# Thomas Crowther (ecologist)

Thomas Ward Crowther (born 1986) is a British ecologist. He is a former professor of ecology at ETH Zürich and a founding co-chair of the Advisory Board for the United Nations Decade on Ecosystem Restoration. At ETH Zürich, he started Crowther Lab, an interdisciplinary group of scientists exploring the role of biodiversity in regulating the Earth's climate.
Crowther is the founder of Restor, an online platform that supports thousands of community-led restoration projects around the world. In 2021, the World Economic Forum named Crowther a Young Global Leader.

## Career

Crowther conducted his undergraduate and PhD studies at Cardiff University, under the supervision of Dr. Hefin Jones. Following his PhD, Crowther received a postdoctoral fellowship from the Climate and Energy Institute at Yale University. In 2015, Crowther was awarded a Marie Curie fellowship to research the impact of carbon cycle feedbacks on climate change at the Netherlands Institute of Ecology (NIOO).
In 2017, Crowther obtained a tenure track professorship at ETH Zürich. In 2024, ETH Zürich dismissed Crowther from his post following allegations of misconduct, which remain unsubstantiated to date. Crowther denied any wrongdoing. The investigation was still ongoing as of December 2024. In February 2025, current and past members of his lab have spoken about the supportive and enriching environment—both scientifically and personally—that he fostered.

## Research

Crowther is a leader in the field of global biodiversity research. His work is best known for helping to develop the field of global restoration ecology. This work has formed the scientific motivation for international conservation and restoration initiatives including the UN Decade on Ecosystem Restoration, and the Trillion Tree Campaigns of the World Economic Forum, WWF and UNEP.
His early work focused on soil biodiversity and their interactions with plants. In the journal Science, he stressed that ‘soil organisms represent the most biologically diverse community on land’. His research has mapped the distribution of mycorrhizal fungi and nematodes across global soils, revealing the importance of these soil organisms for global carbon cycling. Crowther’s work highlights how warming of soils can increase the rates of carbon emissions from soil. In 2016, Crowther’s research suggested that warming might stimulate the activity of soil organisms in high-latitude arctic and sub-arctic soils, leading to the loss of 30 Gt of Carbon by 2050, which could accelerate climate change by 12-17%. Crowther stresses that protecting the soil community might be one of the best way to buffer ecosystems against these potential impacts of climate change.
In 2015, Crowther led an international team to show that the Earth is home to approximately 3.04 trillion trees. The research also estimated that humans have reduced that number by almost half, and Earth continues to lose around 10 billion trees each year. Ongoing research on global forests also showed that there are over 79,000 tree species in the global forest system, and that the productivity of forests increases as species diversity increases.
Crowther’s work has estimated the global tree restoration potential, showing that there are 0.9 billion hectares of land where trees would naturally be able to grow outside of urban and agricultural land. If this land could be protected, the study suggested that this is room for one trillion new trees, and the recovering ecosystems could capture over 205 Gt Carbon. Crowther has described nature restoration as one of the most effective carbon drawdown strategies to date, with the potential to help people, biodiversity, and climate.
A number of scientists criticized the idea that planting trees across the globe is a simple solution to climate change. In particular, several articles suggested that it is dangerous and misleading to propose that tree planting can be a silver bullet to stop climate change. Crowther agreed with those criticisms, stating that ecosystem restoration cannot be used as an excuse to ignore the challenges of cutting greenhouse gas emissions and protecting existing ecosystems. He also emphasized that ecosystem restoration is not simply about planting trees for carbon capture. Instead, it is about the many solutions that promote the protection, regeneration and sustainable management of nature for local people and the biodiversity that they depend on. Crowther warned about the risks of mass tree plantations, highlighting the need for socially and ecologically responsible restoration of ecosystems across the globe.
Following this work, Crowther teamed up with 220 scientists to create the Integrated Forest Assessment. They showed that the conservation and recovery of diverse forests can account for roughly 1/3 of our climate change mitigation requirements, providing empirical data to support the commitments made under the Kunming-Montreal Global Biodiversity Framework and the Glasgow Leaders Declaration on Forests and Land Use.

