Earth's life-support systems

Proposed and experimental methods

Methods that are proposed, under trial, approved in some places, or tried and then failed. Each shows a stage label and an evidence rating. A stage label shows how far a method has progressed, not whether it works. The stage labels are explained on the environmental factor page.

• Payments for ecosystem services (Large trial, B). Landowners are paid to keep forest standing. In a randomized trial in 121 Ugandan villages, forest-owning households in the 60 treatment villages were offered 70,000 Ugandan shillings per hectare per year for 2 years, tree cover measured from satellite images fell by 4.2% versus 9.1% in control villages, there was no sign that clearing shifted to nearby land, and the value of delayed carbon dioxide emissions was 2.4 times the program cost (Jayachandran et al., 2017). In a separate payment program in western Uganda with 268 sampled households, the link with less deforestation had vanished four years after payments ended, although the forest gained during the program was kept (Kemigisha et al., 2023).
• Protecting 30% of land and sea by 2030 ("30 by 30") (Approved but not scaled, B). A meta-analysis of 186 studies (665 trials) that compared conservation actions with no action found that in two-thirds of cases conservation improved biodiversity or slowed its decline, and protected areas, habitat restoration, invasive species control, and sustainable management had large effects (Langhammer et al., 2024). In 2024, 17.6% of land and inland waters and 8.4% of ocean and coastal areas were in documented protected and conserved areas, coverage had risen less than 0.5 percentage points since 2020, management effectiveness had been assessed for under 5% of protected land, and only 8.5% of the world's land was both protected and well connected (IUCN, 2024).
• Debt-for-nature swaps (Approved but not scaled, contested, C). A country's debt is bought back at a discount in exchange for conservation spending. In May 2023, Ecuador converted $1.6 billion of commercial debt into a new $656 million loan and committed more than $450 million to conservation over 20 years for the Galápagos and Hermandad marine reserves (Pew, 2023). An IMF staff analysis concluded that such swaps are generally less efficient than conditional grants or broad debt restructuring, because part of the benefit goes to creditors who do not take part, but can expand fiscal space when grants or deeper debt relief are not available (Chamon et al., 2022).
• Biodiversity credits (Early trial, C). Companies or governments would buy credits that pay for measured gains in nature. An international advisory panel launched a framework at the COP16 biodiversity meeting in October 2024, with pilot projects, saying high-integrity markets are feasible, a standard tradable unit is not appropriate because biodiversity is not interchangeable, and it does not support secondary trading at this stage (IAPB, 2024). In the closest existing market, a study of 26 forest-protection carbon offset projects in six countries found most had not significantly reduced deforestation, and those that did reduced it far less than claimed (West et al., 2023).
• Not shown to help: de-extinction by gene editing (Early trial, contested, C). Colossal Biosciences announced that it had brought back the extinct dire wolf by editing gray wolf genomes, but the result was three pups with a small amount of dire wolf-like DNA born to a domestic dog surrogate, and reviewers argue this is not a resurrected species (Jensen-Seaman et al., 2025).

Sources cited on this page

1. Chamon, M., Klok, E., Thakoor, V. V., & Zettelmeyer, J. (2022). Debt-for-climate swaps: Analysis, design, and implementation (IMF Working Paper). International Monetary Fund. link C Limited
2. Jayachandran, S., de Laat, J., Lambin, E. F., Stanton, C. Y., Audy, R., & Thomas, N. E. (2017). Cash for carbon: A randomized trial of payments for ecosystem services to reduce deforestation. Science, 357(6348), 267-273. link B Moderate
3. Jensen-Seaman, M. I., Hartstone-Rose, A., Burrows, A. M., & Smith, H. F. (2025). The dire wolf (Aenocyon dirus) resurrection that wasn't. Anatomical Record, 309(7), 1788-1796. link C Limited
4. Kemigisha, E., Babweteera, F., Mugisha, J., & Angelsen, A. (2023). Payment for environmental services to reduce deforestation: Do the positive effects last? Ecological Economics, 209, 107840. link C Limited
5. Langhammer, P. F., Bull, J. W., Bicknell, J. E., Oakley, J. L., Brown, M. H., Bruford, M. W., et al. (2024). The positive impact of conservation action. Science, 384(6694), 453-458. link B Moderate
6. West, T. A. P., Wunder, S., Sills, E. O., Börner, J., Rifai, S. W., Neidermeier, A. N., et al. (2023). Action needed to make carbon offsets from forest conservation work for climate change mitigation. Science, 381(6660), 873-877. link B Moderate

Every source for this factor is listed on the environmental factor page.