Hopkins professor studies Baltimore’s ‘urban heat islands’

This article originally appeared on Inside Climate News. It is republished with permission. Sign up for their newsletter here.

As a professor and climate scientist in the Department of Earth and Planetary Sciences at Johns Hopkins University in Baltimore, Benjamin Zaitchik has found the perfect workshop: the rest of the city.

A Boston native, Zaitchik intended to work on desert plants and agriculture after his doctoral studies at Yale University, and started out in the Middle East, studying ecology and chasing after hurricane-induced landslides to understand extreme events, such as heat waves. Political instability put an end to all that.

Now, with a focus on atmospheric modeling and climate analysis, he studies the impacts of extreme weather and opportunities to enhance resilience to these extremes, including those related to urban heat islands. He also serves as a member of the Baltimore Commission on Sustainability, and advises communities and city managers on mitigation strategies to beat back urban heat and other weather events, such as flash floods.

“Baltimore isn’t too different from other eastern U.S. cities in its form or climate,” he said.

But, he pointed out, it has little tree cover and a large amount of impervious surfaces like asphalt and metal.

“So, the urban heat island effect,” he said, “can be dramatic.”

Urban heat islands are formed in cities because construction materials such as asphalt, steel and concrete absorb and retain daytime heat, raising air temperatures significantly higher than the surrounding suburban or rural areas.

A little over 700 yearly heat-related deaths were reported in the United States between 2004 and 2018, the Centers for Disease Control and Prevention estimated in 2020, adding that heat exposure was fatally aggravating certain chronic medical conditions, drug overdoses and alcohol poisoning.

In a 2021 study, the Environmental Protection Agency (EPA) reported that economically disadvantaged groups such as non-Hispanic Blacks were especially vulnerable to excessive heat exposure and counted respiratory and cardiovascular illnesses among the preexisting conditions exacerbated by urban heat.

High urban heat is particularly challenging for a city like Baltimore, where high summertime temperatures and heat-retaining sprawl produce extremely high temperature and humidity, the Baltimore Office of Sustainability says, warning of serious health impacts for the elderly, children with asthma and people with pulmonary conditions.

Zaitchik said that research showed that temperatures are particularly high in neighborhoods that are historically redlined, with greater risks for people with underlying conditions. With extreme heat waves becoming more frequent and intense due to climate change, he said, the challenge to protect city dwellers and vulnerable populations is set to grow manifold.

In Baltimore, a “rust belt, majority Black, port city,” Zaitchik said, the legacy of redlining could be seen in neighborhoods that, when compared to mostly while affluent areas, have little tree cover and fewer open green spaces that could help cool down sizzling summer temperatures.

“There are neighborhoods in the eastern and western parts of the city, which are much more challenged than the north and south side,” he said, “and this distinction is pretty clear.”

Zaitchik said the fact that heat waves and urban heat islands impacted economically-depressed neighborhoods more severely led him to shift his focus to the environmental justice impacts of extreme weather events.

“It was my colleagues who drew attention to the health and environmental justice importance of the urban heat island,” he said. “That’s what got me involved.”

Pollution adds another deadly spin to the heat island effect because people with medical conditions are most vulnerable to the respiratory effects of poor air quality when it’s hotter. And this combination of heat and air pollution deals a deadly blow to poor neighborhoods, which are historically more exposed to air pollutants because of the industrial activities nearby — such as the city’s trash-burning incinerator, Wheelabrator Baltimore.

The city’s single largest standing source of air pollution, Wheelabrator began operations in 1985. After a settlement with the city, Wheelabrator installed nearly $40 million in emissions control upgrades. In exchange, Baltimore agreed to continue sending waste there through 2031 and pay it an estimated $106 million under the new contract signed in early 2021.

“The incinerators are a very big deal here in Baltimore, and so is traffic,” Zaitchik said. “Industrial activity directly contributes heat to the environment. These factors work in concert to create a bigger public health problem.”

