Zimbabwean ecologist and rancher Allan Savory points to the carbon sequestration benefits of grazing cattle on grasslands as an environmental justification for continuing to raise and sell livestock. Credit: James Duncan Davidson, FlickrCC.

Dear EarthTalk: Even though I know a vegetarian diet is better for the environment, I love cheeseburgers and a good steak every now and then. If I stick to grass-fed beef, can I live with myself environmentally? — Jeanine Smith, Hixson, TN

Yes and no, depending on how much imperfection you’re willing to tolerate. Calorie-for-calorie, an acre of land can feed more mouths growing vegetables and grains for direct human consumption that it can growing feedstock for farm animals that end up on our plates.

But for years beef industry defenders have pointed to the “carbon sequestration” benefits of grazing cattle on grasslands as an environmental justification for continuing to raise and sell livestock. According to the theory, grasslands around the world hold the potential to store (sequester) enough atmospheric carbon dioxide (CO2) to reverse global warming if they are used to graze livestock “bunched and moving, as a proxy for former herds and predators” — in the words of “holistic management” guru Allan Savory — to mimic what were once naturally occurring processes in nature. Since grasses, like all plants, consume (and then store) atmospheric CO2 — a key component of photosynthesis — to grow to full maturity, using grassland to graze cattle helps sequester untold amounts of greenhouse gases, as new grasses shoot up after the livestock has passed through.

But a recent analysis by Tara Garnett and researchers at Oxford’s Food Climate Research Network found that the carbon sequestration benefits of even “holistic management” based livestock grazing are limited at best. They concluded that, even under “very generous assumptions,” livestock grazing could only offset 20-60 percent of the average annual greenhouse gas emissions of grass-fed beef — and only between 0.6 and 1.6 percent of total annual greenhouse gas emissions. This last figure is the real clincher, given that livestock account for some 18 percent of global greenhouse gas emissions, all told.

Livestock agriculture — grass-fed or otherwise — is already a big contributor to global warming, purely as a result of methane gas “emissions” from cattle. (Methane is an even more potent greenhouse gas than CO2.) All of this cattle belching and flatulence, combined with millions of tons of off-gassing manure generated on farms around the world, combine to make animal agriculture responsible for 35-40 percent of annual “anthropogenic” (human-caused) methane emissions worldwide.

And it turns out that grass-fed cattle actually generate significantly more methane than their feedlot-held counterparts due to how difficult it is to digest wild grasses versus the corn- and soy-based feed offered back in the barn. Meanwhile, agricultural researchers are working on ways to reduce methane emissions even further for feedlot cattle by adding chemical and biological agents into feed that cancel out the “methanogenic” microorganisms that lead to intestinal production of so much methane in the first place.

That said, environmentalists warn that we shouldn’t rely on such “interventions” when we can solve our problems the old-fashioned way: Reducing your overall intake of meat, if not going vegetarian or vegan altogether, is the only way to guarantee that our meat addiction doesn’t kill us in the end.

Contacts: Food Climate Research Network, www.fcrn.org.uk; “Restoring The Climate Through Capture And Storage Of Soil Carbon Through Holistic Planned Grazing,” The Savory Institute, www.savory.global/wp-content/uploads/2017/02/restoring-the-climate.pdf; “Carbon, Methane Emissions and the Dairy Cow,” Penn State Extension, https://extension.psu.edu/carbon-methane-emissions-and-the-dairy-cow.


Our pets may be cute, but they are contributing millions of tons of greenhouse gas emissions annually into the atmosphere which only serves to exacerbate our global warming woes. Credit: Kevin Dooley, FlickrCC.
Dear EarthTalk: Is it really true that our dogs and cats are major contributors to climate change, and if so what can we do about it? — Carmen Santiago, Newark, NJ

Unfortunately, our beloved dogs and cats do produce shockingly high amounts of greenhouse gases that contribute to climate change. According to a recent study by UCLA Professor Gregory Okin, American dogs and cats generate the equivalent of almost 64 million tons of greenhouse gas emissions (primarily in the form of methane and nitrous oxide) per year, an amount equivalent to driving 13.6 million cars for a year.

