Measuring a fair and ambitious climate agreement using cumulative emissions

Abstract

Policy makers have called for a 'fair and ambitious' global climate agreement. Scientific constraints, such as the allowable carbon emissions to avoid exceeding a 2°C global warming limit with 66% probability, can help define ambitious approaches to climate targets. However, fairly sharing the mitigation challenge to meet a global target involves human values rather than just scientific facts. We develop a framework based on cumulative emissions of carbon dioxide to compare the consistency of countries' current emission pledges to the ambition of keeping global temperatures below 2°C, and, further, compare two alternative methods of sharing the remaining emission allowance. We focus on the recent pledges and other official statements of the EU, USA, and China. The EU and US pledges are close to a 2°C level of ambition only if the remaining emission allowance is distributed based on current emission shares, which is unlikely to be viewed as 'fair and ambitious' by others who presently emit less. China's stated emissions target also differs from measures of global fairness, owing to emissions that continue to grow into the 2020s. We find that, combined, the EU, US, and Chinese pledges leave little room for other countries to emit CO 2 if a 2°C limit is the objective, essentially requiring all other countries to move towards per capita emissions 7 to 14 times lower than the EU, USA, or China by 2030. We argue that a fair and ambitious agreement for a 2°C limit that would be globally inclusive and effective in the long term will require stronger mitigation than the goals currently proposed. Given such necessary and unprecedented mitigation and the current lack of availability of some key technologies, we suggest a new diplomatic effort directed at ensuring that the necessary technologies become available in the near future.

Assessment of China’s Mitigation Targets in an Effort-Sharing Framework

“…The 60-65% targets (with the GDP prediction in GCAM4.0) thus translate to approximately 9.8-11.2 GtCO 2 emissions (energy-related) in 2030 (in this study, CO 2 emissions levels in 2030 are assumed as the product of the projected GDP and emissions intensity (determined by the 60-65% targets) at that year), which is largely consistent with the projection in Peters et al [53] (9.9-11.3 GtCO 2 ). The projected NDC emissions (red lines) are compared with fair ranges of emissions allowances in Figure 1.…”

Value-Added-Based Accounting of CO2 Emissions: A Multi-Regional Input-Output Approach

“…Substantial reductions in global emissions are needed to reduce the risk of "dangerous" anthropogenic climate change [1,2]. According to the datum from The Carbon Dioxide Information Analysis Center (CDIAC), during 2000-2010, global total emissions increase at a rate of 3.1% per year, a significant growth compared with the rate of 1.0% per year around the 1990s, and global per capita emissions also have a surprisingly large growth rate.…”

Achieving net-zero emissions through the reframing of UK national targets in the post-Paris Agreement era

“…An extensive literature exists that considers allocation of climate mitigation from different perspectives [17][18][19] . A recent approach is that proposed by Raupach et al 20 , also used in Peters et al 21 , which applies effort sharing principles of equity (per capita basis) and inertia (current total emissions basis, also known as grandfathering) to carbon budgets. For a developed country such as the UK, equity leads to the allocation of a much more stringent, lower budget, compared to what would be achieved under inertia, based on current emissions.…”