This summer in Ellsworth, Lindsay Moon worked two jobs in the city’s expanding commercial district of High Street, splitting time between Mr. Paperback in the Mill Mall and the UPS store across the busy four-lane street. She said the parking lots at both locations were often unbearably hot.
“There’s so much asphalt and no trees and so many people and so many cars,” she said. “I’d go to get into my car and there’s no air.”
She said High Street was always hotter than her home at Fletcher’s Landing a few miles away.
The temperature difference between Ellsworth’s commercial district and the rural area that surrounds it is a result of a phenomenon that climate scientists call the heat island effect. In a heat island, manmade structures, pollution, and a lack of vegetation combine to change the microclimate of an urban area to make it two to eight degrees hotter than rural areas surrounding it.
Dr. Paul Andrew Mayewski, director of the Climate Change Institute at the University of Maine, said that while heat islands are usually found in big cities, mid-sized communities like Ellsworth are not immune to the problem. Large parking lots and big box stores in Ellsworth can create their own mini-heat islands, he said.
“They have a very significant local effect,” Mayewski said.
He said that heat islands operate in much the same way that scientists believe the greenhouse effect changes the world’s climate.
“An urban heat island is just a magnified version of a greenhouse-gas world,” he said.
In a natural environment, when the sun hits vegetation, solar energy evaporates the water stored in plants; the evaporating process cools the air and moderates temperature. But impermeable surfaces such as shopping center parking lots quickly shed water, so on a hot day, little evaporation can take place.
Meanwhile, buildings and cars will actually contribute to an increase in temperature by shedding waste heat.
Removing vegetation for a parking lot also will stop the important photosynthetic cycle of converting carbon dioxide from passing cars into oxygen. With nowhere else to go, freefloating pollution will combine to create a layer of ground-level ozone that can trap heat and further reduce air quality.
“To pave over a natural surface…is a pretty extreme thing to do with a landscape,” Mayewski said.
Left unmitigated, heat islands can cause a cycle of ever-rising temperatures and ever-poorer air quality, and may lead to an increase in respiratory ailments and heat-related illness among urban populations. According to the Centers for Disease Control, excessive heat claims more lives annually than all other natural disasters combined.
The easiest way to reduce heat islands is to reintroduce vegetation back into a developed area or to leave vegetation standing when development occurs. But like those in most growing towns, Ellsworth’s current land use ordinances have few requirements for landscaping.
“It’s minimal, it’s not a lot,” said a city official in the code enforcement office.
At best, the city’s planning office can ask developers to add a bit of greenery to their parking lots, the official said.
That may soon change. Jeff Fitzgerald, Ellsworth’s new deputy city planner, said city officials are reexamining those ordinances and considering writing new rules mandating increased green space in development.
“There’s a desire to revise the ordinances,” Fitzgerald said.
But a recent change in the ordinances proves how tough it can be to hold developers accountable for green development.
After receiving numerous complaints about a vast and largely empty Home Depot parking lot, city officials succeeded in changing the amount of parking spaces needed for a new business from five per 1,000 square feet to 3.6. However, the new ordinance only mandates the minimum number of spaces required, and sets no maximum. The developers behind a proposed Lowe’s superstore on High Street elected to go with a corporate blueprint that called for many more spaces than the city required.
But the city is now taking its own steps to “green up” its commercial district with a beautification project launched in conjunction with a Maine Department of Transportation widening of High Street. The final phase of the beautification project this August included the planting of additional trees and shrubs along the street.
“It should be a real benefit,” Fitzgerald said.
Some feel there just isn’t enough green space to offset development. While the city has a ballpark and a few school playgrounds, it lacks a true park. Recently, business leaders and the city have worked together in an attempt to acquire a former used car lot downtown for a future public green space.
However, the proposed Lowe’s and another as-yet-unnamed development on High Street, if approved, will easily dwarf all other big box stores in Ellsworth.
Still Mayewski remains optimistic. He believes a new “green” economy is emerging as corporations are forced to become more energy-efficient in order to survive rising energy costs.