## Tech for nature

In a 2020 TED Talk, Crowther announced the development of an online platform for the conservation and restoration of nature. Described as a “Google Maps for nature,” Restor is an online open data platform and not-for-profit organization that provides ecological data, transparency, and connectivity to nature-based solutions. In 2021, Restor was a finalist for the Royal Foundation’s Earthshot Prize in the Protect and Restore Nature category. As of early 2022, the platform connected and supported more than 200,000 conservation and restoration projects worldwide.
As part of his research, Crowther compiled a large inventory of tree data based on a combination of satellite observations and on-the-ground ecological research. In 2016 he co-founded the Global Forest Biodiversity Initiative (GFBI), which manages the world's largest tree-level forest inventory database with over 30 million observations of tree measurements from 1.2 million locations around the world. The database was used to identify that across the global forest system, a greater number of tree species consistently leads to increases in the carbon storage of local forests, even with the same number of trees.
Crowther is also the founder of SEED, a tool that allows organizations to assess the complexity of life at any location on Earth.

## Policy and engagement

Based on the global tree potential research, the World Economic Forum (WEF) launched its Trillion Trees initiative in January 2020 in partnership with Lynne and Marc Benioff. Benioff later described Crowther as the “Steve Jobs of ecology” for his role in driving global ecological recovery. Crowther now serves on the advisory board of 1T.org. In 2021, Crowther Lab was appointed as a supporting partner to the UN Decade on Ecosystem Restoration, and Crowther served as a founding co-chair of the advisory board for the Decade on Ecosystem Restoration.
The research has also featured in the United Nations’ Trillion Tree campaign and a similar initiative with the same name led by WWF and BirdLife international, which aims to protect and regenerate 1 trillion trees within healthy ecosystems across the globe.

