The United Nations’ climate change body has put geoengineering back on the agenda as a potential means of dealing with worsening global warming.
A report released by the UN's Intergovernmental Panel on Climate Change (IPCC) has triggered controversy within the scientific and environmental community by making guarded reference to "geoengineering" in its summary.
Geoengineering, also referred to as "climate engineering," involves the use of artificial means to tinker with the Earth's atmosphere. At present the field is primarily comprised of Solar Radiation Management (SRM), which entails reflecting sunlight away from the Earth via means including the seeding of artificial clouds; and Carbon Dioxide Removal (CDR), which encompasses various technologies for the capture and storage of carbon dioxide.
Climate engineering has long had its detractors, who say that the broader ramifications of employing such technologies remains unknown, their efficacy is unproven, and their promotion could have the adverse effect of impeding broader efforts to cut down on greenhouse gas emissions.
While the summary is extremely cautious in its reference to geoengineering, stating that "limited evidence precludes a comprehensive quantitative assessment" of the technologies and their impact on the climate system, advocates of the field consider its very mention in the IPCC's fifth report as a source of succour which could serve to bolster its prospects.
"To some extent the treatment of geoengineering in the IPCC reports is a reflection of growing governmental interest in these ideas," said Ken Caldeira, a climate researcher at the Carnegie Institution for Science to Nature. "It is hard to determine the extent to which possible increases in funding would be driven directly from this governmental interest and how much would be driven by the report itself."
Other parts of the document would imply that geoengineering could become a necessity in future, with the report stating that a "large fraction" of human-caused climate change will be irreversible barring a "large net removal of CO2 from the atmosphere over a sustained period."
Geoengineering remains very much a fledgling discipline, with only small-scale trial projects in operation. Many of these projects are based in Russia, which reportedly insisted on the inclusion of a reference to geoengineering in the report.
While advocates of the field may celebrate its very mention in such an influential document, the report's authors say the point of including a reference to geoengineering was not so much to promote its usage as to highlight the dire ramifications of unabated climate change.
"The policy relevance of the information is that if you do not start mitigating [reducing greenhouse gas emissions] tomorrow we will have to start to consider these unattractive options," said Piers Forster, a researcher into climate change from the University of Leed and an author of the summary.