Published in the Los Angeles Times (Nov. 5, 2019:) https://www.latimes.com/opinion/story/2019-11-05/climate-carbon-emissions-consumer-choices
It can be confusing for climate-conscious consumers to sort through all of the carbon-reduction options out there in search of the ones that can truly make a difference. Even with a background in carbon footprint analysis, I still find it tricky to separate the good ideas from the bad.
I have learned to follow a simple rule of thumb that helps me cut through all the climate-related noise: Don’t sweat the small things when it comes to climate change. Focus your energies and investments on a few big actions that you can sustain over the long term.
But common misconceptions about what can move the climate-change needle make it harder for consumers to make the right choice.
In 2014, California became the first state to pass legislation to ban single-use plastic bags at retail stores. The question of whether paper or plastic is better for the environment has become largely irrelevant as a growing list of states and cities have banned all single-use plastic carryout bags. Yet this high-profile movement does little to reduce the nation’s total carbon emissions.
Even if every shopper in the U.S. switched from plastic to reusable bags, we would reduce our annual national emissions by only 0.02%.
Making a point of purchasing locally produced food is another common action that provides little climate benefit. Much concern has been expressed over the years about “food miles” — the distance that food travels from farms to consumers — and the associated emissions from transportation.
However, transportation emissions are generally much smaller than those from production, so consumers would be better off focusing more on how foods are produced. For example, the carbon footprints of animal-based foods can be two to 20 times larger than those of plant-based foods.
Even when emissions from production are low — as they are with many fruits and vegetables — transportation alters their carbon footprint in a counterintuitive way.
Long-distance transportation via semi-trailers is generally more efficient than local transportation in smaller vehicles. Farm-to-retail transportation emissions of local farmers market produce can end up being more than double that of similar supermarket produce.
In addition, emissions from packaging materials are rarely large enough to justify making purchasing decisions based on how a product is packaged. Packaging typically accounts for less than 10% of the total emissions for most food products, and significantly less than that for durable goods.
Sometimes it helps to put the action you want to take in perspective. The American Cleaning Institute, an organization that represents the cleaning products industry, recently estimated that a household could cut its emissions by 864 pounds of carbon per year by washing four out of five loads in cold water. That number sounded impressive until I calculated that it works out to about one-half of 1% of the annual carbon footprint for a family of four.
Even if every family in America adopted the cold-water washing method, national emissions would only be reduced by less than 1%.
Consider the widely held belief that organic farming is better for the climate. Multiple studies have shown that net emissions would be higher in the long run with organic production due to lower yields. I buy some organic produce to minimize the pesticides my family ingests, but I have no illusions about helping the climate when I do that.
But consumers are not powerless. Significant emission reductions are possible in the areas of transportation and electricity, which are responsible for more than 60% of net U.S. greenhouse gas emissions.
A typical passenger vehicle generates about 4.6 metric tons of carbon dioxide per year, which accounts for a quarter of U.S. per-capita carbon emissions. Driving the vehicle 20% fewer miles a year would translate to a 5% reduction relative to per-capita emissions. If public transportation is substituted for half the miles driven, it results in a 15% emission reduction.
Driving an electric vehicle can cut emissions by 10 to 20%. Eliminating a single coast-to-coast flight can save nearly 4% relative to per-capita emissions, but these savings only become significant when enough people avoid flying and fewer planes are in the air.
Many electric utilities in California and elsewhere offer green-energy programs that can supply 100% of a home’s electricity with renewables like solar or wind energy for less than an additional penny per kilowatt-hour. This inexpensive option could cut per-capita emissions an average of 10% while helping to boost investments in additional renewable energy capacity.
Big consumer commitments like these really could have an effect on climate change. Just think of the less-impactful moves you make to “save the environment” as a bonus.
Kumar Venkat is a technologist based in Portland, Ore. As the founder of CleanMetrics Corp., he helped companies quantify and reduce greenhouse gas emissions.