Climate Change Update

Date Of Article: 2009-08-11

Almost a century ahead of schedule - the critical climate processes might have begun.

Despite the political rhetoric, media headlines and corporate promises,  carbon emissions are soaring far above the worst scenarios considered by the Intergovernmental Panel on Climate Change, driven mainly by the coal-fuelled economies in the developing world. So much extra pollution is now being pumped out that most of the climate targets debated by politicians and campaigners are fanciful at best. The battle against dangerous climate change is been lost, and the world needs to prepare for things to get very, very bad.

The official position is that the world should aim to cap this rise at 450ppm. but even this offers only a 50/50 chance of limiting the temperature rise to 2C, which the EU defines as dangerous. (We have had 0.7C of this rise already and an estimated extra 0.5C is guaranteed because of emissions to date.)

Many scientists, politicians and campaigners privately admit that 2C is a lost cause. Ask for projections around the dinner table after a few bottles of wine and more vote for 650ppm than 450ppm as the more likely outcome. At 650ppm, the science says the world would face a catastrophic 4C average rise.

Bob Watson, chief scientist at the UK Environment Department and a former head of the IPCC, warned this year that the world needed to prepare for a 4C rise, which would wipe out hundreds of species, bring extreme food and water shortages in vulnerable countries and cause floods that would displace hundreds of millions of people. Warming would be much more severe towards the poles, which could accelerate melting of the Greenland and West Antarctic ice sheets.

The escalating scale of human emissions could not have come at a worse time, as scientists have discovered that the Earth's forests and oceans could be losing their ability to soak up carbon pollution. Most climate projections assume that about half of all carbon emissions are reabsorbed in these natural sinks. However a string of recent studies suggests that the carbon sinks are already failing

The Southern Ocean's ability to absorb carbon dioxide has weakened by about 15% a decade since 1981, while in the North Atlantic, scientists at the University of East Anglia also found a dramatic decline in the CO2 sink between the mid-1990s and mid-2000s.

A separate study published this year showed the ability of forests to soak up anthropogenic carbon dioxide - that caused by human activity - was weakening, because the changing length of the seasons alters the time when trees switch from being a sink of carbon to a source.

The Arctic permafrost, the largest frozen peat bog in the world, has begun to melt for the first time since it formed 11,000 years ago. Scientists believe the bog could begin to release billions of tonnes of methane locked up in the soils, a greenhouse gas 20 times more potent than carbon dioxide (The Arctic permafrost contains twice as much greenhouse gas as the entire global atmosphere. It remains safe for as long as the ground stays frozen. But the melting has begun). The World Meteorological Organisation recently reported the largest annual rise of methane levels in the atmosphere for a decade.

Earlier this year, Jim Hansen, senior climate scientist with Nasa, published a paper that said the world's carbon targets needed to be urgently revised because of the risk of feedbacks in the climate system. He used reconstructions of the Earth's past climate to show that a target of 350ppm, significantly below where we are today, is needed to "preserve a planet similar to that on which civilisation developed and to which life on Earth is adapted".

Bob Watson former head of the IPCC has warned "We must alert everybody that at the moment we're at the very top end of the worst case scenario” .... “It was already very urgent to start with. It's now become very, very urgent."



This is a summery of an artical “Too late? Why scientists say we should expect the worst of global warming” by David Adam , The original artical was first published on on Tuesday 9 December 2008. It appeared in the Guardian/UK Tuesday 9 December 2008 on p22 of the International section.