Earth Talk | April 2019

Reducing red meat, dairy, processed and air-freighted foods is an easy way to lower your own carbon footprint and help the world battle global warming. Credit: Pixabay.

Dear EarthTalk: What is a low-carbon diet and is it good for losing weight or is it only about saving the planet? — Jane Monroe, Scranton, PA

Not to be confused with a “low-carb” diet, which involves avoiding carbohydrates (bread, rice, pasta) as a way to lose weight or keep it off, a low-carbon diet — whereby you limit foods that generate a lot of carbon (CO2) emissions in their production and distribution — is indeed more about reducing your carbon footprint than your waistline. That said, proponents of a low-carbon diet say that eating with reduced greenhouse gas emissions in mind is healthier for us than the typical American diet whereby carbon-intensive meat, dairy and processed foods occupy too large a share of our overall food intake.

A recent study from the University of Michigan Center for Sustainable Systems backs up these assertions. Researchers correlated data from the National Health and Nutrition Examination Survey — a snapshot of what 16,000 Americans consumed over one 24-hour period — with information on the nutritional value and greenhouse gas impacts of different food items, concluding that the better a diet is for the planet, the better it is for our health. Furthermore, the 20 percent of Americans who eat what researchers consider a “high-carbon” diet (rich in red meat, dairy and exotic and processed foods) are responsible for almost half of the nation’s food-related CO2 emissions. The upshot is that changing the behavior and food choices of this small segment of the population could pay big dividends for public health and for reducing our overall national carbon footprint.

The concept of a low-carbon diet was first popularized in the U.S. by Bon Appétit Management Company, which runs more than 1,000 cafés in 33 states for corporations, universities and venues. Back in 2007, the company partnered with the non-profit Ecotrust to compile and conduct Life Cycle Assessments (LCAs) — measuring the amount of CO2 emitted during a given food product’s entire life cycle — for thousands of different foods. These LCAs became the basis for the “Food Scores” section of its website, which provides information to help people reduce their carbon footprints through food choices.

Besides launching, Bon Appétit’s managers also embarked on a five-year internal campaign to ratchet down the emissions generated by the company’s own operations and offerings by 25 percent. The company stopped buying air-freighted seafood, reduced its use of tropical fruit by half, shrank beef purchases by 33 percent and cheese by 10 percent while cutting food waste by one-third. Overall these moves shaved some five million pounds of carbon emissions per month off Bon Appétit’s contribution to global warming.

The fact that food and the systems to produce and distribute it are responsible for about a third of all greenhouse gas emissions means that everyone has a lot of potential for fighting global warming through sourcing locally produced and in-season foods to minimize emissions-intensive “food miles,” buying only as much as we can eat to reduce waste, and minimizing consumption of red meat, dairy and processed foods. In the case of climate change, if we don’t watch what we eat, it could really come back to haunt us.

Contacts: National Health and Nutrition Examination Survey,; “Greenhouse gas emissions and energy use associated with production of individual self-selected U.S. diets,”; Bon Appétit Management Company,; Ecotrust,; Eat Low Carbon,

You never know these days whether the engine inside an old VW bus or other classic car is the original gas guzzler or a new “restomod” all-electric one — unless you hear it rumbling at a stop light. Credit: Todd Lappin, FlickrCC.
Dear EarthTalk: I saw a news item about overhauling classic old cars with electric engines, and wondering if this can be done with any old car, such as my 1999 Subaru Outback? If this is feasible, maybe I should reconsider my plan of trading up for a new Prius. — Tim St. Germain, Boise, ID

It’s true that there’s never been a better time to convert an old gas guzzling car into an emissions-free electric vehicle (EV), but some makes and models are better suited for a so-called “EV swap” than others.

Michael Bream of San Marcos, California’s EV West, which made news recently with its conversions of old VWs and Porsches into EVs, says you could convert a ’99 Subaru — but EV Swaps are typically reserved for classic cars. “A newer Subaru has a ULEV certified (low emission) engine, so it’s not as bad a polluter as a classic car, and doesn’t suffer from reliability and power issues that classic cars typically suffer from,” he says. “A typical conversion of a Subaru would cost about the same with parts and labor as a brand-new all-wheel drive Tesla Model 3, so unless your vehicle is extremely well loved, or you can’t stand the thought of selling it, then it might be a better solution to buy or lease a new EV.”

