The 28 million acres of natural and working lands across California provide a unique opportunity to meet greenhouse gas emission reduction goals through various land-use strategies, such as expanding urban forest areas or restoring woodlands. However, the need to mitigate wildfire severity is also a critical priority for California, and one that can increase emissions and thus presents challenging tradeoffs for land use policy.
A new paper in Environmental Research Letters describes research by EESA scientists and is the first to quantify the landscape carbon effects of different policy scenarios identified in California’s 2030 Natural and Working Lands Climate Change Implementation Plan. This plan aims to fulfill the state’s multiple land-use goals while reducing carbon dioxide and methane emissions from natural and working lands across California.
Using the CALAND model developed by EESA scientists Alan Di Vittorio and Maegen Simmonds for this purpose, the team showed that emissions from efforts to reduce the amount of combustible biomass (fuel reduction) in forestlands initially outweigh emissions reductions from other strategies, such as land restoration and conservation. However, over the longer term the avoided emissions and enhanced carbon sequestration from the other strategies cumulatively outweigh fuel reduction emissions.
One novelty of the CALAND model is that it simultaneously evaluates the landscape-carbon effects of these scenarios (which include 14 land-based strategies), inherent uncertainties in carbon stocks and fluxes, and interactions with land-use and land-cover change, wildfire, and climate change.
“In planning for how to mitigate the issues that are impacting natural and working lands in California, it’s necessary to have the ability to take a comprehensive view of the various land use goals in the context of climate change, increasing risk of catastrophic wildfire, and competing priorities, like fuel reduction and emissions reduction,” Simmonds said. “This study is different from others which focus on technical potential or specific emissions reduction goals. These policy scenarios include a portfolio of land use priorities for the state (some that emit carbon) at two levels of implementation areas deemed feasible by the state in terms of its investment potential and landowner participation.”
While greater emissions reductions can be achieved with greater scales of management, this would require more aggressive policies, resources, and landowner participation than the current group of policies currently deemed achievable by the state. This study showed that large scale wildfire mitigation needs in California need to be offset by a greater extent of emissions-reducing practices in order to make a considerable contribution to broader reduction targets.
The Nature Conservancy recently recruited Simmonds, a project scientist in the Energy Geosciences Division (EGD), and Di Vitorrio, a research scientist in the Climate and Ecosystem Sciences Division (CESD), to adapt CALAND to Colorado and New Mexico. Additionally, Simmonds and CESD scientist Andrew Jones are modeling co-leads, along with EGD scientist Peter Nico and CESD scientist Margaret Torn, on a multi-million dollar, multi-institutional grant with the Working Lands Innovation Center to further develop CALAND for simulating the carbon sequestration potential of pulverised rock, compost, and biochar amendments on agricultural lands across California.