EarthTalk® | May 2020

A few dogs and cats tested positive for Covid-19 in Hong Kong, but experts don’t think these animals can spread it to humans. Muhannad Alatawi, Pexels.

Dear EarthTalk: Can our pets get sick from the coronavirus too, and can they pass it along to people? — J.M., Bridgeport, CT

Given that COVID-19 probably originated in bats means that it’s no surprise that the dreaded virus can pass between animals and humans. But when a 4-year-old Malayan tiger at the Bronx Zoo tested positive for the coronavirus recently (and six of his peers showed similar symptoms), it sent shock waves across the United States, especially in the two-thirds of American households with pets.

Zoo officials report that the tiger started getting sick on March 27 after exposure to a human handler who later tested positive for COVID-19. (The zoo has been closed to the public since March 16.) While the sick tigers are expected to recover fully, the spread of the infection beyond humans is worrisome to not only pet owners but also to those of us concerned about the health of the planet’s wildlife and biodiversity, which is already teetering on the ropes given the one-two punch of habitat loss and climate change.

And if tigers can get it, what about house cats? What about dogs? “There have been reports outside the U.S. of pet dogs or cats becoming infected after close contact with contagious people, including a Hong Kong dog that tested positive for a low level of the pathogen in February and early March,” reports Jennifer Peltz for the Associated Press. “Hong Kong agriculture authorities concluded that pet dogs and cats couldn’t pass the virus to human beings but could test positive if exposed by their owner.”

The Centers for Disease Control and Prevention (CDC) concurs that it’s not our pets we should be worrying about, as the pandemic is spreading as a result of human-to-human transmission thanks to our coughing, sneezing and even just talking. “There is no reason to think that any animals or pets in the United States might be a source of infection with this novel coronavirus.”

But CDC nevertheless recommends staying out of contact with pets if you have contracted the virus (or if you suspect you have it). “Although there have been no reports of pets becoming sick with COVID-19 in the United States, it is still recommended that people sick with COVID-19 limit contact with animals until more information is known about the virus,” warns CDC. “This can help ensure both you and your animals stay healthy.”

If you are sick, CDC recommends trying to get other people to take care of your animals until you’re all better. And if that’s not possible, minimize contact with your pets (especially petting, snuggling, kissing or licking, and sharing food) and wash your hands before and after your interactions.

“If pets go out and have contact with an infected person, they have the chance to get infected,” reports Li Lanjuan, an epidemiologist with China’s National Health Commission, adding that a pet who has been exposed to COVID-19 should be isolated just like any human who has shown symptoms or tested positive. “In addition to people, we should be careful with other mammals, especially pets.”

Contacts: “Can Dogs Get Coronavirus,”; Coronavirus and pets: How COVID-19 affects cats and dogs,; CDC’s “If You Have Animals,”

Although Americans love corn, its ubiquity in our diets and agricultural sector isn’t so good for the planet. Credit: Livier Garcia, Pexels.
Dear EarthTalk: How did corn become such a dominant crop in the U.S. and what’s the effect on the environment of growing so much of it? — J.S., Washington, DC

It’s true that corn is the most dominant agricultural product in the U.S., and perhaps the world. Originally domesticated in Central America, European explorers initially shunned it. But when their crops failed, the conquerors of the New World decided to integrate corn into their agricultural efforts. Fast forward: A couple of hundred years and this tall grass now covers 90 million acres of land in America alone, and accounts for some 10 percent of total crop production globally.

Corn is so ubiquitous in our food system that an estimated 70 percent of the atoms in the body of the average American originally came from it.

One of the reasons corn is so dominant is that, as far as crops go, it excels at converting raw materials into chemical energy. Growing corn generates far more calories per unit of land than nearly any other crop. Another key factor in corn’s rise was the surplus of ammonium nitrate after the end of World War II. Agricultural scientists repurposed this compound, originally stockpiled for explosives, into a cheap form of fertilizer. This allowed corn to be grown in the same fields year after year, without depleting the nitrogen already in the soil. Additionally, corn is incredibly versatile. We can eat it, process it into syrup and use it as a sweetener, fuel our cars with it, and feed it to our animals.

Currently, we use approximately 40 percent of corn grown in the U.S to create ethanol, and 36 percent to feed animals. Unfortunately, both uses wreak havoc on the environment. Ethanol has a low “energy-returned-on-energy-invested” ratio, meaning we must put a large amount of energy into producing it, in some cases even more than ethanol itself generates.

Even just growing corn is far from environmentally friendly. Conventional monoculture farming (the way most corn is grown) degrades soil and often leads to harmful runoff into streams and rivers. Pesticides, herbicides and fertilizers can all wreak havoc on aquatic organisms.

An indirect negative effect of the supremacy of corn has been its help in fueling explosive growth in the livestock industry at home and abroad. These days we use about 80 percent of the world’s farmland for animal production. But as a result of animals’ inefficiency in converting feed to energy, animal agriculture produces only 18 percent of the world’s calories.

So, what can we do? On a political level, agricultural subsidies for corn can be either eliminated or redistributed. Some 60 percent of farm subsidies in the U.S. go toward corn and other grains, while only 1 percent goes toward promoting healthier and more eco-friendly fruits and non-grain vegetables.

Farmers themselves can transition from monoculture practices to those that incorporate a wider variety of species into the mix. As consumers, one of the best measures we can take is to buy organic corn. Although organic agriculture is not quite as eco-friendly as some make it out to be, it’s miles ahead of conventional farming.