EV West is one of a handful of garages across North America now specializing in EV conversions. Some others include: Zelectric Motors (San Diego, CA), ElectricGT (Chatsworth, CA), Make Mine Electric (Sebastopol, CA), Electric Vehicles of Washington (Bellingham, WA), Shockwave Motors (Russellville, TN), Epic Car Conversions (Toronto, ON) and Green Shed Conversions (Crystal River, FL).

If you don’t want to wait to get your car converted by one of these shops, you’ll just have to do it yourself (or find a local mechanic looking for an interesting project). Luckily lots of companies now sell EV conversion kits (Canadian Electric Vehicles, Electro Automotive, Wilderness Electric Vehicles, DIY EV, EV Source, Metric Mind Corporation, EV Drive) that include new engines, batteries and components. Expect to spend at least $8,000 on all the parts needed for the job (and tack on an additional 50 percent more if you opt for longer-range lithium ion batteries). The labor will be up to you. DIYers should check out’s “How to Build Your own Electric Vehicle in 5 Easy Steps” or Mechanic Doctor’s “How to Convert Your Car to an Electric Vehicle” for step-by-step instructions. Meanwhile, California-based EV4U runs “3-Day Hands-On Conversion Workshops” near Sacramento for $495.

With a new base model Prius starting at $23,000 you may well be better off doing the EV Swap on your old car. According to EVW, the operating costs of driving a Prius hybrid ($0.14/mile) are about four times what it costs to get around in an EV (whether native or a conversion). “In addition to the fuel savings, electric cars do not need oil changes, spark plugs, distributors, timing belts, etc.,” EVW adds.

What you won’t get is that new car smell or the nervous feeling of driving a brand-new car off the dealer’s lot. But you will get the satisfaction of knowing that you saved two tons of metal from the junk heap–and saved the world the trouble of sourcing materials for and building another brand-new Prius.

Contacts: EV West,;  Zelectric Motors,; Make Mine Electric,; Electric Vehicles of Washington,; Epic Car Conversions,; Green Shed Conversions,; EVRater,; Mechanic Doctor,; EV4U Workshops,; Canadian Electric Vehicles,; Electro Automotive,; Wilderness Electric Vehicles,; EV Source,; Metric Mind Corporation,; EV Drive,

Repeated exposure to poor air quality has been linked to lower scores on IQ tests for teenagers and the cognitive equivalent to losing one or more years of education for adults. Credit: Pixabay.
Dear EarthTalk: I heard a pundit on TV say that the way we can “Make America Great Again” is by reducing air pollution as it’s making us dumb. Is there any truth to this? — Jane V., via e-mail

Unfortunately for the 40 percent of Americans (and 90 percent of the inhabitants of the rest of the world) who live in regions with air quality below healthy standards, it is true that air pollution can take a toll on our cognitive abilities.

A collaborative study by American and Chinese researchers in September 2018 found that “long-term exposure to air pollution impedes cognitive performance in verbal and math tests” with verbal performance specifically trailing off further as we age, especially for men. Researchers derived the findings after analyzing language and arithmetic tests taken by 20,000 Chinese kids and adults between 2010 and 2014 correlated against shifting levels of airborne pollution.

“Polluted air can cause everyone to reduce their level of education by one year, which is huge,” reports Xi Chen, a Yale professor and a co-author of the study. He adds that for the elderly, the effect can be more like a few years of lost education. “The damage on the aging brain by air pollution likely imposes substantial health and economic costs, considering that cognitive functioning is critical for the elderly for both running daily errands and making high-stake decisions.”

But it’s not just the elderly who should worry about air pollution making them dumber. A January 2018 study by researchers at the University of Southern California (USC) and University of California, Los Angeles (UCLA) tracked more than 1,300 pre-teens living in and around Los Angeles over a 12-year period and linked repeated exposure to higher levels of airborne particulate matter (from car exhausts and factory smokestacks) with lower “Performance IQ” scores that measure our ability to solve problems we’ve never encountered. For every increase of 2.5 micrograms per cubic meter in particulate matter pollution surrounding the teens’ homes, performance IQ scores dropped by one point. The teens living in the most polluted areas saw about a three point drop on average.

