WHY SHOULD I DO IT?
Note: this website does not address the big “why” - the science of climate change, or its impacts - and assumes that is why you are here: you want to take responsibility for your personal contribution to the problem. This site accepts the scientific consensus, and focuses on getting at solutions, by building knowledge around how we generate CO2, and how to eliminate those sources. Thus, this section focused on the details of “why” the climate responsible “what” specifics are recommended on this site.
THE BIG PICTURE—what do Americans’ carbon footprints look like, and how are they generating them?
Americans generate big carbon footprints per capita relative to other nationalities. Per capita carbon footprint comparisons of a number of countries and continents, as of 2021—this does not include all countries and is meant to give a flavor. One thing that jumps out to me is that the countries many of us so dearly love and travel to, such as the UK and France, manage to have per capita carbon footprints about one-third of ours.
Carbon dioxide and its equivalents
Carbon dioxide isn’t the only gas we are increasing in the atmosphere—another significant one is methane, which has 22 times the climate impact per molecule than carbon dioxide. Methane is nearly the same thing as natural gas. While we don’t produce methane at nearly the same rate as carbon dioxide, it makes an impact because it is so potent. There are other super impactive molecules, created for an array of applications. These too have an impact. Collectively, the footprint of climate impacting gasses are normalized to their “carbon dioxide equivalent,” or CO2e.
American carbon footprint per capita has dropped over 25% since 2005. So, it’s not all bad news—Americans HAVE gotten more efficient and less carbon intensive in the last 15 years. We have individual carbon footprints similar to our grandparents and great grandparents in the 1920s and 1950s (we peaked per capita in 1973). A couple countervailing facts: our population is increasing, nearly cancelling out our individual reduction, and because our carbon emissions are outpacing the planet’s ability to convert CO2 back to oxygen, atmospheric carbon loading continues to increase. I would argue too: our ability to live healthy, thriving, modern lives with a low carbon footprint is much greater than it was for our grandparents. So: we should do that.
Americans generate CO2 in four major ways
Direct combustion of fossil fuels related to buildings and transportation
Heating (furnaces, boilers, etc.)
Engines (internal combustion for ground transportation, jets for air travel, etc.)
Indirect (remote) combustion of fossil fuels to generate electricity
55% of US electricity is generated from fossil fuels, another 19% from nuclear—26% is from renewable sources
Non-combustion emissions of CO2 equivalents, especially methane
Natural gas leakage during extraction and distribution
Ruminants (mainly cows)
Garbage degradation
Sewage processing
Industrial processes with CO2 as a byproduct (e.g., concrete)
Degradation of natural systems that store CO2
Jungle and forest clearing for pasture, palm plantations, and so on, to produce food we eat (cheap beef, processed foods)
The tyranny of the little differences—death by a thousand cuts—each thing by itself not always so much, but taken together, it’s a lot. With a few exceptions, like air travel, or long-term systems choices like heating, individual, day-to-day decisions don’t impact the math that much. Half a percent here, there. Writ large, that is also a problem. Taking a slice of activity from the broader range of all the ways our society generates carbon, it is all too easy just to say an individual action or policy doesn’t move the dial all that much. We all have responsibility, and all our choices add up to our problem. Treating it like the whole system problem it is is the only way we’ll get where we need to be.
Higher density downtown areas support low-carbon living. Living in a dense, compact area well served by transit simply makes low-carbon living far easier. Car trips become unnecessary; living spaces are smaller which limits space for more stuff; and, the shared walls of multifamily buildings reduces the exterior wall area relative to living space, which in turn reduces heating and cooling demand. Densifying leaves more room for nature—which sequesters rather than generates carbon. The actual numbers bear this out. To be clear, urban living isn’t required for low-carbon living—a vegan permaculturalist farmer living close to the land in the countryside definitely has a lower carbon footprint than me—but at scale, dense urban living is beneficial for carbon reduction.
A note on investment, value, and cobenefits. A lot of the more challenging actions described throughout this site, especially related to your home, add value—it is not all money out without a return. While you are taking these steps because you care about your climate impacts, they also generate benefits. For example, insulating your house not only reduces carbon, it lowers your utility bills and makes for a cozier, quieter house. Studies show that things done to improve the sustainability of buildings increases their value at the time of sale.
Here’s another way of considering our CO2 generation—by life sectors—and comparing average US and European footprints.
Source: Scott Johnson, ArsTechnica
More:
arstechnica.com/science/2020/04/americans-have-texas-sized-carbon-footprints-heres-why/
pbs.org/newshour/science/5-charts-show-how-your-household-drives-up-global-greenhouse-gas-emissions
pnas.org/content/117/32/19122
coolclimate.org/calculator
nytimes.com/2023/02/28/climate/climate-change-carbon-footprint-america.html
It bears stating that those most responsible for climate impacts are also those most able to limit them. This is true for Americans generally, and wealthy Americans particularly.