Contacts: “The Environmental Risks Of Corn Production,”; “How a national food policy could save millions of American lives,”

Data centers like this one use up lots of power; that’s why environmentalists are urging the biggest players in the industry to go with renewable energy sources where possible. Credit: CommScope.
Dear EarthTalk: Internet data centers are fast becoming the largest power hogs in the world. What’s being done in this industry to make Internet usage more energy-efficient? — M. T., Reno, NV

Though our online activity uses no paper, it still consumes quite a lot of energy. Data centers account for much of this energy use. These warehouse-sized buildings contain arrays or “farms” of servers, which are essentially souped-up computers that have many uses, including storing data and supporting all the activity on the internet. They are the hardware behind the proverbial “cloud.”

Like the personal computers we all use, servers require electricity to function. Since internet users can call upon them to provide information at any time, they must remain on 24/7. Furthermore, as with any form of electrical activity, the functioning of this large number of servers packed together in a small area can result in overheating, making the need for cooling an additional energy cost for data center managers.

According to data center provider vXchnge, U.S. data centers alone use over 90 billion kilowatt-hours of electricity annually — about what 34 coal-powered plants generating 500 megawatts each produce. ComputerWorld magazine reports that the energy consumption of data centers worldwide will likely account for 3.2 percent of global carbon emissions by 2025 — about as much as the airline industry — and as much as 14 percent by 2040.

In light of all this, finding ways to cut energy use has become a big priority in the industry. One of the simplest strategies is to locate data centers in cool climates, and use outdoor air to counter excessive heating. Alternate options include cooling inlet air by running it underground, or using a nearby water source for liquid cooling. Another issue is separating hot air produced by servers from the colder air used to cool them — no easy task if the servers are all housed together. But there are plenty of cheap solutions. Google, for example, uses low-cost dividers from meat lockers for this purpose.

Another way data centers can reduce cooling costs is to design servers that can operate at high temperatures without overheating. Recent research shows that servers can operate at much higher temperatures than initially believed without compromising safety or efficiency. But not all data centers are comfortable letting their servers run hot. Other ways to make server farms more efficient include optimizing grid-to-server electrical conversions and reducing the energy required by “sleeping” servers.

The good news is the industry is making strides in the right direction. Apple, Facebook and Google all power 100 percent of their data center and other operations with renewables, albeit through the purchase of “renewable energy credits” akin to carbon offsets that air travelers can buy to keep their carbon footprints in check. Microsoft is moving toward 70 percent renewable energy by 2023, while laggard Amazon still only gets about half its data center power from renewables. And Switch, one of the largest U.S.-based data center companies, transitioned all of its facilities to run on nothing but renewables in 2016, including the nation’s largest data center in Reno, Nevada.

Contacts: “How to Improve Data Center Power Consumption & Energy Efficiency,”; “Why data centres are the new frontier in the fight against climate change,” ; “Amazon is breaking its renewable energy commitments, Greenpeace claims,” .

The Permafrost which covers ~25 percent of exposed land in the Northern Hemisphere is melting fast — and Arctic communities are scrambling to react. Credit: Bernard Polet, FlickrCC.
Dear EarthTalk: How is melting permafrost affecting communities in the Arctic and beyond? — William James, Barre, VT

In the northern regions of the world, a great change is taking place. Permafrost, which covers around 25 percent of exposed land in the Northern Hemisphere, is melting. Defined as a layer of soil that remains completely frozen for over two years at a time, permafrost is often located a meter or so below the surface. Its thawing creates issues for both the environment and human infrastructure.

These issues result largely because that water expands and hardens when it freezes, and does the opposite when it melts. When the water in soil freezes, it acts somewhat like cement, maintaining structure and stability. Initial efforts to develop cities and towns in these northern regions over the last century led to countless buildings and roads being built on top of ground held together by permafrost. Now, thawing is putting this infrastructure in jeopardy.

In the remote Arctic settlement of Tuktoyaktuk in Canada’s Northwest Territories, thawing permafrost is a huge problem for the 1,000 or residents who live there. Melting permafrost there means that houses that have stood for decades are now collapsing. And it’s not just buildings. The entire coastline, once held in place by the permafrost, is rapidly disappearing into the ocean. In some Arctic areas, coastal land is eroding at a rate of up to two meters per year. The thawing permafrost also compromises both land and sea transportation. All across the northern parts of the world, roads are beginning to buckle as the ground beneath them shifts. In some instances, roads are rendered impassable. On the ocean, erosion driven by thawing permafrost is filling in shipping channels, some of which are already too shallow for boat traffic.

Unfortunately, all of these issues pale compared to the effects that the thawing permafrost could have on the climate. While frozen, the organic matter stored in permafrost is relatively inert. Once it thaws, however, bacteria and other microorganisms immediately begin to digest it. Two of the primary byproducts of this digestion are methane and carbon dioxide, both potent greenhouse gases. Around three times more organic (and digestible) material is stored in the permafrost than there is in all the forests left on the planet. All in all, the permafrost stores more carbon than humans have released into the atmosphere since the beginning of the Industrial Revolution.

The digestion of this organic matter could create a dangerous feedback loop, whereby warming triggers increased bacterial activity — and greenhouse gas emissions — in turn triggering more warming. Researchers worry that by 2100, 70 percent of the world’s permafrost may have thawed. If it does, it will likely release about 10 percent of total permafrost-stored carbon (150 billion tons) into the atmosphere.

The solution is in our hands. If we can start ratcheting down our emissions significantly, we can reduce the total thawing to just 30 percent of the permafrost by the end of the century. Traveling and consuming less — and spreading the word to your family, friends, neighbors and coworkers — are the two most important things you can do to move the needle in the right direction for everybody, human or otherwise.

Contacts: E Magazine’s “Is Our Tundra In Trouble,”; NRDC’s “Permafrost: Everything You Need To Know,”; Columbia Earth Institute’s “Why Thawing Permafrost Matters,”

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