Leveraging the potential of nature to meet net zero greenhouse gas emissions in Washington State

Abstract

The State of Washington, USA, has set a goal to reach net zero greenhouse gas emissions by 2050, the year around which the Intergovernmental Panel on Climate Change (IPCC) recommended we must limit global warming to 1.5 °C above that of pre-industrial times or face catastrophic changes. We employed existing approaches to calculate the potential for a suite of Natural Climate Solution (NCS) pathways to reduce Washington’s net emissions under three implementation scenarios: Limited, Moderate, and Ambitious. We found that NCS could reduce emissions between 4.3 and 8.8 MMT CO2eyr−1 in thirty-one years, accounting for 4% to 9% of the State’s net zero goal. These potential reductions largely rely on changing forest management practices on portions of private and public timber lands. We also mapped the distribution of each pathway’s Ambitious potential emissions reductions by county, revealing spatial clustering of high potential reductions in three regions closely tied to major business sectors: private industrial forestry in southwestern coastal forests, cropland agriculture in the Columbia Basin, and urban and rural development in the Puget Trough. Overall, potential emissions reductions are provided largely by a single pathway, Extended Timber Harvest Rotations, which mostly clusters in southwestern counties. However, mapping distribution of each of the other pathways reveals wider distribution of each pathway’s unique geographic relevance to support fair, just, and efficient deployment. Although the relative potential for a single pathway to contribute to statewide emissions reductions may be small, they could provide co-benefits to people, communities, economies, and nature for adaptation and resiliency across the state.

Conserving biodiversity in the face of rapid climate change requires a shift in priorities

“…Forests, wetlands, grasslands, and mangroves, all have the potential to sequester and store carbon and simultaneously provide habitat for biodiversity (Morecroft et al, 2019). Although reforestation and avoided conversion of natural systems provide some of the largest carbon benefits (Griscom et al, 2017), nature‐based solutions also include forest management to increase harvest rotation lengths, using cover crops, adding trees to croplands, and restoring wetlands, grasslands, and urban forests (Fargione et al, 2018; Robertson et al, 2021). Conservation biologists and conservation organizations can play a critical role in ensuring that the contributions of nature‐based climate solutions are properly calculated and that solutions are designed not only to maximize carbon sequestration (e.g., through forest plantations), but also to protect functioning ecosystems and biodiversity (Seddon et al, 2019).…”

Natural climate solutions provide robust carbon mitigation capacity under future climate change scenarios

“…Natural climate solutions (NCS, also known as Nature Based Solutions)—land conservation, restoration, and management practices and policies—are strategies intended to reduce emission of greenhouse gases or increase the biological sequestration of CO 2 . Increasingly, NCS are recognized as important climate change mitigation strategies at global 2 , national 3 , 4 , and subnational 5 – 7 scales.…”