Natural climate solutions could help Canada mitigate up to 78.2 teragrams of carbon dioxide per year, equivalent to the emissions associated with powering every home in Canada for 3 years, helping the country meet or exceed its goals under the 2015 Paris Agreement, according to new research published Friday.
In a study published in Science Advances, researchers show the efficacy of natural climate solutions in combating climate change, identifying 24 such solutions related to the protection, management and restoration of natural systems, which would mitigate 394.4 teragrams of carbon dioxide cumulatively by 2030 in Canada. One teragram is equivalent to 1 billion kilograms (2.2 billion pounds).
The researchers also identify a suite of co-benefits that carbon taxes and fuel standards can't produce, including soil productivity, clean air and water and biodiversity conservation, with the latter particularly important for the 30x30 framework — the United Nation's biodiversity plan to protect 30% of Earth's oceans, land areas and inland waters by 2030.
Natural climate solutions are actions that humans can take to protect Earth's natural systems, chiefly forests, grasslands, wetlands and agricultural lands. The pathways to these solutions include protection, improved management and restoration of natural systems, and they work to mitigate climate change in one of two ways.
These solutions can either avoid the carbon emissions that arise from land-use changes or increase the ability of natural systems to take back carbon dioxide from the atmosphere, according to Ronnie Drever, the lead author of the paper and conservation scientist at Nature United.
"We're dealing with a climate crisis, so we have less and less time to act as a society," Drever said. "Nature is an ally in our fight against climate change."
Out of 24 distinct pathways of natural climate solutions in Canada, the researchers identified four that offer the largest mitigation opportunities: avoiding conversion of grassland, avoiding peatland disturbance, expanding adoption of cover crops and improving forest management.
Avoiding grassland conversion offers the largest opportunity for reduction of emissions, potentially mitigating 12.7 teragrams of carbon dioxide per year. This pathway seeks to avoid carbon emissions related to loss of grassy land cover by not disturbing native grasslands and working pastures, which typically get converted into cropland. Tilling these areas releases a lot of emissions through activities such as soil erosion, Drever told The Academic Times.
Preventing the disturbance of peatlands from extraction, mine development or road and seismic line construction offers the second-largest mitigation opportunity, with the potential to mitigate up to 10.1 teragrams of carbon dioxide per year. Peatlands are "what we call irrevocable carbon storage, meaning that carbon in that area has been built up over centuries," Drever said.
"Once it's converted and emissions released," he said, "the capacity of the ecosystem to take back those emissions won't happen in anything resembling the timeframe that we need for rapid climate action."
The third-largest mitigation opportunity resides in expanding adoption of cover crops, which are crops grown for the soil that help commercial crops thrive. Expanding the use of cover crops offers mitigation of up to 9.8 teragrams of carbon dioxide per year.
Among other benefits, cover crops prevent erosion of soil, increasing the productivity of agricultural soils and allowing the soil to take back more carbon, according to Drever. The researchers of the study identified over 20 million hectares of agricultural lands that could be used to expand the use of cover crops.
Lastly, improved forest management could mitigate up to 7.9 teragrams of carbon dioxide per year. Under the study, improving forest management includes three actions working in tandem.
First, it includes conserving old forests and enhancing the regeneration of those forests after harvest. Second, it contemplates increasing the use of harvest residues — such as branches and other debris that are burned in slash piles, which are associated with a lot of emissions — for local bioenergy production. And lastly, improved forest management includes a shift toward long-lasting wood products,
Alongside the suite of co-benefits that natural climate solutions provide, these mitigation strategies also have a key advantage over other fossil fuel emission mitigation actions. According to the study, natural climate solutions are broadly scalable and deployable now, compared to carbon-capture technologies that are either too expensive or still being developed.
"Nature has been doing this for a really long time," Drever said. "Photosynthesis is a tried and true carbon capture storage technology. And so we really think we need to work with nature in our fight to tackle climate change."
This isn't to say that natural climate solutions would replace other fossil fuel mitigation efforts. Rather, these solutions are a complement to ongoing and future efforts to mitigate fossil fuel emissions. The global implementation of all cost-effective natural climate solutions could actually provide up to 33% of the global mitigation needed in 2030 in order to keep global warming below 2 degrees Celsius, according to previous research, which also showed that these solutions could mitigate up to 21% of net annual emissions in the United States.
Natural climate solutions vary by country and ecological setting, highlighting the need for science-based information that can guide decision-making on these issues. Drever said that he and his colleagues believe this study is an important advancement in terms of providing information to decision-makers that contextualizes the role of nature in climate mitigation.
"We think it's really important to get that number right," he said. "Because if people overstate the case for natural climate solutions, that might lead to decisions that just are not good for the climate or for biodiversity."
The study "Natural climate solutions for Canada," published June 4 in Science Advances, was authored by C. Ronnie Drever, Nature United; Susan C. Cook-Patton, The Nature Conservancy and Smithsonian Conservation Biology Institute; Fardausi Akhter and Raju Y. Soolanayakanahally, Agriculture and Agri-Food Canada, Indian Head; Pascal H. Badiou, Ducks Unlimited Canada, Institute for Wetland and Waterfowl Research; Gail L. Chmura, McGill University; Scott J. Davidson and Maria Strack, University of Waterloo; Raymond L. Desjardins and Devon E. Worth, Agriculture and Agri-Food Canada, Ottawa; Andrew Dyk, Max Fellows, Marie-Eve LeClerc, Eric Neilson, Carolyn Smyth and Werner A. Kurz, Canadian Forest Service, Natural Resources Canada; Joseph E. Fargione, The Nature Conservancy; Ben Filewod and Danijela Puric-Mladenovic, University of Toron; Margot Hessing-Lewis, Hakai Institute; Susantha Jayasundara and Naresh Thevathasan, University of Guelph; William S. Keeton, University of Vermont; Timm Kroeger, Sara M. Leavitt and Samantha Yeo, The Nature Conservancy; Tyler J. Lark and Seth A. Spawn, University of Wisconsin-Madison; Edward Le and Zhen Xu, Canadian Forest Service, Natural Resources Canada, Ottawa; Tony C. Lemprière, Canadian Forest Service, Natural Resources Canada, Toronto; Juha Metsaranta, Sebastien Rodrigue and Mihai Voicu, Canadian Forest Service, Natural Resources Canada, Edmonton; Brian McConkey, Viresco Solutions; Guillaume Peterson St-Laurent, University of British Columbia; Christopher A. Williams, Clark University; Peter B. Woodbury, Cornell University.