I’d also like to emphasize that if you are American, or wealthy, or both, there is nothing inevitable about your carbon footprint—indeed that is what this website is about. You control your carbon destiny. Learn more.
Key contributors—the basics
Mobility
Transportation is the single largest contributor to the average American’s CO2 footprint—32%. Driving makes up the biggest chunk of that, but air travel is rapidly growing.
However, note that this is highly variable by person—take a look at your own CoolClimate carbon footprint to see where it stands for you.
Transportation is the single largest contributor to the average American’s CO2 footprint—32%.
Source: CoolClimate calculator
This chart does not include EV micromobility (escooters, etc.), with a footprint close to zero and human-powered transport, with no footprint. More: ourworldindata.org/transport
EVs
I want to acknowledge that electric vehicles have a larger footprint in the manufacturing process than gas vehicles do—an EV’s battery essentially doubles the car’s manufacturing footprint (which is already large: 5-10 tons of CO2 for a gas car; 10-20 for electric). However, internal combustion engines are incredibly inefficient in their operations—about 75% of the gas energy is wasted as unusable heat. This means EVs have a lower operating carbon footprint than gas cars, even in locations with a dirty grid. However, using an EV in conjunction with buying 100% renewable electricity is the gold standard—effectively taking the car’s operating footprint to zero.
Flying, more than any other activity, creates a massive impact in a very short period of time. On a per mile basis, the CO2 generated is about the same between driving (alone) and flying. When you fly, it is just SO easy to rack up the CO2 footprint. On shorter flights, a large amount of fuel is used just to reach a short-lived cruising altitude. A longer intercontinental flight is essentially like driving there CO2-wise—imagine the carbon footprint of driving to Europe, or Asia, and back—yikes! In fact, a person flying economy roundtrip from San Francisco to Paris creates 2.7 tons of CO2—about 16% of the average American’s annual CO2 footprint, and more than the average Brazilian’s total annual footprint. That’s a lot for a single act, especially considering that air travel is one of the most challenging things to truly offset. That long weekend via jet is the CO2 footprint’s binger; you wouldn’t drive from Seattle to LA for the weekend, but people do that by air all the time.
The footprint of a first/business class flight is three times that of coach. This is starting to be a frequent splurge or mileage plan upgrade—just sayin’.
More: documents1.worldbank.org/curated/en/141851468168853188/pdf/WPS6471.pdf
Lyft, Uber, taxis, etc., have 69% higher emissions than typical driving. Lyft, Uber, and other ridesharing have a higher footprint than private cars, due to deadheading (driving to pick up their next ride), and displace much lower footprint movement like subways and micromobility.
More: ucsusa.org/sites/default/files/2020-02/Ride-Hailing%27s-Climate-Risks.pdf
On a per mile basis, the CO2 generated is about the same between driving (alone) and flying. When you fly, it is just SO easy to rack up the CO2 footprint.
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A longer intercontinental flight is essentially like driving there CO2-wise—imagine the carbon footprint of driving to Europe, or Asia, and back—yikes!
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The footprint of a first/business class flight is three times that of coach.
Home and buildings
Shelter falls into several categories:
22% of total US energy use:
Where we live
18% of total US energy use:
Where we work
Where we shop, eat out, recreate, etc.
Where we make things
You have most control over the carbon footprint of where you live—and that accounts for a lot of your carbon footprint.
More: eia.gov/consumption/residential/data/2015/c&e/pdf/ce4.6.pdf
Embodied carbon of water. In some arid areas in particular, a large amount of energy is used to simply transporting potable water. In southern California, water is pumped over a thousand miles before it reaches the consumer—representing “embodied” energy, and thus carbon. (A shocking 8% of California’s entire electricity demand is used to convey and treat water.)
More: iopscience.iop.org/article/10.1088/1748-9326/10/11/114002
You have most control over the carbon footprint of where you live—and that accounts for a lot of your carbon footprint.
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In southern California, water is pumped over a thousand miles before it reaches the consumer—representing “embodied” energy, and thus carbon. (A shocking 8% of California’s entire electricity demand is used to convey and treat water.)
Eating—foodprints
Worldwide, food accounts for 26% of greenhouse gas emissions. See: ourworldindata.org/food-ghg-emissions
Here is an excellent summary of the CO2 generated by different types of food:
More:
ourworldindata.org/grapher/food-emissions-supply-chain
science.org/doi/epdf/10.1126/science.aaq0216 (you will need to sign up for a free Science account to see this)
I also find Table Debates to be a very thoughtful, research-based communications platform around food sustainability generally.
iopscience.iop.org/article/10.1088/1748-9326/aab0ac © Institute of Physics and IOP Publishing Limited 2019 I find this graph (from a US-specific study) compelling because it shows what a wide range of actual foodprints there are out there. The study also highlights the high carbon foodprint of bottled/canned beverages.
