Editor's note: This article is part of an occasional series on air-quality issues in Texas. Read the first article, on ozone, here.

The greenhouse gas wars are about to heat up again in Texas. Next month, a federal court hears oral arguments in lawsuits that Texas has filed to challenge the Environmental Protection Agency, which began regulating heat-trapping emissions a year ago.

The EPA is hardly backing down. On Wednesday, the agency released an easily searchable database of big greenhouse gas polluters across the nation, prompting Texas environmentalists to immediately list the largest polluters in the state. Topping the list is the 1970s-era Martin Lake coal plant (pictured) in the East Texas city of Tatum. In 2010 it emitted nearly 19 million metric tons of carbon dioxide, about 13 percent more than the runner-up, the W.A. Parish coal plant in Thompsons, southwest of Houston. In third place is the Monticello coal plant in Northeast Texas, which narrowly avoided a shutdown when a federal appeals court issued a last-minute stay to an EPA pollution rule last month.

"This will be the first time that this data is publicly available and will inform Americans about the heat-trapping greenhouse gases emitted in their communities," wrote Elena Craft, a health scientist with the Austin office of the Environmental Defense Fund, in a blog post. Power plant data has always been available, she said, but now industries like pulp and paper and landfills must also report it.

Texas is believed to be the largest greenhouse gas emitter of any state, according to David Bary, a regional spokesman for the EPA. That's largely because of the preponderance of refineries, power plants and other heavy industry in Texas, as well as Texans' driving habits and the sheer size of the state.

Despite its status as the top polluter, Texas has fiercely resisted the EPA's nascent attempts to regulate greenhouse gases. Besides the legal challenges, Texas has been the only state refusing to implement the regulations, which began at the beginning of last year after efforts to create a federal "cap-and-trade" system failed.

As a result, the EPA took the unusual step of taking over greenhouse gas permitting in Texas; otherwise it would have been done by the Texas Commission on Environmental Quality. The takeover was temporarily delayed by the courts, but the EPA issued its first such permit in November, for a yet-to-be-built natural gas plant in Llano County that will replace an existing plant.

Fifteen other Texas plants have applied for greenhouse gas permits, according to Bary. Only plants that are being built from scratch, or undergoing major upgrades, must apply for the permits.

Additional regulations could be on the way. More specific greenhouse gas performance rules for new power plants could be proposed in the next few months, according to Manik Roy, vice president for strategic outreach at the Arlington, Va.-based Center for Climate and Energy Solutions. Other rules for existing power plants and refineries should also follow, Roy said.

Top 10 Large Facilities in Greenhouse Gas Emissions in Texas - CO2

Facility Location Industry CO2 Emissions (in Metric Tons) Martin Lake Tatum, TX Stationary Combustion, Electricity Generation 18,603,904.2 W.A. Parish Thompsons, TX Stationary Combustion, Electricity Generation 16,459,497.1 Monticello Mount Pleasant, TX Stationary Combustion, Electricity Generation 13,807,893.2 Limestone Jewett, TX Electricity Generation 12,971,465.2 Sam Seymour La Grange, TX Stationary Combustion, Electricity Generation 11,203,343.5 Welsh Power Plant Pittsburg, TX Electricity Generation 11,018,827.9 ExxonMobil BT Site Baytown, TX Stationary Combustion, Petrochemical Production and Refining 10,742,680.7 Big Brown Fairfield, TX Stationary Combustion, Electricity Generation 9,419,225.1 Oak Grove Franklin, TX Stationary Combustion, Electricity Generation 8,167,441.1 Texas City Refinery Texas City, TX Stationary Combustion, Petrochemical Production and Refining 7,575,614.1

Those are sure to elicit the usual frenzied response from Texas politicians. Gov. Rick Perry, who has questioned the science behind climate change, has made the EPA a favorite target on the campaign trail. On Tuesday in South Carolina, according to Fox News, Perry spoke out against the EPA's takeover of greenhouse gas permitting in Texas, saying, "The states are under assault by this administration."

Attorney General Greg Abbott is suing on several fronts to halt the EPA's greenhouse gas regulations. His office is challenging the EPA's finding that greenhouse gases endanger human "health and welfare," words within the Clean Air Act that trigger action. Texas is also challenging federal specifications of what types of businesses will be exempt from the regulations (the "tailoring rule"), and an attempt to regulate tailpipe emissions.

A three-judge panel with the U.S. Court of Appeals for the D.C. Circuit is scheduled to hear oral arguments for all three cases on Feb. 28 and 29, the attorney general's office said.

Intriguingly enough, carbon dioxide emissions from the combustion of fossil fuels — a major source of greenhouse gases — fell 10 percent in Texas between 2002, their peak, and 2009. Much of the drop occurred on the industrial side, as opposed to power generation or transportation, so possible reasons include plants cleaning up or becoming more efficient, or switching from coal to cleaner natural gas.

But emissions of methane are a growing concern in Texas, according to the Environmental Defense Fund's Craft, who says methane has 23 times the heat-trapping ability of carbon dioxide. Methane can easily leak from oil and gas operations. The EPA database says that the two top methane emitters in Texas in 2010 were a power plant in Odessa and a landfill in Houston.

Top 10 Large Facilities in Greenhouse Gas Emissions in Texas - Methane

Facility Location Industry Type Methane Emissions (in Metric Tons) Odessa-Ector Generating Station Odessa, TX Electricity Generation 1,293,478.0 Mccarty Road Landfill Houston, TX Stationary Combustion, Landfills 1,292,306.4 Texas Disposal Systems Landfill Buda, TX Landfills 587,065.3 Seabreeze Environmental Landfill Angleton, TX Landfills 533,856.1 Arlington Landfill Arlington, TX Stationary Combustion, Landfills 344,473.5 Pinehill Landfill Longview, TX Stationary Combustion, Landfills 329,441.7 Covel Gardens Recycling And Disposal Facility San Antonio, TX Landfills 321,934.8 BFI Tessman Road Landfill San Antonio, TX Stationary Combustion, Landfills 314,569.5 Blue Ridge Landfill Fresno, TX Stationary Combustion, Landfills 267,330.0 Sunset Farms Austin, TX Stationary Combustion, Landfills 259,434.0

But some environmentalists have not cast Texas off as a lost cause on greenhouse gas emissions. Roy, of the Center for Climate and Energy Solutions, said Texas was a hub for innovation in the energy sector. "Yes, you are the center of a lot of petroleum refining in the country. But you're also a huge, huge wind state," he said.

Wind — 8.5 percent of the power on the Texas grid last year — can also help bring greenhouse gas emissions down. Even Perry, before his string of challenges to the EPA, praised wind's greenhouse gas benefits.

"The best part is that wind energy produces less than 1 percent of the carbon dioxide and consumes less than 1 percent of the water of traditional plants," Perry wrote in a 2004 editorial.

Editor's note: This article has been corrected to reflect the accurate emissions number for the Martin Lake coal plant, and also the right year for the EPA data (2010).