MADISON, Wis. - Although the hottest days of summer are still many weeks away, a new University of Wisconsin-Madison study is the first to shed light on the exact relationship between air conditioning use and power plant emissions.
Soaring temperatures typically coincide with the days of highest air pollution, and the study is the first to establish that on peak power-demand days, normally idle power plants are fired up to meet the increased demand for electricity to cool buildings.
Tracey Holloway, professor in the Nelson Institute for Environmental Studies at UW-Madison, and her team completed this study, which offers new insight for cleaner air policies.
"Oftentimes these peaking power plants are the dirtiest power plants, because they only are used a few days a year," said Holloway, "and so it doesn't make sense economically to invest in these very expensive controls if you're only going to use them a couple of days a year."
Holloway was surprised that no one had studied this before, and said a combination of energy efficiency and renewable technologies such as solar may offer cost-effective strategies to spend less money on electricity, and have healthier air.
According to Holloway, most of the prior research on climate and air pollution has focused on other emission sources, chemical reactions in the air, and how weather patterns can trap pollution. She said the public-policy implications of the study, which was published in the journal Environmental Science and Technology, suggest that changes should be made.
"One way is to have more energy-efficient air conditioners." said Holloway, "Another is to have more energy-efficient buildings, so that it takes less energy to cool them. A third strategy is to be getting more of our electricity from solar."
The study showed that heavy use of air conditioning contributes to air pollution, and Holloway and her team are working on more projects that can help scientists and policymakers make better decisions.
"Computer models can recreate this complicated link between buildings, power plants and air," said Holloway, "so that we can test out strategies for reducing the air pollution on these dirtiest days."
She said efforts to reduce peak electricity demand on the hot days of summer could be beneficial to public health.
Read an abstract of the report at Response of Power Plant Emissions to Ambient Temperature in the Eastern United States. (Must purchase temporary or full membership to view full article.)
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A new study raised red flags about respiratory health in Pennsylvania, particularly for those living near oil and gas activity.
The study by GeoHealth said nationwide, oil and gas venting and flaring exacerbate asthma in 73,000 children, including nearly 12,000 in Pennsylvania.
Jackson Zeiler, public health analyst for the Environmental Health Project, said energy developers do flaring and venting on a regular basis to remove excess gas. He explained the study looked at the potential health risks associated with the practice.
"There's adverse birth outcomes, there's cancer outcomes," Zeiler pointed out. "Volatile Organic Compounds are a big part of these emissions, which have a whole host of health effects, including respiratory health issues, different neurological effects like headaches and dizziness for people who are working in those facilities, and people who live really close by."
Zeiler noted flaring also contributes to an increased risk of hospitalizations, emergency room visits, worsening asthma and even premature death. But the energy industry said flaring is needed to minimize pressure at well sites, for testing and other reasons.
The study used satellite images and gas-imaging techniques to visualize emissions. Zeiler added companies are required to report their emissions to regulatory authorities and the data is compiled into a National Emissions Inventory through various sensors.
"They looked at the National Emissions Inventory numbers and compared it to the actual imaging that they looked at," Zeiler emphasized. "They found that the imaging saw way more emissions than was accounted for in the National Emissions Inventory. They're able to conclude that companies are underreporting, essentially, what they're flaring and what they're emitting."
He suggested Pennsylvanians could work with lawmakers on stricter reporting guidelines and transparency requirements for oil and gas operators. He also recommended advocating for greater setback distances between well sites and residential areas to minimize exposure.
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Balancing the needs of the many with those who have traditionally reaped benefits from public lands is behind a new rule issued Thursday by the Bureau of Land Management.
A quarter-million acres of public lands, including 13 million in New Mexico, now fall under the Public Lands Rule. The BLM is charged with managing multiple uses but has historically prioritized extraction, such as oil and gas drilling, along with cattle grazing, over conservation and outdoor recreation.
Jesse Duebel, executive director of the New Mexico Wildlife Federation, believes the new rule is more fair-minded.
"I really feel like this new rule doesn't minimize those other things," Duebel asserted. "The other uses are still going to be allowed to continue but now, decisions are going to be made with conservation in the forefront. And of course, conservation by definition, is the 'wise use' of our natural resources."
