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Paris-Consistent Carbon Budgeting 1-pager & literature review [CCAC Carbon Budgeting Fellowship Blogpost 4]

posted 19 Jul 2021, 05:06 by Paul Price   [ updated 19 Jul 2021, 05:21 ]
As part of his Carbon Budgeting Fellowship, Paul Price prepared a carbon budgeting literature review and a one-page summary for Ireland's Climate Change Advisory Council. Submitted in April 2021, minor revisions in July 2021 are included in these linked DCU website versions.

The literature review is entitled "Assessing Ireland's fair contribution to the global effort to limit global warming to 1.5ºC or well below 2ºC". This will have increased relevance for Ireland with the passing of Ireland's amended Climate Bill which sets out the requirement for a national carbon budgeting programme consistent with the Paris Agreement's Article 2 commitments to equitable implementation and alignment with the 1.5ºC and well below 2ºC temperature targets.

A key conclusion of this literature review is the importance of including non-CO2 gases as well as CO2 in carbon budgeting. Strengthened science over the past five years shows how non-CO2 GHGs can be included in global and national carbon budgeting by using "CO2 warming equivalent" measures via "step pulse GHG equivalence metrics, such as GWP*. 

This conclusion is especially important for wealthier nations, which are very rapidly exhausting even a "minimally equitable", Paris-aligned carbon budget and also for nations with a high proportion of methane and nitrous oxide emissions. Both are true for Ireland, therefore this review sets out an estimated range for Ireland's "NCQ*", its national carbon quota based on aggregated warming due to CO2, N2O and CH4.

From the conclusion:

It is important to note though that even if, or once they are exceeded, the Paris Agreement temperature targets remain salient, demanding a focus by Parties on keeping the temperature peak as low as possible, and on reversing any overshoot as quickly as possible. To be consistent with the Paris Agreement focus on equitable implementation of mitigation action aligned with the 1.5ºC and well below 2ºC temperature targets, climate action in Ireland now requires: radical cuts in fossil fuel use to net zero and then net negative as soon as possible; maintaining and increasing land carbon sinks, and sustained and permanent deep cuts in methane and nitrous oxide emissions due to agriculture. Policies and measures continue to fall far short of delivering on these objectives.