Beef and dairy production account for 15% of our global carbon footprint—they are the air travel (or coal-based electricity) equivalent in the food sector. The literature is crystal clear—beef cattle have a huge carbon foodprint, and cheese is definitely up there. Cheap beef from recently cleared rainforest land has the absolute worst carbon foodprint—several times higher than shown in the graph above. Think about this: there are 92 million cows in the United States—more than one for every four American—and outweighing us by total living mass by a factor of two.
While grass-fed and grass-finished beef is better than beef raised in your typical feedlot on industrial grain, it still has a high carbon footprint, and, based on scalability, is a red herring solution. For a while, my consolation was that I could always eat grass-fed/finished beef. However, this Oxford meta-analysis looked at this very topic and found that grass-fed/finished beef still has a substantial carbon footprint.
Cute video summary of report: youtube.com/watch?v=nub7pToY3jU
More: Sustainable Food Trust’s disagreements with Oxford study and Oxford response: tabledebates.org/blog/fcrn-response-sustainable-food-trust-commentary-grazed-and-confused
Aside from this, grass-fed/ finished beef accounts for less than 5% of US beef production—even if pasture beef were a solution, it can’t be scaled to meet anywhere close to overall current beef demand. I’ve reached the conclusion that the grass-fed/finished conversation is a side show, and we should stay focused on simply moving away from beef given our current realities.
Food choice is more important than local production. Eating lower on the food carbon chain has more carbon benefit than avoiding emissions related to transporting food—unless it’s been air freighted. I know, this is different than has been messaged in the past—and there are other benefits of local food production—so do both low and local! More: ourworldindata.org/food-choice-vs-eating-local
31% of US food is wasted. 21% of waste is with the consumer, 10% at retail. This is obviously a huge source of potential improvement. More: ers.usda.gov/webdocs/publications/43833/43680_eib121.pdf?v=8608.1
Worldwide, food accounts for 26% of greenhouse gas emissions.
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Beef and dairy production account for 15% of our global carbon footprint—they are the air travel (or coal-based electricity) equivalent in the food sector.
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Eating lower on the food carbon chain has more carbon benefit than avoiding emissions related to transporting food—unless it’s been air freighted.
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31% of US food is wasted. 21% of waste is with the consumer, 10% at retail. This is obviously a huge source of potential improvement.
Source: https://ourworldindata.org/food-transport-by-mode
Things that travel by air are typically things that are out of season and produced long distances away—it can be hard to know if something has been air shipped or not. But there’s a good bet that the following items were air freighted:
Out of season asparagus and green beans
Out of season fresh berries
Fresh fish from places farther than a couple days by truck
Chocolate and coffee. These both have high foodprints, in large part due to associated land clearing, resulting in less CO2 sequestration/exchange. Fair Trade, Equal Exchange, and Rainforest Alliance certifications support small farms which avoid widespread land clearing and less monocultural farming.
https://rgs-ibg.onlinelibrary.wiley.com/doi/10.1002/geo2.96
earthbound.report/2022/09/21/why-does-chocolate-have-a-high-carbon-footprint/
Palm oil. Use of palm oil is rapidly expanding. Palm oil can only be grown in tropical regions, meaning it is sometimes grown on recently cleared rainforest—obviously bad. This has led to boycotts of palm oil generally. However, palm oil production density per acre is very high relative to other oils, suggesting that on a net forestation level it may be a good option, if deforestation can be avoided.
wwf.panda.org/discover/our_focus/food_practice/sustainable_production/palm_oil/
Fundamentals make a difference
Fossil fuel divestment. I believe ethically divesting from fossil fuels is the right thing to do, and there is evidence that suggests it also does impact the ability of fossil fuel companies, especially those based in liberal democracies, to invest in expansion. academic.oup.com/joeg/article/21/1/141/6042790
Carbon offsets should be the last, not first, step. Carbon offsets are a bit like indulgences—essentially you are paying someone else to reduce an amount of carbon equal to your emissions. There are many problems with this, not the least of which is that, at scale, offsetting carbon emissions do not get us where we need to be—we’re just emitting too much to offset. There is also a general consensus that carbon offsets are far less efficacious than stated. I personally still like to buy them to offset our annual footprint anyway—but view it as icing rather than cake.
nytimes.com/2022/05/18/climate/offset-carbon-footprint-air-travel.html
Carbon offsets are a bit like indulgences—essentially you are paying someone else to reduce an amount of carbon equal to your emissions. There are many problems with this, not the least of which is that, at scale, offsetting carbon emissions do not get us where we need to be—we’re just emitting too much to offset.
