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Quantifying the “Carbon Gap” – Unmasking the Shortfalls in Global Climate Efforts

Insufficient carbon dioxide removal efforts jeopardize meeting the Paris Agreement’s climate goals, highlighting the urgent need for enhanced technologies and strategies. New research suggests that…

Carbon Dioxide Atmosphere Concept

Research shows that current plans to remove carbon dioxide are not enough to meet the Paris Agreement’s 1.5 ºC warming limit. More awareness and action are needed to bridge the gap between projected increases and the requirements identified in IPCC focus scenarios.

Not enough efforts to remove carbon dioxide put the Paris Agreement’s climate goals at risk, emphasizing the urgent need for better technologies and strategies.

New research suggests that countries’ current plans to remove CO from the atmosphere will not be enough to comply with the 1.5 ºC warming limit set out under the Paris Agreement.

Since 2010, the United Nations environmental organization UNEP has taken an annual measurement of the emissions gap — 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 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 most important greenhouse gas, CO, from the atmosphere.

The study, published today (May 3) 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.

“In the Emissions Gap Reports, carbon removals are only accounted for indirectly,” said lead author Dr. William Lamb, of the MCC Applied Sustainability Science working group.

“After all, the usual benchmark for climate protection pledges is net emissions, ie emissions minus removals. We are now making transparent the specific ambition gap in scaling up removals.

“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.”

Co-author Dr. Naomi Vaughan, of the Tyndall Centre for Climate Change Research at UEA, added: “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.”

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

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.

But, the main scenario still depends on increasing carbon removal. So, in 2050, at least 3.2 gigatonnes of CO2 need to be removed. (5.1 minus a maximum of 1.9).

Another scenario, based on the IPCC, assumes a big decrease in global energy demand due to changes in behavior caused by politics as the main part of the climate protection strategy.

In this case, carbon removals would go up by a smaller amount: 2.5 gigatonnes in 2050. National targets, if fully met, would almost be enough when compared to this scenario, with a gap of 0.4 gigatonnes in 2050.

The research team highlights the issue of limits on sustainability when scaling up carbon removals; for example, the need for a lot of land could harm biodiversity and food security. However, there is still a lot of opportunity to create fair and sustainable land management policies.

Also, new carbon removal options, like air filter systems, or ‘enhanced rock weathering’, have not been promoted much by politicians so far.

They currently only remove 0.002 gigatonnes of CO2 per year from the atmosphere, compared to 3 gigatonnes through conventional options like afforestation, and they are unlikely to significantly increase by 2030. According to the scenarios, they must become more common than conventional options by 2010.

Since only 40 countries have so far 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,” said Dr. Lamb. “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.”

Reference: “The carbon dioxide removal gap” by William F. Lamb, Thomas Gasser, Rosa M. Roman-Cuesta, Giacomo Grassi, Matthew J. Gidden, Carter M. Powis, Oliver Geden, Gregory Nemet, Yoga Pratama, Keywan Riahi, Stephen M. Smith, Jan Steinhauser, Naomi E. Vaughan, Harry B. Smith and Jan C. Minx, 3 May 2024, Nature Climate Change.
DOI: 10.1038/s41558-024-01984-6

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