Reducing land use and returning agricultural land to nature

Below are the key takeaways and introduction to our research into land use. Read the full report.

Our key takeaways

• Returning land to nature and the restoration of prior ecosystems depend on the continued existence of the animal and plant species that originally populated the land. Without its original species, land can never be returned to its original state. Species richness is decreasing sharply around the world, mostly because of agricultural land use expansion and the resulting habitat loss. As a problem area, returning land to nature is thus marked by the irreversibility of species extinction: once a species is extinct, it cannot be brought back into existence, whereas species can grow to become more abundant in the future after starting from a small initial population. As a result, philanthropists should focus on medium- to long-term large-scale reductions in land use as well as short-term targeted conservation and restoration efforts to preserve the most at-risk species and, with them, the potential for future land return.
• Within medium- to long-term land use reductions, we particularly examine accelerating the adoption of alternative proteins to reduce the demand for livestock and find it to be a high-impact area for philanthropy. Within the alternative proteins space, philanthropists should consider supporting policy advocacy for governmental support of cultivated meat R&D and plant-based meat commercialization in order to reach price parity sooner. The history of public funding for alternative proteins over the last several years suggests that high-income countries with high meat consumption and future food security risks are suitable targets for such advocacy.
• Increasing agricultural yields, particularly in sub-Saharan Africa, can potentially reduce land use, but the evidence is more mixed. Philanthropists that decide to focus on yield improvements should focus on technology that imposes little to no cost on farmers in order to incentivize them to choose intensification over land expansion.
• Within short-term conservation and restoration, interventions are most likely to be effective if they target low-income countries in regions that have high extinction rates and low agricultural yields: Southeast Asia, East Africa, and Mesoamerica. The most cost-effective programs leverage economies of scale by covering large areas over a long period of time. Restoration of degraded ecosystems is most likely to be highly effective if it focuses on shrublands and forests. Conservation of uncultivated ecosystems can be more cost-effective but requires precise identification of areas that, without conservation, would be used for future agriculture. Conserving areas that would not otherwise be developed provides no value. Many high-impact conservation projects are close to large wilderness areas (e.g., Amazon).

An introduction

Agriculture today uses 46% of the earth’s habitable land, up from about 10% 300 years ago and around 4% in 1000 AD (See figures 1 and 2A in full report, Goldewijk et al. 2017, FAOSTAT). To visualize the scale of these numbers, the additional land used for agriculture now compared to 300 years ago amounts to the entire landmass of Africa and Europe combined (around 4 billion hectares). While there is broad consensus that humans have reached peak agricultural land use (Goldewijk et al. 2017, Taylor and Rising 2021), i.e., total agricultural land has begun to decline, it isn’t declining in every part of the world. Projections indicate that by 2050, most of South America, Africa, and parts of South East Asia will clear considerably more of their land and use it for agriculture, often twice as much (See figure 2B in full report and Williams et al. 2020).

The enormous increase in agricultural land use has changed the environment on earth, as natural ecosystems have been transformed into arable land through deforestation (Pendrill et al. 2019), the draining of wetlands (Verhoeven and Setter 2010), and other human interventions. Because species rely on the original ecosystems, the cultivation of agricultural land has resulted in large-scale habitat loss for many of the world’s animals, plants, and fungi. Overall, this changing land use has substantially decreased biodiversity—here defined as the overall number of species. Today, the IUCN Red List estimates that about 42,000 species (around 28% of all species) are under threat of extinction. While species would also go extinct without human development, the academic literature puts the rate of species extinction over the 20th century at between 100x and 10,000x higher than in pre-human times (see Ceballos et al. 2015), with habitat loss being the primary driver (Royal Society). Similarly, many unique ecosystems, from the Aral Sea in Kazakhstan and Uzbekistan to the Bago Semi-Evergreen Forest in Myanmar have collapsed or are critically endangered.

