Sunday, November 01, 2009

A Thought Experiment on Global Warming

Hard numbers tend to put people to sleep. But numbers can tell a story. Imagine a warlord of some faraway country who's awakened in the middle of the night and told his enemy has sent 100 soldiers across the border. "You awakened me for a hundred soldiers? Take care of it and don't bother me!" says the warlord before falling back asleep. An hour later, another aide comes in and wakens the warlord to tell him 500 soldiers have crossed the border. "What? Can't my pitiful generals take care of 500 soldiers? Wake me when a real army comes or I'll have your head!" Three hours later a third aide comes in. "How many?" growls the warlord. "One million, sir." The third aide finally has the full attention of the warlord.

The scenario, by the way, has happened in the past. It pretty much happened to Stalin in 1941 when Hitler sent his troops across the border. Stalin first refused to believe the early reports and pretty much panicked hours later when he realized how big the invasion was. Stalin eventually threw the Germans back but without the help of the United States, it is highly probable that Hitler's invasion would have succeeded.

Today many people can't believe global warming is real. One part of the problem is that numbers are clearly putting people to sleep. But another part of the problem—besides coal and petroleum companies with vested interests—is that there are people who can't believe humans can have that much impact on the environment. I find this odd since there are plenty of examples of human impact if one simply takes a good look around. I've seen, for example, large deforested areas that once held logging communities back in the 1930s. Those communities are now ghost towns so old and neglected there isn't much left of them.

My grandmother many years ago showed me any number of areas in Southern California that used to be wetlands before they were drained and turned into large housing developments. It takes willful ignorance to pretend that we haven't had a major impact on biological life. We have driven many species to extinction or near extinction. We have now been over-harvesting the world's oceans for a number of years. But even by the 1960s, the average person ought to have known we were having an impact on fish populations. Why? Because many types of fish people were catching were considerably smaller than the ones caught in the 1920s.

In California, it's almost startling to realize that many of the mining areas famous during the Gold Rush haven't produced significant ore for over a hundred years.

Actually humans have been having an impact for a very long time. The pyramids have been visible from space for thousands of years. Today, from space, one can see smog covering many large areas around the world.

For some reason, many examples of human impact get ignored. So I'm going to suggest a thought experiment that might suggest just how much influences humans have on the earth. Thought experiments are just illustrations and after I present the following thought experiment, I'll add some sensible qualifications.

First, we have to start with some numbers. In 2008, humans consumed at least 474,000,000 terajoules of energy. Other estimates are in the same ballpark but this number comes from various published sources (though it does not include minor sources of energy such as burning firewood). The important thing to know is that 80-90% of the consumed energy has come from burning various kinds of fossil fuels. It's not a quaint metaphor to say we live in the age of oil.

Now there are 6.8 billion people in the world and maybe it's not all that amazing that so many people would produce so many terajoules. But consider this: the atomic bomb that was dropped on Hiroshima in 1945 produced some 60 terajoules of energy. That's a tiny fraction of the energy humans now produce in a year. The largest hydrogen bomb the United States exploded was a bit more than 45,000 terajoules but that's still a very tiny percentage of yearly energy production.

Let's look at this another way. At the height of the Cold War, the U.S. and Soviet Union had in excess of 20,000 nuclear weapons. The yield of the weapons ranged from 1 kiloton up to something like 15-45 megatons of dynamite. If we assume an average size of 100 kilotons, the destructive yield of 20,000 nuclear weapons is 6,000,000 terajoules. That is still less than 2 percent of the energy humans produce and consume in a year.

Now many global warming naysayers say humans don't have enough impact on the climate to affect global warming. So now for the thought experiment. It's actually just the reverse of a thought experiment that was done some thirty years ago. Scientists asked what if 20,000 nuclear weapons were released in a massive all-out nuclear war. The affect on the climate was interesting. It was argued at first that all-out nuclear war would lead to a nuclear winter lasting two years. The reason was diminished sunlight as a result of all the dirt and debris from the explosion thrown up in the air as well as all the smoke from the ensuing fires. However, later calculations showed that the result would only be a kind of nuclear autumn lasting a few months. Nuclear war of such size of course would create an unimaginable level of destruction. Notice that exploding 20,000 nuclear weapons would not raise the temperature of the earth in the ensuing days (at least not at first). That's because most of the heat would be radiated into space but the debris would have the effect of blocking out sunlight.

As it happens, heat is also supposed to escape into space when we release all that heat from burning fossil fuels. To a large extent that's exactly what happens even now. Except that greenhouse gases are trapping a certain percentage of escaping heat and reflecting it back to earth.

There is a possible though far-fetched way that humans could accelerate global warming with only a tiny percentage of our annual energy production—not that anybody in their right mind would do it. But we're talking about a thought experiment. If 20,000 nuclear weapons were sent to Greenland for use in late spring or summer, a geologist with knowledge of glaciers and the specific underlying drainage basins working together with a demolition expert could probably figure out where to explode the weapons to release somewhere around a third of the ice pack. This would be sufficient to raise the world's sea levels by seven feet. Even if the released radiation is discounted—which of course it can't—the result of the higher sea level alone would be devasting within days, if not hours. In addition, there would be very little in the way of fires and most of the material that would enter the atmosphere would be water. It is probable that the remaining ice would melt at an accelerated rate thus eventually raising sea levels even further.

Now this is just a thought experiment to show how just a tiny fraction of the energy we use every year could be channeled so that the physically world would dramatically change. Just as no one in their right mind would launch an all-out nuclear war, no one in their right mind would send 20,000 nuclear weapons to melt a third of Greenland ice sheet. When we understand the possible consequences of our actions, there are certain things human beings do not do. Let me repeat that: there are certain things human beings do not do.

Every year the evidence of global warming grows stronger, not weaker. When any corporation talks about cleaning up the environment, find out if they're simply exporting their excess carbon dioxide or even their pollution to a third world country. Most global warming naysayers are funded by coal companies and the oil corporations. These are the same people who have taken years and years to clean up their own pollution in other areas involving their operations. When there are oil spills, the first response of many oil companies is to call the lawyers before they call the clean-up specialists. The climate doesn't pay much attention to lawyers. If humans do certain things, there are consequences. That's just the way it is. It is the early 21st century and it's time for all of us to bite off some responsibility. It begins by agreeing there are certain things human being do not do.

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