Thursday, December 08, 2005

The Economist and "Global Warming"

The Economist has an excellent roundup on the climate change debate today. If you are not sure what to think of "global warming," read this article.

However, I do have a few comments to make about its content. The Economist uses six reasons to conclude that "global warming" is caused by human activities. All of these issues are important, but none of them point to global climate change as anything but natural.

The first, and most basic, is the continuation of the warming trend at the Earth’s surface that has been happening since the early 20th century. The first chart below, assembled by Britain’s Hadley Centre for Climate Prediction and Research and the University of East Anglia, shows that the ten years to 2004 were the warmest decade since reliable measurements began in the early 19th century. Estimates of earlier temperatures made from data such as ice cores and tree rings, though not as reliable as thermometers, suggest the decade may have been the warmest in the past millennium.

All of these statements are true, but so short-term they hardly are conclusive evidence. Going back 100 or even 1,000 years to base climate predictions on is like basing your opinion of a movie on only the last 25 seconds. We do not have long-term enough climate information to conclude that the current trend of warming is anything other than natural.

The second result is that the Arctic, a place where any warming trend would be amplified by changes in local absorption of heat as the ice melts, does, indeed, show signs of rapid warming.

This, too, is not evidence of human-caused climate change. There is no evidence that climate change by carbon dioxide or climate change by solar radiation change would affect the poles differently.

The third finding is the resolution of an inconsistency that called into question whether the atmosphere was really warming. This was a disagreement between the temperature trend on the ground, which appeared to be rising, and that further up in the atmosphere, which did not. Now, both are known to be rising in parallel.

This, too, is not evidence that the temperature change is caused by human activities any more than caused by solar radiation.

The fourth is a study by researchers at the Scripps Institution of Oceanography, in California, into changes in the way the world’s oceans have warmed up at different depths over the past 65 years. These match climate models’ predictions of what happens when warming is induced by greenhouse gases better than it matches predictions of the result of changes in the sun’s activity, the main alternative hypothesis for what might be causing the climate to change.

This one is the weakest explanation yet. It says that these researchers made estimates for what the ocean temperatures would like due to changes in greenhouse gasses and solar activity each - and the current trend of ocean temperatures more closely matches the prediction they made for ocean temperature changes caused by greenhouse gases. Not exactly conclusive evidence.

The fifth is the observation in reality of a predicted link between increased sea-surface temperatures and the frequency of the most intense categories of hurricane, typhoon and tropical storm.

This comment has been thoroughly debunked by the NOAA. Read about it here - the strength and number of hurricanes is a natural pattern.

And the sixth, as reported in last week’s Economist, is an observation that ocean currents in the North Atlantic are faltering in ways that computer models of the climate previously suggested would happen in response to increased temperatures.

This, too, is an attempt for researchers to claim the causes of ocean changes based on predictions of how they think the oceans may change. Again, it draws no distinction between natural warming and human-caused warming.

This article by the Economist is excellent, though, and I encourage you all read it. However, it does nothing to prove "global warming" is nothing more than a natural pattern in Earth's temperatures that has been ongoing for literally millions and millions of years.

1 comment:

The Big Ticket said...

I wonder if these people simply deny an Ice Age ever existed. It is a known fact that planet temperatures fluxuate and change over periods of time. However, noone can argue humans help reduce global warming either, but as for 10,000,000 BC I wonder if we should blame the dinosaurs?