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Credit: Macduff Everton/National Geographic Creative

Food

Farmland Restoration

In the Gulu District of Uganda villagers learn permagardening, which integrates water-saving practices, soil fertility, companion-planting knowledge, and enriched raised beds.

Around the world, farmers are walking away from lands that were once cultivated or grazed because those lands have been “farmed out.” The causes range from damaging agricultural practices to desertification, from lack of market access to migration. It can be cheaper to walk away from the land than to work it.

There are an estimated 950 million to 1.1 billion acres of deserted farmland around the world—acreage once used for crops or pasture that has not been restored as forest or converted to development. This land offers an opportunity to improve food security, farmers’ livelihoods, ecosystem health, and carbon drawdown simultaneously.

To feed a growing population and protect forests from deforestation for fresh farmland, restoring abandoned cropland and pastureland is key. Bringing abandoned lands back into productive use can also turn them into carbon sinks. Where soils are left to erode, abandoned farmlands can be a source of emissions.

Restoration can mean the return of native vegetation, the establishment of tree plantations, or the introduction of regenerative farming methods. Active restoration is labor intensive, yet necessary for cultivation to revive. Programs to finance regeneration are a necessary stimulus to action, helping landowners make changes without having to bet the farm.

References

Measuring…deserted farmland: Gibbs, H. K., and J. M. Salmon. “Mapping the World’s Degraded Lands.” Applied Geography 57 (2015): 12-21.

950 million to 1.1 billion acres: Campbell, J. Elliott, David B. Lobell, Robert C. Genova, and Christopher B. Field. “The Global Potential of Bioenergy on Abandoned Agriculture Lands.” Environmental Science & Technology 42, no. 15 (2008): 5791-5794.

Rattan Lal…[loss of] carbon stock: Olson, Kenneth R., Mahdi Al-Kaisi, Rattan Lal, and Larry Cihacek. “Impact of Soil Erosion on Soil Organic Carbon Stocks.” Journal of Soil and Water Conservation 71, no. 3 (2016): 61A-67A; Schwartz, Judith D. “Soil as Carbon Storehouse: New Weapon in Climate Fight.” Yale Environment 360. March 4, 2014.

depleted farmland soils could reabsorb…carbon: Gardiner, Beth. “A Boon for Soil, and for the Environment.” New York Times. May 17, 2016.

view all book references

Technical Summary

Farmland Restoration

Project Drawdown describes farmland restoration as: a set of processes for restoring degraded, abandoned land to productivity and biosequestration. This solution replaces the conventional practice of abandoning degraded farmland.

Globally, an estimated 414 million hectares of farmland have been abandoned in the last two centuries. The failure of these lands to continue to produce the desired economic benefits has forced the land owners to abandon them. The loss of the agricultural productivity of these lands poses a serious threat to food security. These lands have also lost substantial carbon from soil and biomass in the process of becoming degraded.

Restoring these lands to productivity sequesters carbon, while bringing land back into production. This can also result in substantial reduced emissions from avoided deforestation, though that impact is not modeled here. This model looks only at agricultural restoration, though restoration to forests and other ecosystems is also practiced on abandoned farmland.

Given the urgency of preventing emissions from deforestation, and the pressure of meeting food demand given the trend towards increasing meat consumption, farmland restoration is highly desirable. Its impressive carbon sequestration impact, along with these co-benefits, makes it an essential component of mitigation efforts.

Methodology

Total Land Area [1]

The total available land for the farmland restoration solution is 414 million hectares, [2] which is the global area of abandoned farmland. Though abandoned land that has been restored is by definition now in agricultural production or is a restored forest or other ecosystem, 9.7 million hectares are reported to be under active restoration in India (Government of India Planning Commission, 2017); thus, this number is used as current adoption [3] of farmland restoration.