The rule requires BLM managers to prioritize designating more "Areas of Critical Environmental Concern" in their land use planning. Right now the number is small, but they help protect cultural sites and wildlife habitat.
The rule also allows BLM managers to issue conservation leases to nonprofit and community organizations, including tribal communities, for landscape restoration work on public lands.
Keegan King, executive director of the Native Land Institute, believes in the face of climate change, the long-term health of public lands must be a priority.
"I'm a conservationist but I'm also a hunter, and it's important that we protect these places for a variety of different uses," King explained. "There are ranchers and other people that utilize federal lands and it's important that all of it is maintained for future generations."
According to the Commerce Department's 2022 Bureau of Economic Analysis data, outdoor recreation generated $2.4 billion in added value for New Mexico and created almost 28,000 jobs.
During the BLM's public process on the issue, more than 90% of comments were in favor of elevating conservation for a more balanced approach to public land management.
Support for this reporting was provided by The Pew Charitable Trusts.
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By Max Graham for Grist.
Broadcast version by Alex Gonzalez for Arizona News Connection reporting for the Solutions Journalism Network-Public News Service Collaboration
Below the red-tile roofs of the Catalina Foothills, an affluent area on the north end of Tucson, Arizona, lies a blanket of desert green: spiky cacti, sword-shaped yucca leaves, and the spindly limbs of palo verde and mesquite trees. Head south into the city, and the vegetation thins. Trees are especially scarce on the south side of town, where shops and schools and housing complexes sprawl across a land encrusted in concrete.
On hot summer days, you don’t just see but feel the difference. Tucson’s shadeless neighborhoods, which are predominantly low-income and Latino, soak up the heat. They swelter at summer temperatures that eclipse the city average by 8 degrees Fahrenheit and the Catalina Foothills by 12 degrees. That disparity can be deadly in a city that experienced 40 straight days above 100 degrees last year — heat that’s sure to get worse with climate change.
The good news is there’s a simple way to cool things down: Plant trees. “You’re easily 10 degrees cooler stepping under the shade of a tree,” said Brad Lancaster, an urban forester in Tucson. “It’s dramatically cooler.”
A movement is underway to populate the city’s street corners and vacant lots with groves of trees. Tucson’s city government, which has pledged to plant 1 million trees by 2030, recently got $5 million from the Biden administration to spur the effort — a portion of the $1 billion that the U.S. Forest Service committed last fall to urban and small-scale forestry projects across the United States, aiming to make communities more resilient to climate change and extreme heat.
But in Tucson and many other cities, tree-planting initiatives can tackle a lot more than scorching temperatures. What if Tucson’s million new trees — and the rest of the country’s — didn’t just keep sidewalks cool? What if they helped feed people, too?
That’s what Brandon Merchant hopes will happen on the shadeless south side of Tucson, a city where about one-fifth of the population lives more than a mile from a grocery store. He’s working on a project to plant velvet mesquite trees that thrive in the dry Sonoran Desert and have been used for centuries as a food source. The mesquite trees’ seed pods can be ground into a sweet, protein-rich flour used to make bread, cookies, and pancakes. Merchant, who works at the Community Food Bank of Southern Arizona, sees cultivating mesquite around the city and surrounding areas as an opportunity to ease both heat and hunger. The outcome could be a network of “food forests,” community spaces where volunteers tend fruit trees and other edible plants for neighbors to forage.
“Thinking about the root causes of hunger and the root causes of health issues, there are all these things that tie together: lack of green spaces, lack of biodiversity,” Merchant said. (The food bank received half a million dollars from the Biden administration through the Inflation Reduction Act.)
Merchant’s initiative fits into a national trend of combining forestry — and Forest Service funding — with efforts to feed people. Volunteers, school teachers, and urban farmers in cities across the country are planting fruit and nut trees, berry bushes, and other edible plants in public spaces to create shade, provide access to green space, and supply neighbors with free and healthy food. These food forests, forest gardens, and edible parks have sprouted up at churches, schools, empty lots, and street corners in numerous cities, including Boston, Philadelphia, Atlanta, Seattle, and Miami.
“It’s definitely growing in popularity,” said Cara Rockwell, who researches agroforestry and sustainable food systems at Florida International University. “Food security is one of the huge benefits.”