## References and selected publications

* ↑ Mulenkei, Thomas Crowther and Lucy (7 September 2021). "This summer is a terrible reminder of why we must build back nature". CNN. Retrieved 2022-02-18.
* ↑ Crowther, Thomas. "Thomas Crowther | Speaker | TED". www.ted.com. Retrieved 2022-02-18.
* ↑ Jones, Benji (2022-01-21). "This map may make you feel better about the state of the planet". Vox. Retrieved 2022-02-18.
* ↑ "Meet the 2021 class of Young Global Leaders". World Economic Forum. Retrieved 2022-02-18.
* ↑ "New Class". The Forum of Young Global Leaders. Retrieved 2022-02-18.
* ↑ "Thomas Crowther". gfbi-portal. Retrieved 2022-02-18.
* ↑ Dennehy, Kevin (2016-11-30). "Losses of soil carbon under global warming might equal U.S. emissions". YaleNews. Retrieved 2022-02-18.
* ↑ "5 professors appointed". ethz.ch. 29 September 2017. Retrieved 2022-02-18.
* 1 2 3 Boss, Catherine; Zihlmann, Oliver (2024-12-19). "Weltbekannter Klimaforscher muss die ETH Zürich nach Vorwürfen verlassen". Der Bund (in German). Retrieved 2024-12-19.
* ↑ Else, Holly (24 January 2025). "Star ecologist accused of misconduct loses university post". Nature. Retrieved 27 January 2025.
* ↑ https://medium.com/@ian.brettell_51041/our-experience-our-voice-an-open-letter-from-members-of-the-crowther-lab-410a76a4c705
* ↑ Greenfield, Patrick (2023-11-13). "Let forests grow old to store huge volume of carbon – study". The Guardian. ISSN 0261-3077. Retrieved 2024-02-29.
* ↑ Greenfield, Patrick; @pgreenfielduk (2021-09-01). "'I've never said we should plant a trillion trees': what ecopreneur Thomas Crowther did next". The Guardian. ISSN 0261-3077. Retrieved 2024-02-29.
* ↑ "Thomas Crowther". UN Decade on Restoration. Retrieved 2024-02-29.
* ↑ "A platform for the trillion trees community". 1t.org. Retrieved 2024-02-29.
* ↑ "Why Trillion Trees?". Trillion Trees. Retrieved 2024-02-29.
* ↑ ACTION PLAN FOR THE UN DECADE ON ECOSYSTEM RESTORATION, 20212030 (PDF).
* ↑ Crowther, T. W.; Hoogen, J. van den; Wan, J.; Mayes, M. A.; Keiser, A. D.; Mo, L.; Averill, C.; Maynard, D. S. (2019-08-23). "The global soil community and its influence on biogeochemistry". Science. 365 (6455): 0550. Bibcode:2019Sci...365.0550C. doi:10.1126/science.aav0550. OSTI 1559650. PMID 31439761. S2CID 201616655.
* ↑ Crowther, T. W.; van den Hoogen, J.; Wan, J.; Mayes, M. A.; Keiser, A. D.; Mo, L.; Averill, C.; Maynard, D. S. (2019-08-23). "The global soil community and its influence on biogeochemistry". Science. 365 (6455): 0550. Bibcode:2019Sci...365.0550C. doi:10.1126/science.aav0550. ISSN 0036-8075. PMID 31439761.
* ↑ Steidinger, B. S.; Crowther, T. W.; Liang, J.; Van Nuland, M. E.; Werner, G. D. A.; Reich, P. B.; Nabuurs, G. J.; de-Miguel, S.; Zhou, M.; Picard, N.; Herault, B. (May 2019). "Climatic controls of decomposition drive the global biogeography of forest-tree symbioses". Nature. 569 (7756): 404–408. Bibcode:2019Natur.569..404S. doi:10.1038/s41586-019-1128-0. ISSN 0028-0836. PMID 31092941. S2CID 155103602.
* ↑ van den Hoogen, Johan; Geisen, Stefan; Routh, Devin; Ferris, Howard; Traunspurger, Walter; Wardle, David A.; de Goede, Ron G. M.; Adams, Byron J.; Ahmad, Wasim; Andriuzzi, Walter S.; Bardgett, Richard D. (August 2019). "Soil nematode abundance and functional group composition at a global scale". Nature. 572 (7768): 194–198. Bibcode:2019Natur.572..194V. doi:10.1038/s41586-019-1418-6. ISSN 1476-4687. PMID 31341281. S2CID 198492891.
