Science Paper Finds Indirect Emissions Account for 15 Percent of Human-Driven Warming

A paper published Thursday in the journal Science concludes that indirect interactions triggered by certain emissions have produced 15 percent of human-driven global warming. The study identifies carbon monoxide and non-methane volatile organic compounds as the largest contributors, with black carbon, or soot, also adding to the total.

U.S. Department of State and now senior climate scientist at Spark Climate Solutions, said the emissions do not warm the planet directly. “We’re emitting things into the atmosphere that don’t directly warm the planet, but they increase the amount of the greenhouse gases that do directly warm the planet,” Ocko said.

None of the three pollutants appear on the list of gases covered by the 1997 Kyoto Protocol.

U.S. deputy special envoy for climate, argue that enough data now exist to include them in climate accounting. The study synthesized findings that include data from the Intergovernmental Panel on Climate Change’s Sixth Assessment Report released in 2021.

Vaishali Naik, a co-author of that report and a scientist at the National Oceanic and Atmospheric Administration, wrote that “persistent scientific and political challenges remain” to adding the gases to formal climate frameworks. Michael Gerrard, founder of Columbia University’s Sabin Center for Climate Change Law, said the political climate in many countries makes adoption of stronger rules unlikely.

He added that the paper “highlights an important missing piece of the climate regulatory picture” because the pollutants remain unregulated under existing climate agreements.