While urging reductions in carbon emissions, the National Academy of Sciences today issued two reports which urge ongoing research into geoengineering methods.

According to the Oxford Geoengineering Programme, “geoengineering is the deliberate large-scale intervention in the Earth’s natural systems to counteract climate change.”

Methods of geoengineering include strategies to cool the Earth by reflecting sunlight back into space, filtering carbon out of the air and sequestering it undergound and seeding the oceans with iron to promote the growth of carbon eating organism.

The committee made it clear that they vastly prefer reducing carbon emissions and using lower impact methods of carbon reduction such as forest replanting and low-till farming. However, with greenhouse gasses in the atmosphere above 400 parts per million (PPM) and emissions continuing to rise, the committee felt that geoengineering should be further researched in case it is needed to avoid catastrophe.

“We may need to employ some of these climate interventions techniques to avoid a catastrophe such as the loss of the Antarctic ice sheets, or even to remain below levels of climate change that are considered dangerous in the political arena,” said The University of Michigan’s Joyce Penner, a member of the committee, to phys.org.

The reports, Climate Intervention: Reflecting Sunlight to Cool the Earth and the other is Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration specifically looked at two primary areas of non-traditional strategies to fight global warming. For each method, the committee considered the cost and technological readiness of the method as well as the environmental and socioeconomic impacts.

The committee found that some of the strategies for “carbon capture and sequestration” have the potential to be a part of a viable plan to reduce carbon in the atmosphere. The group noted however that only prototype systems exist today and that significant development of the technologies would have to take place before it was ready to use.

For other strategies, the committee recommended further research but warned against implementation at this time.

One method of reflecting sunlight involves pumping sulfur into the atmosphere. This has shown to be an effective way of cooling temperatures when it happens following volcanic eruptions, but it is also the source of acid rain. Another strategy involves spraying the oceans with finer-than-usual particles. These small particles lead to brighter clouds, which in turn reflect more light.

This strategy has the potential to reduce temperatures quickly and inexpensively however, once implemented, it would have to be kept up permanently and could have negative side effects in terms of ozone, weather and human health.

While the committee warned against this strategy, they recommended continued research in the field and all climate intervention possibilities.

“U.S. agencies may have been reluctant to fund this area because of the sense of what we call ‘moral hazard’—that if you start down the road of doing this research you may end up relying on this or condoning this as a way of saving the planet from the cost of decreasing CO2 emissions. But we’ve stated that decreasing emissions must go hand in hand with any climate intervention efforts. We need to develop the knowledge base to allow informed decisions before these dangerous effects are upon us,” said Penner.

Geoengineering has many critics, including Al Gore who called the idea “insane” and Slate‘s Raymond T. Pierrehumbert who calls the ideas “wildly, utterly, howlingly barking mad”.

However, as the committees report says, additional research is still needed. Right now neither side in the discussion really knows what the impact might be.