January 28, 2009
Among the findings, according to a statement from UEA:
Enhancing carbon sinks will take nearly 100 years to bring atmospheric carbon dioxide levels back to pre-industrial levels and will require sharp cuts in emissions.
Stratospheric aerosol injections and sunshades in space — a concept supported by Paul J. Crutzen, winner of the 1995 Nobel Prize in Chemistry for his work on the hole in the ozone layer — have "by far the greatest potential to cool the climate by 2050" but carry the greatest risk.
Sequestering carbon by planting forests and as 'bio-char' — charcoal added back to the soil — have greater short-term cooling potential than ocean fertilization. Bio-char also offers to potential to boost soil productivity for agriculture.
Increasing the reflectivity of urban areas could reduce urban heat islands but will have minimal global effect. The same goes for schemes involving ocean pipes and stimulating biologically-driven increases in cloud reflectivity.
The beneficial effects of some geo-engineering schemes have been over-estimated and mis-calculated in previous calculations
"The realization that existing efforts to mitigate the effects of human-induced climate change are proving wholly ineffectual has fuelled a resurgence of interest in geo-engineering," said lead author Tim Lenton of UEA's School of Environmental Sciences. "This paper provides the first extensive evaluation of their relative merits in terms of their climate cooling potential and should help inform the prioritisation of future research."
“We found that some geoengineering options could usefully complement mitigation, and together they could cool the climate, but geoengineering alone cannot solve the climate problem,” he added.
CITATION: T. M. Lenton and N. E. Vaughan. The radiative forcing potential of different climate geoengineering options [PDF]. Atmos. Chem. Phys. Discuss., 9, 2559-2608, 2009
Geoengineering schemes need ranking system to avoid wasting money, destroying the planet
(10/26/2008) Schemes to alter Earth's climate on a planetary scale should be ranked according to their efficacy, cost, risks and their rate of mitigation, argues a new editorial published in Nature Geoscience. With so-called geoengineering proposals proliferating as concerns over climate change mount, Philip Boyd of New Zealand's NIWA warns that "no geo-engineering proposal has been tested or even subjected to preliminary trials". He says that despite widespread media attention, scientists have yet to even come up with a way to rank geoegineering schemes for their efficacy, cost, associated risk, and timeframe. Thus is it unclear whether ideas like carbon burial, geochemical carbon capture, atmospheric carbon capture, ocean fertilization, cloud manipulation, "space sunshades", or strategically-placed pollution can be effective on a time-scale relevant to humankind, economical, or even safe.
Geoengineering solution to global warming could destroy the ozone layer
(04/24/2008) A proposed plan to fight global warming by injecting sulfate particles into Earth's upper atmosphere could damage the ozone layer over the Arctic and Antarctic, report researchers writing in the journal Science.
Geoengineering could stop global warming but carries big risks
(06/04/2007) Using radical techniques to ,engineer, Earth's climate by blocking sunlight could cool Earth but presents great risks that could well worsen global warming should they fail or be discontinued, reports a new study published in the June 4 early online edition of The Proceedings of the National Academy of Sciences.