Thomas Crowther (ecologist)

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Thomas Crowther
A photo of Thomas Crowther (ecologist)
Born (1986-06-18) June 18, 1986 (age 33)
Known forGlobal Ecology
Scientific career
InstitutionsETH Zurich, Switzerland
Yale University, USA
Cardiff University, UK

Thomas Ward Crowther (born 18 June 1986) is a British scientist specialising in ecosystem ecology and the chief scientific advisor to the UN's Trillion Tree Campaign. He is a tenure-track professor of Global Ecosystem Ecology at ETH Zürich where he formed the Crowther Lab. His work aims to generate a holistic understanding of the global scale ecological systems which regulate the Earth's climate.[1][2][3][4]

Research career[edit]

After his PhD, Crowther received a postdoctoral fellowship from the Yale Climate and Energy Institute, to pursue his postgraduate research 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 started a tenure track professorship at ETH Zürich.[5] His ongoing research is supported through a unique partnership with DOB Ecology – a private foundation focussed on supporting projects which protect and restore threatened ecosystems across the globe.[6]

Three Trillion Trees[edit]

During his post-doctoral research, Crowther received acclaim for his research which mapped the diversity and distribution of forest trees across the world for the first time.[7] This research revealed that there are approximately 3.04 trillion trees on Earth, and quantified the scale of human impact over time (the number of trees worldwide has dropped by 46% since the onset of agriculture about 12,000 years ago). Previous estimates suggested there may only be 400 billion trees on Earth.[8][9][10][11][12][13][14][15]

Crowther was inspired to conduct his tree study by Plant-for-the-Planet, the youth-led NGO leading the UN's Billion Tree Campaign.[16] After he made the discovery, Crowther's story featured in a textbook to be distributed at global Plant-for-the-Planet Academies, stating "Tom was teased over the years by his fellow Professors for being the 'tree counter'. But Tom stuck with it and on 2 September 2015, his findings were published in the Journal Nature, the most prestigious paper in his field".[17]

With the knowledge that there were now three trillion trees on Earth, Plant-for-the-Planet increased their restoration targets and transformed the Billion Tree Campaign into the Trillion Tree Campaign. Crowther is now the lead science advisor to Plant-for-the-Planet.[18][19][20] As part of his tree study Crowther was able to compile one of the largest inventories of tree data ever recorded. In 2016 he co-founded the Global Forest Biodiversity Initiative (GFBI) – a foundation which manages the world's largest tree-level forest inventory database with 1.2 million plots from more than 70 countries.[21][22]

Climate Change Ecology[edit]

Whilst at NIOO Crowther's research found that a 1 °C increase in temperatures could release an additional 55 billion tonnes of soil carbon (200 billion tonnes of carbon dioxide), not previously accounted for by scientists, into the atmosphere by 2050. Further, his research suggested that warming generally stimulates decomposition more than photosynthesis.[23][24][25] Increased activity of microbes and soil animals, such as worms, would be the source of the additional carbon emissions, which could accelerate global warming by 17%.[26] Prof Ivan Janssens, seen as one of the godfathers in the global change ecology field commented "the research had provided essential data to climate change models". The study's data was since incorporated into ongoing work by the UN's Intergovernmental Panel on Climate Change.[27][28][29][30] In a more recent scientific review of research on soil carbon feedback, Crowther's work was highly cited as the "new finding of a statistical dependence of decomposition on the initial carbon content of the soil may prove to be a useful benchmark for [Earth System Model] simulations".[31]

Whilst Crowther acknowledges humanity has passed the "point of no return" in reversing the effects of climate change, he does believe action to dampen these effects is possible. He was outspoken about Donald Trump's decision to remove the United States from the Paris Agreement, calling it "catastrophic for humanity".[32] Crowther also criticised the Trump administration for lifting the moratorium on the coal industry, noting that "renewable energies employ more people" and calling the decision "ridiculously short term and short sighted".[33]

In July 2016, Crowther provided an expert declaration on the carbon cycle, and the sequestration potential of forests and soil for the Western Environmental Law Center to support the proposed Clean Air Rule to limit greenhouse gases in Washington. He went on to give a keynote address at the FAO's 2017 Global symposium on soil organic carbon alongside Nobel Prize winner Dr. Rattan Lal.[34][35]

In May 2019 Crowther co-authored research on global mycorrhizal fungal networks, revealing that 60% of trees are connected by ectomycorrhizal fungi (EM) but, as temperatures rise, these fungi - and their associated tree species - will decline and be replaced by arbuscular mycorrhizal fungi (AM). Whilst EM fungi support huge carbon stores, the transition to AM fungi could increase the release of carbon into the atmosphere. The research estimated that if there isn't a reduction in carbon emissions by 2100, there could be a 10% reduction in EM - and the trees that depend on them.[36]

