Saturday, March 22, 2008

Climate change due to solar radiation and human emissions

When we look at climate change we have to look at changes in

(1) solar radiation

(2) human emissions of CO2.

Professor Peter Cox, a climate expert at the UK's University of Exeter, has studied the Little Ice Age, 400 years ago (Geographical Research letters Vol 33; New Scientist 22 March 2008). (Rising temperatures bring their own CO2 / Grains of Sand)

Cox has noted that:

This Little Ice Age began with reduced solar radiation due to a variation in sunspots.

When it gets colder, the oceans, and eventually the land, absorb more CO2.

So CO2 levels went down after the Little Ice Age began.

Cox notes that when temperatures rise, due to increased solar radiation, there is eventually a rise in CO2 levels.

The oceans and the land absorb less CO2

The temperature rise comes first, and is followed by the rise in CO2.

Cox believes that what we have now, in the present time, is both a rise in CO2 levels due to increased solar radiation and an increase due to human-made emissions.

Things are worse than we thought, argues Cox.

According to Cox (Rising temperatures bring their own CO2):

"There seems to be a change of about 40 parts per million (ppm) in CO2 levels for every 1 °C change in temperature.

"Since further global warming is inevitable in the near future, it means we're heading for big natural increases in CO2 on top of human-made emissions.

"This extra increase will boost global warming in the coming century to about 50 per cent above mainstream climate projections, says Cox, because they only include the effect of CO2 on temperature, and not temperature's effect on CO2.

"The system turns out to be more sensitive than we thought. If we get 4 °C of warming in the coming century, that by itself will raise CO2 levels by an extra 160 ppm."

Pre-industrial levels of CO 2 were 270 ppm

Current levels of CO2 are 380 ppm

Many scientists believe there will be a devastating global climate at 450 ppm.


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