Traffic emissions were an even greater source of air pollution in Baltimore than trash incineration, resulting in 43 days with elevated pollution levels in 2020, according to a 2021 report by a federation of environmental advocacy groups. It tied air pollution to 100,000 to 200,000 deaths nationally per year.

Researchers looked at two pollutants associated with cardiovascular and respiratory problems: ozone, the main ingredient in smog, and PM2.5, or particulate matter one-thirtieth of the width of a human hair or smaller.

The report, “Trouble in the Air,” found that air pollution had significantly improved in Baltimore since 2005, when it had the worst air pollution mortality rate among the 20 most populated cities in the country. By 2020, the report found, Baltimore fared far better than many other densely populated locales, such as San Diego, which experienced 232 days of elevated pollution levels in 2020. Two other Californian cities rounded out the top three for the most populated places with the worst air — Los Angeles and Riverside.

Zaitchik said it is encouraging to see that the Biden administration has prioritized health equity and environmental justice to an unprecedented degree by adding cabinet-level positions to elevate climate concerns to the highest realm of policymaking.

With the Justice40 Initiative, administration officials have said they intend to target 40% of all federal funding on projects to address environmental injustices created during previous decades. “I worked briefly in the Obama administration and, as much as that administration leaned into climate and, implicitly, justice, they didn’t do this. They didn’t make it front and center,” Zaitchik noted.

Still, environmental justice activists have recently expressed frustration that too much federal money, including three-quarters of the funds in President Biden’s infrastructure bill, are being distributed through ordinary funding formulas, not Justice40.

Zaitchik said the federal government’s climate initiatives align with the city of Baltimore’s sustainability plan, enabling policymakers to approach extreme weather events through the lens of racial justice. The Biden approach, he said, “recognizes that there can’t be a sustainable society when there’s structural racism and injustice going on.”

“I found that really an inspiring project to work with because it means that sustainability is not just about recycling,” he said. “Sustainability is about really addressing some of the fundamental ways in which we interact.”

The city is aware of these inequities, he said, noting that Baltimore is one of the few cities that has increased its tree canopy cover over the past decade.

“Baltimore has been doing a lot of tree planting and maintenance and is prioritizing the neighborhoods with low tree cover,” he said.

Some simpler ideas offer huge cooling benefits, he said, such as recoating roofs of homes with white paint to reflect the sun and cool the bedrooms upstairs — a move that also lowers energy consumption.

Ideas such as white rooftops and regenerating urban green spaces also move the city closer to its greenhouse gas emissions reduction goals, Zaitchik said.

But despite the renewed emphasis on combating urban heat, Baltimore still lacks a comprehensive heat reduction strategy and has mainly relied on tree planting and greening initiatives for mitigation. “In terms of the long-term plan for heat reduction, some of that will come in the coming year as Baltimore is revising its climate action plan,” Zaitchik said, noting that Baltimore faces myriad challenges.

At the city level, for instance, the stormwater and wastewater issue is tremendous. More than 45 percent of Baltimore is covered by asphalt and other impermeable surfaces, producing flooding and sewage backups. The runoff ultimately flows into local waterways, including the Chesapeake Bay. And climate change has made precipitation 24% greater than it was in the 1980s.

“And this is affecting a lot of rural homes in the city, the basement flooding from sewage backups,” Zaitchik said, “That’s a major health issue that disproportionately affects poor people.”

As a stressor, he said, climate change disproportionately affects communities where people of color live.

“In Baltimore, we see that in the relationship between hot conditions and violence, and in the distribution of flooding during heavy rain events,” he said. “In the long run, climate change will affect Baltimore in other ways as well, as storm surge gets worse and longer warm seasons cause ecological change. Those impacts will likely be substantial and will affect many different communities.”

Aman Azhar is a Washington, D.C.-based journalist who covers environmental justice for Inside Climate News with a focus on the Baltimore-Maryland area.

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