Carbon Dioxide Emissions Have Already Peaked

“If greenhouse gas emissions continue to rise at current rates, then global temperatures could rise by more than 6 °C over this century.”

This familiar projection opened a short article from the Met Office this week, which went on to say that in order to have a 50/50 chance of keeping global temperature rise below 2 °C, emissions should peak within the next 10 years.

The first point could be regarded as a straw man. The phrase “If greenhouse gas emissions continue to rise at current rates” contains a very large “if” and implies tremendous future fossil fuel extraction rates of approximately three times what they are today. The reserves needed to support such rates simply do not seem to exist. The second point is more interesting though. The concept of peaking emissions is relatively new, I’ve only heard the Met Office and DECC using this expression recently.

The climate change author Mark Lynas recently wrote about the 1.5 °C target more than 100 poorer countries are calling for at Copenhagen this week. Referring to the same Met Office study he reports that in order to have a 50/50 chance of 1.5 °C emissions have to peak around about now.

What everyone seems to be missing, at least I’ve seen no reference to it in the media, is that there is a good chance global CO2 emissions have already peaked. Anthropogenic emissions of CO2 in 2009 are likely lower than they were in 2008.

The USA is the 2nd largest emitter of CO2. The US EIA has just announced that 2009 emission are down by 6.1% on last year (EIA link). This driven mainly by a 12% fall in electricity use. Europe has experienced a similar economic downturn, it’s likely our emissions have also decreased proportionately.

Globally 36% of fossil fuel CO2 emissions are from the combustion of oil. According to this week’s publication of the IEA Oil Market Report, 2008 oil extraction was 86.2 million barrels per day but in 2009 this has fallen 1.6% to 84.9 million barrels per day. China, the world’s number one CO2 emitter does buck this trend. Whilst their electricity production was a few percent down during the first half of the year, it has since rebounded and the latest data states a 5.2% increase over the last 11 months from 2008. This isn’t enough to offset the US decline let alone global oil.

Whilst this quick analysis isn’t comprehensive I think it is enough to conclude that 2008 represents at least a local maxima in CO2 emissions. A peak. The peak in emissions we need to have a chance of 1.5 °C and good odds of limiting warming to 2 °C.

Of course this is not the result of pro-action but rather the result of the global recession. It is virtually unanimously assumed that 2010 will bring recovery and with it a pick up in emissions. The nature of this recovery seems critical to me. We’ve already taken the pain, why not take this opportunity to mark 2008 as the peak and ‘recover’ on a new trajectory?