My new paper ‘Implications of Earth system tipping pathways for climate change mitigation investment’ has now been published in the peer-reviewed journal Discover Sustainability. It can be freely downloaded here. In it, I explore some implications of an anticipated biosphere-wide tipping point (BTP) in the year 2050 ± 10, including:

• that all climate change mitigation investments should be designed, chosen and judged against this hard and dated deadline, thus urgently prioritising early delivery of net GHG savings;
• that deadline-compliant investments should aim transparently for optimum cost-effectiveness in their biophysical outcomes, especially net GHG emission savings but also biodiversity, ecosystem service and climate change adaptation co-benefits; and
• that investors and markets should prefer actions that yield highly cost-effective biophysical returns, especially where valuable co-benefits are expected.

I explain how to do the necessary calculations, and I provide examples from recent mitigation aid portfolios to support a change of focus from financial to biophysical returns on investment. From these cases, key ways to prevent the BTP include protecting and restoring high carbon-density natural ecosystems, and improving choice awareness and building capacity to promote decarbonisation in all economic sectors.

Three urgent research priorities remain: (1) on the consequences of an Arctic Ocean imminently free of summer sea ice, and options for remedial action including the recapture of methane at large scale and high speed; (2) on testing a new dated mitigation value metric in justifying precautionary mitigation investments in multiple sectors and contexts; and (3) on integrating diverse co-benefit values (biodiversity, ecosystem services, adaptation, etc.) into mitigation investment decision making.