Week 4 was about predicting the future using climate models, seeing that warming is going to happen and looking at alternatives to simply reducing carbon usage. (Simply – ha!)
Even if anthropogenic CO2 emissions stop now, the CO2 already in the atmosphere will continue to cause warming. And CO2 emissions will not stop right now.
First we need to cut emissions – using less carbon is the main thing. But capturing and storing CO2 where we still produce it (CCS) is also vital. This is more effectively done in large establishments like power stations than small, mobile objects like cars. Drax power station is switching to burning wood rather than coal on half its generating units, saving 80% of carbon emissions. If Drax applied CCS to the wood burning units, it could become carbon-negative there.
We do not understand all the mechanisms and feedbacks well enough yet to deploy geo-engineering. If we did, the climate models would work better and we wouldn’t be surprised by the pause in temerature rise and such like. We are still discovering new things when the models go wrong. I’d hate to discover new things by making the climate itself go wrong! No way back from there…
That said, we should still research geo-engineering and all the other aspects of climate, to improve our knowledge, and establish an international legal framework. If we cannot cut emissions, we might well need a ‘Plan B’ one day. Aside from that, geoengineering might be necessary to hold temperatures down for a period once CO2 emissions have been eliminated, but while CO2 already in the atmosphere continues to cause warming. (Let’s do the cutting first, OK?)
Final point. The question of whether of or not to deploy geo-engineering might well be taken out of our hands. Climate change itself will re-engineer the planet. The residents of New Orleans after Katrina and the Philippines after Haiyan (and even, on a smaller scale, Somerset after constant flooding) might well consider themselves geo-engineered out of their homes and livelihoods.