Alexandra Scoville

The Republic | azcentral.com

Cal-Berkeley researchers determined the carbon footprints of communities across the United States

Of areas around Litchfield Park's ZIP code%2C Goodyear and Avondale had the largest carbon footprints

Of areas around Youngtown%2C Sun City and Surprise had the smallest carbon footprints

West Valley communities are making a big mark on the environment — and not always a good one.

Areas surrounding Litchfield Park and Avondale leave larger carbon footprints — carbon-dioxide emissions — compared with other West Valley cities. And areas such as Sun City and Youngtown make smaller ones, according to research from the University of California-Berkeley.

Since 2007, dozens of Berkeley researchers have participated in the CoolClimate Network project. The project, funded by the California Air Resources Board, initially focused on helping California cities educate their populace about carbon consumption, research associate Chris Jones said. It has since expanded to measure carbon-dioxide use in cities across the United States.

"One of the main goals was to help cities understand the primary drivers of greenhouse-gas emissions," Jones said.

The study used a number of factors to determine carbon footprinting, including motor vehicles, public transportation, air travel, household energy usage, water and waste, shelter, and food, goods and services.

Data discrepancies

Jones and fellow researchers use ZIP code data from U.S. census records to make their calculations, which include average household size and annual incomes. Because the study uses ZIP codes and not city boundaries, the city information is sometimes skewed.

For example, the 59.2 tons of carbon dioxide produced a year from ZIP code 85340 reflects not just the 3.3 square miles of Litchfield Park, but its entire 48-square-mile ZIP code.

Litchfield Park City Manager Darryl Crossman said the city's inclusion in a large ZIP code has caused problems before. Litchfield Park occasionally gets pinned with the crime rate representing the entire area and population, not just the city's.

Because of this, Crossman said the carbon-footprint number for Litchfield Park is "totally inaccurate."

"If you go to one of our local restaurants any night, you'll see a number of golf carts and bicycles parked out front," he said. "Litchfield Park prides itself on being a walkable, golf-cart-friendly, bicycle-friendly city."

Kevin Gurney, a life scientist with Arizona State University's Global Institute of Sustainability, has mapped the carbon output in Salt Lake City, the Los Angeles Basin and Indianapolis. While Gurney said the calculator and map CoolClimate Network produced are useful, he warns that viewers "have to understand what (they're) getting."

Because the researchers based their information on Census Bureau data, they have to make assumptions.

When he maps cities, Gurney retrieves records from local tax assessors and departments of transportation and models every structure in the city for efficiency. While the CoolClimate Network measures carbon consumption, Gurney tries to measure carbon emission.

Still, Gurney said that when it comes to pushing others to take action, both types of research are important.

"They're good for comparing broadly between communities," he said. "These things give you a kind of feel for what's going on. You just have to be cautious with them."

Jones said the Berkeley researchers are stuck with census data for now, but they hope to eventually drill down to the block-by-block level.

Jones said he's excited the work has gained traction.

"We sit behind a computer desk and run data and publish academic articles, but the real work needs to be done at the community level," he said. "It's really interesting us to see how communities and individuals are reacting. In a way, it's more important than the science itself."

Suburbs' big footprints

For most areas, vehicle fuel and home electricity use are the biggest contributors to a carbon footprint.

Jones said the research shows that city centers often have the smallest carbon footprint in a metropolitan area, with suburbs having the largest footprint.

Two ZIP codes for downtown Phoenix, 85004 and 85003,have footprints of 31 and 34.7 tons of carbon dioxide a year, respectively. Both are smaller than any other footprint in metro Phoenix.

In the West Valley, eight cities were above both the 45.7-ton Arizona average and the 48.5-ton national average for carbon footprints, while four cities fell below.

One reason is that West Valley residents have longer commutes. The average Avondale resident's commute is nearly 26 minutes, and only 12.7 percent of residents work in Avondale, according to census data. But 78 percent of downtown Phoenix residents who live in 85004 work there, too, according to the data.

Valley Metro does have bus lines running north-south through the West Valley and several that run east-west on major roads, including Camelback Road, Peoria Avenue and Buckeye Road. However, these routes don't extend far west. Large stretches of many West Valley cities have little to no bus access.

Valley Metro representative Susan Tierney said that while the transit system has no concrete plans for West Valley expansion yet, it knows more people want transit service.

"We've seen a lot more interest in transit, especially in the past five years," Tierney said. "I would say light rail probably has a lot to do in that shift in how we think about transit now. It's given it a lot more positive feeling, and they're much more accepting after experiencing light rail."

Reducing footprints

While Litchfield Park has no access to Valley Metro bus lines, the city does have 12 miles of pathways and 35 acres of parks, Crossman said. A significant number of Litchfield Park residents also own golf carts and use them, he added.

The city added guidelines for solar panels to the city code in 2010 following the release of its General Plan. Since 2009, before the guidelines were in place, Litchfield Park's Building Department has issued 114 solar-panel permits.

Youngtown's work to retrofit its older buildings with more-efficient windows and air-conditioning as well as streamlining the application process for residential solar panels has probably helped keep the town's carbon footprint small, Mayor Michael LeVault said. Youngtown also has made an effort to work with other West Valley cities to improve public transportation.

"All of these thing ultimately have a big impact on reducing our carbon footprint," LeVault said.

Republic reporter Philip Haldiman contributed to this article.

Yearly carbon-emissions averages, by ZIP code

U.S. average: 48.5 tons of CO 2 per year.

Arizona: 45.7 tons.

Phoenix: 44.4 tons.

Litchfield Park: 59.2 tons.

Goodyear: 56.8 tons.

Avondale: 51.1 tons.

Peoria: 50.1 tons.

Laveen: 49.6 tons.

Glendale: 49.4 tons.

Tolleson: 49.1 tons.

Buckeye: 48.8 tons.

Surprise: 44.8 tons.

Sun City West: 42.8 tons.

Sun City: 39.1 tons.

Youngtown: 36.8 tons.

Source: CoolClimate Network