Reforestation: What Is Its Potential Impact In Mitigating the Climate Crisis

Planting trees is widely recognised as an important form of climate mitigation, but it comes with major challenges, including competition for land use and high risks of reversal. However, even conservative analyses of its potential place reforestation at the top of the list of climate solutions needed to achieve global net zero.

by Samuel Abel

Planting trees is widely recognised as an important form of climate mitigation. Indeed, healthy forests store more carbon than they release into the atmosphere by sequestering (storing) it in tree trunks, root systems, and the soil, and are thus a net carbon sink [1]. Reforestation is therefore recognised by the IPCC as a form of ‘carbon dioxide removal’ (CDR) [2]. 

What has been contested is the scale at which reforestation can be deployed as a solution without incurring substantial costs, given the competing demands on land and risks of reversal. This article examines the benefits, risks, and potential of reforestation. 

A note on terminology: ‘reforestation’ will be used to cover both afforestation (planting new forests) and reforestation (restoring previous forests), unless otherwise specified.

Benefits and Progress

Beyond its mitigation potential, reforestation is essential for climate adaptation – helping the world cope with global warming by reducing desertification, reducing urban temperatures and flood risks [3,2,4]. Forests provide significant co-benefits for nature, including enhancing biodiversity and ecosystem functions [2,5]. 

There can also be significant social benefits, including improved local employment and livelihoods created through local reforestation projects and planting crops alongside trees, a practice known as agroforestry [6,7]. Most of all, as a mitigation method, restoring existing natural forests through reforestation is one of the best understood and most cost-effective forms of removing carbon dioxide from the atmosphere [2].

Global reforestation efforts have been counteracted by continued deforestation on a vast scale [2]. Deforestation rates of 10 million hectares – roughly the size of Portugal – have resulted in a net loss of 4.7 million hectares annually between 2010 and 2020. 

However, deforestation rates have been declining and reforestation rates have been increasing, and “many countries have not only ended deforestation but have actually achieved substantial reforestation” [8].

Key Risks and Limitations

Some studies in the mid-2010s suggested that the mitigation potential of reforestation could be as much as 10 gigatonnes of CO2 equivalent (GtCO2e) [9]. Considering that current global emissions are close to 40 GtCO2e, this would be an extraordinary figure [10]. However, more recent studies have found this mitigation potential to be unrealistic. 

The main environmental issue is that reforestation leads to trade-offs due to competing demands on land: land that is reforested cannot be used for agriculture, forcing a trade-off between prioritising land for removing carbon over food production [2]. This can cause social justice issues where there are vulnerable populations whose food and fuel needs conflict with reforestation. 

Additionally, unlike other carbon removal methods, there is a high risk of reversal. Global warming is increasing the likelihood of wildfires and disease, and natural tree death and future deforestation remain serious risks if a project is not properly implemented [6,1]. Worse, the effectiveness of reforestation as a mitigation method declines at higher degrees of warming, due to higher temperatures, droughts, and wildfires [2]. Lastly, the standards used to ensure the efficacy of reforestation projects are largely seen as too weak to mitigate these risks [2]. 

What’s the Potential?

These risks have led to recent studies producing more conservative, but still significant, estimates of reforestation’s mitigation potential. In 2022, the IPCC estimated an annual mitigation potential of 7.3 GtCO2e from reforestation, peatland and grassland restoration, and improved forest management, of which reforestation specifically would make a “substantial contribution” [6]. 

UNEP’s 2024 Emissions Gap Report examined over 50 mitigation categories and put reforestation in third place after wind and solar energy with an annual potential 3.6 GtCO2e [5]. A recent Nature study, which put even stricter requirements on reducing risks associated with reforestation, nonetheless concluded that 2.25 GtCO2e and up to 195?million hectares – about the size of Mexico – are suitable for reforestation [11].

