The Carbon Budget
In these tough economic times none of us are strangers to the concept of ‘budgeting’. It makes perfect sense doesn’t it? You have a limited amount of funds to allocate so you try to live within those means. Of course you could ‘live now, pay later’ but that way disaster lies.
That concept is applied to carbon in the context of climate change in a new study published today in the science journal Nature.
Keeping global temperature increase below 2 degrees C – beyond which we can expect climate chaos – requires limiting greenhouse gas emissions. According to the study, staying within a ‘budget’ of one trillion tonnes of CO2 in the first 50 years of this century would give us 75% chance of staying below 2 degrees.
This has huge implications for the 192 governments currently negotiating a new climate deal, due to be agreed at the Copenhagen Climate Summit in December - not least because we have, in the last nine years, already used a third of that carbon budget. If emissions stay at current levels, the rest will be gone by 2030, - much earlier, if they continue to increase according to current trends.
Staying within the carbon budget means we cannot afford to burn even a quarter of the oil, coal and gas that has already been discovered. Searching for more or developing technology to extract unconventional sources such as highly polluting tar sands is unnecessary at best and madness at worst.
The sooner we can turn the global growth trend in emissions into a rapidly declining trend, the better chance we will have in staying within the budget and consequently - below the 2 degree threshold.
However, with 2°C warming, the Earth is likely to be warmer than it has been for millions of years. For Greenpeace the associated impacts would be totally unacceptable. Even a 1 in 4 chance of overshooting this limit is too high a risk. We believe global emissions will need to peak by 2015 and then decline rapidly to as close to zero as possible by 2050. This would reduce the risk of exceeding 2 degrees C to roughly 13 % and leave a reasonable chance of limiting warming to 1.5 degrees C or less.
Live now pay later is as dangerous for the climate as it has proven to be for the economy. The longer we wait to cut emissions, the faster and deeper the cuts will need to be in the future. As the study shows, if we don’t take the bull by the horns now we will find ourselves locked into a fossil fuelled future where it will be incredibly difficult and expensive to make the cuts needed to stay well below a 2 degree increase. Instead of adapting our energy systems to a low-carbon future, which is today’s opportunity, the change will have to be immediate and painful - and that is assuming it will still be possible.
As the international negotiations limp towards their Copenhagen conclusion governments need to take heed of this study and apply the lessons learned from the economic crisis. Use the budget wisely and fairly, live within your means and don’t put off until tomorrow what must be done today.
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