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The University of Southampton
Ocean and Earth Science, National Oceanography Centre Southampton

Geoengineering of climate: Science, governance and uncertainty

Research at the University of Southampton has revealed the extent of the long-term damage caused to our environment by the burning of fossil fuels. Professor John Shepherd and his colleagues have developed a fast but realistic computer model of the Earth’s climate systems that can simulate changes over thousands of years. The results have informed and stimulated worldwide debate about whether deliberate modification of the climate may be needed to counter dangerous climate change.

The results of GENIE long term modelling into global warming and the implications for geoengineering have influenced policy-makers in the UK and across the world.
Geoengineering of climate

Research challenge

Despite widespread concern about climate change, levels of carbon dioxide in the atmosphere are still rising by more than two per cent each year. As a result, we are facing the prospect of floods, extreme weather and food shortages. The 2006 Stern Review estimated the world’s economy could lose at least five per cent of gross domestic product (GDP) annually. Scientists suggest that CO2 concentrations must soon start to fall by three per cent a year to mitigate the effects of climate change but reductions on this scale are not happening.

Predictions of what will happen if levels of CO2 continue to rise are essential so policymakers have the facts and can take informed decisions. However, conventional climate models are too complex, slow and expensive to provide reliable information on the long term consequences of what we are doing now.


Although some governments across the world are taking action to reduce carbon emissions, not enough is being done globally to tackle the problem. Scientists now warn that the legacy of man-made climate change could last for several millennia. Even if countries succeed in reducing emissions in the near future, policymakers may have to consider ‘geoengineering the climate’ by developing and implementing new technologies to reflect sunlight or to reduce carbon in the atmosphere.

Our solution

During the late 1990s, researchers at the University of Southampton’s National Oceanography Centre started to design a more efficient computer model capable of simulating changes in the Earth’s climate over the last million years.

In the early 2000s, with the aid of grants from the Natural Environment Research Council (NERC) and fellow scientists from the Universities of Reading, Bristol, East Anglia and others, Southampton academics extended their C-Goldstein coupled ocean-atmosphere model to include the land surface, the cryosphere and other parts of the Earth system. They developed the Grid Enabled Integrated Earth system Model (GENIE) which can run simulations over time periods of a thousand to a million years with sufficient complexity to give realistic and valuable results.

These simulations have revealed a fossil fuel ‘hangover’, showing that the effects of CO2 emissions will persist for many millennia after they end, and warning that reducing emissions may not be enough to avoid dangerous climate change. Insights from this research have prompted more work at Southampton and elsewhere into geoengineering – techniques to reflect a little sunlight or to capture and reduce carbon dioxide, including increasing the uptake of CO2 by the world’s oceans.

Our impact

The results of GENIE long term modelling into global warming and the implications for geoengineering have influenced policy-makers in the UK and across the world.

Results from long-term simulations were submitted to the Intergovernmental Panel on Climate Change (IPCC) and were incorporated in its 2007 report. Professor Shepherd was later asked to chair the Royal Society working group on geoengineering; its report in 2009 assessing geoengineering strategies and their effects attracted widespread media coverage and has become the global standard reference work on the subject. Group members called for more research on the feasibility and safety of proposed methods, and increased engagement with members of the public.

As a result, NERC invested in a public dialogue programme Experiment Earth in 2010 and the Engineering and Physical Sciences Research Council (EPSRC) has committed £3.3million to further research, but much more remains to be done. Professor Shepherd now chairs the Scientific Advisory Group for the Department of Energy and Climate Change.

Featured article | Engineering the climate?
Featured article | Engineering the climate?

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