In 2006 Al Gore claimed that industry was causing 2-5°C of global warming per century, and that this, in turn, would cause the oceans to rise by 8 m by 2100. Despite a record cold snap this week, and record ice levels in the antarctic, the US this week banned all incandescent light bulbs of 40W and over in an effort to stop the tragedy. This was a bad move, in my opinion, for a variety of reasons, not least because it seems the preferred replacement, compact fluorescents, produce more pollution than incandescents when you include disposal of the mercury and heavy metals they contain. And then there is the weak connection between US industry and global warming.
From the geologic record, we know that 2-5° higher temperatures have been seen without major industrial outputs of pollution. These temperatures do produce the sea level rises that Al Gore warns about. Temperatures and sea levels were higher 3200 years ago (the Trojan war period), without any significant technology. Temperatures and sea levels were also higher 1900 years ago during the Roman warming. In those days Pevensey Castle (England), shown below, was surrounded by water.
During Roman times the world was warmer, and Pevensey Castle (right) was surrounded by water;. If Al Gore is right about global warming, it will be surrounded by water again by 2100.
From a plot of sea level and global temperature, below, we see that during cooler periods the sea was much shallower than today: 140 m shallower 20,000 years ago at the end of the last ice age, for example. In those days, people could walk from Asia to Alaska. Climate, like weather appears to be cyclically chaotic. I don’t think the last ice age ended because of industry, but it is possible that industry might help the earth to warm by 2-5°C by 2100, as Gore predicts. That would raise the sea levels, assuming there is no new ice age.
Global temperatures and ocean levels change by a lot; thousands of years ago.
While I doubt there is much we could stop the next ice age — it is very hard to change a chaotic cycle — trying to stop global cooling seems more worthwhile than trying to stop warming. We could survive a 2 m rise in the seas, e.g. by building dykes, but a 2° of cooling would be disastrous. It would come with a drastic reduction in crops, as during the famine year of 1814. And if the drop continued to a new ice age, that would be much worse. The last ice age included mile high glaciers that extended over all of Canada and reached to New York. Only the polar bear and saber-toothed tiger did well (here’s a Canada joke, and my saber toothed tiger sculpture).
The good news is that the current global temperature models appear to be wrong, or highly over-estimated. Average global temperatures have not changed in the last 16 years, though the Chinese keep polluting the air (for some reason, Gore doesn’t mind Chinese pollution). It is true that arctic ice extent is low, but then antarctic ice is at record high levels. Perhaps it’s time to do nothing. While I don’t want more air pollution, I’d certainly re-allow US incandescent light bulbs. In cases where you don’t know otherwise, perhaps the wisest course is to do nothing.
Robert Buxbaum, January 8, 2014