The drive to return land to nature aims to restore landscapes and ecosystems to their state before human industrial influence. When returning land to nature, typically, areas that were previously used by humans are selected with the goal of restoring them to the state of a “pre-disturbance” reference site that is intended to look as similar as possible to the original ecosystem. Ruiz-Jaen and Mitchell Aide (2005) in a review article outline how to measure the success of restoration projects based on guidelines by the Society for Ecological Restoration (Society for Ecological Restoration International Science & Policy Working Group 2004). Broadly, they find three dimensions based on the existing literature on which restoration should achieve a pre-disturbance state to be considered successful:

• Biodiversity, the species richness and abundance within a site
• Vegetation structure, measured, for example, through tree cover, biomass or woody plant density
• Ecological processes, such as nutrient cycling or symbiotic relationships between different species (e.g., mycorrhizae)

Out of these criteria, biodiversity, and species richness in particular, deserve particular attention from philanthropists seeking to make an impact. Restoring the vegetation structure, species abundance, and symbiotic relationships of original ecosystems is to a large extent always possible after those ecosystems have been used for agriculture even though that restoration might require intensive measures such as terracing and turf translocation for forests and channel reprofiling for rivers (e.g., Crouzeilles et al. 2016). However, once species that inhabited a place are extinct, those species can never be brought back and, on the biodiversity dimension, land return will not be fully possible—reductions in species richness are irreversible.

This irreversibility suggests placing particular importance on preventing the extinction of species, as species can be made more abundant by increasing their habitat or even be re-introduced into their original habitats in the future if there is a small but sustainable population left. However, once species are lost, more and more land can no longer be fully returned to nature and restored to a pre-disturbance state as the original species no longer exist. Because of the permanence of extinction, the goals for philanthropists seeking to return land to nature are two-fold. Firstly, reducing agricultural land use as much as possible to create land that can be returned to nature. Secondly, safeguarding the most vulnerable species now to ensure that such future land return and restoration is still possible.

Based on this problem structure, this report investigates two sets of strategies for returning land to nature and. within each set of strategies, identifies heuristics for high-impact giving opportunities:

1. Reducing the demand for agricultural land to a) avoid further transformation of uncultivated land into agricultural land and b) decrease costs for the restoration of degraded ecosystems by reducing land acquisition costs¹ (Land Use Reduction – medium- to long-term)
2. Reducing the extinction risk of the most threatened species in the short-term to avoid a permanent limit to the possibility of returning land to nature in the future. (Conservation/Restoration – short-term)

The remainder of this report proceeds as follows.

First, we investigate land use reduction to return land to nature on a large scale in the future. We conclude that reducing demand for livestock, and beef in particular, through alternative proteins has the potential for outsized impact. We identify advocacy for public funding of cultivated meat R&D and plant-based meat commercialization to reduce their prices to be likely most cost-effective. Potential countries to target for policy advocacy are high-income, consume a lot of meat, and face potential future food security risks.

We then review high-yield farming to reduce future land expansion mainly in sub-Saharan Africa. Interventions that improve yields at low to no cost for farmers are most likely to succeed as it is in farmers’ interest to cheaply increase their production. However, we caution that the overall land use effects of high-yield farming are more uncertain, and possibly more muted, than those caused by alternative proteins.

In the second part of the report, we explore the problem structure of species extinction, the prevention of which is a prerequisite for returning land to nature in the future. We find that in certain types of biomes and geographical areas, the threats to species richness are more than 10x larger than in others (Strassburg et al. 2020), including some areas with the largest existing rewilding programs—suggesting that existing initiatives are not targeted effectively.

Lastly, we investigate conservation and restoration programs and find conditions for high-impact philanthropy, specifically a focus on low-income countries within East Africa, Southeast Asia, and Mesoamerica, on low-agricultural yield areas, and on large-scale, long-time projects that restore or conserve forests and shrublands.

Read the full report.

Notes

1. We explain this reduction in costs in more detail in the Restoration section. ↩