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Waterfront showdown” describes a conflict between the Puyallup Tribe and Puget Sound Energy (PSE) over a partially completed liquefied natural gas (LNG) facility under construction in Tacoma. Proponents of the project claim cleaner energy compared with coal.

This claim is true only in the very limited sense that no natural gas at all is permitted to leak to the atmosphere. With about 1 percent leakage, all benefits of reduced greenhouse effect are lost. This follows from the much greater greenhouse potential of methane (CH4, the principal component of LNG), compared to carbon dioxide (CO2), the combustion product of both LNG and coal, and to the very long residence time of CH4 in the atmosphere before it finally oxidizes to CO2.

Our Environmental Protection Agency well knows about this, of course, but the information is neither widely distributed, nor widely discussed. Nor do we have believable estimates of the global leakage of methane to the atmosphere, which certainly exceeds several percent.

As it so frequently happens, a good idea (substituting LNG for other fuels) has nasty consequences that are neither well appreciated nor well controlled. Let’s stop and think about it.

Halstead Harrison, Mercer Island, professor emeritus, Atmospheric Sciences, University of Washington