Two UCSB geography professors have completed a study of household environmental effects on urban ecosystems, which was published in the April issue of the journal Ecological Applications.

Professors Joe McFadden and Jennifer King, along with a team of graduate students, have gathered data on households in the twin cities — Minneapolis and St. Paul in Minnesota. They assessed the study’s data in order to analyze how the daily activities of households affect the environment of an urban city.

King said they specifically wanted to measure the households’ effect on carbon, nitrogen and phosphorous levels and flow, all of which are well-known greenhouse gases that contribute to global warming. The scientists took detailed measurements of the amount of gases flowing between households over the span of a year and compared the variations from household to household.

The team of scientists collected important and useful information regarding household energy consumption. Although the amount of energy consumed did not vary much among households — nearly everyone in Minnesota uses some energy in order to stay warm for survival — the top 20 percent of energy-consuming households accounted for 32 percent of the total carbon emitted, according to the study.

This statistic seems relatively small when compared with the top 20 percent of households who regularly travel via airplane; the team found that frequent fliers accounted for 75 percent of carbon emitted.

“To reduce carbon dioxide emissions from the whole city, you would need a different approach for each case,” McFadden said. “For home energy, you would want to find things that everybody could do, such as improving insulation in the home. But for air travel, you would do better to focus on the handful of frequent fliers — are they traveling for work or vacation? Do they have to take long connecting flights or short ones? And so on.”

Although there are many ways to reduce toxic emissions, McFadden said that the biggest issues need to be fixed first.

“Of course, everything you can do helps,” McFadden said. “But we found that 79 percent of a household’s carbon dioxide emissions came from the gasoline you use in your car and the energy you use in the house. If you want to make a big difference, you have to work on the big factors — you can’t avoid it.”

Although other factors like office buildings and businesses also affect the urban environment, the amount of data which is still to be collected on household emissions will keep the UCSB team busy for the time being.

“It turns out that households are really important — they cover more of the city’s land area and account for a big percentage of the material flows — about 40 percent of the carbon, for example,” King said. “We’re also interested in studying households because we want to better understand how decisions made by individuals might affect biogeochemical fluxes.”

In addition to the Twin Cities Project, McFadden and King are also currently working on side projects. King is examining the controls on carbon cycling in grasslands and McFadden is working on a project in L.A. that researches residential water usage, including where water is recycled to and how usage varies throughout the city.

According to McFadden and King, they are always looking for new students with backgrounds in the natural and physical sciences who are interested in helping with their research.