May 11, 2013

Where Is the Global Warming of Yesteryear?

During the last decade, the rate of global warming has slowed ... for once, a fact about climate science that the deniers don't deny. Instead, they leap on it as proof that global warming is a hoax. What they do is take the chart below and look only at the last 10 years and not at the whole 100+ years that it covers. They also stop reading the articles on this after the lede paragraph describing the lack of warming over the last decade. They never get to the fourth paragraph down that says this does nothing to negate the science or the reality of climate change driven by global warming.

Why the rate of warming has slowed is something of a mystery. Some attribute it to emissions of sulfur dioxide from volcanic eruptions. These emissions reach the stratosphere some 20 miles up where they change into sulfuric acid and water that reflect sunlight, thereby cooling the planet. Others say the oceans are absorbing the excess heat. The science is complicated, something to do with wind patterns and the Pacific Decadal Oscillation (PDO), which act together to produce a see-sawing of ocean surface temperatures through warm and cold phases lasting several decades.

But like a see-saw, what goes up must come down. Right now the PDO is working in our favor. That won't last forever. Inevitably, the mixing that pushed the warmth to the bottom of the sea will reverse and bring it back up. So too, the volcanic emissions will eventually clear in about 10 years. The net effect will likely be a sharp rebound effect where temperature rises that were held down spring back with a vengeance.

Now consider the recent news that we have crossed the 400 parts per million (ppm) threshold in terms of carbon dioxide levels in the atmosphere. When I first started reading about climate change and global warming, 350 ppm was considered a red line of sorts. Well, looks like that ship has sailed.

After decades of scientific research, reams of studies, and more promises made by governments than you care to count, the net result has been little or no effective action to counter the effects of rising levels of carbon dioxide in the atmosphere. We have made our choice, and now we must live with it.

We can't prevent it. We can only adapt to it. Not much of a legacy for our children, but at least you can teach them well by doing the research and connecting the dots from carbon dioxide emissions to heat trapped in the atmosphere to rising global temperatures to changes in global weather patterns. We owe them at least that much.

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