SCIENCE

Shelter From the Smoke

For much of this summer, the skies across California have been tinted with a smoky haze from dozens of wildfires that have torn through the state. Many people seek refuge indoors from the sooty, polluted air that can cause lung and heart disease and other health problems. With a warming climate increasing the frequency and intensity of wildfires in the West, more people are purchasing in-home air quality monitors to ensure the air where they shelter from smoke is really safer than what they’re breathing outside.

A study by researchers at the University of California, Berkeley looked at data in San Francisco and Los Angeles from 1,400 indoor and outdoor air quality sensors in the crowdsourced PurpleAir network. They found that during air pollution events, such as a wildfire, people were able to keep indoor air significantly cleaner than what was outside, with reduced concentrations of PM2.5—particulate matter less than 2.5 microns in diameter—which causes the most severe health conditions. 

On non-wildfire days, concentrations of PM2.5 inside homes was about 40 percent of the levels outside, a metric known as the infiltration ratio, which shows how much of the polluted air is making its way into the house. On wildfire days when PM2.5 reached hazardous concentrations outside, levels inside homes were only about 20 percent of those heightened amounts. 

“Across this whole network of observations, people were taking action by closing up their houses and potentially by adding filtration that decreased the infiltration ratio by 50 percent,” said Allen Goldstein, the study’s senior author and a professor of environmental engineering and environmental science, policy and management at UC-Berkeley, “which really indicates that they were protecting themselves significantly from wildfire smoke.”

But, the study relied on data from sensors that must be purchased by residents for about $200 each, Goldstein said, potentially biasing the sample to households that are more likely to take precautions like closing windows and doors and running an air filter to keep the hazardous air out.

The researchers also looked at data from the real estate website Zillow, where they learned that these homes tended to be more valuable, showing the analysis potentially excluded low-income neighborhoods, Goldstein said.

“For the future, it would be really nice to see a more equitable, broader distribution of sensors across the population of homes that are affected by air pollution and by smoke so that we can get a better sense of what these infiltration ratios and levels in homes might look like for the complete population,” he said. 

SCIENCE

Fish That Went to Supreme Court No Longer Threatened

A tiny fish that was once at the center of the first Supreme Court case related to the Endangered Species Act is no longer threatened, the U.S. Fish and Wildlife Service has announced. 

The snail darter, a three-inch-long fish, was listed as endangered under the Endangered Species Act in 1975, shortly after it was discovered near the site where the Tennessee Valley Authority’s Tellico Dam was slated to be built on the Little Tennessee River. 

The discovery of the little fish put the dam’s construction in jeopardy, because this was the only known location where the snail darter lived and the dam could threaten the fish while it’s in its larval stage, when it depends on flowing water to keep from sinking and suffocating.

The TVA took the issue to court, where the case became the first Endangered Species Act dispute to rise all the way to the Supreme Court since President Richard Nixon signed the law in 1973. The court favored the snail darter in 1978. 

But in 1979, Congress passed an amendment to the Endangered Species Act that allowed exemptions for projects that are deemed important and beneficial. The Tellico Dam was completed under this exemption later that year. 

But in the following years, the U.S. Fish and Wildlife Service partnered with the TVA to help the snail darter. Populations were established in other rivers in Tennessee and new populations were discovered. TVA began its Reservoir Release Improvement Program, intended to improve water quality around its dams, especially by increasing water oxygen levels.

“This helped not only the snail darter, but it was important for a lot of the mussels that were still hanging on below the dams and brought quick rebounds in the overall fish populations,” said Warren Stiles, the listing and recovery biologist in the Tennessee Ecological Services Field Office of the U.S. Fish and Wildlife Service. 

The snail darter’s status was downgraded from endangered to threatened in 1984, and by 2015, the fish was found in hundreds of miles of riverways in Tennessee. Now, the U.S. Fish and Wildlife Service is proposing that the species be removed from the list of threatened species. The snail darter is the first fish east of the Mississippi River to recover and be delisted under the Endangered Species Act.

“It takes some time, but the Endangered Species Act does work,” said Stiles. “Without the act, we wouldn’t have the snail darter because there wouldn’t have been as much effort made to establish and find new populations.”

CULTURE

Film Shows Ancient Tribal Land Management Confronting Today’s Challenges

From prescribed burns and selective logging, to food forests and dryland agriculture, Native American communities have maintained land management practices for thousands of years that are beginning to be widely recognized for their benefits to the climate. 

A new film highlights the land management practices of five Indigenous communities that have proven to be resilient in the face of climate change and colonization. 

Costa Boutsikaris, co-director of the film, hesitates to call these strategies solutions, because ”that almost sounds like it’s a newly invented idea,” he said. These traditions are ancient and have been passed down for generations.

The film, called “Inhabitants,” includes the story of a farmer in the Hopi tribe of northern Arizona who grows corn without irrigation, and relies on just a fraction of the rainfall that industrial farmers told him he would need to be successful. Another is about the Karuk tribe, which was recently allowed to resume prescribed burns on their land in northern California after a century and a half when the traditional practice was outlawed. The tribe’s burning techniques have proven to be vital protections against wildfires, which the warming and drying climate is making larger and more destructive. These stories stand alongside three others from the Blackfeet tribe in Montana who manage a bison herd, the Menominee tribe in Wisconsin who run a sustainable logging business and Indigenous Hawaiians who rely on agroforestry practices to supply their food needs.

“Native Americans have been sustaining their landscapes for millennia,” said film co-director Anna Palmer. “By bringing in these five examples of that happening with a film that only highlights Native people talking about their land stewardship projects and elevates those initiatives, that will hopefully create more opportunity for Native people to talk about the practices that they’re doing in a way that inspires other people.”

The film will likely be available widely in early 2022, but the creators will be offering free online screenings in September, October and November. They are also working to get the film into tribal schools and colleges as well as public schools around the country to serve as an education tool. 

“And also an empowerment tool for Native youth who might be looking for examples and models of restoring traditional practices,” Boutsikaris said. “Kind of taking back traditional ways of living in a modern context.”

SCIENCE

Here Be Dragon(flies) Marking More of UK’s Climate Map

Dragonflies are spreading across Britain and Ireland. But this isn’t exactly a good sign.

According to the first State of Dragonflies in Britain and Ireland report issued by the British Dragonfly Society on Tuesday, dragonflies are on the rise in the region because of global warming. U.K. temperatures have risen nearly 1 degree Celsius in the summer and 0.6 degrees in the winter over the 50-year study period, and so has the presence of dragonflies, which favor a tropical climate. The data in the report, which is based on thousands of records collected by volunteers over half a century, did not cover dragonfly populations, but rather dragonfly occupation, or the amount of area where a given dragonfly species is present.

“Obviously insects, they can’t make their own body heat so they’ve done really well in a warmer climate,” said Fiona McKenna, Conservation Outreach Officer with the British Dragonfly Society. “It’s great if you like dragonflies. It’s great if you are a dragonfly. But it’s not that great because it’s kind of showing us our climate is warming.”

According to the report, 19 dragonfly species that are considered residents or regular migrants in Britain and Ireland have increased their occupancy, while only five have decreased their range. And six new dragonfly species have appeared in the region.

The dragonfly success isn’t all bad news, though. McKenna said dragonflies are an important group of insects to understand because their success is linked to the quality of the ecosystem. They live in the water as larvae and live on land and in the air as adults; plus, they depend on a wide array of other insects for food. 

“Dragonflies are really good bioindicators,” McKenna said. “If they’re doing well, a lot of other things are going to have to do well beneath them in the food chain, so you’ve got a good, healthy ecosystem if they are doing well.”