Human Sources of Greenhouse Gases

Woman and kids looking at solar array

Sources of the avg MA resident's carbon emissions
Data Source: State of Massachusetts (estimated) & Union of Concerned Scientists

Roughly speaking, Americans are typically responsible for greenhouse gas emissions in four categories:

  • how we move
  • how we use energy at home
  • what we eat
  • stuff we buy

For most of us, the two major sources of our emissions are from the burning of fossil fuels when we drive and use energy at home. Another significant but usually lesser source comes from the food choices we make.

In each of these categories, we can take simple steps to drastically reduce our own greenhouse gas emissions.


Energy We Use

The energy we use at home comes in two basic categories, electricity and fuel for heat. There are extremely effective ways to reduce our emissions from electrical use. We can purchase renewable electricity for our homes, reduce what we consume with energy-efficient appliances, install photovoltaic solar panels, and make use of home batteries.

Reducing the fuel we use for heating our homes and water is more challenging, but there are still things we can do. The first step is to get a free home energy audit (many vendors offer the service) and insulate our homes as best we can. Buying efficient water heaters, furnaces, and appliances is the next step.

Potential Impact

By doing each of those things, the typical Massachusetts household could reduce their carbon emissions by about 20%.


How We Move

It won’t come as a surprise to most Bay Staters that we burn huge amounts of fossil fuels in cars to get us from place to place. One only needs to spend a few minutes on I-95 during rush hour traffic to understand why. So, it follows that the most effective way we can reduce emissions from transportation is by reducing the number of gas-powered cars on the road. There are many ways to do that. We can put pressure on state and local leaders for more public transportation, especially to rapidly developing Boston suburbs. We can carpool and we can, of course, walk or bike to work when possible.

The single most effective thing we can do as individuals, however, is to purchase an electric vehicle or plug-in hybrid when it comes time to replace our old cars. If you’ve switched your home over to renewable electricity, you’ll also be charging your car sustainably. The result is that you’ve brought your emissions from transportation to a tiny fraction of what they were.

Potential Impact

We’ll estimate that scenario reduces our carbon emissions by about 30%.


Stuff We Eat

Often overlooked, the stuff we eat contributes quite a lot to our carbon emissions. It’s easy to drive ourselves crazy trying to find the most sustainably-sourced foodstuffs by making a hundred choices for each grocery store trip, but the good news is that while those decisions add up to significant carbon savings over time, we can reduce our emissions dramatically just by eating less meat, and beef specifically.

Beef production is responsible for 5-10 times the carbon emissions of other meats in the United States. Compared to fruits and vegetables, the difference is even larger. Beef production, as it’s usually conducted in the US, is also tremendously hard on land and water resources, requiring 28 times more land and 11 times more water to produce than pork or chicken. For a typical American, beef and beef-related food-processing accounts for almost half of their food-related carbon emissions.

Potential Impact

Simply by choosing not to eat beef entirely, we can eliminate, say, 6-7% of our emissions.


Stuff We Buy

This is a harder category in which to find ways to reduce our emissions. Healthcare, sewage treatment, and other services we buy are mostly beyond our control, and we wouldn’t argue for changes in those systems unless the service would be improved.

On the other hand, producing and selling non-food consumables, like furniture, electronics, clothing, and housewares does contribute to our carbon emissions, and by using common sense, we can buy responsibly. When buying furniture, buying antiques or used furniture has a meaningful positive impact. When buying electronics, especially phones, waiting as long as possible between upgrades is a good strategy. And buying clothes as they wear out, rather than as they go out of fashion, is also helpful. In short, it is usually best to buy less, buy used, or buy less frequently. The exceptions to that rule are buying home appliances and cars. In those cases, it’s almost usually better to buy more efficient models.

The water we use is another part of the stuff we buy. Reducing water usage is a great thing to do for a number of reasons, but simply using less will reduce the carbon emissions needed to get the water to your tap or shower head.

Potential Impact

In this category, a typical consumer can have a modest but meaningful impact, reducing emissions by about 10%.


The Realistic Goal for the Typical Consumer

Putting all this together, we can estimate that ideal carbon saver could reduce their emissions by two-thirds or more. In some cases, reducing emissions by 80% could be possible. But we are unlikely to reach such high standards, and certainly will not do so quickly. There are many other factors that determine what we emit and why. We might buy gas-guzzling SUVs for safety and carrying capacity. We might work too far from home to bike to work or we might not be able to afford a hybrid vehicle or a new washing machine. Life is complicated, and our emissions are as well.

But that’s not reason to despair or an excuse for us to turn away. The typical New England resident can, with a few steps, still reduce their carbon footprint by 20-40%.

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