference. The question is how much of a difference can we make.

Martin LaBar said...

Yes, gavelect, we each need to take some personal responsibility.

Thanks.