NATURAL GAS is tantalizing. It’s cheap. It’s abundant in the United States, which has reserves sufficient to meet American energy demand for a century. It’s much cleaner than coal, producing fewer harmful substances that foul air around power plants and half the greenhouse emissions.

Or does it? A provocative study from scientists at Cornell University, published last week in the journal Climatic Change Letters, contends that much of the natural gas America would produce over coming decades has a massive carbon footprint — bigger than its sooty cousin’s. America has huge reserves of “unconventional” natural gas trapped deep underground. Drilling for that natural gas, which is mostly methane, involves pumping a cocktail of water and chemicals below the surface at high pressure. Some of that water flows back up, bringing along methane, an extremely potent greenhouse gas. Collecting the natural gas and transporting it via high-pressure pipeline, meanwhile, also results in leaks.

Yet, though the Cornell study relies in part on Environmental Protection Agency (EPA) figures to account for this “fugitive methane,” even the authors admit some of the numbers aren’t “well-documented,” and mainstream environmentalists agree that the data are thin. Nor does the study account for the efficiency of power plants fired by natural gas relative to coal-fired ones.

What the study demonstrates is that policymakers need more reliable information about this burgeoning industry. The EPA is already poised to require reporting from gas producers on the amount of fugitive methane escaping from their wells and equipment. The industry shouldn’t drag its feet. Ongoing state and federal studies about the environmental impacts of natural gas drilling should also account for fugitive methane.

Even before better numbers show up, natural gas producers can start clamping down on the problem methane with an array of relatively inexpensive and available technologies, such as devices that separate natural gas from the material that rises to the surface during well completion. Other techniques are as simple as making sure the seals on drilling and transportation equipment are tight and well-maintained. Many of these pay for themselves in gas saved and sold. Besides, the industry should want its claims about natural gas’s environmental benefits to have credibility. Policymakers may have to step in with new rules.

That’s no argument for environmentalists to give up on natural gas — if they had to, it would be a real blow to the fight against global warming. Just reason to make sure that America can tap its reserves responsibly.