How Close To Runaway Warming? - Guardian

[hatrack]

EDIT

So the key question is how close are we to a 2˚C rise, and when will we get there? 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? Warming is directly related to the quantities of greenhouse gases there are in the air, the chief of which is carbon dioxide.

Concentrations of carbon dioxide in the atmosphere are already at 382 parts per million (ppm). That is up from the pre-industrial level of 280ppm, a considerable increase. To get that in perspective we need to realise that the 280ppm figure had remained more or less unchanged for 10,000 years, the period which accounts for the entire span of modern human history. The benign climate that has allowed the human race to multiply, develop and prosper has remained stable through that period.

There have been minor variations: warm periods that allowed places like Greenland to be settled by the Vikings or mediaeval monks to make wine in Britain, and cold periods, known as mini-ice ages, that made it possible to have frost fairs on the frozen Thames in London during the 17th and 18th centuries. The last one was held in the winter of 1814.

These so-called natural variations in the climate have allowed those trying to rubbish global warming theories plenty of ammunition. But those changes have now been well studied and are better understood. It is no longer credible to suggest that what is happening now is a natural variation of a sort recorded in the last 2,000 years. In fact the variations in the quantities of carbon dioxide in the atmosphere have been small in that period, and other natural variations like sunspots have been the culprits for the previous warm and cool periods. The recent increases in greenhouse gases have changed all the rules and the stability in the climate system man has enjoyed so long. Current calculations 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.

EDIT

http://books.guardian.co.uk/extracts/story/0,,1922045,00.html

[villager]

1. sigh.

But thanks for posting...

[Boomer]

2. K&R

This should be front page news on every media outlet of the nation and the world.

[Gregorian]

3. The combination of population and modern lifestyle will increase.

The co2 concentrations are going to increase at a rapid pace. India and China. And just watch the Discovery channel on mega building and extreme engineering to see just what is being done. Massive construction projects all over the world. And it is required in order to keep all humans employed. Sorry to be the bearer of bad news, but it's just started. And it isn't going to slow down until there is a crisis, which is long long after the runaway point.

I simply cannot believe that people haven't been paying attention to this over the last thirty years. Like the first post, I can only sigh and watch.

[tavalon]

4. It is cold comfort to know that in the long run

Gaia will be okay. We won't but she will. She needs to get rid of us. We are a cancer on her body. Hope whatever comes next has a bigger brain and a bigger heart than we had.