* ↑ Crowther, T. W.; Todd-Brown, K. E. O.; Rowe, C. W.; Wieder, W. R.; Carey, J. C.; Machmuller, M. B.; Snoek, B. L.; Fang, S.; Zhou, G.; Allison, S. D.; Blair, J. M. (December 2016). "Quantifying global soil carbon losses in response to warming". Nature. 540 (7631): 104–108. Bibcode:2016Natur.540..104C. doi:10.1038/nature20150. ISSN 0028-0836. PMID 27905442. S2CID 205251843.
* ↑ Wieder, William R.; Hartman, Melannie D.; Sulman, Benjamin N.; Wang, Ying-Ping; Koven, Charles D.; Bonan, Gordon B. (2018-04-01). "Carbon cycle confidence and uncertainty: Exploring variation among soil biogeochemical models". Global Change Biology. 24 (4): 1563–1579. Bibcode:2018GCBio..24.1563W. doi:10.1111/gcb.13979. ISSN 1354-1013. PMID 29120516. S2CID 3642883.
* ↑ "Climate change escalating so fast it is 'beyond point of no return'". The Independent. 2016-12-01. Archived from the original on 2022-05-07. Retrieved 2022-02-18.
* ↑ "The diet of worms: Soil dwellers emerge as climate change heroes in study". america.aljazeera.com. Retrieved 2022-02-18.
* ↑ Crowther, T. W.; Glick, H. B.; Covey, K. R.; Bettigole, C.; Maynard, D. S.; Thomas, S. M.; Smith, J. R.; Hintler, G.; Duguid, M. C.; Amatulli, G.; Tuanmu, M. -N. (2015-09-01). "Mapping tree density at a global scale". Nature. 525 (7568): 201–205. Bibcode:2015Natur.525..201C. doi:10.1038/nature14967. ISSN 0028-0836. PMID 26331545. S2CID 4464317.
* ↑ "Science In Action - Counting the World's Trees - BBC Sounds". www.bbc.co.uk. Retrieved 2022-02-18.
* ↑ "COP21: 'A trillion trees to the rescue'". BBC News. 2015-12-07. Retrieved 2022-02-18.
* ↑ Ehrenberg, Rachel (2015-09-02). "Global forest survey finds trillions of trees". Nature. doi:10.1038/nature.2015.18287. ISSN 1476-4687. S2CID 189415504.
* ↑ "The Tall Task of Counting Every Tree on Earth". Connecticut Public. 2015-09-03. Retrieved 2022-02-18.
* ↑ "Earth has 3 trillion trees but they're falling at alarming rate". news.yahoo.com. Retrieved 2022-02-18.
* ↑ Arup, Tom (2015-09-03). "Earth home to 3 trillion trees, but billions are disappearing every year". The Sydney Morning Herald. Retrieved 2022-02-18.
* ↑ Gatti, Roberto Cazzolla; Reich, Peter B.; Gamarra, Javier G. P.; Crowther, Tom; Hui, Cang; Morera, Albert; Bastin, Jean-Francois; de-Miguel, Sergio; Nabuurs, Gert-Jan; Svenning, Jens-Christian; Serra-Diaz, Josep M. (2022-02-08). "The number of tree species on Earth". Proceedings of the National Academy of Sciences. 119 (6): e2115329119. Bibcode:2022PNAS..11915329C. doi:10.1073/pnas.2115329119. ISSN 0027-8424. PMC 8833151. PMID 35101981.
* ↑ Liang, Jingjing; Crowther, Thomas W.; Picard, Nicolas; Wiser, Susan; Zhou, Mo; Alberti, Giorgio; Schulze, Ernst-Detlef; McGuire, A. David; Bozzato, Fabio; Pretzsch, Hans; de-Miguel, Sergio (2016-10-14). "Positive biodiversity-productivity relationship predominant in global forests". Science. 354 (6309). doi:10.1126/science.aaf8957. PMID 27738143. S2CID 32049832.
* ↑ "The global tree restoration potential". EurekAlert!. Retrieved 2022-02-18.
* ↑ Dickinson, Tim (2020-03-13). "Can We Plant Enough Trees?". Rolling Stone. Retrieved 2022-02-18.
* ↑ "Massive restoration of world's forests would cancel out a decade of CO2 emissions, analysis suggests". The Independent. 2019-02-18. Archived from the original on 2022-05-07. Retrieved 2022-02-18.
* ↑ "Planting 1.2 Trillion Trees Could Cancel Out a Decade of CO2 Emissions, Scientists Find". Yale E360. Retrieved 2022-02-18.
* ↑ "Research: Planting trillions of trees could cancel out CO2 emissions". Futurism. 17 February 2019. Retrieved 2022-02-18.
* ↑ Rogers, Adam. "Trying to Plant a Trillion Trees Won't Solve Anything". Wired. ISSN 1059-1028. Retrieved 2022-02-18.
