March 16, 2007

Thin Ice

Al Gore's attempts to legitimize the climate change debate have drawn criticism from mostly the least credentialed of our society. Attention seeking scientists with no expertise in the field, infotainment publications and the occasional current affairs show trying to masquerade as news.

The New York Times has published a clever piece of work that demonstrates the essential problem of debating climate change - most people don't understand the science, especially the media.

The article in question was reprinted in the Sydney Morning Herald, minus an estimated 770 words. The author takes the position that Al Gore fudged his numbers and ignores dissent within the scientific community. To support this assertion the author brings up a few old chestnuts that have been floating around the media for years, which suggests to me that the real scientific debate was a little too complex and wouldn't make for interesting reading.

The pitfall this author has fallen into lies in trying to fit the data into a different model instead of reporting on what the experts have been able to conclude.

The most common error is made by comparing 20,000 years of climate changes to our present situation. Many journos have fallen for this trap - the current temperature changes are not outside the ranges of those previously experienced and naturally occurring. The statement is true, but the interpretation is usually wrong. The key issue is whether the weather is changing *because* of man or nature, and the cause of the change is of paramount importance when estimating the future changes heading our way.

This is not a trivial distinction. The scientists know that global temperature changes in the last 20,000 have tracked with CO2 levels in the atmosphere. The data shows that when CO2 levels rise, so does the temperature. What is most alarming is the rise in CO2 in recent years, which goes well beyond the levels recorded over the last 20,000 and is still rising. We know that our modern lifestyle has created enormous CO2 emissions, we know that the atmosphere is filling up beyond previously recorded levels, and we know that global temperatures have historically risen with CO2 levels.

To ignore this data and fob it off as "part of the earth's natural cycle" is folly. The ability of civilized man to load the atmosphere with CO2 is not part of any natural cycle, and we are heading into uncharted territory.

The secondary issue is that regardless of the cause, if global warming is happening then we need to do something in order to minimise the impact on the lives of billions of people. It's not just about rising sea levels, ecological destruction by regional temperature anomalies, or an increase in natural disasters - when you put these all together the challenge of sustaining the current human population on earth becomes even more difficult.

I'll add a third issue into the mix, tipping points. Scientists of any specialisation will be familiar with this concept, not to mention a few of the more savvy marketing people out there. Tipping points reflect the inertial nature of all dynamic systems, and remind us that dramatic changes are often preceded by the most subtle of signals.

Cause and effect are rarely linear.

Take a glass of milk sitting on the table. You can slide it towards the edge and nothing happens. No milk is spilled. Maybe if you slide it quickly a few drops spill over the edge, but not much. Keep sliding it. Once you reach the edge of the table the whole glass tumbles over and the milk is all over the floor.

At that point there will be no use in crying.

>Sydney Morning Herald abridged version of the story

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