A trio of government-funded studies emerging from the UK have concluded that geoengineering is far from an easy, quick-fix expedient for addressing the dilemma of anthropogenic climate change.
The three projects - IAGP led by the University of Leeds, SPICE led by the University of Bristol, and CGG led by the University of Oxford, employed varied approaches to assessing the potential impacts of geoengineering, yet all reached similar conclusions on the challenging and uncertain nature of such undertakings.
The University of Leeds' Integrated Assessment of Geoengineering Proposals (IAGP) employed an interdisciplinary approach incorporating philosophy and public perception in addition to climate modelling and engineering.
Its climate modelling experiment simulated the use of airplanes to spray sulphate aerosols into the atmosphere in order to make cloud formations brighter and increase the amount of solar radiation that they reflect away from the earth.
IAGP's modelling discovered that interactions between the sprayed particles and atmospheric moisture were unpredictable due to the variable nature of clouds, and under certain circumstances the method would prove ineffective. The sprayed particles would often clump together and fall to the earth before reaching the clouds base.
For these practical reasons, IAGP concluded that geoengineering would be a far more parlous task that many would hope, and that its efficacy would be limited.
"Our research shows that the devil is in the detail," said Piers Forster, Professor of Physical Climate Change at the University of Leeds and IAGP's principal investigator. "Geoengineering will be much more expensive and challenging than previous estimates suggest and any benefits would be limited."
The University of Bristol's Stratospheric Particle Injection for Climate Engineering (SPICE) researchers also simulated the injection of sulphate aerosols into the atmosphere to increase cloud reflectivity, in this case by using volcanoes as models.
In addition to practical difficulties, the SPICE project's conclusion also highlighted the risks involved in geoengineering.
"Whilst it is clear that temperatures could be reduced during deployment, the potential for mishap is considerable," said Dr. Matthew Watson, a reader in natural hazards from the University of Bristol and the SPICE project's principal investigator. "By identifying risks, we hope to contribute to the evidence base around geoengineering that will determine whether deployment, in the face of the threat of climate change, has the capacity to do more good then harm."
The University of Oxford's Climate Geoengineering Governance (CGG) project adopted a highly innovative research approach, being the first study in the world to focus on the governance and regulatory challenges involved in tinkering with the climate.
CGG concluded that cost estimates for major projects are unrealistic, and that immense uncertainty surrounds the actual outcomes of large-scale climate engineering.
"Take everything you hear both for and against geoengineering with a large grain of salt," said Professor Steve Rayner of the James Martin Professor of Science and Civilization at the University of Oxford and principal investigator for the CGG project."Mostly it is too soon to know what any of these technology ideas would look like in practice or what would be their true cost and benefit.
"But it's almost certain that geoengineering will be neither a magic bullet nor Pandora's Box."