{"id":147,"date":"2025-05-10T10:03:19","date_gmt":"2025-05-10T10:03:19","guid":{"rendered":"https:\/\/sarahfinch.co.uk\/?p=147"},"modified":"2025-05-10T11:44:55","modified_gmt":"2025-05-10T11:44:55","slug":"lessons-from-the-past-a-talk-by-michael-mann","status":"publish","type":"post","link":"https:\/\/sarahfinch.co.uk\/?p=147","title":{"rendered":"Lessons from the past: a talk by Michael Mann"},"content":{"rendered":"
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An artist’s depiction of the asteroid impact 66 million years ago that scientists believe did for the dinosaurs. Don Davis\/NASA<\/figcaption><\/figure>\n

One of many great things about living in Exeter is being able to go to lectures at the University\u2019s Global Systems Institute.<\/p>\n

Exeter University is a world-leading centre in climate change research, with more IPCC authors than any other city in the world. Its Global Systems Institute brings these academics together with policy-makers, NGOs, citizens and others to tackle shared problems. They host regular lectures with interesting speakers \u2013 and local residents are welcome to attend. I\u2019ve been to several very informative and truly thought-provoking talks (including one by Andreas Malm and Wim Carton on the crazy concept of \u2018climate overshoot\u2019, which I wrote about here<\/a>).<\/p>\n

This week it was the turn of distinguished scientist Michael Mann. Dr Mann is Professor of Earth and Environmental Science at the University of Pennsylvania (and has several other appointments), a leading IPCC author, winner of many awards and plaudits, and one of the creators of the hockey stick graph<\/a>.<\/p>\n

<\/p>\n

Our Fragile Moment<\/strong><\/p>\n

His latest book, Our Fragile Moment, <\/em><\/a>is about climate changes in the past and what they can teach us about the current crisis. Dr Mann gave us a whistle-stop tour of some past climatic events, with a brief musical interlude, and a passionate plea not to give in to doomism.<\/p>\n

He started off by showing a graph of past global mean surface temperatures. The last 6,000 years stood out as a stable period when the mean temperature varied very little. This is the era in which human civilisation emerged. People in Mesopotamia (now Iraq) developed farming and built the first city states. The stable climatic conditions enabled humans to thrive and spread across the world.<\/p>\n

Now there are 8-plus billion of us, living in a civilisational infrastructure that was created in a specific climate niche. Which is veering off course as the temperature rises.<\/p>\n

Dr Mann showed graphs demonstrating how the measured temperature rise pretty much exactly matches the predictions scientists have been making for decades now. Including scientists at Exxon whose warnings of the \u201cpotentially catastrophic effects\u201d of climate change in the 1980s were criminally covered up<\/a>. Some of the impacts of that warming \u2013 sea level rise, ice loss \u2013 are exceeding what was predicted, but the predictions of warming itself were just about spot on.<\/p>\n

He then took us back to earlier periods when the climate went through comparable temperature changes.<\/p>\n

66 million years ago an asteroid crashed into the Earth. The impact threw a lot of dust and debris into the stratosphere, blocking sunlight from reaching the Earth, reducing photosynthesis and ushering in a period of global cooling. This famously led to the demise of non-avian dinosaurs \u2013 and much else besides. Tyrannosaurus Rex was wiped out at this time. (But not the Brontosaurus, which lived much earlier. Fun fact: We live closer in time to T. Rex than the Brontosaurus did.)<\/p>\n

Carl Sagan used the term \u2018nuclear winter\u2019 to warn that large-scale nuclear war would have the same devastating global cooling effect as the asteroid.<\/p>\n

(How do we know about the asteroid? Scientists led by father-and-son team Luis and Walter Alvarez found a geological layer of iridium \u2013 an element rare on Earth \u2013 and deduced it had come from an asteroid<\/a>. The collision site has since been found at Chicxulub on the Yucatan Peninsula.)<\/p>\n