Geospatial Mapping[edit]

Crowther's ongoing research employs location intelligence and mapping technologies to convey the status of Earth's terrestrial ecosystems. Through the latest machine learning approaches they generate predictive models for a detailed understanding of the biosphere's spatial and temporal patterns.[37][38]

In October 2018 he delivered a keynote address at the 2018 conference for the Association for Forest Spatial Analysis Technologies (ForestSAT), hosted by the NASA Goddard Space Flight Center and the University of Maryland.[39] In February 2019, at the American Association for the Advancement of Science, Crowther announced that scientists had established there was room for an additional 1.2 trillion trees, noting that such a scale of reforestation could be one of the most powerful tools in the fight against climate change. [40][41][42]


A major paper on 'The Global Tree Restoration Potential' (published in July 2019) has been criticized by other researchers of the field for an allegedly low quality of scientific work. [43]

References and selected publications[edit]

  1. ^ "Thomas Crowther - Nature-based solutions in the fight against climate change at TEDxLausanne". 2019-09-19. Retrieved 2019-12-12.
  2. ^ "Tom Crowther". ForestSAT 2018. 2018-07-04. Retrieved 2018-10-21.
  3. ^ "On the Business of Battling Climate Change". Esri. Retrieved 2018-10-31.
  4. ^ (2018-06-29), Thomas Crowther - Atmosphärischer Wissenschafter, retrieved 2018-10-31
  5. ^ "5 professors appointed". Retrieved 2018-10-21.
  6. ^ Ecology, DOB. "DOB Ecology » Partners". DOB Ecology. Retrieved 2018-11-02.
  7. ^ 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.; Jetz, W.; Salas, C.; Stam, C.; Piotto, D.; Tavani, R.; Green, S.; Bruce, G.; Williams, S. J.; Wiser, S. K.; Huber, M. O.; Hengeveld, G. M.; Nabuurs, G.-J.; Tikhonova, E.; Borchardt, P.; Li, C.-F.; Powrie, L. W.; Fischer, M.; Hemp, A.; Homeier, J.; Cho, P.; Vibrans, A. C.; Umunay, P. M.; Piao, S. L.; Rowe, C. W.; Ashton, M. S.; Crane, P. R.; Bradford, M. A. (2 September 2015). "Mapping tree density at a global scale". Nature. 525 (7568): 201–5. Bibcode:2015Natur.525..201C. doi:10.1038/nature14967. PMID 26331545.
  8. ^ Ehrenberg, Rachel (2 September 2015). "Global count reaches 3 trillion trees". Nature. doi:10.1038/nature.2015.18287.
  9. ^ Skahill, Patrick. "The Tall Task of Counting Every Tree on Earth". Retrieved 2018-10-31.
  10. ^ CNN, Brandon Griggs. "The Earth has 3 trillion trees, study says - CNN". CNN. Retrieved 2018-10-31.
  11. ^ "Here's How Many Trees Humans Cut Down Each Year". Time. Retrieved 2018-10-31.
  12. ^ Writer, SETH BORENSTEIN, AP Science. "Lots of trees to hug: Study counts 3 trillion trees on Earth". KFOX. Retrieved 2018-10-31.
  13. ^ McMahon, Sean; Parnell, John (September 2018). "The deep history of Earth's biomass" (PDF). Journal of the Geological Society. 175 (5): 716–720. Bibcode:2018JGSoc.175..716M. doi:10.1144/jgs2018-061. hdl:2164/12379.
  14. ^ "Earth has 3 trillion trees but they're falling at alarming rate". Retrieved 2018-10-31.
  15. ^ Arup, Tom (2015-09-03). "Earth home to 3 trillion trees, but billions are disappearing every year". The Sydney Morning Herald. Retrieved 2018-10-31.
  16. ^ "BBC Sounds - Science in Action - Counting the World's Trees". BBC. Retrieved 2018-11-01.
  17. ^ "Tree by Tree - Now We Children Save the World". Issuu. Retrieved 2018-10-31.
  18. ^ "A trillion trees to the rescue". BBC News. 2015-12-07. Retrieved 2018-10-21.
  19. ^ Silberg, Bob. "Nine-year-old boy plants seed that yields 3 trillion trees – Climate Change: Vital Signs of the Planet". Climate Change: Vital Signs of the Planet. Retrieved 2018-10-21.
