Grassland Protection

Project Drawdown defines grassland protection as: the legal protection of natural, ungrazed grasslands from future grazing and/or conversion to annual cropland, perennial cropland, biomass or bioenergy crops. Protection leads to reduced land use change and the safeguarding of carbon sinks. This solution replaces unprotected grassland. It is assumed that grassland protection primarily happens at the government and non-governmental organization (NGO) level. Grasslands here includes rangeland, shrubland, and savanna. Grasslands hold 20% of global carbon stocks. Tropical savanna and grassland carbon stocks total 326 Gt CO2-eq, while temperate grasslands and shrublands store 199 Gt C02-eq. Grasslands are also important storehouses of biodiversity and provide essential ecosystem services. Conversion of grasslands to other uses causes emissions of stored carbon.

Grasslands are heavily used for agriculture and are at high risk of future land use change and emissions from loss of carbon stocks. Between 20-25% of grasslands have already been converted to cropland, while 75% of the remaining grasslands are grazed, leaving 590-1,040 Mha of ungrazed grasslands, though this includes some wetland as well. Grassland are particularly targeted for afforestation and cropland conversion at present. For example scenarios with high adoption of Bioenergy Carbon Capture and Storage rely on large-scale land use change of grasslands, as do business-as-usual food supply scenarios.

Methodology

Total Land Area[1]

The total land area available for the grassland protection solution was set to 500 million hectares on non-degraded grasslands.^[2] Current adoption[3] of grassland protection is 159 million hectares.

Adoption Scenarios[4]

Four custom adoption scenarios were developed for grassland protection based on the protection commitment made for the temperate grassland and based on historical data available on protected grassland area globally in the temperate in the year 1996 and 2009. All begin with current adoption of 159 million hectares.

Impacts of increased adoption of grassland protection from 2020-2050 were generated based on two growth scenarios, which were assessed in comparison to a Reference Scenario where the solution’s market share was fixed at the current levels.

Scenario 1: Analysis of the six custom scenarios under the Scenario 1 results in the protection of 369.31million hectares of non-degraded forest by 2050.

• Scenario 2: Under this scenario, 403.18million hectares of non-degraded forest are projected to be protected by 2050.

Emissions Model

One-time emissions from deforestation are set to 64.272 tons of carbon dioxide-equivalent per hectare, based on meta-analysis of 13 data points from 7 sources.. Sequestration is set to 0.03 based on 3 data points from 3 sources.

Financial Model

It is assumed that any costs for grassland protection (e.g. carbon payments or payment for ecosystem services) are borne at a government or NGO level. Drawdown land solutions only model costs that are incurred at the landowner or manager level.

Integration[5]

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. Grassland protection was the second priority for use of non-degraded grassland, following peatlands, protection.

Results

Total adoption in the Scenario 1 is 369.31 million hectares in 2050, representing 74 percent of the total available land. Of this,  209.86 million hectares are adopted from 2020-2050. The impact of this scenario is 3.35 gigatons of carbon dioxide-equivalent emissions averted by 2050. Total carbon stock protected is 124.9gigatons of carbon dioxide-equivalent. Financial impacts are not modeled.

Total adoption in the Scenario 2 is 403.18million hectares in 2050, representing 87 percent of the total available land. Of this,  277.58 million hectares are adopted from 2020-2050. The impact of this scenario is 4.25 gigatons of carbon dioxide-equivalent by 2050. Total carbon stock protected is 136.3 gigatons of carbon dioxide-equivalent. Financial impacts are not modeled.

Discussion

Benchmarks

The IPCC Climate Change and Land report notes a range of 0.03-0.72 Gt CO2-eq/yr from reduced conversion of cropland to grassland. Griscom (2017) estimates 0.1 Gt CO2-eq/yr form avoided cropland conversion, assuming a 30% reduction. Project Drawdown estimates 0.1-0.16 gigatons per year in 2030, thus are in line with the available benchmarks.

grassland protection

Limitations

This solution does not model avoided deforestation from agricultural intensification or reduced food demand due to diet change or food waste reduction. Inclusion of economic impacts, e.g. costs to governments and NGOs, would be a valuable addition to future updates.

Conclusions

Grasslands preserve important global carbon stocks and provide important ecosystem services.

They are highly at risk of conversion to grazing, cropland, and biomass/bioenergy crops. Protection of grassland is an important strategy to limit emissions from land use change.