An international team of scientists from the University of East Anglia (UEA) led by the Berlin-based Mercator Research Institute on Global Commons and Climate Change (MCC) conducted a study, which was published today in the journal Nature Climate Change. The study highlights that nations' current plans to remove CO2 from the atmosphere will not be sufficient to keep global warming below the 1.5 ºC warming limit specified in the Paris Agreement.
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Since 2010, the United Nations Environment Programme (UNEP) has conducted an annual assessment of the emissions gap, which is the difference between countries' climate protection pledges and what is necessary to limit global heating to 1.5 ºC, or at least below 2 ºC.
The UNEP Emissions Gap Reports underscore a pressing need for greater ambition in climate policy. This new study specifically applies this analytical framework to carbon dioxide removal (CDR) - the critical process of extracting CO2, the primary greenhouse gas, from the atmosphere.
In the Emissions Gap Reports, carbon removals are only accounted for indirectly, after all, the usual benchmark for climate protection pledges is net emissions, i.e. emissions minus removals. We are now making transparent the specific ambition gap in scaling up removals.
Dr. William Lamb, Study Lead Author, Applied Sustainability Science Working Group, Mercator Research Institute on Global Commons and Climate Change
Dr. Lamb added, “This planetary waste management will soon place completely new requirements on policymakers and may even become a central pillar of climate protection in the second half of the century.”
Carbon dioxide removal methods have a small but vital role to play in achieving net zero and limiting the impacts of climate change. Our analysis shows that countries need more awareness, ambition, and action on scaling up CDR methods together with deep emissions reductions to achieve the aspirations of the Paris Agreement.
Dr. Naomi Vaughan, Study Co-Author, Tyndall Centre for Climate Change Research, University of East Anglia
The study estimates that annual human-induced carbon removals could rise by a maximum of 0.5 Gt of CO2 (500 million tons) by 2030 and a maximum of 1.9 Gt by 2050 if national targets are fully implemented.
This contrasts with the 5.1 gigatonne increase required in a ‘focus scenario’, which the research team depicts as typical from the latest Intergovernmental Panel on Climate Change (IPCC) assessment report.
There, global heating, calculated over the entire course of this century, is limited to 1.5 ºC, and a particularly rapid expansion of renewable energies and reduction of fossil emissions is depicted as the core climate protection strategy.
However, increasing carbon removals remains a key component of the focus scenario. Thus, for 2050, there will be a minimum of 3.2 Gt of CO2 gap (5.1 minus a maximum of 1.9).
An alternative focus scenario that is also derived from the IPCC assumes that the primary component of a strategy to protect the climate is a significant reduction in global energy demand as a result of politically instigated behavioral changes.
In this case, a more moderate increase in carbon removals would occur in 2050: 2.5 Gt. Compared to this scenario, fully implemented national targets would be nearly sufficient, with a 0.4 Gt gap in 2050.
The research team highlights the issue of sustainability limitations when increasing carbon removals; for instance, the resulting demand for land area will eventually endanger food security and biodiversity. However, there is still a lot of space left to create fair and sustainable land management policies.
In addition, novel carbon removal options, such as air filter systems or ‘enhanced rock weathering’, have hardly been promoted by politicians to date.
They presently only remove 0.002 gigatonnes of CO2 per year from the atmosphere, compared to 3 gigatonnes through conventional options such as afforestation, and they are unlikely to significantly increase by 2030. According to the scenarios, they must become more prevalent than conventional options by 2100.
As only 40 countries have quantified their removal plans in their long-term low-emissions development strategies, the study also relies on other national documents and best-guess assumptions.
“The calculation should certainly be refined. But our proposal using the focus scenarios further opens the discourse on how much carbon removal is necessary to meet the Paris Agreement. This much is clear: without a rapid reduction in emissions towards zero, across all sectors, the 1.5 ºC limit will not be met under any circumstances,” said Dr. Lamb.
Journal Reference:
Lamb, W. F., et al. (2024). The carbon dioxide removal gap. Nature Climate Change. doi.org/10.1038/s41558-024-01984-6.
Source: https://www.uea.ac.uk/