Different River

”You can never step in the same river twice.” –Heraclitus

April 7, 2006

Clean Air Causes Global Warming?

Filed under: — Different River @ 1:09 pm

Well, you can’t win for losing, if this study reported by the BBC has any truth to it:

Research presented at a major European science meeting adds to other evidence that cleaner air is letting more solar energy through to the Earth’s surface.

The decline in Soviet industry and clean air laws in western countries apparently reduced concentrations of aerosols, tiny particles, in the atmosphere.

These aerosols may block solar radiation directly, or help clouds to form which in turn constitute a barrier; or both effects may occur.

So there you have it: If we increase pollution, we cause global warming — and if we decrease pollution we also cause global warming. And as I’ve pointed out before, higher temperatures are evidence of global warming, and lower temperatures are also evidence of global warming. This is how we know that global warming is not really a scientific theory — a scientific theory has to be subject to evidence. That is, it need to make “falsifiable predictions” — predictions that, if contradicted, would be regarded as evidence against the theory. If any possible outcome can be viewed as consistent with the theory, then it’s not really a theory since it doesn’t explain anything.

The BBC article also had the following interesting tidbit:

Between the 1950s and 1980s, the amount of solar energy penetrating through the atmosphere to the Earth’s surface appeared to be declining, by about 2% per decade.

This trend received some publicity under the term “global dimming.”

It was also called “the New Ice Age.” I’m just old enough to remember reading in the mid-1970s in elementary school — in the Weekly Reader distributed in over 90% of American elementary schools — that the burning of fossil fuels was causing pollution that would eventually block out enough of the sun’s rays to cause a “New Ice Age.”

In retrospect, this must have come about from the research of Dr. Murray Mitchell, and reported in the famous article Peter Gwynne wrote in Newsweek in 1975 – i “The Cooling World” (excerpted here):

The central fact is that after three quarters of a century of extraordinarily mild conditions, the earth’s climate seems to be cooling down. Meteorologists disagree about the cause and extent of the cooling trend, as well as over its specific impact on local weather conditions. But they are almost unanimous in the view that the trend will reduce agricultural productivity for the rest of the century. If the climatic change is as profound as some of the pessimists fear, the resulting famines could be catastrophic. “A major climatic change would force economic and social adjustments on a worldwide scale,” warns a recent report by the National Academy of Sciences, “because the global patterns of food production and population that have evolved are implicitly dependent on the climate of the present century.”

A survey completed last year by Dr. Murray Mitchell of the National Oceanic and Atmospheric Administration reveals a drop of half a degree in average ground temperatures in the Northern Hemisphere between 1945 and 1968. According to George Kukla of Columbia University, satellite photos indicated a sudden, large increase in Northern Hemisphere snow cover in the winter of 1971-72. And a study released last month by two NOAA scientists notes that the amount of sunshine reaching the ground in the continental U.S. diminished by 1.3% between 1964 and 1972.

The BBC article on the more recent research quotes the lead author as follows:

The reversal of “global dimming” has been proposed in some circles as an alternative explanation for climatic change, removing the need to invoke human emissions of greenhouse gases.

Dr[. Martin] Wild dismissed this picture. [We can't have anything contradicting the theory of human-caused global warming, now, can we? --DR] His analysis suggests that “global dimming” and the man-made greenhouse effect may have cancelled each other out until the early 1980s, but now “global brightening” is adding to the impact of human greenhouse emissions.

So if I understand this correctly: we used to have high levels of pollution, which caused both a decrease in sunlight penetrating the atmosphere (“global dimming”), and an increase in heat retained in the atmosphere (“global warming”). These two effects cancelled each other out. Now, however, we have lower levels of pollution, so there is more global warming than global dimming.

This doesn’t make any sense, unless the theory is that low levels of pollution cause only warming, but high levels cause both warming and dimming. I’m not sure what sort of theory would predict that, but if that’s the theory, then emission-reduction programs like the Kyoto treaty will increase global warming — and I kind of doubt that’s what Dr. Wild meant. It would also mean that before the industrial revolution, when fossil fuel emmissions were (presumably) lower, that the temperature should have been higher. I think the opposite is actually true — the “Little Ice Age” ended around 1850 — and it’s certainly the opposite of that the global warming crowd claims.

I’m going to give Dr. Wild the benefit of the doubt here and assume the BBC mangled the quote or took it out of context. That happens all the time to scientists. Unfortunately, there wasn’t enough information in the article to allow me to find Dr. Wild’s paper yet, so I can’t see what it really says.

2 Responses to “Clean Air Causes Global Warming?”

  1. Chad Says:

    Global dimming, as you have written above, is a phenomenon that obviously happens closer to the earth than the global warming (greenhouse effect), is the process of pollutants blocking the rays of the sun, allowing less long-wave solar radiation to pass through the atmosphere, as it is blocked by these particles. The effects of global warming and global blockage due to soot particles “global dimming,” do not cancel each other out. The data suggests that the world will warm more, as sooty pollutants (sulfur etc.) are filtered better using new technologies and converters in poorer nations. Combining this reduction in particles that block the warming rays from the sun with the continued output of gases such as methane and carbon dioxide (which cause global warming, a separate phenomenon) will allow more solar radiation as well as more greenhouse effect, doubling the impact of warming on the atmosphere.

  2. Bob Says:

    If we do add all of this up, then using the logic that has been prevailing lately in the environmental circles we should remove catalytic converters from our cars. Their original intent was to eliminate carbon monoxide by turning it into clear, clean carbon dioxide. Now that there is a belief that carbon dioxide is the scourge of the earth’s existence, and the massive carbon footprint that is generated from the mining of the precious metals and manufacture of the catalytic converter (compared to a straight stainless steel pipe of the same length), it is clear they need to go. Urban environmental gorillas seem to have started on this mission, as catalytic converters are being cut off of vehicles in droves. Oh, wait, I am sorry….I hear that they are simply being stolen to make money on scrap. Pity, there was such a hope that it was being done for a higher purpose. Oh, well, at least we will be saving on fossil fuels as our winter home heating bills go down, handy as the price of these fuels skyrocket. Less heating homes in the winter will surely clean the air more – making in warmer??

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