To keep global heating below 2°C, the world must cut short-lived climate pollutants like methane, hydrofluorocarbons (HFCs), black carbon (soot), and low-level ozone in tandem with carbon dioxide emissions, says a new study in the Proceedings of the National Academy of Sciences.
Using climate models to project what will happen to global temperatures if countries focus entirely on cutting CO2 emissions while ignoring short-lived but potent pollutants like methane and soot, researchers at the Washington-based Institute for Governance and Sustainable Development (IGSD) found the result would be “increased warming over the near term,” reports Inside Climate News.
- Concise headlines. Original content. Timely news and views from a select group of opinion leaders. Special extras.
- Everything you need, nothing you don’t.
- The Weekender: The climate news you need.
That’s because when fossil fuels are burned, they release highly-reflective sulphate aerosols that offset roughly 0.5°C of warming that would otherwise occur as a result of such combustion.
With the short-term curb on warming removed as renewables take hold, the planet “will continue to heat up for a couple of decades before the longer-term cooling from cutting CO2 emissions takes hold.”
That points to the urgent need to minimize the extremely potent warming produced by methane, HFCs, and soot, as well as nitrous oxide and low-level ozone.
“Sharp cuts to methane and other SLCPs could result in temperatures lower by 0.26°C by 2050, almost four times greater than the benefit of pursuing CO2 cuts alone, which the scientists estimated would result in lowering temperatures by 0.07°C by 2050,” the Guardian explains.
And those “sharp cuts” can be easily made with the necessary regulations in place and enforced.
“This is an optimistic message, as we have low- or no-cost strategies available, with no- or low-cost interventions, that can slow global warming in the critical near term,” study lead and IGSD chief scientist Gabrielle Dreyfus told the paper.
At the COP 26 climate summit in Glasgow last November, more than 100 countries pledged to reduce methane emissions 30% by 2030. But Inside Climate notes that the target is voluntary, “and it remains unclear how the United States and other countries will meet their goals.” And the signatories did not include Russia, whose leaky oil and gas infrastructure makes it one of the world’s biggest methane emitters.
“Similarly, more than 100 countries have ratified an international agreement in recent years to phase down HFC production and use,” Inside Climate adds. Known as the Kigali Amendment to the Montreal Protocol, the agreement is expected to eliminate as much as half a degree of additional warming by 2100, or more if it’s combined with energy efficiency measures.
While the Kigali Amendment has yet to be ratified by the U.S. Senate, it “enjoys rare bipartisan support as well as the support of industry,” and was passed by the Senate Foreign Relations Committee earlier this month. A full senate vote has yet to be scheduled.
Study co-author and IGSD President Durwood Zaelke has also “called on European governments to stipulate that any gas they import to replace supplies from Russia should come from sources with low rates of methane leaks,” the Guardian writes.
