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The Evidence for Climate Change

by James Lea, November 2004

A graph showing the sudden rise in CO2 from 270 parts per million (ppm) to 370ppm in the last 200 years, with no sign of stopping.

For those of us who care about the planet, this graph is scary. It shows carbon dioxide gas (CO2) concentrations in the atmosphere, from the years 1000 to 2003, using data from ice core samples and the Mauna Loa sampling station in Hawaii, both reputable sources.

As we can see, after 800 years of near steady CO2 levels, concentrations started rising rapidly in the 19th century during the industrial revolution. Following the second world war, CO2 levels climbed ever more steeply, with no sign of a fall off. Today levels are climbing by 2ppm every year - and that rate itself is rising.

CO2 is a greenhouse gas. Too little and the earth would be a frozen planet. Too much, and the earth will become an inhospitable planet - potentially like Venus, where the ground swelters at 450 degrees centigrade, under sulphuric acid skies - an environment in which humans could never survive.

However until now we have been fortunate. Over millions of years, through an incredibly complex ecosystem, nature has found the optimum concentration of CO2 - around 270 parts per million (ppm). We are now soaring up well above this level, having reached 379ppm already and still climbing rapidly.

Scientists are now concerned that when CO2 levels reach 400ppm - within the next ten years - we might be entering a completely new phase - one in which climate change becomes unstoppable as warming induces further warming. Sea levels could rise by 80 metres, flooding entire countries and forcing a mass exodus of peoples seeking higher ground. Wars will take place over diminishing resources as our agricultural, industrial and economic systems collapse. Perhaps only then will politicians acknowledge that endless economic growth in a world of finite resources was never a viable strategy.

This is what climate change is about. The biggest experiment humankind has ever started. An experiment we might be keen to ignore, except this time, we cannot step outside the lab. Our home planet is the laboratory.

 

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-- (c) James Lea, www.GreenLiving.co.uk, 2005 - 2007 --