We really thought we had all the climate records for 2010 neatly piled, but had all forgotten about this one. Deforestation and other land use changes excluded, simply burning fossil fuels in 2010 we emitted 30,600,000,000 tonnes of CO2. That’s 5 percent more than the previous record (2008), which stood at 29.3 Gt.

Of course as long as emissions keep rising there is nothing odd or unexpected about setting new records each year.

‘Last year’ (we mean 2009) was a bit different, due to the global recession. That saved the atmosphere some 4 days of breathing space – because for the climate we should not be calculating CO2 as ‘absolute emissions,’ but as concentrations – cumulative.

[Once you let them slip into free air these nasty molecules won’t listen. Although it may seem a rather simple question, climate experts have great difficulty answering just how long a single molecule of CO2 lasts (circulating between ocean and atmosphere) before it is finally, chemically, neutralised. All we know is it is somewhere between 100 years and several millennia – so for the sake of proper calculations we can keep things simple: don’t expect a decline, at any point in this century. The above graph is a climate model illustrating how an emissions peak of fossil CO2 translates into 400,000 years of elevated CO2 concentrations. The picture comes from The Long Thaw, by University of Chicago geophysical sciences professor David Archer.]

Doing the CO2 math

That brings us to climate targets and emission scenarios. The entire world has agreed (in UNFCCC contexts as well as G8, G21) to the 2 degrees Celsius climate target that IPCC AR4 links to stabilisation of combined greenhouse gases at no more than 450 parts per million (ppm) CO2 equivalents.

With both UNFCCC and IPCC pretty much out of the picture (for months/years and years respectively) – and politicians talking about Twitter uprises and IMF downfalls instead of CO2 we owe some respect to the International Energy Agency.

Because when even the green NGOs seem to understand bashing Fukushimas makes for better PR, in Paris they still don’t shy away from tackling the real quantitative sustainability problems head on.

‘We all agreed on the 450 scenario? Then let’s write it as The 450 Scenario from now [World Energy Outlook, November 2010] and let’s keep doing the math.’

Today the IEA issued another warning that we are heading the wrong way and using up almost all the remaining emissions space for the year 2020 well before that date, sliding from the 450 pathway:

“Our latest estimates are another wake-up call,” says Fatih Birol, Chief Economist at the IEA. “The world has edged incredibly close to the level of emissions that should not be reached until 2020.”

“[…]unless bold and decisive decisions are made very soon, it will be extremely challenging to succeed in achieving this global goal agreed in Cancún.”

All about the numbers: 450 requirements

According to IEA calculations the world can keep the 450 Scenario in sight if global emissions would rise by no more towards 2020 than they did between 2009 and 2010. To quantify this, a linear growth of 1.4 Gt towards a total CO2 emission of 32 Gt in 2020 would be the upper limit.

To translate this to practice: immediate break in the emissions trend – and aiming for a plateau over the rest of the decade. That should let us grow accustomed to a new idea: plunging decline from 2020 onwards. Because we* then need to catch up with Hansen’s FFPO Scenario.

*) ‘We’ should include our friends from China and India. Because 75 percent of the net global CO2 increase between 2009 and 2010 did not come from the ‘Annex 1’ countries, the industrialised west, the IEA notes.

© Rolf Schuttenhelm | www.bitsofscience.org