In his latest book, Paul Brown ex-environment editor at The Guardian ponders how close we are to the tipping point of runaway climate change.

The phrase “tipping point” is certainly heard a lot more from scientists these days. It is, says Brown, where a small amount of warming sets off unstoppable changes, for example the melting of the ice caps and tundra.

The tipping point in many scientists’ view is the 2?C rise that the EU has adopted as the maximum limit that mankind can risk. Beyond that, as unwelcome changes in the earth’s reaction to extra warmth continue, it is possible to trigger runaway climate change, threatening life on earth as we know it.

So how close are we to the 2 ?C rise and when will we get there? Brown writes: “The first thing to admit is that nobody knows for sure, but many who understand the science say the answer to this twin question is, first, that we are already very close, and second, we might get there terrifyingly soon. In fact the 2?C threshold is much closer than almost anyone outside the specialist scientific community is prepared to acknowledge. By any standard, if you care about the future of the human race, it is too close for comfort. So to the vital question of when we might reach 2?C above pre-industrial levels; in other words how much time do we have to curb our excess emissions?”

“Current calculations” says brown “suggest that if and when the level reaches 450ppm there will be a 50% chance of the earth’s temperature exceeding a rise of 2?C – in other words an even chance of potentially catastrophic climate change. To be on the safe side (the so-called precautionary principle, which so many politicians claim they endorse) some scientists believe that the carbon dioxide in the atmosphere must be pegged back to 400ppm – a mere 18ppm above the current level. So, on their current calculations, since man began the industrial revolution, and unwittingly an experiment with the climate, the human race has already got more than 80% of the way to causing a potential disaster. On this evidence it is clear that drastic action is needed”.

“Some scientists have certainly been urging politicians to take urgent and immediate action. Recent evidence demands, according to a consensus of the world’s best climate scientists, that we need to cut existing emissions by between 60% and 80% in the next 40 years to stand a chance of preventing climate change becoming unstoppable, and keeping control of our own destiny.”

Well that makes the Kyoto agreement – where emissions were cut by 5.2 per cent look pretty pathetic. And the reaction of countries such as America… well its like carrying on driving happily over the cliff. ..