\u201cThe PETM was a runaway CO2-driven warming event\u201d<\/strong><\/p>\n

Another mass extinction event followed 10 million years later: the snappily named Paleocene Eocene Thermal Maximum (PETM). This one was kicked off by the release of large amounts of carbon into the atmosphere \u2013 mostly from volcanic eruptions in the North Atlantic<\/a> \u2013 and saw a 5\u20138\u00b0C global average temperature rise. Many species went extinct, particularly large ones. There are always winners and losers. The PETM was a boom time for small animals \u2013 and saw the first primate, Dryomomys<\/em>, a tiny, tree-dwelling insectivore, ancestor of us all.<\/p>\n

Dr Mann said that the PETM is the best analogy for the kind of warming we\u2019re experiencing now. It had the same cause: an excess of CO2<\/sub>. But it occurred about a hundred times more slowly <\/em>than the warming we\u2019re causing now. He is scathing about people who suggest we can simply adapt to change on this scale. Life adapts \u2013 by mass dying and extinctions.<\/p>\n

Hey mighty brontosaurus! Don\u2019t you have a lesson for us?<\/strong><\/p>\n

Mann played a clip of \u2018Walking in your footsteps\u2019, from the 1983 Police album Synchronicity<\/em>.<\/p>\n

Fifty million years ago
\n<\/em>You walked upon the planet so
\n<\/em>Lord of all that you could see
\n<\/em>Just a little bit like me<\/em><\/p>\n

Hey mighty brontosaurus
\n<\/em>Don’t you have a lesson for us?
\n<\/em>You thought your rule would always last
\n<\/em>There were no lessons in your past<\/em><\/p>\n

Sting can be forgiven for getting the date wrong. It doesn\u2019t detract from his message. He was responding to the threat of nuclear war \u2013 which has not gone away \u2013 but his message equally applies to the other existential threat of our own making: the climate crisis.<\/p>\n

\u201cThere\u2019s urgency, but there\u2019s agency\u201d<\/strong><\/p>\n

As Mann said: \u201cThe dinosaurs had no agency. We do.\u201d<\/p>\n

Even if the dinosaurs had known what was coming, they couldn\u2019t have done anything about it. But we do know what\u2019s causing our predicament \u2013 CO2<\/sub> \u2013 and we could stop releasing it.<\/p>\n

The lecture ended on an optimistic note. We can <\/em>avert catastrophic warming.<\/p>\n

This was surprising to me. I had understood that even if we stopped all carbon emissions today, inertia in the system means that warming would continue. Apparently this is wrong. New evidence (produced by Professor Pierre Friedlingstein of Exeter University and others) says that the warming will stop when the CO2<\/sub> emissions stop. The inertia is less than we thought. I didn\u2019t grasp the physics of this and must look into it.<\/p>\n

\u201cThe antidote to doom is doing\u201d<\/strong><\/p>\n

Now that outright denial is no longer a tenable position, those that want business-as-usual to continue have adopted a new strategy to stop us tackling it: doomism. They say it\u2019s too late, there is nothing we can do to fend off the climate apocalypse.<\/p>\n

\u201cBad actors are fanning the flames of climate doomism\u201d, Mann said. They are removing people who would otherwise be on the frontlines of campaigning for change.<\/p>\n

But the antidote to doom is doing. Doing everything we can to influence policy-makers and to stop greenhouse gas emissions. And to fight for democracy and science-based policy-making. We probably won’t be able to stabilise the temperature at less than 1.5\u00b0C above the human-friendly level of the last 6,000 years, but every fraction of a degree of warming we can prevent will make the future less worse. That last sentence is not from Dr Mann, it is my response to his talk.<\/p>\n

I walked home from the university feeling renewed determination to do whatever is in my power to stop the UK permitting any new fossil fuel production. Not just not issuing new licences, but ending development consents for fields \u2013 like Rosebank \u2013 that have already been licensed but not yet developed for extraction<\/a>.<\/p>\n

I feel extremely fortunate to be able to hear from some of the world\u2019s greatest thinkers on climate change thanks to the GSI. And honoured that they\u2019ve invited me to speak there next month.<\/p>\n