Although carbon dioxide (CO2) may be the world’s biggest contributor to climate change, lesser discussed pollutants such as methane, black carbon (a.k.a. soot), chlorofluorocarbons and hydrofluorocarbons (HFCs) are taking center stage in the discussion, especially as U.S. states take on more of the responsibility for climate change reduction.
While these pollutants do not last as long in the atmosphere (days or years as compared to centuries), scientists believe they play a larger role in warming the atmosphere in the short time they exist.
The U.S. Climate Alliance feels that these “super pollutants” are so problematic that they committed to reducing emissions of these short-lived climate pollutants, and challenged all national and subnational jurisdictions to do so as well at last Fall’s Global Climate Action Summit.
And many states are rising to the challenge.
Methane, for example, “is estimated to be 34 times more potent than CO2 over 100 years” and “is responsible for about 20%-25% of current global climate forcing.” The Alliance suggests that capturing and converting methane to energy, fuels, and soil additives would not only cut this percentage, but also create diverse revenue streams.
Five coal-mining states — Alabama, California, Connecticut, Colorado and Kentucky — limit the amount of methane gas allowed in a mine and developed procedures for cases of elevated levels and leakage.
Sixteen states have passed laws setting specific goals that restrict methane emissions in order to reduce overall negative impacts, or regulations to minimize leakage.
The Environmental Defense Fund (EDF) announced that it has plans to launch MethaneSAT, a satellite whose job is to identify and measure methane from “human-made sources.” The satellite will use a wide, 200-kilometer view path at intervals of seven days or less, making it feasible to regularly monitor fifty major oil and gas regions, which accounts for more than 80% of global production. The data will be freely available to interested parties.
Hydrofluorocarbons (HFCs) are used as refrigerants and in air conditioning, foams, aerosols, and other applications. HFCs are the fastest growing source of greenhouse gas emissions in the U.S. and globally, and “are thousands of times more potent than CO2.” The Alliance is suggesting that individual states invest in more efficient refrigeration and cooling technologies, and replace HFCs with gases that have a lower Global Warming Potential (GWP). GWP is a measure of how much heat a greenhouse gas traps in the atmosphere up to a specific time horizon, relative to CO2. It compares the amount of heat trapped by a certain mass of the gas to the amount of heat trapped by a similar mass of CO2 (whose GWP is standardized to 1).
According to the GreenBiz report, “State of Green Business 2019,” California ruled last January to phaseout HFCs entirely, and Maryland, Connecticut and New York voted last fall to follow suit.
The Alliance’s long-term vision is to reduce emissions from these “short-lived climate pollutants” by up to 50% by 2030.
Black carbon, or soot, is a component of toxic particulate matter that accelerates snowmelt and sea level rise, and modifies rainfall patterns. The Alliance suggests that the transportation industry, especially heavy-duty diesel vehicles, could contribute to offsetting the effect of black carbon. New vehicles that include particulate filters that eliminate about 99% of fine particulate matter and black carbon should be put on the road. In addition, they would like to see investments in renewable diesel, renewable natural gas, and zero emissions technologies i.e. electricity or hydrogen.
The Alliance’s report, From SLCP Challenge to Action: A Roadmap for Reducing Short-lived Climate Pollutants to Meet the Goals of the Paris Agreement, outlines a menu of actions for states to consider that “have the potential to reduce SLCP emissions in the U.S. Climate Alliance as a whole by 40%-50% below current levels by 2030.”
If you work in corporate sustainability, be sure to look at ways to reduce releases of pollutants, in addition to CO2. And if you work in environmental compliance, be sure that you’re keeping track of potentially updated laws that regulate these super pollutants, especially regulations pertaining to individual States.
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