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​Taking it back: Removing CO2 from the atmosphere to limit climate change

Published on: 12-Mar-2019

Event Type: Seminar

Event Date: 12 March 2019 - 4:00pm to 5:00pm

Venue: ASE 3D Viz Laboratory Room (N2-B1c-16c)

Speaker: Prof. Gideon Henderson


About the speaker:

Prof. Henderson is a geochemist working to understand the long-term operation of the climate system and the carbon cycle. His research relies on geological records of past climates (from caves and marine sediments) and on chemical measurements of the modern ocean.  He seeks to understand components of the climate system with particular relevance to the future, including changes in rainfall, sea level, permafrost, and ocean circulation. Gideon is one of the founding committee chairs of GEOTRACES, an international research programme to study biogeochemical cycles in the oceans. He also chaired the recent Royal Society working group on Greenhouse gas removal. He has spoken to diverse audiences on issues relating to climate, oceanography, and geoengineering, including to the World Economic Forum (Davos and Dalian); Virgin Unite (Necker); Intelligence Squared (London); and Commonwealth Science Conference (Singapore).

Gideon Henderson is a professor of Earth Sciences at the University of Oxford (UK).  He has a degree in Earth Sciences from the University of Oxford, a PhD in Geochemistry from the University of Cambridge (UK), and previously worked at Columbia University (USA).  He was elected a Fellow of the Royal Society in 2013.


 

About the event:

At the time of the Paris Agreement on climate change, 87% of the future energy scenarios that meet the agreed 2 degrees celsius warming target, and all of those consistent with 1.5 degree celsius, required humans to remove greenhouse gases from the atmosphere as well as making stringent cuts to emissions.  The need for hundreds of billions of tonnes of greenhouse gas removal (GGR) continues to be recognized in the recent IPCC 1.5 degree celsius report.  

The UK government asked the Royal Society to assess the various methods by which large scale GGR might be achieved.  I chaired the resulting report1, published in September 2018.  In this lecture I will summarize the findings of the report, and discuss some of my own research in this subject.  

A broad range of methods for GGR have been suggested.  To be successful, these need to both remove CO2 from the atmosphere, and then store is securely.  The removal can be achieved by accelerating biological processes (e.g. growth of plants), by accelerating natural inorganic reactions (e.g. weathering), or by directly engineering removal by chemical processes. I will describe all three approaches, but pay particular attention to methods that accelerate natural inorganic reactions, including enhanced weathering of silicates on land, and addition of alkalinity to the oceans.  How do these approaches work in theory?  Will they still work at large scale to consume significant amounts of CO2?  What are the environmental consequences if we pursue them at such scale?  And what are the social, political and economic limitations on their pursuit?  

There is a clear need for GGR to control climate.  This need will only become greater as emissions and climate change continues.  Researchers with diverse expertise must mobilize to assess how best to achieve this removal, including Earth and environmental scientists who understand the complex network of processes that operate on our planet’s surface.

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