Confronting climate change: Not just carbon dioxide

Matt Frades, MPA


When you think about avoiding dangerous climate change, what comes to mind? Thanks to a decade of climate education efforts, much of the public is now aware of the scientific consensus on the need for reductions in global emissions of the greenhouse gas carbon dioxide (CO2). Awareness of carbon dioxide’s role in the climate is a crucial step towards building support for policies that address climate change. However, while carbon dioxide is the most important climate warmer, it is not the only player that demands attention.

The full story of how humans affect Earth’s climate is complicated, multi-faceted, and involves some uncertainty (just like everything else in life). The most popular climate change messaging is simple and short enough to tweet: “We need to reduce emissions of CO2, a greenhouse gas, in order to avoid dangerous climate change.” While this message goes a long way, a slightly more nuanced and accurate view is apropos: “We need to address a variety of human activities, including the emission of various greenhouse substances to the atmosphere—the most prominent of which is CO2—in order to avoid dangerous climate change.” At 200 characters, this revised message may be over the sacred Twitter limit, but the extra words are worth it. Here’s why:

• climate warmers other than CO2 are responsible for between 30 and 60 percent of human-caused warming (depending on how you choose to account for future warming), and
• addressing climate warmers other than CO2 presents opportunities to meaningfully address climate change right away, despite the present political and fiscal constraints.

The human-caused climate warmers are diverse, including methane from agriculture and landfills, black carbon particles emitted from vehicles, gases used to make foams and semiconductors, gases contained in air-conditioners and refrigerators, the lightness or darkness of manmade surfaces like rooftops, and others. Acknowledging the true diversity of mankind’s impacts on the climate compels us to address a broad set of human activities that significantly warm the planet but propitiously it also provides policymakers with a more diverse set of politically-feasible policy opportunities to address climate change in the short term.


Editor’s Note: You can read more about this subject in “Complements to Carbon: Opportunities for Near-Term Action on Non-CO2 Climate Forcers,” a WWS graduate policy workshop final report presented to the U.S. Department of Energy and the Environmental Protection Agency, identifying domestic and international fast-action strategies that are available under current agency authority to address non-CO2 climate warmers. Available here.