Although more conservative, these figures nonetheless apportion a huge role to reforestation in achieving global net zero. The UNEP figures indicate that global afforestation and reforestation alone can provide 8.8% of total mitigation potential by 2035 [5]. This is a strikingly high percentage for reforestation alone, which excludes improved forest management and reducing deforestation.

Conclusion

In summary, even conservative studies conclude that reforestation is one of the biggest tools at our disposal to address the climate crisis, especially when combined with reduced deforestation and the restoration of global wetlands and grasslands. But, we should be wary of viewing reforestation as the ‘easy fix’, which would reduce societal pressure to decarbonise. 

Furthermore, the standards used to measure the carbon removal achieved through reforestation need to be improved over time with the help of organisations such as the Integrity Council for the Voluntary Carbon Market [1,13]. 

Despite challenges and shortcomings, there are examples of progress, including the ambitious ‘Great Green Walls’ in Sub-Saharan Africa and China, or Scotland, where forests are being restored to levels not seen since the Dark Ages [8]. Forests can be greatly useful in the fight against the climate crisis, but we must not lose sight of the risks that come with this opportunity.

References:

[1] Kirschbaum, M. U. F., Cowie, A. L., Peñuelas, J., Smith, P., Conant, R. T., Sage, R. F., … Way, D. A. (2023). Is tree planting an effective strategy for climate change mitigation? Science of the Total Environment. Advance online publication. https://doi.org/10.1016/j.scitotenv.2023.XXX azocleantech.com+3biochar.groups.io+3sciencedirect.com+3
[2] IPCC, 2023: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland, pp. 35-115, doi: 10.59327/IPCC/AR6-9789291691647.
[3] Justin Langan. (2024, October 29). Desertification, land degradation & climate change. ClimaTalk. https://climatalk.org/2024/10/29/desertification-land-degradation-climate-change/
[4] Trees for Cities. (n.d.). Urban heat: How trees help reduce it. Retrieved 2025 from https://www.treesforcities.org/urban-heat
[5] United Nations Environment Programme. (2024). Emissions Gap Report 2024: No more hot air … please! With a massive gap between rhetoric and reality, countries draft new climate commitments. Nairobi. https://doi.org/10.59117/20.500.11822/46404
[6] IPCC, 2022*: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change* [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926
[7] The Nature Conservancy. (n.d.). Reforestation & natural climate solutions. Retrieved 2025 from https://www.nature.org/en-us/what-we-do/our-priorities/tackle-climate-change/climate-change-stories/reforestation-natural-climate-solutions/
[8] Ritchie, H., & Roser, M. (2024). Deforestation & reforestation. Our World in Data. https://ourworldindata.org/deforestation
[9] Bastin, J.-F., Finegold, Y., Garcia, C., Mollicone, D., Rezende, M., Nathan, T., … Crowther, T. W. (2019). The global tree restoration potential. Proceedings of the National Academy of Sciences of the United States of America, 116(106), 232–237. https://doi.org/10.1073/pnas.1710465114
[10] Ritchie, H. (2025). CO? emissions. Our World in Data. https://ourworldindata.org/co2-emissions
[11] Fesenmyer, K. A., Poor, E. E., Terasaki Hart, D. E., Veldman, J. W., Fleischman, F., Choksi, P., Archibald, S., Armani, M., Fagan, M. E., Fricke, E. C., Terrer, C., Hasler, N., Williams, C. A., Ellis, P. W., & Cook?Patton, S. C. (2025). Addressing critiques refines global estimates of reforestation potential for climate change mitigation. Nature Communications, 16(1), Article 4572. https://doi.org/10.1038/s41467-025-59799-8 pubmed.ncbi.nlm.nih.govscienceopen.com+7nature.com+7experts.umn.edu+7
[12] Samuel Abel. (2024). Greenwaving: The ugly twin of greenwashing. The Eden Foundation. https://www.theedenfoundation.co.uk/articles/greenwaving-the-ugly-twin-of-greenwashing
[13] Integrity Council for the Voluntary Carbon Market. (n.d.). Retrieved 2025 from https://icvcm.org/