Households are responsible for 72% of global greenhouse gas emissions, but it isn't always clear what actions we should be taking as households or individuals to do our part to reduce our carbon footprint.
In fact, we're more commonly inundated with messaging that relate to moderate or low impact actions, such as mowing our lawn less often or reducing water consumption. When measured against the high-impact actions below, some of these commonly recommended actions are comparatively insignificant. For example...
Using reusable shopping bags is less than 1% as effective as a year without eating meat (1).
6. Adopt a Plant-Based Diet - 800kg CO2e reduced per year
Based on a 2018 study from the journal Nature, a significant reduction in meat consumption will be essential to mitigate climate change, especially as the global population grows (3). According to a study in 2019 in the journal Scientific Reports, if Americans reduced their consumption of poultry, pork, and beef by a quarter, we'd reduce greenhouse gas emissions by 82 million metric tons per year (4).
5. Buy a More Efficient Car - 1200kg CO2e reduced per year
Resources like the EPA provide a Green Vehicle Guide with information to help you learn more about what might suit your needs. They even offer a search tool to find certified vehicles that earn high marks for being green and efficient with their SmartWay tool.
4. Buy Green Energy - 1400kg CO2e reduced per year
You can pay a premium for green pricing, or if you live in a part of the country with a competitive energy market, you can choose how your electricity is generated and who generates it. In the state we live in, Ohio, the state provides a website where you can compare all providers, including what percentage of their electricity generated comes from renewable.
3. Avoid One Transatlantic Flight - 1500kg CO2e reduced per year
The largest amount of travel from the United States is to Europe, with roughly 70 million passengers being transported there per year (based on passenger statistics from the U.S. Department of Transportation).
2. Live Car Free - 2200-3100kg CO2e reduced per year
Obviously this is location dependent, but if you're wondering about your city, Habitat for Humanity put together a list of the top 10 cities where you can live without a car. The list includes many of the most populous cities, with D.C., Chicago, Boston, San Francisco, and New York taking the top five spots.
1. Have One Fewer Child - 117,700kg CO2e reduced per year
U.S. birth rates fell to a 32-year low in 2018, according to the CDC, although in that same year a Pew study found that among those families that have children, a growing share say that three or more is the ideal number.
The actions above are from the analysis of 148 scenarios relating to the climate impact of individual behavior changes across 10 countries (including the United States). The actions analyzed came from 36 different sources. The resulting list is the collection of high-impact actions identified across all parameters, and they are ranked by impact for residents in the United States. Some readers may find these impractical or unreasonable based on preferences or current life situation, but this information was a surprise based on what we're used to hearing, so I wanted to share for awareness.
CO2e figures above are approximate based on the source material. This graph from our research(1) provides a different view of the data.
Many of the common things we're told we should do to reduce our carbon footprint have a low impact compared to the actions detailed in this research. Household living situations such as number of children or source of energy consumption, greatly impact the potential to reduce emissions, more so even than does home location. Mobility choices, such as car and plane travel, along with diet choices, are also among the most dominant areas of household carbon footprint.
(1) Seth Wynes and Kimberly A Nicholas. The Climate Mitigation Gap: Education and Government Recommendations Miss the Most Effective Individual Actions. Published 12 July 2017.
(2) G. Dubois, et. al. It Starts at Home? Climate Policies Targeting Household Consumption and Behavorial Decisions are Key to Low-Carbon Futures. Published June 2019, Energy Research & Social Science, Vol. 52, pp. 144-58.
(3) Springmann, M., Clark, M., Mason-D’Croz, D. et al. Options for keeping the food system within environmental limits. Nature 562, 519–525 (2018). https://doi.org/10.1038/s41586-018-0594-0
(4) Eshel, G., Stainier, P., Shepon, A. et al. Environmentally Optimal, Nutritionally Sound, Protein and Energy Conserving Plant Based Alternatives to U.S. Meat. Sci Rep 9, 10345 (2019). https://doi.org/10.1038/s41598-019-46590-1