Global warming won’t end if net zero is redefined

In a recent study published in Nature, an international team of authors who created the science behind net zero, led by the Department of Physics at the University of Oxford, show that relying on ‘natural carbon sinks’ like forests and oceans to offset ongoing CO2 emissions from the use of fossil fuels will not truly stop global warming.

These natural carbon sinks are not included in the concept of net human-induced CO2 emissions by the science of net zero, which was established more than 15 years ago.

In order to stabilize global temperatures after the date of net zero, natural sinks are essential for reducing the effects of present emissions and lowering atmospheric CO2 concentrations. However, instead of cutting back on the use of fossil fuels or creating more long-term CO2 disposal solutions, governments and businesses are increasingly using them to offset emissions. By establishing an apparent equivalency between emissions from fossil fuels and CO2 drawdown by some natural carbon sinks, emissions accounting standards promote this. This means that a nation may appear to have “achieved net zero” while continuing to contribute to global warming.

In addition to acknowledging the necessity of Geological Net Zero, the authors urge governments and businesses to make clear how much they rely on natural carbon sinks to achieve their climate goals.

In order to achieve Geological Net Zero, carbon flows into and out of the solid Earth must be balanced, with one tonne of CO2 going into geological storage for every tonne that is still produced by the ongoing use of fossil fuels. A significant decrease in the use of fossil fuels will be necessary to reach Geological Net Zero due to the expense and difficulties of permanent geological CO2 storage.

The authors agree that maintaining and safeguarding natural carbon sinks will not compensate for the continued use of fossil fuels. A country’s or company’s total historical CO2 emissions indicate how much they have contributed to the global need for continuing natural carbon sinks. The UK has tacitly committed other countries to maintaining natural sinks for many years after its emissions drop to net zero because of its large historical emissions and limited natural sinks. This is not currently discussed in climate talks.