Monday, April 13, 2009

Dynamism and precision 

Like many people my age, I learned first about chaos theory reading James Gleick. One of the stories that made an impression on me was the story of Edward Lorenz, whose attempts to replicate meteorological data with a computer model led to discovery of the butterfly effect. The story is that he got entirely different results in replication because he truncated data at five significant digits (unsure of the number; it's been years since I read the book.)

I was flashed to that insight in reading this today:

The Earth's climate is driven by the receipt and redistribution of solar energy. Despite this crucial relationship, the sun tends to be brushed aside as the most important driver of climate. Calculations on supercomputers are primitive compared with the complex dynamism of the Earth's climate and ignore the crucial relationship between climate and solar energy.

"To reduce modern climate change to one variable, CO2, or a small proportion of one variable - human-induced CO2 - is not science. To try to predict the future based on just one variable (CO2) in extraordinarily complex natural systems is folly. Yet when astronomers have the temerity to show that climate is driven by solar activities rather than CO2 emissions, they are dismissed as dinosaurs undertaking the methods of old-fashioned science."

Over time, the history of CO2 content in the atmosphere has been far higher than at present for most of time. Atmospheric CO2 follows temperature rise. It does not create a temperature rise. CO2 is not a pollutant. Global warming and a high CO2 content bring prosperity and longer life.

Emphasis added. Ian Plimer's new book is due out tomorrow in Australia and next month in the USA.