Written by Ron Bennett

Imagine, if you will, that I lived in a home with solar panels on the roof, an electric vehicle out front, and all the latest technology, but I left a big old truck running in the garage 24/7. You’d probably, think “how incredibly irresponsible and outright dangerous!” Well, I’d never do that, but that’s sort of what’s happening to our beautiful state of Colorado.

We have a climate plan that heralds deep decarbonization across multiple sectors while ignoring that big old truck running in the garage –  the industry that got us into this pickle in the first place. The oil and gas industry, whose product – fossil fuels – has driven atmospheric carbon levels higher than at any other time in human history and whose fugitive emissions have caused an extraordinary spike in atmospheric methane. Yet it’s been given the green light by our state to continue operating as usual while emissions remain dangerously under-reported.

Some evidence indicates that shale-gas development in North America may have contributed one-third of the total global increase in methane emissions from all sources over the past decade. (Howarth 2019)

Those carbon and methane emissions come back to haunt us in the form of decades-long drought and powerful winds that fuel unprecedented and destructive wildfires. Last year in Colorado, the Cameron Peak, East Troublesome, and Pine Gulch fires set records for the three largest fires in the state’s recorded history, burning over a half-million acres along with hundreds of homes and important wildlife habitats.

Metrics matter

The Colorado State Legislature passed HB 19-1261, the Climate Action Plan to Reduce Pollution, in 2019 in response to the global climate crisis and its devastating effects felt here in Colorado. This bill and the resulting greenhouse gas (GHG) reduction roadmap set GHG reduction targets for 2025, 2030, and 2050. Unfortunately, the resulting GHG reduction roadmap drastically discounts the near-term effects of fugitive methane – from oil and gas operations – by spreading the damage it causes over a 100-year timeframe. The trouble is that methane is a short-lived climate pollutant (SLCP) that only persists in the atmosphere for about twelve years.

Just a little math: When evaluating any SLCP’s global warming potential (GWP), you convert the SLCP to its equivalent quantity of carbon dioxide (CO2) over a specified time period. The GWP100 (100-years) of methane is 28 but the GWP20 (20-years) jumps to 86, causing numerous indirect climate feedbacks. All that to say methane is 86x more powerful at trapping heat than CO2 over these next 20 years. Methane emissions have the potential to cause massive irreversible damage in the short term and should not be overlooked. HB 19-1261’s GHG reduction roadmap, whose reduction targets are based on five-, ten- and thirty-year milestones, should consider methane’s limited atmospheric lifetime and adopt GWP20 as the more appropriate and accurate metric.

New York State leads the way

New York State enacted the Climate Leadership and Community Protection Act (CLCPA) in 2019 to mandate the inclusion of GHG emissions from outside the state’s borders if they are associated with New York’s energy use. By including fugitive methane emissions primarily from the production of Marcellus shale gas in Pennsylvania, New York is better accounting for the full impact of fossil-fuel production and consumption. What’s remarkable is that while virtually every other state uses GWP100, New York is instead using the GWP20 metric, comparing fugitive methane emissions to CO2 over a twenty-year time horizon.

New York’s total GHG emissions were unchanged from 1990 to 2015, but methane’s share of those emissions climbed from 28% in 1990 to 37% in 2015, offsetting carbon reductions from coal and oil. Acknowledging methane’s expanding role in New York’s GHG inventory, policymakers chose the GWP20 metric to better represent methane’s near-term climate impacts.


Despite all the praise for the GWP20 metric, Berlin-based climate science and policy institute Climate Analytics cautions against the use of GWP20. Their concern is that if SLCP reductions are achieved, but CO2 reductions are not, temperatures will continue to rise for hundreds of years because of carbon dioxide’s extended persistence in the atmosphere. The risk is that GWP20 “would likely give countries a perverse incentive to refrain from the deep reductions of CO2 emissions that already have been delayed for far too long.”

While methane’s effects are strongest in the decades after release, half of the CO2 emissions remain after 37 years and 22% will remain indefinitely. Calculating CO2 equivalence for SLCPs exclusively on a short time horizon, like twenty years, minimizes the long-term impacts of CO2 emissions and thus can be detrimental to achieving climate stabilization. Climate metrics that represent CO2 equivalence over a range of time frames, illustrate the trade-offs when making policy decisions about a complex and dynamic climate.

Dual-term accounting standard

Researchers have urged the United Nations Framework Convention on Climate Change (UNFCCC) and the International Panel on Climate Change (IPCC) to consider a dual-term GHG accounting standard that better represents the impact of methane and other short-lived climate pollutants. Studies indicate that a two-value approach can better describe effects over different time horizons. A Harvard/Princeton study proposes “that these time scales be ubiquitously reported as an inseparable pair, much like systolic-diastolic blood pressure… to make the climate effect of using one or the other time scale explicit. Policymakers often treat GWP as a value-neutral measure, but the time-scale choice is central to achieving specific objectives.”

For larger-scale integrated assessment models which project emissions up-to, and beyond, climate stabilization periods, the use of a single GWP value such as the GWP100 would significantly undervalue the impact of methane emissions. Thus, the inclusion of both short and long-term metrics is imperative to assess the robustness of any projections, especially where the contribution of methane emissions is significant. (Balcombe 2018)

California sets a good example for our home state, by using both GWP20 and GWP100 in its short-lived climate pollutant planning.

GWP’s Impacts to Colorado Policy

Objectives defined by Colorado’s HB 19-1261 are based on specific GHG reductions with milestones at the five-, ten-, and thirty-year marks. Currently, the state uses GWP100 for methane, thus diluting its contribution to the state’s GHG inventory. A 350 Colorado report based on research from Cornell University shows that, when adjusted for actual leakage rates and assessed using GWP20, methane represents not just a significant share but, indeed the largest share of Colorado GHG emissions.

Tipping points

The end game is climate stabilization but sadly it’s a long way off. In the meantime, let’s not discount the powerful heat-trapping impact of methane leaks over these next critical decades. Negative climate feedback loops such as melting permafrost and massive wildfires pump more carbon into the atmosphere, pushing stabilization further out of reach. Global mass extinction, coral bleaching, desertification, and the human costs associated with these events are too high a price to pay.

Closer to home, we’ve seen reduced mountain snowpack, forests suffering around the state, wildlife pushed from their habitats due to warming temperatures, and precious aquifers not being replenished. We find ourselves amid a climate emergency that requires every tool in the toolbox to slow it down. We can no longer give oil and gas a free pass. It is time for ambitious rules and accurate metrics that fully recognize the oil and gas industry’s role in this crisis.

Take action

Call Governor Polis’ office and tell them to use the 20-year GWP for methane! (303) 866-2471

Become a volunteer with one of our campaign committees to help advance GHG emissions across all sectors and secure a phase-out of oil and gas extraction and production in Colorado over the next decade! Sign up here!

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