The new paper on climate change produced by James Hansen, et al., ought to be headline news. Some hope! It looks at the current situation , compares it with the paleoclimate record, and offers what seems to be a last chance to get the level of CO2 in the atmosphere down to a reasonable 350ppm. http://www.columbia.edu/~jeh1/mailings/2011/20110505_CaseForYoungPeople.pdf
In fact, it reassesses what is a dangerous level of global warming. We are now at less than 1C above pre-industrial levels, but these are some of the effects:
1) Summer sea ice in the Arctic plummeted in 2007.
2) Greenland and Antarctica are shedding ice at several hundred cubic kilometres a year and accelerating.
3) Mountain glaciers are receding almost everywhere.
4) Hot, dry subtropical climate belts are expanding especially in the US, Australia, the Middle East and the Mediterranean.
5) Coral reef systems are declining by 1-2% annually due to ocean warming and acidification.
Looking at the paleoclimate record Hansen says ‘amplifying feedbacks are responsible for practically the entire glacial-to-interglacial temperature change’, which ought to sound a warning to us about the consequences of triggering feedbacks such as loss of the Arctic ice and methane release. The global temperature is now higher than at any time during the Holocene, and we’re about 1C above the 1880-1920 mean. A 2C rise above pre-industrial levels, which is generally seen as ‘safe’ by governments, he calls ‘unwise’. It would lead to ‘massive and continual disruptions of both society and ecosystems…….There are no credible arguments that such rapid change would not have catastophic circumstances for human well-being.’ This is just 2C remember.
He reaffirms the need to get CO2 levels down to 350ppm to restore Earth’s energy balance. But how can that be done? If CO2 emissions stopped now, we’d be down to 350ppm by 2050. If there’s a 20-year delay, it will take until 2250. If there’s a 40-year delay, it will take until 3000. Well, there’s obviously no way we’re going to stop all CO2 emissions this year, so what hope is there?
The good news is, there is a way out of this dilemma. 80% of the increase in CO2 has been due to fossil fuel emissions; the other 20% has been due to deforestation. Hansen says that if we carry out a massive reforestation programme, change our agricultural practices to minimum tillage and biological nutrient recycling, and cut CO2 emissions by 6% a year, we can get down to 350ppm by 2050. That’s a big ask, but it seems to be the only realistic chance we have of stopping the planet from frying. Slow feedbacks are not included in this scenario, but if we carry on with business as usual (BAU) then these will become very significant indeed. Just continuing with BAU until 2020 will mean the temperature rise will exceed 1C for 100 years, which will cause further instability in the ice sheets. The changes that we are effecting are so rapid that there are no analogies in the paleoclimate record. All in all, it seems that we are at the point of no return: either we take drastic action now in line with what Hansen says, or we are going to pass the tipping points which will make anything we do irrelevant because the planet itself will have taken over via the various feedback mechanisms. We are indeed in deep shit.
What can we, as a Transition group, do? We can support local organic farmers – we have Mabel’s farm in Mui Wo, and the farmers’ market at the ferry pier on Wednesdays and Sundays – and we can grow some of our own produce organically. We can join tree-planting programmes such as Paul Melsom’s Eagle Owl and Jenny Quinton’s Ark Eden, both in Mui Wo, and the annual planting up at Ngong Ping. And we can reduce our own emissions by 6% a year. Perhaps what we need is something like a Carbon Conversations group, http://carbonconversations.org/
where we meet once a fortnight to discuss ways of reducing our emissions, and monitor our progress as well as support each other’s efforts, and think of ways to get more people involved in the task. This is not going to save the world by itself, but that is an unrealistic target to set ourselves. We start with where we are, making sure that we walk our talk, and do everything we can to reduce our emissions by 6% a year. Beyond that, who knows what influence we might have. Is there anyone willing to start such a group? The one thing that’s absolutely certain is that we’ve got to stop using fossil fuels. That’s the bottom line.