Temperate Forest Restoration
Project Drawdown defines temperate forest restoration as the restoration and protection of temperate-climate forests on degraded lands. This solution replaces degraded forest.
Young forests sequester carbon in both soils and biomass at impressive rates. Temperate forests include coniferous, broad-leaved evergreen, broad-leaved deciduous, and mixed associations. The primary regions featuring temperate forests are Europe, northeast Asia, southern Chile, New Zealand, the Mediterranean, and North America. Temperate forests hold roughly 10 percent of all terrestrial carbon and 20 percent of global plant biomass (Bonan, 2008). Compared with tropical forests, a greater proportion of the carbon is held in soils (Lal and Lorenz, 2012). Soil carbon stocks account for 60 percent of the carbon in these ecosystems (Lal, 2005). Temperate forest soils typically contain roughly 100 tons of carbon per hectare (Lal and Lorenz, 2012).
Restoring degraded and deforested temperate lands to forest can offer substantial climate change mitigation opportunities. Temperate forest regrowth is often rapid and results in impressive rates of carbon sequestration. Compared with tropical forest restoration, this solution is less often discussed and somewhat less powerful in terms of mitigation.
The temperate forest restoration solution models natural regeneration, which has the benefit of being a low-cost strategy. Natural regeneration also offers co-benefits that make it an appealing option. These include biodiversity conservation, watershed protection, soil protection, and resilience to pests and disease.
It is assumed that all land in this solution is legally protected from deforestation, so that it will not be cleared or degraded again.
Total Land Area
The total area allocated to temperate forest restoration is 150 million hectares, comprising degraded temperate forests. Current adoption is set at 0 hectares, because forests that have already been restored are accounted for as existing forests in Project Drawdown's Agro-Ecological Zone model.
Future restoration of temperate forest was calculated using the targets from the New York Declaration of Forests, which commits to reforesting 350 million hectares by 2030 (United Nations Framework Convention on Climate Change, 2014), and estimates from the World Resources Institute (n.d.), which predict that 304 million hectares of land are available for wide-scale restoration.
Nine custom adoption scenarios were developed based on: (a) current restoration commitments to date; (b) potential future commitments; (c) the proportion of committed land restored to intact forest; and (d) the year commitments are realized (2030, 2045, or 2060).
Impacts of increased adoption of temperate forest restoration from 2020 to 2050 were generated based on two growth scenarios. These were assessed in comparison with a Reference Scenario, in which the solution’s market share was fixed at the current levels.
- Scenario 1: Analysis of the scenarios under the most conservative approach yields the restoration of 92.6 million hectares of temperate degraded land area by 2050.
- Scenario 2: Based on the most aggressive adoption approach with a peak adoption by 2030 or later, this scenario yields the restoration of 128.4 million hectares of degraded temperate land.
Sequestration rates of temperate forests are set at 2.7 tons of carbon per hectare per year, based on meta-analysis of 20 data points from nine sources.
It is assumed that any costs (e.g., carbon payments or payment for ecosystem services) are borne at a government or non-governmental organization level. Project Drawdown land solutions only model costs that are incurred at the landowner or manager level.
Project Drawdown’s Agro-Ecological Zone model allocates current and projected adoption of solutions to the planet’s forest, grassland, rainfed cropland, and irrigated cropland areas. Temperate forest restoration is the highest-priority solution for degraded temperate forest land.
Total adoption in Scenario 1 is 92.6 million hectares in 2050, representing 62 percent of the total suitable land. Of this, 92.6 million hectares are adopted from 2020 to 2050. The emissions impact of this scenario is 19.42 gigatons of carbon dioxide-equivalent sequestered by 2050. Financial impacts are not modeled.
Total adoption in Scenario 2 is 128.4 million hectares in 2050, representing 86 percent of the total suitable land. Of this, 128.4 million hectares are adopted from 2020 to 2050. The impact of this scenario is 27.85 gigatons of carbon dioxide-equivalent by 2050.
Mitigation benchmarks for temperate/boreal forest restoration are rare. For global forestry of all types, the Intergovernmental Panel on Climate Change (IPCC) reports ranges of 0.0–1.45, 0.1–9.5, and 0.2–13.8 gigatons of carbon dioxide-equivalent sequestered per year by 2030, at carbon prices of US$20, US$50, and US$100 per ton of carbon dioxide-equivalent (IPCC, 2014). Griscom et al. (2017)’s “natural climate solutions” calculate 2.7–17.9 gigatons of carbon dioxide equivalent per year in 2030 for “reforestation” in all climate, temperate, boreal, and tropical. The Project Drawdown model shows 1.7–2.9 gigatons carbon dioxide-equivalent per year by 2030 for tropical forest restoration and 0.6–0.9 for temperate forest restoration, for a combined 2.3–3.8 gigatons carbon dioxide-equivalent per year in 2030. Thus, when considering it as one component of a larger forest strategy that includes tree plantation, tropical forests restortion, forest protection, and indigenous peoples' forest tenure, its contribution is in line with the benchmark.
This study does not include impacts of albedo from forest growth in temperate and boreal climates, which can substantially offset sequestration. Future upgrades of the Drawdown land model will include this capability. Inclusion of economic impacts (e.g., costs to governments and NGOs) would be a valuable addition to future updates. As benchmarks become available, they should be included in the study as well.
Project Drawdown considers temperate forest restoration to be a very high priority, given its impressive sequestration potential and numerous co-benefits. It is assumed that these new forests will be legally protected, as in the forest protection solution. Reduction of land demand for food helps ease pressure on these new forests. Solutions like health & education, plant-rich diets, and reduced food waste reduce demand. Agroecological intensification due to increased yields from solutions like conservation agriculture, silvopasture, and tropical staple trees also makes room for these new forests. Farmland restoration also helps make land available by bringing degraded farmland back in to production.
 Determining the total available land for a solution is a two-part process. The technical potential is based on the suitability of climate, soils, and slopes, and on degraded or non-degraded status. In the second stage, land is allocated using the Project Drawdown Agro-Ecological Zone model, based on priorities for each class of land. The total land allocated for each solution is capped at the solution’s maximum adoption in the Optimum Scenario. Thus, in most cases the total available land is less than the technical potential.
 Current adoption is defined as the amount of functional demand supplied by the solution in the base year of study. This study uses 2014 as the base year due to the availability of global adoption data for all Project Drawdown solutions evaluated.