If we can’t bring actual emissions down to within the IPCC projections range – than why don’t we bend the spectrum upwards. It’s easier.

Does that sound terribly fatalistic? We’re not saying it is happening, but we wouldn’t be surprised to find out, at the planned release of IPCC AR5 in 2013. After all, there will be geoengineering in it as well – another clear way to say hello to reality.

Besides, it’s been a while since IPCC’s Special Report on Emissions Scenarios (SRES) of 2000 – the one that served to tell us what we then thought would be the upper and lower limits of an atmospheric crisis unfolding – and that were reproduced for the Third and Fourth Assessment Report (of 2001 and 2007).

Why exactly again does reality not fit into a RANGE of scenarios?

In the year 2000 perhaps the world was a little overoptimistic. We had just had the booming years of the 90s during which all countries failed to address sustainability issues ranging from energy transitions to tackling public debt. Instead everyone enjoyed the party, was rich for a while, consumed a little extra – and thought it would be like that forever. The nineties (with in the US a Democrat in office – so an opportunity window to do anything environmental in the UN) however were a missed chance to spend temporary wealth where it would count for generations. Now the whole world is poor, so ‘let’s at least stick to business as usual scenarios – because else we may make the economy even angrier with us.’

In climate terms 2000 was before the renaissance of coal and before China showed itself a bit sooner than expected as the world’s top emitter. It was also well before the world in Copenhagen decided not to agree on actually tackling climate change.

Could you cut geopolitics and be a bit more specific?

In scientific literature a few comparisons between the SRES projections and reality exist, like a 2007 PNAS study, which stated “The emissions growth rate since 2000 was greater than for the most fossil-fuel intensive of the Intergovernmental Panel on Climate Change emissions scenarios developed in the late 1990s.” And for example that new emissions record of 2010 didn’t help much either.

In their 2007 report the IPCC already acknowledged some emissions drivers had been underestimated in the 2000 SRES forecasts, like world population growth. Well, then there too a 2010 Revision didn’t help much.

SRES still at base of most climate consequence studies

Problem is the old scenarios are still at the base of many climate studies. Remember that Nature Climate Change publication from August that tried to forecast biodiversity loss under continued climate change over the next 7 decades? Such studies use SRES input – so science journalists will always have to add ‘oh yeah, but in reality things will be worse’ as a final note to their articles.

Presently French researchers of the National Centre for Scientific Research are investigating a possible update of emissions scenarios for IPCC AR5. In their press release from Friday they announce they have created a database [which seems not always to work] with updated data on current emissions sources, not just for CO2 and methane, but also for various nitrogen compounds and for instance soot – that most-ignored climate forcer.

The researchers say they took a particular interest in emissions generated by human activity and the combustion of biomass. So we wonder if in IPCC AR5 we allow some extra room for pessimism, will there also be a new emissions scenario centred on a world free of tuk-tuks and slash & burn agriculture? Because some of these new maps the French made do show a lot of red paint to the South and East of Annex 1 countries, the rich industrialised world. Once you start to stop ignoring reality, there really is no end to it…

© Rolf Schuttenhelm | www.bitsofscience.org