The Paris Agreement and the Committee on Climate Change

When I wrote my blog post a couple of weeks ago on the implications of the Paris Agreement, I was looking forward to seeing how the Committee on Climate Change would respond. Last week it gave its first response, as you can see from this report from The Guardian.

The main thrust of the response was to reaffirm its recommended fifth carbon budget for the UK covering the period 2028-32. This has disappointed some climate activists and made me curious to see what was the committee's logic. Given the major gaps in my knowledge, I found the committee's letter to Amber Rudd interesting and informative, particularly the Annex.

The letter comes over as only a preliminary response to the Paris Agreement. In particular, we should note the final paragraph of the Annex, which says:-

A key element of the Paris Agreement that goes beyond our assumptions is the aim to hold the increase in global average temperature to well below 2°C above pre-industrial levels, and pursue efforts to limit it to 1.5°C. This draws into question whether three distinct, but inter-related, aspects of the climate regime are still sufficiently ambitious: the fifth carbon budget advice, the 2050 target and the most appropriate target for the UK after 2050. The work we commit to in this letter will consider the latter two issues in more detail. We have concluded that the fifth carbon budget remains appropriate based on current evidence.

The last sentence may look disappointing but I think the implication is that the committee will be reviewing the adequacy of the 2050 target and looking at a target for post 2050. That work may or may not produce evidence that the the fifth carbon budget needs to be reduced. The letter itself is more explicit. It says: 

Our judgement is that our existing recommendation is sufficient at this time, although a tighter budget may be needed in the future.

In other words, as might be expected after such a short time, the Committee has not yet investigated the implications of the Paris Agreement and we have yet to see the full response.

My guess remains that the 2050 target (of an 80% reduction in emissions from the 1990 rate) will be shown to be inadequate. Apart from anything else, any target for the rate of emissions in a particular year is in itself inadequate. What really matters is the accumulation of emissions in the meantime and the resulting volume of greenhouse gases in the atmosphere - hence the need for five-year carbon budgets.

However the target has a certain significance in that "It is based on an equal share of emissions per person worldwide in 2050". That looks superficially equitable but takes no account of historic responsibility of developed countries such as the UK for the current level of greenhouse gases in the atmosphere.  I think we can say that the current 2050 target represented the very minimum we could have expected to get away with before the Paris Agreement.

We look forward to the full response to the Paris Agreement by the Committee on Climate Change.