EarthTalk® | October 2020

This view shows off Helsinki’s underground water works. The Finnish capital is a world leader in moving people and their infrastructure below the surface where they can live more energy-efficient lifestyles. Credit: Jordi Cueto-Felgueroso Arocha, FlickrCC.

Dear EarthTalk: If we lived in underground buildings (and cities), would it be better for the environment overall? — Marty M., Hoboken, NJ

It’s certainly true that moving more of our infrastructure, let alone work and live space, underground would relieve some of the pressure that our conventional above-ground development and habitation puts on the environment. While building below the surface presents its own set of challenges, underground spaces are less susceptible to external influences and their overall impact (including carbon emissions) tends to be less than the equivalent amount of space above ground. Indeed, given the environmental problems we’re experiencing, moving more below the surface does indeed have the potential to make things safer, healthier and more sustainable for all of us.

In and of themselves, underground buildings have a built-in advantage in regard to energy usage for heating/cooling, given their typically more constant temperature, humidity, heat insulation, shading and airtightness. Furthermore, underground buildings are much less affected by wind, rain, frost, snow, sun radiation or other external conditions. At the same time, the temperature fluctuation range of underground space is small, especially as compared to the “hot-and-cold load” in above-ground buildings. In short, underground buildings use only a fraction of the energy required by conventional buildings to keep the interior environment comfortable, with most of the energy consumption concentrated instead on less power-intensive lighting and ventilation systems.

Beyond being better for the planet in some ways as compared to above-ground buildings, just having some underground buildings in the mix — even below regular cities — could yield vast benefits. “Underground solutions can solve or help improve multiple of the problems that urban developments face: traffic congestion; environmental problems; lack of (green) space; need for protection against disasters; and lack of infrastructure for food, energy, water and sanitation,” reports Dutch researcher Wout Broere.

“Placement of infrastructure and other facilities underground presents an opportunity for realizing new functions in urban areas without destroying heritages or negatively impacting the surface environment, and at the same time brings opportunities for long-term improvements in the environmental impact of cities and more efficient use of space and resources,” adds Broere.

Many cities around the world — from Helsinki to Moscow to Montreal to Beijing — are developing underground space to alleviate population and environmental pressures. Helsinki, for instance, has adopted a strategic “Underground City Plan” that calls for the construction of some 200 more underground buildings there to accompany the city’s existing subterranean swimming complex, shopping area and hockey rink.

Meanwhile, Russian developers are converting a defunct 550-meter-deep mine shaft in Eastern Siberia into an eco-friendly underground city under a huge glass dome. The ambitious project — replete with vertical farms, forests and recreation areas in addition to climate controlled underground offices and housing — promises to eventually accommodate 100,000 residents.

While many of us shudder at the thought of living a subterranean lifestyle, at least making the option available to those who choose it willingly could be a big win for the environment.

Contacts: “Urban Underground Space: Solving The Problems of Today’s Cities,”!; “Future Cities Live Underground—And That’s Not a Pile of Schist,”; “Study on the Energy-Saving Design of Underground Building,”

Mine tailings like this could sequester lots of atmospheric carbon dioxide. Credit: wild trees, flickrCC.
Dear EarthTalk: Is it true that wastes left over from mining operations could be used to absorb carbon dioxide and help solve the climate crisis? — D. Moore, Richmond, VA

Yes, mining wastes (“tailings”) could indeed be part of the solution to our climate woes. Researchers have shown that alkaline wastes — such as the slurries (semi-liquid mixtures), gravel and other industrial detritus that accumulate during and after mining projects — could be “reacted” with airborne carbon dioxide (CO2), which would not only sequester some of this most common of greenhouse gases but also neutralize the otherwise hazardous alkalinity of the waste itself.

This is good news, because tailings in and of themselves can be a major environmental nuisance and health threat for those living nearby. Since most of this mining waste comes in slurry form means it often ends up in or near water, which causes contamination issues and destroys aquatic life. And because tailings can be transported by wind and/or water, they can easily expand their realm of contamination, spreading into nearby waterways and destroying larger and larger swaths of wildlife habitat.

If we can turn our mine tailings into carbon sinks (absorbers) on a large scale, it’s a win-win. Researchers at Canada’s University of Alberta seem to think so: Their March 2019 study found that the minerals in tailings naturally capture atmospheric CO2 if exposed to them, and the findings are backed up by similar research elsewhere. Harnessing this carbon sequestration (capturing) tool on a global scale would do wonders for our collective carbon footprint.

Meanwhile, an ongoing research project at another Canadian college, the University of British Columbia (UBC), is looking into how to facilitate so-called “direct capture” of atmospheric CO2 into mine tailings with the goal of at least offsetting the greenhouse gases generated as a result of the extraction work. In response to this challenge, UBC is identifying common traits among different types of mine tailings that excel at carbon sequestration in hopes of developing a set of protocols that mining operations anywhere in the world can call upon to reduce their impact and suck up at least the emissions their projects create.

“Incorporation of carbon sequestration activities into mine operations…will generate economic, corporate and societal advantages to mines and affiliated industries, including co-benefits such as tailings stabilization, dust mitigation and toxic metal immobilization,” they conclude. “Carrying this out on a global scale could trap between 310 million to 4 billion tons of carbon dioxide annually,” Robert F. Service reports in Nature. “That could provide the world with a much-needed means of lowering atmospheric carbon dioxide.”

It’s much easier said than done, and governments will need to offer incentives on a massive scale needed to make a dent in atmospheric carbon, Service says, adding: “And engineers will need to figure out how to harness the wastes while preventing the release of heavy metals and radioactivity locked in the material.”

