Natural gas has been touted as a more responsible energy source than coal in the face of climate change, but a new study conducted by researchers at Cornell University argues otherwise.

The study, which is scheduled to be published in the journal Climatic Change Letters, argues the advantages that gas produced from fracking has over coal are offset by the fugitive emissions of methane gas.

Methane is a potent greenhouse gas with a impact far greater than carbon dioxide, especially in the first few decades following emission. The study found that the extraction of shale gas—the deposit that energy companies are targeting with their controversial technique known as hydraulic fracturing or “fracking”—has climate impacts comparable to coal over 100 years and could be twice as severe over a 20-year horizon.

The key concern here is the increased amount of fugitive methane gas that goes into the atmosphere from fracking sites as compared to conventional gas drilling.

This development makes it harder and harder for policymakers to cast natural gas as a clean energy source—particularly when fracking has been linked to contaminated drinking water, exploding wells, mysterious animal deaths and other unsettling incidents.

All this should give members of the Senate Environment and Public Works Committee plenty to discuss at tomorrow’s hearing on fracking technology.

The Committee on Science, Space and Technology in the Republican-controlled house had planned a hearing of their own on the issue, but postponed it this morning. No word on whether the findings announced today had anything to do with that abrupt schedule change.