It's getting hotter

Two new studies find that climate change may be taking place at a faster rate than current models predict.

The first find that soot plays a greater role than previously thought in heating the atmosphere.

More alarmingly, the second finds that not only does more carbon dioxide in the atmosphere contribute to global warming, but higher atmospheric temperatures increases the amount of free carbon dioxide, resulting in a potentially devastating feedback loop:

"There seems to be a change of about 40 parts per million (ppm) in CO2 levels for every 1 °C change in temperature," says Cox, who has revisited the Little Ice Age data. 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. And that may be rather conservative." Current levels are 380 ppm, compared with pre-industrial levels of 270 ppm. Many scientists believe anything above 450 ppm will create a devastating global climate.