Reducing carbon dioxide emissions may no longer be enough to halt global warming, according to a new report produced by researchers at the Global Climate and Energy Project (GCEP) on the importance and capabilities of various carbon-negative technologies.

The report, which was co-authored by Professor of Biology and Environmental Earth Science Christopher Field Ph.D. ’81 and energy assessment analyst Jennifer Milne, summarized ideas presented at the GCEP’s June 2012 workshop. The workshop had focused on carbon-negative technologies– those that actually remove carbon from the atmosphere– rather than the more common carbon-neutral approach.

“We have a significant problem with climate change,” Field said. “These carbon-negative technologies are important to understand and we ought to know what we can do– all options and all limitations.”

At the workshop, scientists from universities around the country presented new technologies for extracting carbon dioxide from the atmosphere and reinserting it into the earth and the sea, accentuating a natural process.

“The purpose of the workshop was just choose one particular set of approaches and discuss the limitations, [and ask] could this work, under which circumstances,” Milne said.

Scientists also discussed strategies for storing carbon for longer periods of time, such as through biochar, wetland carbon storage and ocean sequestration.

Dominic Wolf, a postdoctoral research associate at Cornell University, spoke about the potential of biochar, a carbon-rich substance created by heating biomass in the absence of oxygen. According to Wolf, biochar could be used to store excess carbon and enhance degraded soil by improving the soil’s fertility and tilth.

Larry Baxter, a professor at Brigham Young University, presented another carbon capture strategy called cryogenic carbon capture. In this process, flue gas– the gas typically emitted by industrial power plants– is captured, dried, chilled and then expanded until it precipitates carbon dioxide.

The GCEP is currently in the process of reviewing the proposals solicited from the workshop, in hopes of granting $6 million to fund new carbon-negative technologies. According to Field, this review process will likely continue until fall 2013.

“The funding isn’t so much a prize, but a license to work a lot of late nights and weekends.” Field said.

While Milne and Field expressed optimism about some of the technologies presented at the workshop, they acknowledged an ongoing broader debate regarding carbon capture technologies’ economic and practical efficiency. Current carbon-negative technologies are too expensive to implement on a wide scale, and some research suggest that the process required to capture and store carbon may release more carbon dioxide into the atmosphere than it collects.

Given those challenges, Field warned against assuming that carbon-negative technologies will solve the issue of global warming.

“Negative emission technologies might work and if it they do they will be part of a wide portfolio of solutions,” Field said. “It is not a get-out-of-jail-free card. Not a silver bullet.”