Today’s paradox: global warming may offset Criegee cooling

Criegee climate coolingAnd that’s not quite the same as having things the other way around. If you see Criegee biradicals as silver bullet, remember they are already constantly being fired up…

Scientists from The University of Manchester, the University of Bristol and Sandia National Laboratories report in Science that they have traced the brainchild of German chemist Rudolf Criegee in the troposphere.

Criegee biradicals (formaldehyde oxide – CH2OO – atmospheric presence already hypothesised in the 1950s) accelerate the formation of sulphate and nitrate in the atmosphere. These increase the amount of solar energy that is blocked or reflected, through the formation of aerosols and clouds.

If you place this in the perspective of the current global rising temperature trend there appears reason to cheer at the discovery. The University of Manchester press release echoes such optimism, as it refers to a particle that could cool the planet.

Could indeed, but will it?

Finding a ‘global cooling particle’ that has always been there is not the same as actually influencing temperature – offsetting global warming – through some form of solar radiation management geoengineering. First another clever mind would have to think of a way to actually increase these Criegee biradicals.

[*) The Criegee particles are hardly a new tool for geoengineering minds. There seems little extra benefit in pumping formaldehyde oxide or any of its precursors into the atmosphere – when it is equally feasible to emit sulphate directly – if at all we want to go ‘the ocean acidification route.’]

Meanwhile, we could just as well be working in the opposite direction.

Next to plentiful oxygen (for the radicals) the formation of CH2OO requires a methyl group, which would have to come from an organic source.

“A significant ingredient required for the production of these Criegee biradicals comes from chemicals released quite naturally by plants, so natural ecosystems could be playing a significant role in off-setting warming,” says Dudley Shallcross, Professor in Atmospheric Chemistry at the University of Bristol.

When it turns out the stability of the climate actually depends on the amount of by-products of combined biological processes in the Earth’s biosphere – and not just the carbon-based greenhouse gases like CO2 and methane – it may be a good thing to keep an even sharper eye on any possible large-scale disturbances of that biosphere, like deforestation, or climate change.

Because it may just be the case that turning 40 percent of biomes upside down will have a detrimental effect on methyl availability.

[Unfortunately things are indeed very much down to ‘scientific intuition’ here. We’re not even sure by a 25 percent margin just how large our planet’s total photosynthesis is. Measuring a decline may however be relatively easy – as there is one important indication: when you see atmospheric CO2 concentrations rising faster than you would expect based on fossil emissions – you know the sum total of biology probably isn’t feeling too well.]

© Rolf Schuttenhelm |

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