Global Warming Fact-Sheet
Via NASA's Earth Observatory mailing list my attention was drawn to their newly freshened Global Warming fact sheet, written by Holli Riebeek (dated 11 May 2007), and I wanted to take this space to draw more attention to it.
As most of my readers will know, there's a great deal of misleading disinformation and obfuscation in our current global-warming "debate" here in the US, a concerted effort by some business and political forces to confuse the public into thinking that there is no scientific consensus on anthropogenic climate change, i.e., global warming because of carbon-dioxide (and other greenhouse gas) emissions being pumped into the atmosphere from human sources.
There is consensus among scientists working in the field; how and why and what it all means is nicely summarized in this short, succinct, and accurate fact sheet. Without being patronizing and without distorting the information, it's a clear and understandable presentation of what we (the science "we") know about global warming, the trends, the causes, and the likely or possible consequences.
In particular, the author addresses this question:
But why should we worry about a seemingly small increase in temperature? It turns out that the global average temperature is quite stable over long periods of time, and small changes in that temperature correspond to enormous changes in the environment.
It keeps popping up as a joke, especially during wintertime or a cool day in the summer, when people casually say "I wouldn't mind a bit if it were a degree or two warmer".
What is missing in this superficial understanding is a realization that, overall, the Earth's temperatures are quite stable on average, and that very small changes in average temperatures can have very, very large effects on weather patterns and that those changes in weather patters lead to subsequently surprisingly large shifts in the weather we get at any particular location. In other contexts this is sometimes called "the butterfly effect": consequences can be out of all proportion (i.e., nonlinear) to the causes. Ice ages have been accompanied by changes in the average global temperature of only about 5°C — which doesn't sound all that big.
This is discussed quite well in the fact sheet, and summarized (in part) this way:
Potential Effects
The most obvious impact of global warming will be changes in both average and extreme temperature and precipitation, but warming will also enhance coastal erosion, lengthen the growing season, melt ice caps and glaciers, and alter the range of some infectious diseases, among other things.
For most places, global warming will result in more hot days and fewer cool days, with the greatest warming happening over land. Longer, more intense heat waves will become more frequent. High latitudes and generally wet places will tend to receive more rainfall, while tropical regions and generally dry places will probably receive less rain. Increases in rainfall will come in the form of bigger, wetter storms, rather than in the form of more rainy days. In between those larger storms will be longer periods of light or no rain, so the frequency of drought will increase. Hurricanes will likely increase in intensity due to warmer ocean surface temperatures.
It's a good piece and a few minutes invested in reading through it will arm the reader with better understanding that will help cut a confident path through the thicket of opinions and misinformation that have clogged the information superhighway on the issue lately.
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I welcome comments -- even dissent -- but I will delete without notice irrelevant, rude, psychotic, or incomprehensible comments, particularly those that I deem homophobic, unless they are amusing. The same goes for commercial comments and trackbacks. Sorry, but it's my blog and my decisions are final.
on Friday, 25 May 2007 at 00.00
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It's good to have clear information. We're getting more of it and it's more pressing all the time. We're also seeing more signs.
What's lacking is leadership that says what our nation can do and tells individuals what they must do to keep worse from coming to worst. Alas, and not for the first time, I fear we'll have to lapse into a crisis before most people will be ready for that kind of leadership and willing to do their part.
on Wednesday, 30 May 2007 at 14.46
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If I get on board the global warming Express, does that mean I have to vote for Al Gore?
From what I understand, the Earth's temperature has fluctuated as much as 15 deg. C over the last 60 million years, and CO2 levels have been much higher in our distant past.
We are learning more, and it doesn't always line up with the current global warming advocates.
http://www.mises.org/story/2571
on Thursday, 31 May 2007 at 10.44
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Absolutely not, although if you're on the express you might want to think twice about voting for GW deniers.
The Earth's temperature does fluctuate; 15°C would be a large excursion rather than an RMS average. No question there at all, and that's not the issue at hand, really.
Fluctuations in temperature bring large shifts in global weather patterns: desserts and coastlines come and go, and weather phenomena during transitions can be dramatic. It would be nice to avoid a bi temperature change; very nice, presumably, since significant fractions of the world's population live near coastlines that could vanish, and ice ages are not conducive to supporting the current world population.
The Earth appears to be warming currently. Not good for the current human population and its civilization. (We're well beyond the global hunting-gathering stage we were at for the last ice age.)
That warming appears to be at least partly — possibly largely — caused by human actions. In that case we may be in a position to reduce the warming and stave off disastrous disruptions to just about everything we take for granted in modern (i.e., last thousand years or so) civilization.
Taking some steps to head off a potential catastrophe will be much easier and less taxing [pun seriously intended] than reacting to catastrophe as it happens. From working on it now there are many useful things we could learn, too; avoiding it merely avoids it.
From that perspective I feel it is prudent to take steps now to curb anthropogenic GW effects, and imprudent to spend any more time avoiding it.