As the COP29 negotiations continue, a new study published today in Nature demonstrates that protecting and maintaining natural carbon sinks, while vitally important, will not compensate for ongoing fossil fuel use.
Natural carbon sinks such as oceans and forests play an essential role in moderating the impact of current and past emissions. However, the new study, led by Professor Myles Allen, shows that relying on them to offset ongoing fossil fuel emissions will not stop global warming. Due to how emissions accounting rules currently work, governments and corporations increasingly see natural sinks as a way to offset future emissions, rather than focusing on reducing fossil fuel use or developing ways of permanently disposing of CO2. This means that a country could appear to have ‘achieved net zero’ whilst still contributing to ongoing warming.
The authors 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.
As Prof Allen says: “We are already counting on forests and oceans to mop up our past emissions, most of which came from burning stuff we dug out of the ground. We can’t expect them to compensate for future emissions as well. By mid-century, any carbon that still comes out of the ground will have to go back down, to permanent storage. That’s Geological Net Zero.”
The international group of co-authors includes Dr Stuart Jenkins, ONZ Research Fellow on Net Zero for the Fossil Fuel Sector. He says: “This is an accounting anomaly that we can and must fix. To do that in the right way we must respect the science behind net zero. Recognising the need for geological net zero leaves natural carbon sinks free to perform their other vitally important tasks which we will rely on in the decades to come”.
All of the lead authors and most of the co-authors who originally developed the science of net zero in a series of papers in 2009 contributed to the new study.
Read more on the University of Oxford website.
Photo by Kasia Derenda on Unsplash.
