ETH Zurich


Thomas Crowther

Thomas Crowther is a British scientist specializing in ecosystem ecology. He is the founder of an interdisciplinary research group at ETH Zürich. As a supporting partner to the ‘UN Decade on Ecosystem Restoration’, Crowther aims to understand Earth’s ecosystems to help in the fight against biodiversity loss and climate change. Crowther also is the founder of the not-for-profit conservation organization ‘RESTOR’, and scientific advisor to the UN’s ‘Trillion Tree Campaign’. His work is driven by a fascination with biodiversity, and love of the natural world. Inspired by his childhood hero, David Attenborough, he believes that, in order “to restore stability to our planet, we must preserve and revitalize its biodiversity”.


Born in Namibia in 1986, Thomas grew up in North Wales, UK. His obsession with snakes and lizards led him to study ecology in Cardiff University under the supervision of Hefin Jones and Lynne Body. After earning his Ph.D, he was awarded a postdoctoral fellowship from the Climate and Energy Institute at Yale University. In 2015, Crowther received a Marie Curie Fellowship to research the impact of carbon cycle feedbacks on climate change at the Netherlands Institute of Ecology (NIOO). In 2017, he began his tenure-track professorship at ETH Zürich.

Ongoing Research

Crowther’s research explores the ecology of microbes, animals and plants that inhabit the Earths soil, and regulate the global carbon cycle. Changes in the composition, physiology and abundance of these organisms can have striking impacts on carbon cycling under current and future climates. As such, a fundamental understanding of global ecology is essential in efforts to understand climate change, and also to design effective strategies to address it.

Ecology to understand climate change

Soils support the largest proportion of terrestrial biodiversity and the largest carbon stocks on land. How soil carbon stocks will change over the rest of this century remains among the greatest sources of uncertainty in future climate predictions. In 2016, Crowther led a study that showed how warming can stimulate the loss of carbon from high-latitude soils, driving a positive carbon cycle feedback that could accelerate carbon emissions by 12-17%. Yet, his research also shows how protecting and restoring the connectivity of the soil food web may be valuable for mediating these warming-induced soil carbon losses under a changing climate.

Ecology to address climate change

During his post-doctoral research at Yale, Crowther mapped the distribution and density of trees across the world, revealing that there are just over 3 trillion trees on Earth. He also estimated that there were approximately 46% fewer than existed before the start of widespread agriculture over 12,000 years ago. In 2019, this ongoing research revealed that, outside of urban and agricultural areas, there is still room to restore 1 trillion trees in regions where they might naturally exist. This information was central to the initiation of the Trillion-Tree-Campaign. However, Crowther stresses that global ecosystem restoration must not distract resources away from emissions cuts, or the conservation of existing ecosystems, and that responsible restoration requires careful consideration of the local social and ecological context. 

The Future of Climate Change Research

Crowther’s research leverages emerging technological advances and big data approaches to transform our understanding of Earth’s ecosystems. With enough data, and the right analytical approaches, he believes that we can see past the complexity of terrestrial ecosystems to uncover unifying trends that underpin the distribution of organisms and their impacts on the climate. He believes that this can help us to generate the tools to guide effective local decision making, and empower people across the globe to engage in the global conservation and restoration movement.

Ecosystem conservation and restoration is for the local biodiversity and the people that depend on it, but as the network of collective action grows, it benefits all of us.

Notable presentations, events, and news articles

In 2020, Crowther presented his work at the TED countdown event alongside other speakers including Al Gore, Pope Francis and Prince William. 

The same year, Crowther partnered with Christiana Figueres and other environmental leaders to launch the Together With Nature movement to promote socially and ecologically responsible ecosystem restoration.

Crowther was also featured in a Rolling Stones article titled Can We Plant Enough Trees? With an increase in global wildfires, Crowther highlights how forests remain one of our best hopes for “capturing and storing the unsustainable levels of carbon dioxide that humans have released into the atmosphere” stating that the conservation of rainforests can help to buy some time as we “decarbonize our economies.” 

On a similar note, Crowther also discusses the Four Principles of Forest Restoration in a blog posted on ETH Zurich. In light of his Trillion Tree Campaign, he details the need for a holistic and principled approach to minimizing carbon emissions. 

Crowther has also been featured in a wide range of reputable online publications including, The Guardian, The New York Times, New Scientist, and  The World Economic Forum.