We, the undersigned, call on the V20 — the 20 countries that are most vulnerable to the effects of climate change — to take the lead in creating an 'atmospheric trust' that establishes community property rights over the atmospheric commons (www.claimthesky.org). The V20 could use this trust as a legal instrument to address the climate crisis and to help to implement last month's Paris agreement to keep warming well below 2 °C.

Under public-trust doctrine, certain natural resources such as soil and water must be held in trust to serve the public good. It is every government's responsibility as a trustee to protect these assets as natural capital and to maintain them for the public's use, not give them away or sell them to private parties. The global atmosphere is one such asset.

An atmospheric trust would act as an independent agency and trustee. It could collect claims for damages to the atmosphere and invest funds in mitigation, adaptation and compensation, and in resources for the most affected populations. Because only 90 enterprises (mainly extractive industries) are responsible for two-thirds of global carbon emissions (R. Heede Clim. Change 122, 229–241; 2014), damage claims could target a relatively small number of entities.

All governments would eventually be co-trustees in the atmospheric commons, with a fiduciary responsibility to protect it from catastrophic releases of greenhouse gases.