Climate Campaign

In a previous post I touched upon the fact that the association of small island nations want to limit global warming to just 1.5^oC. Such a limit to the extent of temperature rise is associated with the reduction in global concentration of atmospheric carbon dioxide to 350 parts per million, and is seen as vital in securing the survival of societies which inhabit small islands long into the future. In this post I will explore the reason behind setting such a goal for atmospheric CO₂ concentration as well as looking at one particular organization which works to try and make this figure of 350ppm a reality.

The figure of 350ppm emerged not long ago in a paper written by Hansen et al (2008). In this paper Hansen et al look at a wide range of evidence with the aim of deciding on a figure for the level of atmospheric carbon that humanity should aim at if a planet "similar to that on which civilization developed and to which life on Earth is adapted" is going to be preserved.

I’m now going to try and explain why Hansen et al (2008) came to the conclusion that they did (this isn’t as easy as it sounds, as you will see for yourself if you read the paper, it is one of the most densely packed incomprehensible papers I have ever come across).

The main contention of this paper is that climate sensitivity is double what we think; therefore the paper asserts that a doubling of atmospheric CO₂ will result in a 6^oC not a 3^oC global rise in temperature. The paper explains that the models used to come up with this 3^oC rise only took into account fast feedbacks such as changes in water vapour and sea ice. Therefore Hansen et al argue that slow feedbacks must be included; these are mainly positive feedbacks such as changes in the levels of green house gasses (e.g. due to the release of CO₂ by oceans due to changing solubility of CO₂ with changing temperature) and global albedo (largely due to change in the size of ice sheets) which lag behind changes in global temperature by hundreds of years. Therefore by plotting GHG forcing based on Vostok ice core data against temperature data (figure 1) Hansen et al are able show that climate sensitivity is actually double the 3^oC currently accepted by the IPCC.

Figure 1: Graph showing global temperature (left scale) and GHG forcing (right scale) due to CO2, CH4 and N2O from the Vostok ice core. A doubling of CO2 is equivalent to a climate forcing of 4W/m2, here the ratio of temperature of temperature to forcing is 1.5:1 therfore doubling CO2 will result in a 6 degree temperature rise (source). 

Hansen et al explain that the existence of slow feed-backs means that global climate is not presently at an equilibrium temperature and therefore even if levels of carbon in the atmosphere where to stay at the level that they are now an increase in temperature would still be observed and thus sea levels would continue to rise. As such a reduction in global atmospheric carbon levels to 350ppm is set as the goal by Hansen et al, which will therefore limit temperature rise to 1.5^oC, a level that the association of small islands sees as key to ensuring their survival.

So now that we have seen how this figure has been arrived at, what is being done to turn this goal into a reality?

In 2008 Bill McKibben, an author who wrote one of the first popular science books about global warming back in 1989, founded a grass roots organization named 350.org. As suggested by the name this organization advocates science based climate policy which will reduce atmospheric carbon levels to below the magic 350ppm. In addition the organization offers solutions to this issue by campaigning for adaptation strategies such as the move away from fossil fuels and towards green technology. It has a large global presence due to the mass public actions it organizes; an example of this is the ‘Moving Planet’ worldwide day of action which occurred on the 24^th September 2011.  This day saw over 2000 events in around 180 countries where people marched and paraded using various forms of green transport from walking to dancing, cycling to kayaking (see the video below). In addition to these large scale actions members of 350.org can often be seen campaigning at high profile inter-governmental meetings such as the recent Durban Climate conference.

Unfortunately as I showed in my post about Durban many politicians seem to have accepted 2^oC warming as the minimum temperature rise that should be aimed for, and thus, those who support a 350ppm, 1.5^oC world, have a got a big job on their hands convincing some of the most influential politicians otherwise. However, the members of 350.org look like they are up for it! Therefore, if you’re looking for something to do in the New Year that has the potential to have a truly life saving impact, why not visit their website and sign up to show your dissatisfaction with current climate policy and become a member of a global climate campaign!