An increasing number of companies have aggressive, immediate goals to reduce their greenhouse gas emissions with the goal of tackling climate change over the long run, as well as addressing the impacts already being experienced today. However, immediate cuts to emissions of long-lived climate pollutants (LLCPs) like carbon dioxide (CO2), will not mitigate the effects of climate change short-term. This is because LLCP emissions remain in the atmosphere over the long term.
Despite the importance of mitigating climate change in the near term, the most commonly used climate change accounting practices are more suited to tracking long-term impacts of climate action than the effects of near-term warming. In a newly released scientific paper in the journal Environmental Research Letters, scientists from The Nature Conservancy (TNC), Yale University and Fractal Ag propose a new framework to measure the efficacy of near-term efforts to curb climate change—whether those efforts play out over 20 years or 100 years.
“Climate change is not a future problem—we need to address it now and lessen the effects we're already experiencing,” said Stephen Wood, a senior scientist for agriculture and food systems at TNC and lead author of the paper. “We don't use methods that are designed to do that. In fact, the methods that we use disincentivize that.”
The study authors say a credible accounting framework for tracking near-term impacts would require three essential features: firstly, it would create separate accounting for near-term targets; secondly, it would incorporate timely data on how long pollutants linger in the atmosphere; finally, it would leverage a "dynamic baseline” approach in carbon accounting. Dynamic baseline accounting updates the baseline scenario—or, what would have happened in the absence of a carbon project—as conditions in the real-world change. Dynamic baseline approaches improve the accuracy of carbon estimations, showing how much additional carbon was removed as a direct result of a treatment.
Despite nearly all emissions targets being set for less than 35 years, existing progress-tracking platforms such as the Greenhouse Gas Protocol and Science Based Targets Initiative (SBTI) rely largely on long-term accounting methods. For reducing emissions, metrics are used that compare warming impacts over 100 years. For increasing carbon sequestration, carbon is assumed to remain in the biosphere for at least two decades and as much as 100 years.
“This 100-year accounting approach was inherited from Kyoto Protocol, of 1997 when climate change was viewed as a future threat and not the present concern it is today,” explained Katharine Hayhoe, Chief Scientist at The Nature Conservancy and co-author on the paper.
Limiting global warming to 1.5C above pre-industrial levels is no longer possible without overshoot, which means a period of years, or even decades, of higher global temperatures before the climate stabilizes at 1.5C again. Overshoot implies very rapid short-term removal of carbon emissions, which can only be accomplished at scale with nature-based climate solutions and rapid reduction in other forcing agents to minimize warming and positive feedbacks in the climate system over that time.
The solutions exist, but we need to cut our carbon emissions as much as possible and as soon as possible, and to invest in nature to take carbon out of the atmosphere and provide critical benefits for people and biodiversity. The authors hope the carbon accounting framework proposed in the research paper will support the need for urgent climate action in the near-term.
“Because we need immediate climate action to mitigate changes we’re already experiencing, we also need new accounting methods that quantify the impact of even small, short-term removals,” said Hayhoe. “All action is necessary to achieving our goal of keeping warming within the limits laid out by the Paris Agreement.”
Read and download the full paper here:
Wood S.A., Hayhoe K., Bradford M.A., Kuebbing S.E., Ellis P.W., Fuller E., Bossio D. Mitigating near-term climate change. Environmental Research Letters
The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world’s toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at an unprecedented scale, providing food and water sustainably and helping make cities more sustainable. Working in more than 70 countries and territories, we use a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit nature.org or follow @nature_press on Twitter.