Besides all of this off-gassing, our cats and dogs are also big meat eaters, which doesn’t help their carbon footprints. Cats and dogs consume about 20 percent as many calories as people do in the U.S. — or about as much as 62 million Americans. And because our pets are mainly meat eaters, they account for some 30 percent of the animal-derived calories compared to what you and I consume.

So what’s the big deal? In short, raising livestock requires significantly more land, water and energy than growing plants. A recent report by the Worldwatch Institute goes so far as to say that some 51 percent or more of greenhouse gas emissions are caused by animal agriculture. Since we like to feed our pets meat-based dog and cat food, Fido and Buttons are guilty by the ripple effect. Meat used in dog and cat food generally comes from the scraps of meat that humans eat.

Another reason why dogs and cats are contributors to climate change besides their diets is by virtue of all that…feces. The U.S. Environmental Protection Agency (EPA) even categorizes dog waste as a non-point source pollutant, which places it alongside harmful chemicals such as herbicides and insecticides.

Meanwhile, cat litter can contain toxins that are harmful to the environment and even human health. Clay, a common ingredient in most cat litters, must be “strip mined,” a process that has already destroyed millions of acres of land across Appalachia and beyond. Many kitty litter companies also use silica gel in their formulations to absorb and deodorize smells — despite the fact that the International Agency for Research on Cancer classified it as a known human carcinogen back in 1997. And those cats that just go outside aren’t doing the environment any favors either, as cat feces can be toxic to ground soil.

There is no clear or easy solution to this ongoing problem. But little changes can help. For example, try switching your pet over to a plant-based diet — perhaps after a discussion about the options with your veterinarian. After all, you want to make sure your pet is getting enough protein in its vegetarian diet to live an active, happy and healthy life.

If you’re not willing to turn your pet to outright vegetarianism, you can work in more and more vegetarian food over time. Also, you can still be part of the solution by at least buying organic pet food and compostable cat litter. These few changes might not automatically solve the worldwide problem, but at least you — and Fido and Buttons — will be taking a few steps, er, paw prints, in the right direction.

Contacts: EPA’s Pet Car Fact Sheet, https://goo.gl/JX2UXt; “Environmental impacts of food consumption by dogs and cats,” https://goo.gl/4Zykhr.


There’s never been a better time to go solar, given how much prices for panels have come down while efficiency in converting sunlight to electricity—even in less-than-sunny locales—has risen dramatically. Credit: Chris Kantos, FlickrCC.
Dear EarthTalk: I’m finally ready to join the 21st century and commit to putting solar panels on my roof. Where do I start? — Henry Hughes, Washington, DC

Good things may, in fact, come to those who wait. There’s never been a better time to go solar, given how much prices for panels have come down, while efficiency in converting sunlight to electricity — even in less-than-sunny locales — has risen dramatically. Of course, you can’t just snap your fingers and get panels on your roof. First you have to navigate a confusing maze of regulations, incentives and installers before anyone even looks your roof over for feasibility.

The first place to start is to find out which federal, state and local incentives may be available in your neck of the woods for going solar. Check out the free online Database of State Incentives for Renewables and Efficiency (DSIRE), a comprehensive information resource that’s updated by North Carolina State researchers working off a U.S. Department of Energy grant.

How does solar work? Is my home suitable for solar panels? Will I save money by going solar? Can I get financing? How will solar impact my home’s resale value? If you’re looking for answers to questions like these, the Department of Energy’s Homeowner’s Guide to Going Solar has you covered.

Trying to figure out if it’s better to lease or buy your solar panels? You’re not alone, and it’s hard to do the math given the apples/oranges scenario. Luckily, the Solar Energy Industries Association (SEIA) spells it all out clearly — not just whether to lease or buy but also how to get multiple bids to save money and which questions to ask before entering into an agreement with an installer — in its recently updated Residential Consumer Guide to Solar Power.

Given how new the solar industry is, it’s often hard to know whether a given installer is going to be reputable, let alone be able to survive the next economic downturn. Angie’s List offers several pearls of wisdom — how the cheapest bid may not be the best deal, why extended warranties may not be worthwhile, how to save yourself from death by paperwork — in a recent article on the topic.

When you’re finally ready to find an installer, check out the “Find a Certified Professional” page on the website of the North American Board of Certified Energy Practitioners (NABCEP), a trade group that offers the “gold standard” in professional certification and company accreditation programs to renewable energy professionals.