There are also numerous environmental benefits: Trees improve air quality, suck carbon from the atmosphere, and create habitat for wildlife, said Mikaela Schmitt-Harsh, an urban forestry expert at James Madison University in Virginia. “I think food forests are gaining popularity alongside other urban green space efforts, community gardens, green rooftops,” she added. “All of those efforts, I think, are moving us in a positive direction.”
Researchers say food forests are unlikely to produce enough food to feed everyone in need of it. But Schmitt-Harsh said they could help supplement diets, especially in neighborhoods that are far from grocery stores. “A lot has to go into the planning of where the food forest is, when the fruits are harvestable, and whether the harvestable fruits are equitably distributed.”
She pointed to the Philadelphia Orchard Project as an emblem of success. That nonprofit has partnered with schools, churches, public recreation centers, and urban farms to oversee some 68 community orchards across the city. Their network of orchards and food forests generated more than 11,000 pounds of fresh produce last year, according to Phil Forsyth, co-executive director of the nonprofit.
Some of the sites in Philadelphia have only three or four trees. Others have over 100, said Kim Jordan, the organization’s other executive director. “We’re doing a variety of fruit and nut trees, berry bushes and vines, pollinator plants, ground cover, perennial vegetables — a whole range of things,” Jordan said.
The community food bank in Tucson started its project in 2021, when it bought six shade huts to shelter saplings. Each hut can house dozens of baby trees, which are grown in bags and irrigated until they become sturdy enough to be planted in the ground. Over the past three years, Merchant has partnered with a high school, a community farm, and the Tohono O’odham tribal nation to nurse, plant, and maintain the trees. So far they’ve only put a few dozen saplings in the ground, and Merchant aims to ramp up efforts with a few hundred more plantings this year. His initial goal, which he described as “lofty and ambitious,” is to plant 20,000 trees by 2030.
The food bank is also organizing workshops on growing, pruning, and harvesting, as well as courses on cooking with mesquite flour. And they’ve hosted community events, where people bring seed pods to pound into flour — a process that requires a big hammer mill that isn’t easy to use on your own, Merchant said. Those events feature a mesquite-pancake cook-off, using the fresh flour.
Merchant is drawing on a model of tree-planting that Lancaster, the urban forester, has been pioneering for 30 years in a downtown neighborhood called Dunbar Spring. That area was once as barren as much of southern Tucson, but a group of volunteers led by Lancaster — who started planting velvet mesquite and other native trees in 1996 — has built up an impressive canopy. Over three decades, neighborhood foresters have transformed Dunbar Spring’s bald curbsides into lush forests of mesquite, hackberry, cholla and prickly pear cactus, and more — all plants that have edible parts.
“There are over 400 native food plants in the Sonoran Desert, so we tapped into that,” Lancaster said. “That’s what we focused our planting on.”
The Dunbar Spring food forest is now what Lancaster calls a “living pantry.” He told Grist that up to a quarter of the food he eats — and half of what he feeds his Nigerian dwarf goats — is harvested from plants in the neighborhood’s forest. “Those percentages could be much more if I were putting more time into the harvests.” The more than 1,700 trees and shrubs planted by Lancaster’s group have also stored a ton of water — a precious commodity in the Sonoran Desert — by slurping up an estimated 1 million gallons of rainwater that otherwise would have flowed off the pavement into storm drains.
Another well-established food forest skirts the Old West Church in Boston, where volunteers have spent a decade transforming a city lawn into a grove of apple, pear, and cherry trees hovering over vegetable, pollinator, and herb gardens. Their produce — ranging from tomatoes and eggplants to winter melons — gets donated to Women’s Lunch Place, a local shelter for women without permanent housing, according to Karen Spiller, a professor of sustainable food systems at the University of New Hampshire and a member of Old West Church who helps with the project.
“It’s open for harvest at any time,” Spiller said. “It’s not, ‘Leave a dollar, and pick an apple.’ You can pick your apple, and eat your apple.”
Merchant wants to apply the same ethic in Tucson: mesquite pods for all to pick — and free pancakes after a day staying cool in the shade.
Max Graham wrote this article for Grist.
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