Republican asks EPA to prove it isn’t exaggerating greenhouse gas figures

House Oversight and Government Reform Committee Chairman Darrell Issa (R-Calif.), echoing natural gas industry complaints, is alleging that the Environmental Protection Agency might be badly overstating greenhouse gas emissions from gas drilling sites.

Issa, in a letter Tuesday to EPA Administrator Lisa Jackson, asked for detailed information about the methods behind EPA’s revised estimates for emissions of methane — a potent greenhouse gas — from natural gas development.

The revised figures, available here, show that EPA has more than doubled its estimate of methane escaping from natural gas systems.

“The Committee is concerned that these methane emissions estimates, now being relied upon internationally, were not based on sound science,” Issa wrote in the letter.

The letter points to an August study by the energy industry consulting firm IHS CERA that slammed EPA’s estimates, calling them far too high.

An EPA spokeswoman, in response to the letter, issued a statement noting that the agency supports natural gas development and will “continue to take steps to make sure that we leverage this abundant domestic resource, safely and responsibly.”

The statement defends the methane emissions estimates.

“EPA’s methane emissions estimates are based on the best available public data from multiple companies and experts, including data from about 8,000 production wells across the United States,” EPA said.

Industry groups are pushing back against EPA’s tally and a contrarian paper by Cornell University researchers, which argued that once “fugitive” methane emissions are considered, natural gas produced through hydraulic fracturing contributes as much or more to global warming than coal.

An Energy Department advisory panel, in a recent report on the environmental footprint of unconventional gas production, noted that the Cornell conclusion is “not widely accepted.”

 But the panel nonetheless said more data on the greenhouse gas impact of the gas development are needed.