If you’re a quote-comparing type, you’ll also want to check out Energy Sage, a website that lets you compare quotes from solar installers in your area. This free service is maintained by the Department of Energy’s SunShot Initiative, a national effort to support solar energy adoption by making solar energy affordable for all Americans.

While you can’t go wrong with a highly touted local installer, there are also benefits to choosing one of a handful of companies leasing or selling solar panels on a larger scale across the country and beyond. SolarCity/Tesla, Vivint, Sunrun, Sunnova and SunPower are a few of the leaders, each offering solar installs in California and several other states, including New Jersey, Massachusetts, Arizona and Hawaii.

Contacts: DSIRE, www.dsireusa.org; NABCEP, www.nabcep.org/certified-installer-locator; Energy Sage, www.energysage.com; Angie’s List, www.angieslist.com/articles/how-hire-solar-panel-installer.htm; SEIA, www.seia.org; DoE, energy.gov/eere/sunshot/homeowner-s-guide-going-solar.


Peter Wadhams of the University of Cambridge’s Polar Ocean Physics Group is one of an increasing number of climate experts who thinks we may need to employ geoengineering techniques if we are to stave off the worst effects of global climate change. Credit: Takver, FlickrCC.
Dear EarthTalk: Are there any realistic geoengineering solutions to our climate woes and why haven’t we started employing them yet? — Angel Monroe, Miami, FL

Geoengineering our way out of the climate crisis is something so drastic that no one really wants to admit it might be our only hope. But while cutting down on our air miles and switching over to a Prius can’t hurt, at least a few green leaders are starting to get on board with the concept of geoengineering as one weapon in an arsenal including improved energy efficiency and transitioning to renewable energy sources.

In his 2016 book A Farewell to Ice, Peter Wadhams of the University of Cambridge’s Polar Ocean Physics Group lays out several different scenarios where humanity could utilize different geoengineering techniques to stave off cataclysmic climate change.

First and foremost on Wadham’s list is direct air capture of CO2 — “something the whole world should be putting its research money into” — where we literally vacuum the offending pollution out of the air. Wadhams thinks this is the most logical approach, and one we can get started on right away if there is enough political will to get it funded.

Another potential geo-engineering save involves unleashing a fleet of salt-spraying ships around the world’s coastlines that would pipe ocean water hundreds of feet skyward, spraying clouds with salt crystals to reflect more sunlight upwards and away from the Earth’s surface. University of Edinburgh engineers have already designed a prototype fleet of ships to serve as a model for larger efforts.

So-called sparkle blasting balloons represent another tack in the armed battle against global warming. Researchers are proposing sending hot air balloons (or airplanes or even artillery shells) into the sky to shoot or spray sulfuric acid or sulfur dioxide into the upper atmosphere where it would combine with pre-existing water vapor to form sparkly aerosols. When dispersed by the wind, these aerosols would surround the globe with haze that could reflect an estimated one percent of solar radiation back into space.

Yet another geoengineering climate hack involves constructing a supersized space mirror (or reflective mesh) that could be launched into the Earth’s orbit to protect the planet by reflecting some of the sun’s rays skyward.

And no discussion of climate geoengineering would be complete without mentioning carbon sinks. For instance, we could “fertilize” barren sections of open ocean with iron to stimulate the production of CO2-sucking algal blooms and other photosynthesizing marine life. “When the algae die, they sink to the bottom of the sea, taking carbon with them,” writes Jennifer Santisi in E – The Environmental Magazine.

Of course, each of these techniques has potential side effects and unintended consequences, not to mention extreme costs. Researchers are proceeding cautiously to try to work some of the kinks out before we actually need to implement them on a widespread scale.

Meanwhile, environmentalists worry that geoengineering remains a distraction and that we have to “keep our eye on the ball” regarding trimming our carbon footprints. That said, it’s nice to know that scientists have a few Hail Mary plays up their sleeves if we ever do end up needing them.

Contacts: Farewell to Ice, https://goo.gl/ayxy7o; Iron Hypothesis, www.emagazine.com/iron-fertilization/

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EarthTalk® is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E – The Environmental Magazine ( www.emagazine.com). Send questions to: earthtalk@emagazine.com. Subscribe: www.emagazine.com/subscribe. Free Trial Issue: www.emagazine.com/trial.

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