Contacts: “CO2 Sequestration of Mine Tailings,”; “Revaluing mine waste rock for carbon capture and storage,; “Scientists identify new minerals for carbon capture,”

Donald Trump’s actions and words make it known loud and clear that he is no friend to the environment. Credit: Matt Johnson, FlickrCC.
Dear EarthTalk: I’m wondering what President Trump’s perspective is on our environment? He doesn’t seem to be doing much about preserving it, let alone healing it? — Sheila Kaye, via e-mail

From the get-go, Donald Trump has been no friend to the environment, and he has used the highest office in the land to gut environmental protections and conservation initiatives — and open up natural resources to the highest bidders — at every opportunity. That the public hasn’t heard much about this is most likely due to the fact that Donald Trump has given the media so much else to worry about, leaving environmental coverage more of an afterthought in the constantly evolving “breaking news” cycle.

Even before he took office in 2016, Trump had declared global warming a hoax perpetrated by the Chinese to hurt our economy, and vowed to overturn Obama’s huge win to curb U.S. emissions, the Clean Power Plan. Trump also threatened to pull the U.S. out of the landmark (but voluntary) Paris climate accord. When he became President, he made good on those promises, horrific as that may have been to environmentalists who had worked a lifetime to achieve the goals thrown asunder.

But Trump wasn’t done there. He then got busy loosening regulations on everything from toxic air pollution to methane flares to fuel economy standards to wildlife protections. Criminal prosecutions by the U.S. Environmental Protection Agency are at a 30-year low thanks to lack of inspiration from above.

Trump, once and always a developer lest we forget, has also worked to weaken the Endangered Species Act and the Migratory Bird Treaty Act, as well as to downsize two recently designated national monuments (Bear’s Ears and Grand Staircase-Escalante). He also went against the better judgment of his joint chiefs in December 2017 and took climate change off of the list of national security threats, despite that fact that extreme weather events pose a bigger risk to the American people than terrorism.

More recently, under the radar compared to higher-profile scandals, the Trump administration finalized rollbacks to the National Environmental Policy Act that speeds up permitting for federal projects like pipelines, highways and power plants. Long gone are the onerous and time-consuming permitting procedures that used to dog unscrupulous developers and protect key wildlife habitat.

And in July 2020, the Trump administration started moving forward quietly with petroleum exploration in the sacrosanct Arctic National Wildlife Refuge, which environmentalists have been trying to protect from drilling since it was established by Jimmy Carter executive order in 1980.

“All told, the Trump administration’s environmental rollbacks could significantly increase greenhouse gas emissions and lead to thousands of extra deaths from poor air quality each year,” said The New York Times. Simply put, if you care about clean air and water and public health in general (which is what environmentalism is mostly about), Trump is not your man.

Contacts: “What is the Trump administration’s track record on the environment?”; “15 ways the Trump administration has changed environmental policies,”; “The Trump Administration Is Reversing 100 Environmental Rules,”

Some 9,000 satellites already orbit the ionosphere hundreds of miles above Earth’s surface, shedding parts that turn into hurtling “space junk.” Credit: Pixabay.
Dear EarthTalk: Elon Musk plans to put thousands of new satellites into space to blanket Earth with high speed Internet. What are the environmental implications of this? — M. C., Atlanta. GA

Putting satellites up into the ionosphere — the layer of our atmosphere extending from 50-600 miles above the surface where a high concentration of ions and free electrons facilitate the reflection of radio waves — isn’t anything new. The Soviets beat us to the punch when they launched the first satellite, Sputnik, in 1957, but these days there are over 9,000 satellites overhead, the majority from U.S. companies and government agencies. But with Elon Musk’s SpaceX poised to launch tens of thousands of new ones in the next few years, many people wonder whether putting all this technology overhead is such a good idea.

One concern is that all this hardware eventually breaks down and shed parts. Peter Greenstreet of the Institute of Physics reports that this so-called “space junk” orbits at some 7.5 kilometers per second — so fast that even the tiniest pieces create a potential hazard for space stations and other man-made or natural objects making the same rounds. Greenstreet adds that space junk falling to Earth’s surface is less of a concern, given that most of it breaks down into tiny pieces due to the heat and friction encountered upon entry to our atmosphere and thus stands little to no chance of hurting any people or property below.

Another environmental issue with satellite proliferation is so-called “sky pollution.” By reflecting the light of the sun, satellites cause streaks of light across the sky where astronomers would prefer darkness for peering into the heavens and where everyday people will be robbed of their own views of a dark sky.

But despite these drawbacks, there are plenty of good reasons to like satellites if you care about the environment. “From the International Space Station to hundreds of other observational satellites, remote sensing allows for climate and environmental monitoring,” reports Daisy Gill on “These imaging satellites are an incredible source of data for climate change research, enabling us to see the global changes on the planet that are happening more frequently, and with data freely available for anyone to view and use.” Examples include tracking changing oceanic temperatures, currents and sea level.

Satellites are also key to understanding global and local precipitation and flooding patterns, how wildfires start and spread, the distribution of wildlife populations, and other indicators of environmental health. Satellites are also useful as early warning systems for natural disasters and extreme weather events.

If we can figure out ways to clean up space junk, we can use satellites with less guilt. NASA’s e.DeOrbit project is focusing on seeking out and removing satellite debris in the upper reaches of the ionosphere. Meanwhile, the European Space Agency is hard at work on its own “capture mechanisms” to pick up space debris such as nets, harpoons robotic arms and tentacles. Only time will tell if these technologies can help restore the heavens above — or at least the ionosphere — to a more pristine state.

Contacts: “Satellites: What Harm Can They Do?”; “Outside Looking In: Satellites in the Climate Crisis,”; “Space junk and the environment: It’s a very dark picture indeed,”

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