It is assumed that the process of restoration takes one year, after which the land returns to production. Restored land is assumed to be in Drawdown’s regenerative agriculture annual cropping solution, as the majority of restoration measures are based on improving soil fertility through organic inputs. This area, however, is not included in the total adoption area for the regenerative agriculture solution.

Adoption Scenarios [4]

Projections on restoration of abandoned farmland are unavailable. However, abandoned farmland is a subset of degraded farmland, for which published targets are available. Thus, four custom adoption scenarios were developed, based on the Intergovernmental Panel on Climate Change (IPCC) and United Nations Environment Program (UNEP)’s 2013 low and high targets for restoration of degraded land. In the absence of targeted data, this study assumes that both abandoned and degraded land will follow similar trends.

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

  • Plausible Scenario: The analysis of these custom scenarios shows restoration of 171.5 million hectares of abandoned farmland under the Plausible Scenario.
  • Drawdown Scenario: Aggressive adoption of farmland restoration yields restoration of 212.7 million hectares of abandoned farmland.
  • Optimum Scenario: Aggressive adoption of farmland restoration yields restoration of 360.0 million hectares of abandoned farmland.

Sequestration Model

Carbon sequestration rates are set at 1.3 tons per hectare per year, based on meta-analysis of 31 data points from 4 sources.

Financial Model

First cost for the farmland restoration solution is US$446.33 per hectare, [5] based on meta-analysis of 43 data points from 10 sources. There is no conventional first cost for comparison, as the land is assumed to have been abandoned for some time. The net profit margin is US$485.5 per hectare per year, based on 29 data points from 4 sources. There is no conventional net profit as abandoned land is by definition not currently in production.

Integration [6]

In the process of allocating land to solutions by Agro-Ecological Zone, it was assumed that abandoned farmland is currently degraded grassland.

Results

Total adoption in the Plausible Scenario is 171.5 million hectares in 2050, representing 41.4 percent of the total available land. Of this, 161.8 million hectares are adopted from 2020-2050. The sequestration impact of this scenario is 14.1 gigatons of carbon dioxide-equivalent by 2050. Net cost is US$72.2 billion. Net savings is US$1,342.5 billion. Total yield of food from this previously abandoned land is 9,595.0 million metric tons between 2015-2050.

Total adoption in the Drawdown Scenario is 212.7 million hectares in 2050, representing 49.0 percent of the total available land. Of this, 203.0 million hectares are adopted from 2020-2050. The impact of this scenario is 17.7 gigatons of carbon dioxide-equivalent by 2050.

Total adoption in the Optimum Scenario is 360.0 million hectares in 2050, representing 86.9 percent of the total available land. Of this, 350.3 million hectares are adopted from 2020-2050. The impact of this scenario is 30.5 gigatons of carbon dioxide-equivalent by 2050.

Discussion

Benchmarks

Projected impacts for this solution align very closely with IPCC projections for the restoration of degraded land. The IPCC estimates an impact of 0.1-0.7 gigatons of carbon dioxide-equivalent per year by 2030 (Smith, 2007), while the Drawdown model shows 0.4-0.7 gigatons per year in 2030, well within the benchmark range.

Limitations

For future upgrades of this solution, it would be useful to further investigate how “abandoned farmland” is categorized and how it is distinct from degraded lands in general.

Conclusions

It should be seen as somewhat embarrassing for humanity that we continue to clear land for agriculture while leaving degraded, once-fertile lands behind in an abandoned state. The multiple mitigation benefits associated with farmland restoration provide strong incentive to bring these lands back into production and care for them thereafter.


[1] To learn more about the Total Land Area for the Food Sector, click the Sector Summary: Food link below.

[2] 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 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.

[3] 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.

[4] To learn more about Project Drawdown’s three growth scenarios, click the Scenarios link below. For information on Land Use Sector-specific scenarios, click the Sector Summary: Food link.

[5] All monetary values are presented in US2014$.

[6] For more on Project Drawdown’s Food Sector integration model, click the Sector Summary: Food link below.

Full models and technical reports coming in late 2017.

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