For those of you who are worried that Trump’s decision to pull out of the Paris Climate Agreement is a bad thing I would ask you to consider two pragmatic questions: How much was US participation going to change future temperature and how much would it have cost?
Bjorn Lomborg used the standard MAGICC climate model to determine how much the future temperature would change due to the United States “Nationally Determined Contribution”. He found that the full US promise for the COP21 climate conference in Paris will reduce temperature rise by 0.031°C. Mike Hulme posted an estimate for the difference of 0.3°C. For the record, my opinion of the MAGICC model is that it is too sensitive to CO2 so I think the impact would be even less the lower bound. In any event, atmospheric temperature is reported to the nearest whole degree Fahrenheit in the US which is 0.55°C. In other words the temperature change range expected from our Paris commitment is lower than the reporting limit so the change is nothing that could be observed.
So how much was it going to cost? If you bothered to listen to the Trump speech on his decision he talked about the Green Climate Fund. If you have any doubts about the decision look up the briefing note by Climate Focus. I found this quote particularly interesting:
“The Paris Decision, serving as guidance for the implementation of the Paris Agreement and pre-2020 action, ‘strongly urges developed country Parties to scale up their level of financial support, with a concrete roadmap to achieve the goal of jointly providing USD 100 billion annually by 2020 for mitigation and adaptation’ (para 115). The Decision furthermore mentions that prior to 2025 the COP shall set a new ‘collective quantified goal from a floor of USD 100 billion per year’ (para 54). The reason both quantitative targets are missing from the actual Agreement is a pragmatic one – in doing so the COP has enabled the US President to adopt the Agreement as ‘sole-executive agreement’ under US law, without the requirement for the US Senate to approve.”
Think about this paragraph. The Paris agreement wanted to start financial support for mitigation and adaptation at $100 billion per year with plans for going even higher in the future. Clearly all the countries on the receiving end of this largesse are in favor of this agreement and clearly the United States was expected to provide the largest chunk of that money. It is particularly telling that the agreement was crafted without quantitative targets so it could be adopted as a ‘sole-executive agreement’ under US law, without the requirement for the US Senate to approve. If it had included quantitative arguments then US voters would have found out how much money the United States was supposed to dole out when the treaty was debated in the Senate.
In summary we were supposed to pay out billions and billions for an agreement that would not have measurably changed global warming. How is getting out of that a bad thing?