The researchers point out that lower IQ is related to reduced earning power over a person’s lifetime — as well as poorer mental and physical health. The upshot is that reducing air pollution can have a significant effect on the lives of the 130 million Americans disproportionately exposed to bad air on a regular basis.

“I think our study adds to growing evidence that the neurotoxicity of air pollution decreases the nation’s mental capital,” says senior study author and USC professor Jiu-Chiuan Chen. “For anyone who wants to help America succeed in the global competition of the knowledge economy, relaxing the air pollution regulations will very likely do the opposite.”

You can help minimize air pollution. Start by trading the gas guzzler for a hybrid or electric car (or even better, a bike or a pair of good walking shoes and a transit pass). Go solar at home or, if you can’t, ask your utility if they offer a “green power” option. And don’t forget to urge your elected officials to introduce and support legislation aimed at reining in air pollution locally, regionally and beyond.

Contacts: “The impact of exposure to air pollution on cognitive performance,”; “Socioeconomic Disparities and Sexual Dimorphism in Neurotoxic Effects of Ambient Fine Particles on Youth IQ,”; Common Cause’s “Find Your Representative,”

The oceans certainly aren’t as crowded as they used to be now that we have depleted stocks of large marine predators through overfishing, pollution and climate change. Photo by Tom Fisk, Pexels.
Dear EarthTalk: There’s a lot of talk about overfishing and pollution wreaking havoc in marine ecosystems, but has anyone actually studied if there is less wildlife in the oceans these days? — Melissa Cassidy, Raleigh, NC

Environmental advocates do spend a lot of time harping about threats to our oceans, but sadly for all of us the facts bear out the concern. According to the World Wildlife Fund (WWF), population numbers for the majority of marine wildlife species have declined by half since 1970, with many species down as much as 75 percent. Furthermore, a third of all fish stocks are overfished and one in four species of cartilaginous fish (sharks, rays and skates) are living on the brink of extinction. “Driving all these trends are human actions: from overfishing and resource depletion, to coastal development and pollution, to the greenhouse gas emissions causing ocean acidification and warming,” says WWF’s Senior VP for Oceans Brad Ack.

Another recent study by University of British Columbia researchers corroborates WWF’s findings, concluding that the biomass of predatory fish in the world’s oceans has declined by some two-thirds over the last 100 years, and the decline is accelerating, with 54 percent of it occurring in the last 40 years.

No doubt these changes are happening partly as a result of overfishing. According to the United Nation’s Food & Agriculture Organization (FAO), nearly 90 percent of the world’s marine fish stocks are either fully exploited, overexploited or depleted.

Efforts to rein in the industry in the U.S. and elsewhere have led to more sustainable practices, but bad actors still ply deep sea waters with destructive trawlers and other gear which not only collect more fish than is sustainable but also inadvertently kill many other marine wildlife in the process.

There is some hope. Early results of efforts to essentially rope off certain parts of the ocean as “marine protected areas” to let marine wildlife recover are showing promise. A Center for Biological Diversity analysis of 31 marine wildlife populations found that habitat and other protections afforded them under the Endangered Species Act helped them rebound significantly, with three-quarters of endangered marine mammal and sea turtle species increasing population sizes accordingly.

“The Endangered Species Act not only saved whales, sea turtles, sea otters and manatees from extinction, it dramatically increased their population numbers, putting them solidly on the road to full recovery,” says the Center for Biological Diversity’s Shaye Wolf. “Humans often destroy marine ecosystems, but our study shows that with strong laws and careful stewardship, we can also restore them, causing wildlife numbers to surge.”

Another way to stop or slow the overexploitation of marine resources would be to end the approximately $20 billion in yearly subsidies for harmful fisheries that encourage destructive practices. The World Trade Organization has pledged to set new targets by mid-2019 that would require member nations to reroute any such subsidies toward investments in sustainable fisheries, aquaculture and coastal community development to reduce pressure on fish stocks. But even if such a drastic restructuring of the fisheries economy takes place, environmental leaders worry it may be too little too late.

Contacts: “A century of fish biomass decline in the ocean,”; “Marine mammals and sea turtles listed under the U.S. Endangered Species Act are recovering,”; FAO,



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