Redefining net zero will not stop global warming, new study shows

In a new study led by the University of Oxford’s Department of Physics, an international group of researchers who developed the science behind net zero demonstrate that relying on ‘natural carbon sinks’ like forests and oceans to offset ongoing CO₂ emissions from fossil fuel use will not actually stop global warming. The findings have been published today in Nature.

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Natural sinks play a vital role to moderate the impact of current emissions and draw down atmospheric CO₂ concentrations after the date of net zero, stabilizing global temperatures. Yet governments and corporations are increasingly turning to them to offset emissions, rather than reducing fossil fuel use or developing more permanent CO₂ disposal options. Emissions accounting rules encourage this by creating an apparent equivalence between fossil fuel emissions and drawdown of CO₂ by some natural carbon sinks, meaning a country could appear to have ‘achieved net zero’ whilst still contributing to ongoing warming.

The researchers call on governments and corporations to clarify how much they are counting on natural carbon sinks to meet their climate goals, as well as recognising the need for Geological Net Zero.

Geological Net Zero means balancing flows of carbon into and out of the solid Earth, with one tonne of CO₂ committed to geological storage for every tonne still generated by any continued fossil fuel use. Given the cost and challenges of permanent geological CO₂ storage, achieving Geological Net Zero will require a substantial reduction in fossil fuel use.

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