  20. ^ "Plant-for-the-Planet". Retrieved 2018-10-21.
  21. ^ "Thomas Crowther". GFBI Home. Retrieved 2018-10-21.
  22. ^ "GFBI Home". GFBI Home. Retrieved 2018-10-21.
  23. ^ 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.; Bridgham, S. D.; Burton, A. J.; Carrillo, Y.; Reich, P. B.; Clark, J. S.; Classen, A. T.; Dijkstra, F. A.; Elberling, B.; Emmett, B. A.; Estiarte, M.; Frey, S. D.; Guo, J.; Harte, J.; Jiang, L.; Johnson, B. R.; Kröel-Dulay, G.; Larsen, K. S.; Laudon, H.; Lavallee, J. M.; Luo, Y.; Lupascu, M.; Ma, L. N.; Marhan, S.; Michelsen, A.; Mohan, J.; Niu, S.; Pendall, E.; Peñuelas, J.; Pfeifer-Meister, L.; Poll, C.; Reinsch, S.; Reynolds, L. L.; Schmidt, I. K.; Sistla, S.; Sokol, N. W.; Templer, P. H.; Treseder, K. K.; Welker, J. M.; Bradford, M. A. (1 December 2016). "Quantifying global soil carbon losses in response to warming" (PDF). Nature. 540 (7631): 104–8. Bibcode:2016Natur.540..104C. doi:10.1038/nature20150. PMID 27905442.
  24. ^ Singh, Brajesh K., ed. (2018). Soil carbon storage: modulators, mechanisms and modeling. ISBN 978-0-12-812766-7.[page needed]
  25. ^ Wieder, William R.; Hartman, Melannie D.; Sulman, Benjamin N.; Wang, Ying-Ping; Koven, Charles D.; Bonan, Gordon B. (April 2018). "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. PMID 29120516.
  26. ^ "Climate change escalating so fast it is 'beyond point of no return'". The Independent. Retrieved 2018-10-21.
  27. ^ "Scientists have long feared this 'feedback' to the climate system. Now they say it's happening". Washington Post. Retrieved 2018-10-21.
  28. ^ Kinver, Mark (2016-11-30). "Earth warming to 'climate tipping point'". BBC News. Retrieved 2018-10-21.
  29. ^ Loss of soil carbon due to climate change will be 'huge', retrieved 2018-10-21
  30. ^ "Climate change escalating so fast it is 'beyond point of no return'". The Independent. Retrieved 2018-10-21.
  31. ^ Davidson, Eric A. (1 December 2016). "Projections of the soil-carbon deficit". Nature. 540 (7631): 47–48. doi:10.1038/540047a. PMID 27905445.
  32. ^ "A US government science body promoted an article denying climate change". The Independent. Retrieved 2018-10-31.
  33. ^ "Trump's 'insane' climate change policy will destroy more jobs than it creates, says global warming expert". The Independent. Retrieved 2018-10-31.
  34. ^ "Ecology's Proposed Clean Air Rule" (PDF). Western Environmental Law Center. Retrieved 21 October 2018.
  35. ^ "FAO GLOBAL SYMPOSIUM ON SOIL ORGANIC CARBON" (PDF). Food and Agriculture Organisation. Retrieved 21 October 2018.
  36. ^ Marshall, Claire (2019-05-15). "'Wood wide web' tree social network mapped". Retrieved 2019-05-31.
  37. ^ Dangermond, Jack. "Shifting How We Deal With Change Using Location Intelligence". Forbes. Retrieved 2018-10-21.
  38. ^ Esri Events (2018-07-10), The Crowther Lab at ETH Zürich: Ecosystem Science for Global Restoration, retrieved 2018-10-31
  39. ^ "Tom Crowther". ForestSAT 2018. 2018-07-04. Retrieved 2018-10-21.
  40. ^ "Massive restoration of world's forests would cancel out a decade of CO2 emissions, analysis suggests". The Independent. 2019-02-16. Retrieved 2019-03-21.
  41. ^ "Planting 1.2 Trillion Trees Could Cancel Out a Decade of CO2 Emissions, Scientists Find". Yale E360. Retrieved 2019-03-21.
  42. ^ "Research: Planting trillions of trees could cancel out CO2 emissions". Futurism. Retrieved 2019-03-21.
  43. ^ Popkin, Gabriel (2019). "Growing pains. Ecologist Thomas Crowther is having a bumpy rise to prominence". Science. 366 (6464): 412–415. doi:10.1126/science.366.6464.412. PMID 31649178.

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