No geoengineering methods are ready for use to combat climate change, the Government Accountability Office said in a report released late last month, citing concerns about cost, effectiveness and adverse consequences.

"Climate engineering technologies do not now offer a viable response to global climate change," GAO said in the report commissioned by former House Science, Space and Technology Committee Chairman Bart Gordon (D-Tenn.).

Interest in the technologies has grown amid the difficulty of enacting national and international policies to reduce greenhouse gas emissions. Many scientists believe that geoengineering could be a planetary "Plan B," a tool to use only if steep cuts to the world's greenhouse gas output fail to blunt global warming.

In its report, GAO said that "the majority of experts we consulted support starting significant climate engineering research now." But as it stands, geoengineering methods are "currently immature, with many potentially negative consequences," the report adds.

Geoengineering technologies are normally divided into two categories: those that seek to deflect sunlight from Earth, known as "Solar Resource Management," and those that pull carbon dioxide from the atmosphere, known as "Carbon Dioxide Removal."

The GAO report examined a range of proposed geoengineering fixes to determine their "technological readiness" on a scale of 1 to 9.

Direct air capture of carbon dioxide scored the highest, at 3, but GAO cautioned that the technique "is believed to be decades away from large-scale commercialization." No solar resource management approach scored above 2.

The GAO analysis also examined public attitudes toward geoengineering, based on a survey of 1,006 adults across the United States.

Most respondents were not familiar with geoengineering, but when given information about the field by GAO, indicated they were "open to research but concerned about safety," the agency said.

Click here to view the GAO report.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500