UN Intergovernmental Panel on Climate Change Releases New Assessment Report

On 9 August 2021, the UN Intergovernmental Panel on Climate Change (“IPCC”) released the first instalment of its sixth assessment report, entitled: “AR6 Climate Change 2021: The Physical Science Basis” (“IPCC Report”). The IPCC Report was approved by the 195 Member States to the IPCC and, among other things, may have implications for international climate change adjudication – in particular, as regards obligations of international environmental law and evidence.

In 2016, 174 States and the European Union concluded the Paris Agreement on Climate Change (“Paris Agreement”).  Through Article 2(1)(a) of the Paris Agreement, States Parties agreed to “[h]olding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change”.  The IPCC Report warns that, unless “immediate, rapid and large-scale reductions in greenhouse gas emissions” are undertaken, States Parties’ temperature commitments under the Paris Agreement will soon be “beyond reach”. The IPCC Report concludes that “it is unequivocal that human influence has warmed the atmosphere, ocean and land” and “[w]idespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred”.  In particular, “human-induced climate change is already affecting many weather and climate extremes in every region across the globe” and, since the IPCC’s prior reports of 2018 and 2019, “evidence of observed changes in weather and climate extremes”, including their “attribution to human influence”, has strengthened.

It is likely that litigants will seek to invoke the IPCC Report’s findings in international climate change litigation and arbitration.  For example, the IPCC Report might be invoked in connection with the “precautionary principle” of international environmental law, or the general obligation upon States to exercise due diligence to prevent and control transboundary harm (which often includes obligations to undertake environmental impact assessments), as elaborated by a number of international courts and tribunals over the past decade.

It is also possible that litigants will seek to use the IPCC’s report as evidence before international courts and tribunals.  The International Court of Justice (“ICJ” or “Court”), for example, has previously relied on reports by UN bodies.  In its 2007 judgment in Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro), the ICJ described the relevant UN reports as having “considerable authority” and being of “substantial assistance”.  In the environmental context, the Court relied on UN reports in its 2015 and 2018 judgments on merits and compensation, respectively, in Certain Activities Carried out by Nicaragua in the Border Area (Costa Rica. v. Nicaragua).  More recently, in 2020, the ICJ relied on a UN fact-finding mission report in its provisional measures order in Application of the Genocide Convention case (The Gambia v. Myanmar).

The next UN Climate Change Conference (“COP 26”) will take place in November 2021, in Glasgow.  It remains to be seen whether States Parties will agree new climate change commitments at COP 26, and whether such commitments will have further consequences for international dispute resolution relating to environmental protection and beyond.

The IPCC Reports will be completed in their entirety during 2022.

The IPCC’s press release of 9 August 2021 can be found here.

The IPCC Report can be found here.