This article by Enerdata senior energy modelling expert Sylvain Cail and emeritus CNRS energy transition researcher Patrick Criqui aims to clarify the magnitude of the climate challenge we face globally and the role that the four largest greenhouse gas emitters – China, the U.S.A., the European Union and India – could potentially play, if they decided on a “deep collaboration”. It was published in the European Association of Environmental and Resource Economists (EAERE) Magazine - Towards a deep climate collaboration (Winter 2021)The paper focuses on the abatement of CO2 emissions, which represent two thirds of total GHG emissions.
A deep climate collaboration between these emitters could have a major impact in implementing a net zero emissions policy by mid-century (or shortly after). First, because they currently represent nearly 60 % of total CO2 emissions, so carrying out carbon neutrality policies in their own jurisdiction would trigger a major global reduction. Second, implementing these policies will have a significant leverage effect on the other countries, both by the demonstration effect and by the learning effect for low or zero carbon technologies that would benefit every country.
The article starts with a look back at the current situation for atmospheric C02 and methane, before analysing in more detail the trends and bifurcations in the emissions for each of the four entities.
Share of total emissions for the different regions (in billions tCO2)
Source: Global Carbon projects, 2020
It then presents forecasting scenarios contrasting current developments with more constrained trajectories meeting the Paris commitments and, further on, net zero ambitions.