EarthTalk®

Dear EarthTalk: Is the plan to sprinkle dust in the stratosphere to reflect some of the sun’s rays away from Earth to prevent global warming science or science fiction? -- M. Jackson, Tampa, FL

Some certainly do consider it science fiction, or worry that it could end up doing more environmental harm than good. Yet others—including Bill Gates and a team of leading Harvard scientists—think it could be the solution to our planetary climate woes.

What we’re talking about is a form of geo-engineering that entails sending up some 800 jumbo planes to sprinkle their payload of millions of tons of chalk dust in the stratosphere 12 miles above the Earth’s surface in an effort to reflect some of the sun’s heat back into space to turn the tide on climate change.

The so-called Stratospheric Controlled Perturbation Experiment (SCoPEx) was developed by chemist James Anderson and physicist David Keith, both of Harvard—with funding from Bill Gates—“to advance understanding of stratospheric aerosols that could be relevant to solar geoengineering.” The researchers want to test their hypothesis with a $3 million experiment 12 miles above the Southwestern United States where they would steer remote controlled balloons to disperse small plumes of calcium carbonate.

The balloons would then turn around and observe any differences in the amount of solar radiation getting through. This system is adapted from a similar design the researchers used in groundbreaking research analyzing the composition of the stratospheric ozone layer.

But the test plan, initially slated for early 2019, has received some pushback from scientists and environmentalists, who worry that such tinkering could cause negative chain reactions and unforeseen irreversible consequences.

“Some researchers have suggested that solar geoengineering could alter precipitation patterns and even lead to more droughts in some regions,” reports Jeff Tollefson on Nature.com. “Others warn that one of the possible benefits of solar geoengineering—maintaining crop yields by protecting them from heat stress—might not come to pass.” He cites a 2018 study showing that yields of wheat, corn, rice and soy fell after two major volcanic eruptions darkened skies around the planet and took a toll on crop yields.

Given such concerns, Anderson and Keith are erring on the side of caution, setting up an external advisory committee to review the project and point out potential safety concerns to head off negative side effects. “Getting it done right is far more important than getting it done quickly,” says Peter Frumhoff of the Union of Concerned Scientists.

If they can pull off a successful test and then scale the idea, the good news is it might even be something the governments of the world—and/or some rich benefactors—can afford. An October 2018 report from the Intergovernmental Panel on Climate Change found that dispersing enough sulfur in the stratosphere with a similar (cooling) intent could be done for less than $10 billion/year—and possibly for as little as $1 billion/year. While that might seem like a lot, it’s a bargain if it can save our environment, our civilization, and our very existence on the planet.

CONTACTS: SCoPEx, projects.iq.harvard.edu/keutschgroup/scopex; “First sun-dimming experiment will test a way to cool Earth,” https://www.nature.com/articles/d41586-018-07533-4#ref-CR3.

Dear EarthTalk: I’ve heard that school buses cause a lot of pollution, especially for the kids riding inside. Is anyone making greener school buses yet? -- Jake McConnell, Philadelphia, PA

Now that school is back in session, those big yellow diesel-fueled school buses are all over the roads again. While they’re relatively safe—and definitely old school—they’re also big polluters, chugging along at 4-6 miles to the gallon while creating a cloud of harmful airborne pollutants.

According to the non-profit Clean Air Trust (CAT), some 25 million American kids travelling on half a million school buses every day are exposed to five to 15 times more air toxins than the rest of us. “Those buses travel more than four billion miles each year and these kids spend three billion hours on [them],” reports the group. “About 90 percent of these buses run on diesel fuel, annually emitting 3,000 tons of cancer-causing soot and 95,000 tons of smog-causing compounds.”

If you don’t think all that pollution is having a negative effect, think again. A March 2019 study from researchers at Georgia State University found that students did significantly better on standardized English tests and marginally better in math when they spent their commutes riding in school buses retrofitted to reduce emissions by 95 percent as compared to students riding in non-upgraded buses. The researchers conclude that “engine retrofits can have meaningful and cost-effective impacts on health and cognitive functioning.”

Luckily the retrofits are easy to come by and relatively inexpensive, especially when you factor in the costs of health care to treat sick kids, not to mention the price tag for raising kids’ test scores in other ways. Retrofitting 10 percent of the average school district’s bus fleet in Georgia, for instance, would cost less than $100,000, a drop in the bucket of the state’s $10.6 billion K-12 public schools budget.

And beginning in October 2018, the U.S. Environmental Protection Agency (EPA) set aside $9 million to help pay for upgrading older diesel school buses nationwide. School districts and other public agencies charged with transporting school kids can apply for rebates of up to $20,000 per bus to help cover the retrofits on up to 10 individual buses.

Retrofitting is a great start, but even better would be replacing old buses with new, more efficient all-electric models. But few school districts can justify the $300,000 price tag to replace perfectly functional older diesel buses. That didn’t stop the school district in White Plains, New York, though, which purchased five electric buses last year with financial help from the local utility, Consolidated Edison, and a grant from the state.

These outside contributions helped bring the final cost to the school district down to something along the lines of buying new diesel buses. While ConEd gets the benefit of good public relations and good karma, it also gets to use the buses during the summer as excess electricity storage that can be moved around to where it’s needed most (when the air conditioners are blazing). White Plains is hoping other school districts across the country will follow a similar model to clean up their acts.

CONTACTS: Clean Air Trust, cleanairtrust.org; “School bus emissions, student health and academic performance,” sciencedirect.com/science/article/abs/pii/S0272775719301530#!.

