Tipping Points by Professor Tim Lenton

> FOCUS ON SUSTAINABILITY TIPPING POINTS

PROFESSOR TIM LENTON

Photo: University of Exeter

Professor Tim Lenton (Natural Sciences – Physical, 1991) is Director of the Global Systems Institute and Chair in Climate Change and Earth System Science at the University of Exeter. His research focuses on understanding the behaviour of the Earth as a whole system. He is particularly interested in how life has reshaped the planet in the past, and what lessons we can draw from this as we proceed to reshape the planet now. His award-winning work identifying tipping points in the climate system has led him on to examine positive tipping points within our social systems which could help accelerate progress towards a more sustainable future.

It’s been 30 years since I came to Robinson College to read Natural Sciences in autumn 1991. I was already passionate about both science and the environment – and there was plenty to be concerned about at the time. The ozone hole had been discovered1, the Amazon was being rapidly deforested, and global warming was well underway2. The Tripos, alas, was not so switched on to the planet. I found it challenging but detached from ecological reality. I was in the library until 11pm many nights trying to solve abstract physics and mathematics problems (thank you Ian Rudy for helping me through!). The thing that saved me was my Dad giving me Jim Lovelock’s books on “Gaia” for Christmas 1991. I was immediately captivated by Lovelock’s vision of life on Earth as a single self-regulating system. I could see what I wanted to research when I graduated.

I wrote to Lovelock, and we met in the summer of 1992. Slowly I found some like-minded souls in Cambridge and together we founded a student group called ‘Science for the Earth’. Thanks to Tom Wakeford (King’s College), the eminent microbiologist Lynn Margulis – Lovelock’s key collaborator on the Gaia hypothesis – addressed our first forum. Fast forward three decades and I am still on a gripping scientific adventure, trying to understand how Gaia has evolved, how we are disrupting the biosphere now, and how we can achieve a flourishing future within it. Crucial to this personal scientific quest has been continually learning new subjects and – where the problem demands it –synthesising them. That process began for me in Cambridge, although with hindsight I wish I could have studied more subjects than I did. We finally started to study ozone depletion and global warming in Part II chemistry. But the biggest inspiration I got was from Simon Schaffer’s captivating history of science lectures. These opened my eyes to how the polymath pursuit of natural philosophy had become hopelessly subdivided into jealously guarded scientific disciplines. It was obvious even at the time that this was being confronted by a reality that doesn’t know anything about disciplinary boundaries.

Soberingly, since I matriculated greenhouse gas emissions have increased by over 40% and global warming has doubled to over 1 degree centigrade. For the last decade or so I have been researching the climate tipping points we risk crossing because of this3. Hopefully, that has played a small part in increasing international ambitions to try and limit global warming to 1.5C. But as I rapidly learned in Cambridge, ambition is nothing without application. Right now, international action urgently needs to accelerate to avoid a climate crisis. To that end, I have turned my research attention to identifying the positive social tipping points we need to trigger to achieve internationally agreed climate goals4 .

Looking back, we have lost a generation to inaction, and we have one generation left to transform our societies to a sustainable state. All our institutions must rise to this extraordinary challenge. It’s now or never.

1 In 1985, thanks to researchers at the British Antarctic Survey based in Cambridge 2 James Hansen had famously testified to the US congress in 1988 on the reality and risks of global warming 3 https://www.nature.com/articles/d41586-019-03595-0 4 https://www.tandfonline.com/doi/full/10.1080/14693062.2020.1870097