Global Warming

20 April ‘07

I think I’ll spare the politicians this week, and instead discuss another subject that concerns us all, seems to have been in the news a lot lately, and has Al Gore climbing the walls. That subject is global warming. First off, yes, I do think global warming is real, and I do think it’s something that’s going to cause all of us a lot of discomfort for a long time to come. But I also question much of the stance taken by environmentalists concerning its causes, and particularly it’s “cures”. Admittedly I’m not an environmental scientist, nor do I know how to juggle statistics to substantiate whatever position I happen to support. However, I do think that common sense is a much more useful tool than what in many cases is turning out to be little more than well publicized junk science.

The global climate has shifted and varied widely for billions of year, perhaps since the Earth first had an atmosphere. The oldest geo-climatic records have allowed us to reconstruct climatic changes fairly reliably over the last 500 million years. During this time, the global climate has moved from extensive periods of warmth with tropical conditions extending nearly to the poles, to periods of extreme cold several times, each cycle lasting 100 million years or more. Although today we are concerned about global warming, we do in fact lie in the middle of an ice age, which began 40 million years ago when the permanent ice sheets formed over Antarctica. The change from the much warmer global climate which existed during the age of dinosaurs (when the global average temperature was perhaps 10°C higher than at present), is thought to have been caused by changes in the distribution of landmasses, and the associated changes to energy redistribution throughout the entire climatic system.

Within the present interglacial period, further fluctuations in the global climate can be seen in the climatic records, and more recently in the instrumental records. During the last 1000 years, the climate has moved from a period of comparative warmth to a "Little Ice Age" between the 16th and 19th centuries, with changes of between 0.5 and 1°C in the global average surface temperature. A one degree variation may not seem like much, but when considering the size of the planet, that’s a lot of heat energy! Although it is not clear what has caused these climatic shifts, variations in the Sun’s energy output, ocean circulation and the occurrence of major volcanic events are believed to play an important part. Most recently, since the beginning of the 20th century, we have entered a renewed period of warming that some scientists claim is the result of mankind's enhancement of the natural greenhouse effect, through pollution of the atmosphere. I don’t think that any intelligent person could deny that human activity does have a measurable effect on the Earth and its climate. But the question currently being battled over is just how much of this warming effect is actually due to human causes, and how much stems from natural causes. The global average temperature is now about the same as it was during the warm period about 1,500 years ago, although still much lower than it was during the age of the dinosaurs.

So what drives climate change? Solar energy is of course the prime mover. A third of the sun's energy is reflected back into space after hitting Earth's upper atmosphere, but two thirds gets through, driving Earth's weather engine. Consider the possible results of a small increase in the sun’s energy output, and the solar energy dose we receive each day. A balance of gases maintains Earths livable temperature. Known as "greenhouse" gases because they trap heat inside the atmosphere, and reflect a portion of that heat back to Earth's surface. These gases include water vapor, carbon dioxide, methane and nitrous oxide. Covering two thirds of Earth, oceans are the planets primary heat sink and energy transport system. The oceans and marine life also consume huge amounts of carbon dioxide. While water vapor is the most potent greenhouse gas, clouds also affect evaporation, both cooling the Earth by reflecting solar energy, and warming the Earth by trapping heat being radiated up from the surface. The whiteness of polar ice and snow reflects solar heat, helping to cool the planet. A tropical forest will soak up huge amounts of carbon dioxide, but once that land is cleared for agriculture or new cities, that part of the CO2 “sink” is history.

Humans magnify warming to some extent by adding to the greenhouse gases naturally present in the atmosphere. Fossil fuel usage is usually blamed for rising carbon dioxide levels rather that the mega-tons of CO2 released annually by volcanoes. On the other hand, humans create temporary, localized cooling effects through the use of aerosols such as smoke and sulfates from industry, which reflect sunlight away from Earth. A recent scientific study has, with considerable fanfare, determined that New York City is responsible for 1% of the greenhouse gas emissions in the United States. So what are we expected to do with that little detail, ban New York City? The environmentalists have been ranting and raging for years about the human causes, and now, at the start of the 21st century, the political left is making it their newest electioneering cause as well. Al Gore, inventor of the Internet and the famed “hanging chads” of Florida’s elections (who I understand is also known as the “Goracle” among his Hollywierd friends), is busily promoting himself as the Guru of global warming, and apparently has a yet unannounced plan to save the world from it’s Republican ways.

A few years back, I inadvertently got myself into an on-line global warming “discussion” with a few somewhat rabid environmentalists. You can probably imagine what they had to say when they found out that I was a rotten, nasty, evil wildland firefighter, and thus interfering with natures plan to renew the forests. Their idea of saving the planet was that all humans (with the exception of environmentalists of course) should immediately run out and commit mass suicide, leaving those with the proper appreciation of nature to stick around and “repair the damages”. I won’t get into my response to that idea… although my computer didn’t melt down, it was kinda singed around the edges.

As an interesting side note, European spacecraft have recently shown that the climate of Mars is warming nearly as much as Earths for some unknown reason. I suspect Mr. Gore will shortly discover that the Mars rovers “Spirit” and “Opportunity” are the sole cause, and in yet another Hollywood release demand that NASA immediately withdraw the robot vehicles from Mars.