Disclaimer: this is not a project from SoGive.

1. Summary

In this analysis, the mean, and 5th and 95th percentiles of the cost-effectiveness of tree planting in t/£ were estimated to be^[1]:

For the UK, 0.07 (-0.04 to 0.3).
For The Woodland Trust (TWT), 0.04 (-0.02 to 0.2).
For Eden Reforestation Projects’ (ERP’s) mangrove projects in Madagascar, 0.3 (-0.2 to 1).
At best^[2], 1 (-0.8 to 4).

These values are lower than or similar to the bar of 1 t/$ Founders Pledge (FP) arguably considers for the grants of its Climate Change Fund (CCF). In addition, the 5th and 95th percentiles of the cost-effectiveness of CCF in t/$ were guessed to be 10^-1 and 10^4 by Johannes Ackva^[3] (although these should be intended as informed guesses, not resilient estimates; see here). As a result, donating to CCF is expected to be at least 1 order of magnitude more effective than supporting the best tree planting interventions^[4].

Author contributions

The contributions by author are as follows:

Hanzhang Ren: in-depth review.
Melissa Bedinger: background research.
Vasco Grilo: background research, cost-effectiveness modelling, and writing.

Acknowledgements

Thanks to Andrew Baker, Haley Koleszar, Ilona Coulson-Ashworth, Matt Sharp, Sanjay Joshi, and Vince van 't Hoff.

Tree made of stars dancing in space. Generated by OpenAI's DALL-E.

2. Context

Motivation

This research has the goal of assessing the cost-effectiveness of tree planting in the UK, TWT, ERP, and idealised tree planting projects. These are currently not recommended by FP nor Giving Green, which consider themselves aligned with Effective Altruism^[5].

Tree planting can be appealing to donors seeking carbon offsets, especially risk averse ones who perceive it as having a higher likelihood of success than the projects of organisations working on policy advocacy or innovative green technology^[6]. In reality, the risks of tree planting projects are often underestimated.

Analysed projects

The cost-effectiveness of tree planting depends on the specific project. In this analysis, it was assessed for:

Typical UK projects, via:
- “WCC” projects: reference Woodland Carbon Code (WCC) projects^[7].
- “Small” projects^[8]: reference WCC projects with an area no larger than 5 ha.
- “Standard” projects: reference WCC projects with an area larger than 5 ha.
“TWT” projects: reference WCC projects from TWT.
- TW

...

Test 123