Choices: E,Mission for 2°C

I am writing this post just after COP21 presidency has tabled the draft of agreement among representative of more than 195 countries. The draft contains binding actions and commitment to support for achieving warming well below 2°C (see previous post) toward achieving 1.5°C.  In this post I will try to explore the choice that is among us. The choice between mission toward 1.5°C or emission toward more than 2°C. 

Wealth of literature including Meinshausen et al.(2009) has showed increased emission of GHG will increase temperature. They estimate if CO2 emission is limited to 1000Gt in 2000-2050, it is 25% likely the temperature exceeds 2°C and 1440Gt to 50%. They also suggest if 2020 emission is more than 25% by 2000 level, the probability of exceeding 2°C will be 53-87%. See figure below:

Meinshausenet al.2009

However, the effect of emission doesn't end here. Solomon et al. (2008) shows that the concentration of CO2 and climate change it has caused, are not imminently reversible. They discuss further release will push toward more complicated irreversible climate change. 

To Limit irreversible climate change and global warming less than 2°C, emission of CO2 should be controlled. I have discussed about the trillion ton carbon in previous post which will  force 2°C Considering 1000 GtC. as a total budget avaiable budget from 1800-2100; IPCC has prepared a carbon budget. It estimates that available balance with 66% probability of achieving the target of 2°C is 184 GtC. More budget will be available by loosing the probability of achieving like 234 GtC with 33% probability. See figure below.

Carbon budget over time. From: IPCC carbon budget

From the graph above it is clear that we have limited available balance and if we want higher confidence the balance will decrease allowing fewer emission. Reduced carbon in another part might have immediate economic loss. A preliminary analysis by Elzen (2014) shows that achieving  2°C target will cost maximum of 6% of GDP, however will regain the growth after peaking at around 2055. 

We are not only the source of CO2 emission but a potential victim of climate change. We now have only two option left. Either choose "emission" and get prepared for disaster or collectively work in "mission" to make sure temperature rise will remain well below 2°C.

pubs.acs.org

 While concluding this post, COP21 has reached in an agreement to reduce the global warming below  2°C. With this choice of the century; now it is time to make a choice to materialize the commitment. I would like to thank all concerned and global community for setting this landmark target. Now, my urge is for making a sincere choice among emission-to breach and mission- to keep the target well below of 2°C. First one have short term gain with then ever pain and second one has some pain recently then ever gain.