Dear EarthTalk: What are the ramifications of these horrendous fires taking place now in the Amazon Rainforest? What can be done to stop the madness? -- Jane W., Waterbury, CT

Fire isn’t new to the Amazon rainforest of South America, but it has certainly reached epic proportions this year. Some 26,000 different fires are now burning continuously throughout the region. Many of these blazes have been set intentionally by ranchers and farmers trying to (illegally) clear and use more and more land for raising cattle and crops.

These so-called “slash-and-burn” tactics reduce wildlife habitat and biodiversity accordingly while releasing massive amounts of carbon dioxide into the atmosphere, only adding to our climate woes. Meanwhile, indigenous groups who depend on the rainforest for subsistence teeter on the brink of survival in the face of shrinking habitat.

Unfortunately, putting out most of these existing fires isn’t feasible; they’ll have to run their course. Environmentalists agree what we can do is prevent more land from burning in the future as one way of protecting the intact tropical rainforest that remains throughout the Amazon.

But how? For starters, by working on the ground in partnership with local indigenous communities on making their forests sustainable through tourism and responsible use without resorting to clearing/burning the land. One of the leaders in this new breed of rainforest activism is Niyanta Spelman and her group Rainforest Partnership, which currently has four different projects underway with the Achuar, Chipaota and Colibri indigenous communities of Peru and the Sani Isla community of Ecuador.

“When managed sustainably, ecotourism in the rainforest can help protect biodiverse ecosystems, provide reliable income to forest communities, and educate travelers about the importance of conservation,” says Spelman, who launched Rainforest Partnership in 2007 and has built it into one of the most impactful groups working in the region.

Meanwhile, other groups are focusing on converting farmers and ranchers over to more sustainable crops and practices. “Although the fires were set to clear space to occupy the land, a lot of the area is not used productively or is used mainly for land speculation,” reports the Nature Conservancy, another leading non-profit working on the ground in the Amazon and elsewhere to protect tropical rainforests. “There is already a considerable amount of land in the Amazon to increase production of food without deforestation.” The Nature Conservancy sees smarter use of land across the Amazon that’s already been converted to agriculture as one key way to stem the tide of rainforest loss and ultimately global warming.

As for what people can do, being more thoughtful about the foods we eat is a big step in the right direction. That hamburger meat you are eating might well come from cattle on a burned-over pasture in a former slice of the Amazon rainforest. That’ll give you pause when you are thinking about what to put in the shopping cart at the grocery store and what to order off of a restaurant menu. The shocking truth is that 80 percent of tropical rainforest destruction across the Amazon is fueled by beef production. So eating a more plant-based diet is a great way to help protect what’s left of the world’s tropical rainforests.

CONTACTS: Rainforest Partnership, rainforestpartnership.org; The Nature Conservancy, nature.org.

Dear EarthTalk: What’s the latest update on the Paris Climate Agreement? Have the participating nations been meeting their interim goals? Is the U.S. completely out of it? -- T. Jenks, Newark, DE

Global warming has already started to change the face of the planet, and international negotiators are doing all they can to marshal the world’s resources to hold steady against accelerating the output of carbon emissions while we transition to renewable forms of energy. The Paris Agreement, signed by 195 countries in December 2015, calls on the signatories to voluntarily commit to reducing their greenhouse gas emissions in line with the overall global goal of limiting temperature increases to 1.5 degrees Celsius by the middle of the century.

Negotiators from the Obama administration were instrumental in creating the terms and language of the Paris Agreement, emphasizing inclusiveness by allowing participating countries to set their own emissions reductions goals instead of being forced to meet mandatory reductions handed down from the United Nations (UN). President Obama wouldn’t have had the votes in Congress to get legislative approval for the country to join the Paris Agreement, so he signed it into law via Executive Order, committing the U.S. to its own voluntarily derived emissions reductions through early November 2020.

But when Donald Trump took the White House, he made good on his campaign threat to pull the U.S. out of the Paris Agreement. While we are technically still party to the agreement until November 2020, Trump has effectively pulled the plug on planned U.S. efforts to cut emissions in line with promises made at Paris back in December 2015. Trump’s rejection of the Clean Power Plan and other Obama-era policies means there is no way the U.S. can make good on those promises.

Regardless, all the other nations of the world continue to join forces in an unprecedented show of solidarity in trying to augment their Paris commitments with even stronger cutbacks on fossil fuels and more moves to cheaper and cheaper renewables. And while the U.S. remains the only outlier on the Paris Agreement, critics point out that many European nations are way behind on their projected carbon reduction goals, especially given that the first cliff of 2020 is right around the corner. (Ironically, the U.S. has been rapidly reducing its carbon footprint given the glut of cleaner-burning natural gas due to the fracking boom.) Check out how different countries around the world stack up on carbon emissions reductions via the free Climate Action Tracker website.

Beyond the fact that many signatory nations have slacked on their climate goals, environmental leaders worry that the pledges made in 2015 are now already too low to prevent cataclysmic climate change. This is partly why the UN has called the leaders of the world to New York City during the third week of September to step up their commitments initially made almost four years earlier.

Given the potentially existential imperatives, UN Secretary General António Guterres is telling those attending the late September summit to leave their “beautiful speeches” at home and come instead with “concrete plans [and] clear steps to enhance nationally-determined contributions by 2020 and strategies for carbon neutrality by 2050.”

CONTACTS: Paris Agreement, unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement; Climate Action Tracker, climateactiontracker.org; UN Climate Action Summit 2019, www.un.org/en/climatechange/.

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