The big schvitz
Looming heatwaves, droughts spur Denver climate plan
IF you like the scorching summer clime in communities like Sterling or Lamar, you’ll love Denver in 2050, when greenhouse gases will be so thick in the air that 100-degree days will be more common than not, according to the city of Denver’s soon-to-be published climate report.
On long, hot summer days, the invisible and odorless heat-trapping gases will help catalyze nitrates and sulfates to form a toxic ozone brew that corrodes delicate lung tissue and membranes. The haze will linger for weeks at a time, killing some people directly, potentially resulting in thousands of hospital visits and causing untold hours of lost work time. It will stay hot and smoggy for so long that emergency workers will have to go door-to-door to help elderly and sick get to designated cooling shelters, mapped out in a citywide heat-emergency response plan.
By mid-century, temperatures now considered extreme will become the summer norm for the Mile High City, predicts Denver’s forthcoming climate adaptation plan, a copy of which was obtained by the The Colorado Independent.
“The climate is obviously changing,” said Celia Vanderloop, director of the environmental quality division in the city’s public health department. Denver needs to be ready to protect people from climate threats sooner rather than later, she said.
The brutal heatwaves in 2012 clearly showed the need to find effective ways to help residents survive potentially catastrophic climate change impacts. In June of that year, Denver experienced a string of days as hot as the devil’s armpit, with thermometers topping the 100-degree mark five days in a row. That followed a brutally warm spring when the mountain snowpack vanished by the end of March.
Six months later, it was Australia’s turn. Thermometers amped up so high that meteorologists there added a new color — deep purple — to their weather maps, signifying unprecedented temperatures.
The 2012 heatwaves can’t be attributed directly to global warming, but all the science forecasts those events will become more frequent and more intense, Vanderloop said, discussing Denver’s new climate plan, which could be rolled out as soon as this week once Mayor Michael Hancock signs off on it.
The 92-page document is a road map for climate adaptation, with a key emphasis on protecting vulnerable populations, including elderly and chronically ill people, as well as low income and minority citizens, from the effects of extreme weather, poor air quality and deadly heatwaves, Vanderloop said.
“The people who can’t cool their homes are often lower-income people. If you’re living in a small house with no ventilation, it’s going to be brutal.”
Preparedness even extends to measures such as assessing Denver urban landscape to determine which trees will succumb to heat and choosing new varieties that can withstand the new norms to maintain a cooling tree cover that also absorbs at least some of the excess carbon dioxide. The plan also says city officials must consider how climate change will affect fundamental infrastructure such as stormwater runoff systems.
The city has been working on the climate adaptation plan for about a year. The new document complements the city’s 2007 climate action plan by defining ways to deal with higher temperatures, more extreme weather events and changes to annual snowpack. The plan recognizes climate change as a defining issue of the 21st Century and commits to protecting the city’s quality of life in the face of emerging climate threats.
Yet another disaster scenario and yet another government response plan may sound like a mind-numbing exercise in bureaucratic futility. But climate planning should be seen in the context of potential benefits, said Harvard public health researcher Dr. Samuel Myers.
After studying climate change impacts around the world, Myers said it’s clear that different cities face very different challenges related to global warming. Denverites needn’t worry about a rising sea level or hurricanes, but the city is vulnerable to extreme weather, especially more heatwaves.
Because Denver sits in a big bowl at the base of the Rockies and at a high elevation, it’s also particularly susceptible to air quality problems. Smog, along with more extreme weather, probably pose the biggest climate threats, Myers said.
In the long run, measures aimed at curbing carbon emissions and improving air quality will result in a more livable city. Those would include more public transit and bikeways, more trees and more neighborhoods where residents don’t have to use their cars to shop or grab a coffee.
Denver may not be able to take a huge bite out of planet-wide greenhouse gases, but on a regional metropolitan scale, the city can try to control local emissions from auto tailpipes, factories, power plants and even from feedlots and industrial farms in nearby communities — all sources of those sulfate and nitrate-based precursor gases that form smog.
Temperature is a key trigger for that photochemical process. Above 86 degrees Fahrenheit, you can count on smog formation if the chemical ingredients are present. The long-term health benefits of reducing those pollutants manifest themselves in huge societal savings on health care costs. Myers said regularexposure to ozone smog results in millions of cases of chronic and acute illnesses, including asthma and lung disease.
To not prepare for the risks of global warming would be folly anywhere. But failing to do so in a densely populated city with known populations of vulnerable citizens — especially in low income and minority neighborhoods — would be irresponsible governance, said Erika Trigoso, a University of Denver geography professor.
Denver’s concrete jungle concentrates the effects of greenhouse gases, ozone and other pollutants, said Trigoso, who studies the geography of climate change. Scientists call it the “urban heat island effect.” Put a slice of cheese under a glass on a sunny windowsill for a couple of days — and you won’t need an engineering degree to figure it out.
The city’s population has increased by 142 percent since 2000 and there’s little indication the growth will slow anytime soon. That means more asphalt, more buildings — and more heat. Above the expected average global warming of about 2 degrees Fahrenheit by mid-century, cities like Denver will see far greater spikes in temperatures.
There’s a real danger the city could suffocate itself during an intense heatwave, said Trigoso, who focuses on climate change adaptation in Central America but reviewed the public health section of Denver’s new climate adaptation plan at the request of The Colorado Independent.
Trigoso viewed the plan as a call to action.
“We have to stop fighting the science and put our heads together and figure out how to solve it,” she said.
Denver on its own can only play a small role in reducing greenhouse gases on a global scale, but the city can — and must — tackle emissions from car exhausts, factories and even farms to protect citizens from the worst consequences of global warming, she said
Without adequate preparation, the heatwaves could turn into mass-killers, Trigoso said, pointing to a 2003 summer heatwave in Europe as a worst-case scenario. The well-studied European event caused 70,000 deaths in Western Europe — and 13,000 in France alone. Many of the fatalities in Europe were elderly people living along. A disproportionate number of victims were low income, including immigrants living in low-slung metal-roofed buildings where they baked to death.
“And that’s in modern societies. It’s a big concern,” she said. “The imprint of what happened in Europe is all over Denver’s report,” she said
Since Congress is gridlocked on most climate issues, it’s up to cities to help themselves, specifically by limited sources of ozone-causing pollution.
Said Trigoso: “Forget about Washington. We know what global warming is going to do. We know the urban heat island effect is happening. We need more regulations now.”
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