In a previous post six months ago, I reviewed evidence showing that the Paris Agreement is already on the way to failure. Now, end of 2021, after another Conference of the Parties (COP), I cannot see any reason to be more optimistic.
First, evidence on greenhouse gas emissions trends and new results from climate modeling are devastating. After a temporary COVID-19-related drop , global fossil emissions are nearly back to pre-pandemic levels [2, 3], as evident from the left-hand figure below. Fair enough, the trend points to slower growth, but the 1.5°C goal requires emissions to decline at a rate of 1.4 billion tons per year, as of now . A new multi-model study , summarized in the right-hand figure below, shows that current mitigation efforts lead to around 2.5°C warming by 2100, with even the most optimistic scenarios being above 2°C. The catastrophic consequences have been highlighted repeatedly by the IPCC [5, 6].
Second, it is hard to find tangible results in the outcome document of the recent COP in Glasgow, the so-called Glasgow Climate Pact . The usual lengthy platitudes aside, the essence regarding mitigation is:
"The Conference of the Parties [...] resolves to pursue efforts to limit the temperature increase to 1.5 °C, [...] recognizes that [this] requires rapid, deep and sustained reductions in global greenhouse gas emissions, including reducing global carbon dioxide emissions by 45 per cent by 2030 relative to the 2010 level and to net zero around mid-century, as well as deep reductions in other greenhouse gases; [... and] invites Parties to consider further actions to reduce by 2030 non-carbon dioxide greenhouse gas emissions, including methane" (p. 3, paragraph 16, 17, and 19).
In short: guys, remember that we have that goal, now go home a do something, please! But this is just a re-statement of the voluntary contribution mechanism that I have explained previously, which inherently involves an incentive problem: there is a cooperative outcome that is preferred by all (net zero around mid-century), but contributing to it (reducing emissions) is costly for each individual party. There is an incentive to let the others do the work, or at least a bit more.
Yet, we know that the mechanism hasn't worked extraordinarily well so far (cynical economists would remark that this was to be expected). As I explained in my previous post around the Liu & Raftery study , there is a sizable "ambition gap" (the national reduction targets are not consistent with the carbon budget implied by the 1.5°C goal) and on top a sizable "implementation gap" (the concrete policy instruments in place are not consistent with the reduction targets). What I would expect from a "climate pact" that really deserved this name is some concrete idea about how to resolve the fundamental conflict of interest.
I rather see resignation. The terms „pursue efforts“, "invites" and "consider", and the conspiciuous switch to the impersonal passive tense at critical points of the text are not there coincidentally, I assume, typically any single word in such documents is selected for a reason. The terms once again underline the allround voluntariness built into and onto the Paris Agreement. I don't believe it is going to work that way, and this belief is far from exotic in the climate science community [9, note the the survey was done in late summer 2021, before the COP in Glasgow]. It's another year lost for effective global climate action. But hope dies last. COP27 is scheduled for November 2022 in Sharm El-Sheikh, Egypt.
 Le Quéré, C., Jackson, R. B., Jones, M. W., et al. (2020). Temporary reduction in daily global CO2 emissions during the COVID-19 forced confinement. Nature Climate Change 10, 647-653. DOI: https://doi.org/10.1038/s41558-020-0797-x
 Jackson, R. B., Friedlingstein, F., Le Quéré, C., et al. (2021). Global fossil carbon emissions rebound near pre-COVID-19 levels. arXiv Preprint 2111.0222. URL: https://arxiv.org/abs/2111.02222.
 Friedlingstein, P., Jones, M. W., O'Sullivan, M, et al. (2021). Global Carbon Budget 2021. Earth System Science Data Pre-Print 2021-386. DOI: https://doi.org/10.5194/essd-2021-386.
 Sognnaes, I., Gambhir, A., van de Ven, D. J., et al. (2021). A multi-model analysis of long-term emissions and warming implications of current mitigation efforts. Nature Climate Change 11, 1055-1062. DOI: https://doi.org/10.1038/s41558-021-01206-3.
 Masson-Delmotte, V., Zhai, P., Pörtner, H.-O., et al. (2018). Global Warming of 1.5°C. An IPCC Special Report on the Impacts of Global Warming of 1.5°C above Pre-Industrial Levels and Related Global Greenhouse Gas Emission Pathways, in the Context of Strengthening the Global Response to the Threat of Climate Change, Sustainable Development, and Efforts to Eradicate Poverty. Geneva: World Meteorological Organization. URL: https://www.ipcc.ch/sr15/.
 Masson-Delmotte, V., Zhai, P., Pirani, A., et al. (2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. New York: Cambridge University Press. URL: https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/.
 UNFCCC (2021). Decision -/CP.26, Glasgow Climate Pact. Advance Unedited Version (AUV). New York: United Nations Framework Convention on Climate Change. URL: https://unfccc.int/documents/310475.
 Liu, P. R., and Raftery, A. E. (2021). Country-based rate of emissions reductions should increase by 80% beyond nationally determined contributions to meet the 2° C target. Communications Earth & Environment 2, 29. DOI: https://doi.org/10.1038/s43247-021-00097-8.
 Tollefson, J. (2021). Top climate scientists are sceptical that nations will rein in global warming. Nature 599, 22-24. DOI: https://doi.org/10.1038/d41586-021-02990-w.
The headline image is based on a photograph by the NASA released in the public domain.