To Court Expert or Not to Expert?! On the Role of the IPCC Reports and Court Experts in Climate Change Litigation

In many climate change litigation cases, courts are asked to consider scientific evidence, such as the International Panel on Climate Change (IPCC) reports. The European Court of Human Rights (ECtHR) in their decision Klimaseniorinnen v. Switzerland may have misunderstood some aspects in those reports. The International Court of Justice’s (ICJ’s) advisory opinion on the obligations of states regarding climate change was written after the judges had consulted members of the IPCC on the science; possibly, that helped them to a better understanding. This article examines how the ECtHR understood the IPCC reports on the matter of national carbon budgets and discusses whether a court expert could have helped them. While such an expert consultation may have contributed to the ICJ’s understanding, it concludes that the mere presence of a court expert would not guarantee a perfect understanding on the side of the court. Instead of mandatory experts, it suggests, courts should themselves be allowed recourse to experts, where they – honestly – consider fit.