So doing nothing at home for your next vacation is an easy choice. Other better nothings include turning off your car rather than letting the engine idle, which accounts for about 30 million metric tons of carbon dioxide emissions in the United States a year.

Change the way other things in your life do nothing. Similarly when your appliances do nothing, they are often still burning fossil fuels. Standby power accounts for 4.6 percent of residential carbon emissions. Address this by turning off your internet router at night, shutting down your computer, unplugging your cellphone when it’s fully charged and choosing appliances that have low standby power requirements. To go beyond saving standby power, Karl Coplan, the author of “Live Sustainably Now,” suggests “depriving fossil fuel companies of their sales revenues by switching to a renewable-electricity contract and upgrading to an electric car the next chance you get.”

Be really lazy and drink from the tap. What could be lazier than shuffling to your own sink and pouring yourself a glass of water? And yet nowadays we often replace this most low-effort of American habits with driving to a store and buying a plastic bottle of water. This can end up costing us significantly more in carbon dioxide emissions than drinking water from the tap, according to one 2009 Italian scientific analysis.

Ditch the car one day a week. Collectively Americans drive more than three trillion miles annually. (Over 10 years that would take us all the way to Alpha Centauri, the closest star system to Earth.) That comes out to about 4.6 tons of carbon per vehicle a year, according to the Environmental Protection Agency. Transportation is the largest single contributor to American carbon emissions, the agency says. So skipping a day of driving each week would significantly decrease an individual’s contribution to emissions.

Upgrade a forest instead of your phone. A smartphone does not carry a huge carbon burden. Apple reports that a single iPhone 11 results in the emission of about 70 kilograms of carbon dioxide emissions over its life cycle. But if you donated the several hundred dollars you typically spent on a phone upgrade to a program managing a carbon-sequestering ecosystem, you could shave a much greater portion of carbon from your budget. For the best possible carbon sequester, consider the mangrove. Mangrove forests are one of the world’s most powerful carbon sinks; those in the Amazon store twice as much carbon per acre as the region’s rain forests.

Divest from fossil fuels. All of us are implicated in the carbon economy through our daily financial transactions. The headline of a recent New Yorker essay by the climate activist Bill McKibben read, “Money Is the Oxygen on Which the Fire of Global Warming Burns.” How to address this? “Switching to a fossil-free index fund is a no-brainer: Among other things they’re outperforming the market,” Mr. McKibben wrote me recently.

For those who don’t invest but do own a credit card and a bank account, Mr. McKibben suggested going a step further. “As we approach Earth Day at 50, cut up your Chase card or move your money to a new bank — JPMorgan Chase has become by far the largest funder of the fossil fuel industry.”

Here lies the truly profound global effect of the carbon-obese American economy, according to data compiled in a recently released “fossil fuel finance report card” by a group of environmental organizations. Four of the world’s five largest institutional investors in fossil fuels are banks headquartered here in the U.S.A.

Paul Greenberg is the writer in residence at the Safina Center and the author, most recently, of “The Omega Principle: Seafood and the Quest for a Long Life and a Healthier Planet.”

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