Research quantifies the ‘gap’ in carbon removal for the first time

New research involving the University of East Anglia (UEA) shows that countries’ current plans to remove CO2 from the atmosphere will not be enough to meet the 1.5ºC warming limit set out in the Agreement. Paris.

Since 2010, the United Nations environmental agency UNEP has annually measured the emissions gap: the difference between countries’ climate protection commitments and what is needed to limit global warming to 1.5 ºC, or ​​at least below 2 ºC.

The UNEP Emissions Gap Reports are clear: climate policy needs more ambition. This new study now explicitly applies this analytical concept to carbon dioxide removal (CDR) – the removal of the major greenhouse gas, CO2, from the atmosphere.

The study, published today in the journal Nature Climate Change, was led by the Berlin-based Mercator Research Institute on Global Commons and Climate Change (MCC) and involved an international team of scientists.

“The Emissions Gap Reports only indirectly consider carbon removal,” said lead author Dr. William Lamb of the MCC Applied Sustainability Science working group.

“After all, the usual benchmark for climate protection commitments is net emissions, i.e. emissions minus removals. We now make the specific ambition gap when scaling up relocations transparent.

“This planetary waste management will soon place completely new demands on policymakers and could even become a central pillar of climate protection in the second half of the century.”

Co-author Dr Naomi Vaughan, from the Tyndall Center for Climate Change Research at UEA, added: “carbon dioxide removal methods play a small but crucial role in achieving net zero and mitigating the impacts of climate change.

“Our analysis shows that countries need greater awareness, ambition and action in scaling up CDR methods, together with deep emissions reductions, to achieve the ambitions of the Paris Agreement.”

According to the study, if national targets are fully implemented, annual human-induced carbon removal could increase by up to 0.5 gigatonnes of CO2 (500 million tonnes) by 2030, and by up to 1.9 gigatons by 2050.

This contrasts with the 5.1 gigatonne increase required in a ‘focus scenario’, which the research team describes as typical in the latest Intergovernmental Panel on Climate Change (IPCC) assessment report.

There, global warming, calculated over the entire course of this century, is limited to 1.5 ºC, and a particularly rapid expansion of renewable energy sources and reduction of fossil fuel emissions is portrayed as the core strategy for climate protection.

But the focus scenario still depends on scaling up carbon removal. The gap for the year 2050 is therefore at least 3.2 gigatons of CO2 (5.1 minus a maximum of 1.9).

An alternative focus scenario, also derived from the IPCC, assumes a significant reduction in global energy demand, due to politically initiated behavioral changes as a core element of the climate protection strategy.

Here, carbon removal would increase by a more modest amount: 2.5 gigatons in 2050. Fully implemented national targets would be almost sufficient compared to this scenario, with a gap in 2050 of 0.4 gigatons.

The research team highlights the problem of sustainability limits when scaling up carbon removals; For example, the associated demand for land area will endanger biodiversity and food security. Nevertheless, there is still ample room for designing fair and sustainable land management policies.

Furthermore, new options for carbon removal, such as air filtration systems or ‘enhanced stone weathering’, have so far hardly been promoted by politicians.

Currently they remove only 0.002 gigatons of CO2 from the atmosphere per year, compared to 3 gigatons through conventional options such as afforestation, and are unlikely to increase significantly by 2030. According to the scenarios, they should become more common than conventional options by 2100. .

Because only forty countries have so far quantified their removal plans in their long-term low emissions development strategies, the study also uses other national documents and best assumptions.

“The calculation certainly needs to be refined,” said Dr. Lamb. “But our proposal, using the focus scenarios, further opens the discourse on how much carbon removal is needed to meet the Paris Agreement.

“This much is clear: without a rapid reduction of emissions towards zero, in all sectors, the 1.5ºC limit will not be met under any circumstances.”

‘The carbon dioxide removal gap’, Lamb, W, Gasser, T, Roman-Cuesta, R, Grassi, G, Gidden, M, Powis, C, Geden, O, Nemet, G, Pramata, Y, Riahi, K, Smith, S, Steinhauser, J, Vaughan, N, Smith, H, Minx, J, to be published May 3 in Nature Climate Change.

The authors have also written an accompanying Policy Brief, published in the same issue.