* ↑ Sengupta, Somini (2019-07-05). "Restoring Forests Could Help Put a Brake on Global Warming, Study Finds". The New York Times. ISSN 0362-4331. Retrieved 2022-02-18.
* ↑ Pearce, Fred (8 January 2020). "Planting a trillion trees really can help us fight climate change". New Scientist. Retrieved 2022-02-18.
* ↑ Crowther, Thomas (2020-10-10), The global movement to restore nature's biodiversity, retrieved 2022-02-18
* ↑ "'I've never said we should plant a trillion trees': what ecopreneur Thomas Crowther did next". The Guardian. 2021-09-01. Retrieved 2022-02-18.
* ↑ Letters (2020-02-21). "Backing the trillion tree campaign to combat climate crisis | Letter". The Guardian. Retrieved 2022-02-18.
* ↑ "Planting a trillion trees? Ambitious, but doable". 2020-01-23. Retrieved 2022-02-18.
* ↑ "One Trillion Trees to Combat Climate Change: Why It's Not So Outlandish". Salesforce News. 2020-01-22. Retrieved 2022-02-18.
* ↑ Solutions, Nature Based (2020-06-30). ""And/also", not "Either/or" — The need to restore nature AND cut emissions". Medium. Retrieved 2022-02-18.
* ↑ "Climate change: Corporate mass tree planting 'damaging' nature". BBC News. 2021-11-10. Retrieved 2022-02-18.
* ↑ "Integrated Global Forest Assessment". Crowther Lab. Retrieved 2024-02-29.
* ↑ Mo, Lidong; Zohner, Constantin M.; Reich, Peter B.; Liang, Jingjing; de Miguel, Sergio; Nabuurs, Gert-Jan; Renner, Susanne S.; van den Hoogen, Johan; Araza, Arnan; Herold, Martin; Mirzagholi, Leila; Ma, Haozhi; Averill, Colin; Phillips, Oliver L.; Gamarra, Javier G. P. (December 2023). "Integrated global assessment of the natural forest carbon potential". Nature. 624 (7990): 92–101. Bibcode:2023Natur.624...92M. doi:10.1038/s41586-023-06723-z. ISSN 1476-4687. PMC 10700142. PMID 37957399.
* ↑ Crowther, Thomas (2020-10-10), The global movement to restore nature's biodiversity, retrieved 2022-02-18
* ↑ Peters, Adele (2021-10-13). "This Google Maps for nature shows the global potential for restoring forests". Fast Company. Retrieved 2022-02-18.
* ↑ "How monitoring can spur investment in land restoration". World Economic Forum. Retrieved 2022-02-18.
* ↑ "Global restoration now has an online meeting point". Mongabay Environmental News. 2021-07-23. Retrieved 2022-02-18.
* ↑ "Winners & Finalists". Earthshot Prize. Retrieved 2022-02-18.
* ↑ "Restor". restor.eco. Retrieved 2022-02-18.
* ↑ "Scientists discover that the world contains dramatically more trees than previously thought". Washington Post. ISSN 0190-8286. Retrieved 2022-02-18.
* ↑ "GFBI – Global Forest Biodiversity Initiative". Retrieved 2022-02-18.
* ↑ Liang, Jingjing; Crowther, Thomas W.; Picard, Nicolas; Wiser, Susan; Zhou, Mo; Alberti, Giorgio; Schulze, Ernst-Detlef; McGuire, A. David; Bozzato, Fabio; Pretzsch, Hans; de-Miguel, Sergio (2016-10-14). "Positive biodiversity-productivity relationship predominant in global forests". Science. 354 (6309). doi:10.1126/science.aaf8957. PMID 27738143. S2CID 32049832.
* ↑ "SEED Biocomplexity: Valuing nature's complexity". seed-index.com. Retrieved 2024-02-29.
* ↑ "Restoring the Earth: 1t.org Announced to Accelerate Nature Restoration to Tackle Climate and Biodiversity Crises". World Economic Forum. Retrieved 2022-02-18.
* ↑ "1t.org Advisory Council". 1t.org. Retrieved 2022-02-18.
* ↑ "Partners". UN Decade on Restoration. Retrieved 2022-02-18.
* ↑ Mulenkei, Thomas Crowther and Lucy (7 September 2021). "This summer is a terrible reminder of why we must build back nature". CNN. Retrieved 2022-02-18.
* ↑ Pageflow. "Trees against climate change: the global restoration and carbon storage potential". crowtherlab.pageflow.io. Retrieved 2022-02-18.