Global Dimming of the Sun

Published by at 5:56 am under Global Warming

Just saw a fascinating documentary on Nova (Tuesday evening is the best night for TV – Nova and then, typically, Front Line). Here is what I learned:

Global Dimming of the Sun is created by particulate matter in the atmosphere creating conditions that reflect sun energy back into space resulting in a cooling effect on the planet. Although it seems that the developed nations are creating more of the CO2 (the Global Warming agent), we have been steadily reducing our particulate discharge over the last 50 years. It is the developing countries (seen the video-feeds from the Beijing Olympics?) that are spewing the particles.

The show was somewhat sensational and alarmist; no one presented a dissenting opinion; and, of course, it was politically correct: Global Warming was not questioned – e.g. the show said a majority of scientists believe it. Well, as I once heard said, science is not about consensus; it is about developing theories and models and refining them until they accurately reflect reality. People forget that in 1860 most scientists believed in creation and disparaged Darwin’s theory of evolution. Suppose they had taken a vote on that?

There were a couple of things one could intuit from the show. One scientist was saying how the standard Global Warming model did not predict the drought that devastated much of the Sahara in the 70s and 80s. Once he added Global Dimming to the mix, he was better able to model those climate changes. Message: you never know if your model is accurate until its predictions come to pass. One errant assumption, one unknowable process and everything is out the window.

Also, it seemed pretty clear that the piece was suggesting that a great deal of recent weather pattern change can be attributed to the Global Dimming. Perhaps Global Warming is not changing the weather as much as some think and reducing the CO2 may not have much impact on that. However, if we get China and India to reduce particulate matter, we will lose the cooling effect of dimming the sun, leading to faster Global Warming (assuming that it is driven by civilisation’s CO2), but we may also save hundreds of thousands of lives lost to true pollution.

What a dilemma! Spew more particles to reduce global warming and increase illness or try to reduce both particulate and CO2 with the hope of solving all of our problems.

One big take away from the show, if you did any thinking, was the hubris of humans, particularly those in the West, about our ability to control things. Hell, we have invented plastics, cars, airplanes, personal computers and iPhones. We have put men on the moon and space craft on most of the other planets. We have eliminated many devastating diseases and have harnessed nature for our benefit. There ain’t nothing we can’t do! We can heat up the planet or cool it off.

Bjorn Lomborg (The Sceptical Environmentalist) has released another book, Cool It: The Sceptical Environmentalist’s Guide to Global Warming, in which he questions the effectiveness of combating global warming. He says that even the optimists figure that Kyoto, if fully implemented, will have minimal impact on slowing rising temperatures. And the cost would be enormous. Why not, he suggests, spend the money on something that we know for sure will benefit humanity: eliminate malaria, cure AIDS, more direct investment in the third world… the opportunities are endless.

Others have suggested that climate change is inevitable and unstoppable. Better that we prepare for unruly weather than try to stop it. Besides, the greatest threat to civilisation is another gigantic meteorite slamming into the earth. The last one hit 65 million years ago, created the Gulf of Mexico, and destroyed 95% of the life on earth. The other threat is Super Volcanoes. The last one erupted 75,000 years ago in Sumatra with 10,000 times the power of Mount St Helen’s. It is believed to have killed 75% of the plant life in North America. Yellowstone National park sits on one that erupts regularly every 640,000 years. The last time it blew was 600,000 years ago.

Let’s face it; we are doomed one way or the other.

Ron Turley January, 2009.