Colorado has big goals for combatting climate change. By 2050, greenhouse gas emissions must be down 90 percent from 2005 levels, according to House Bill 19-1261, also known as the Climate Action Plan to Reduce Pollution, which Governor Jared Polis signed into law in 2019.

Achieving such a steep decline will require extensive planning, and on January 14, an important part of the state’s blueprint arrived: the Greenhouse Gas Pollution Reduction Roadmap. Compiled by state agencies, climate scientists, and energy consulting firm Environment & Energy Economics (E3), the 162-page document lays out the state’s biggest sources of greenhouse gases and details strategies for reducing those emissions.

According to the roadmap, transportation is the leading contributor to greenhouse gas emissions, followed by electricity generation. Third on the list is oil and gas production; fuel use in residential, commercial, and industrial spaces comes in fourth.

But that order is wrong, according to some researchers and environmental advocacy groups. They argue that oil and gas production should lead the list, and warn that failure to properly account for the industry’s impact on climate change could undercut Colorado’s chances to achieve the goals set out by the state’s Climate Action Plan.

At the root of this discrepancy is an argument about the most appropriate way to include methane emissions in the roadmap. Though methane isn’t the most abundant greenhouse gas—driving cars, burning fuel, running factories and other human activity have released far more carbon dioxide over the years—it’s still very much to blame for the warming climate. “Greenhouse gases absorb infrared heat, preventing it from escaping into space,” says Robert Howarth, a biogeochemist and ecosystem scientist at Cornell University. “Methane absorbs some of that infrared radiation at wavelengths other greenhouse gases, like carbon dioxide and water vapor, do not. Pound for pound, methane in the atmosphere is more than 100 times more effective than carbon dioxide at holding onto the heat.”

Colorado’s oil and gas industry is responsible for some of the highest levels of methane emissions in the state. The molecule escapes during production in a variety of ways, says Anthony Ingraffea, a retired professor of engineering at Cornell who consulted with the oil and gas industry for years about fracking. Drilling into a shale rock deposit to reach large caches of natural gas and oil releases methane. So does venting, when the company releases some of the gas it’s harvesting (this is done when pressure gets too high, risking explosions).

Methane also leaks out of damaged pipelines. In fact, even the devices (called pigs) commonly used to clean and monitor a pipeline for leaky structural weaknesses allow methane to escape. They need to be inserted into existing pipelines, and opening the pipe to place them releases the greenhouse gas. All these emissions and more add up to roughly 17 percent of total greenhouse gas pollution, according to figures used in the roadmap.

Greenhouse gas roadmap emissions pie chart
A pie chart from the Greenhouse Gas Pollution Reduction Roadmap showing how much each sector contributed to Colorado’s total emissions in 2020. The chart uses a 100-year global warming potential.

Many disagree with that assessment, including more than 60 environmental advocacy groups, which signed an open letter to Governor Polis, the Colorado Energy Office, the Air Pollution Control Division (APCD), and the Air Quality Control Commission (AQCC) on this topic. The letter, put together by nonprofit 350 Colorado, argues that the roadmap undercounts the industry’s methane emissions and urges the state to fully phase out oil and gas production by 2030.

Ingraffea echoes one of the problems highlighted in the 350 Colorado letter. It has to do with carbon dioxide equivalents. Instead of simply counting how much of each greenhouse gas escapes into the atmosphere, CO2 equivalents take into account the potency of the gases measured—or, in research-speak, the global warming potential (how much energy one ton of gas will absorb over a given time period). In this case, methane has a higher global warming potential than CO2, so the equation used to calculate the CO2 equivalent puts more weight on the escaped methane.

But there’s one more wrinkle. Like we said above, global warming potential is how much energy one ton of gas will absorb over a given time period. The time period used in this calculation is important because methane dissipates much more quickly than CO2—roughly 10 years compared to CO2’s thousands. (It’s worth noting that methane decays into CO2 and water vapor, so even when it’s officially “gone,” its remnants still cause warming.)

So if you pop a balloon filled with methane and measure the amount of heat-energy your methane unleashed on the atmosphere over the next 100 years, its impact will be significantly thinned out. This 100-year factor is the one used in the roadmap. Measuring that methane for 10 years, though, reveals just how potent methane can be in the short term. And right now, Ingraffea says, we should be thinking in the short term. “It’s irrational to talk about a plan for the next 20 years, and use measurements for 100 years out,” he says.

It’s also dangerous, says Micah Parkin, co-founder and executive director of 350 Colorado. “Over these critical next decades, we are facing the potential for tipping really negative, disastrous feedback loops,” she says. One example: Permafrost, a thick layer of soil below the Earth’s surface that stays frozen year-round, releases high levels of methane and CO2 as it melts. Those greenhouse gases then trap even more energy, warming the planet further—and causing even more permafrost to melt, restarting the vicious cycle.

The writers of the roadmap are not unaware of methane’s danger. “Minimizing the release of methane from the oil and gas industry is essential to achieving the state’s goals, as these make up the largest source of non-combustion emissions in the state,” the report reads. In fact, Colorado’s Air Pollution Control Division (one of the groups that helped write the roadmap), released a draft of an inventory update in January 2021 that lays out how using different global warming potential assumptions can change calculations. That document also states how many tons of each pollutant discussed in the roadmap were reported. APCD spokesperson Andrew Bare told 5280 via email that the raw data “will allow stakeholders and the state to apply and compare various global warming potential values to the GHG emission calculations to inform legislative, regulatory, and policy conversations.”

Even though those numbers aren’t in the roadmap, Bare said sticking with the 100-year global warming potential was the right move because it “maintain[s] consistency with historical inventories as well as Environmental Protection Agency and international standards.”

But those standards, Ingraffea says, are less important than accurately reflecting the impact of methane. He points out that other states haven’t been held back by that logic. “New York state is currently putting together a document similar to Colorado’s roadmap,” he says, “and they are using a 20-year global warming potential. They’re right to do so.” In fact, the Intergovernmental Panel on Climate Change (IPCC), a body of the United Nations that studies climate change, states that the appropriate global warming potential can change depending upon the situation—and, as Ingraffea points out, both the IPCC and EPA are now emphasizing the shortening timeframe for climate action.

The state’s other reason for using the 100-year factor, wrote Bare, was a desire not to overshadow the importance of reducing C02 emissions. “Evaluating the impact of 20-year global warming potential may be appropriate in certain scenarios, but that should be balanced against the impact of de-emphasizing the role of carbon dioxide, and the importance of reducing carbon dioxide emissions in other sectors of Colorado’s economy.”

Ingraffea doesn’t believe putting the appropriate weight on methane diminishes the importance of reducing CO2 emissions. “Emphasizing methane is not automatically de-emphasizing CO2,” he says.

At the end of the day, the roadmap is exactly that—a map. “Roadmaps give you possible ways to arrive at your destination,” Ingraffea says. “They don’t prescribe a specific route.” Actually implementing the roadmap will take more planning, rule-making, and law-passing. There will be debates between stakeholders: The Colorado Oil and Gas Association, which lobbies for the industry and says technology can stem much of the methane emissions, will likely clash with those at 350 Colorado, who believe the state should end all oil and gas drilling.

They’ll have to find a way to work together, Ingraffea says. “Hitting these goals is going to require everyone and everything, every company, every industry, every citizen, in Colorado, to make changes.”

Angela Ufheil
Angela Ufheil
Angela Ufheil is a Denver-based journalist and 5280's former digital senior associate editor.