The latest Wired features a list of contrarian environmental facts (organically raised cattle emit more methane gas than conventionally raised cattle, nuclear power is great, the Prius battery takes a lot of energy to make, etc.) but I was most surprised by this factoid:
Cooling a home in Arizona produces 93 percent few carbon dioxide emissions than warming a house in New England
The math is quite simple. Most people set their thermostat to somewhere between 68 and 76 degrees. When it's really hot outside (let's pretend it's August in Phoenix, which means 105 and humid) that means you need to cool the home by 35 degrees. But when it's really cold outside (and I just survived a long New England winter, which meant lots of 10 degree days) you need to heat the home by more than 60 degrees. As Wired notes, "a typical house heated by fuel oil emits 13,000 pounds of CO2 annually. Cooling a similar dwelling in Phoenix produces on 900 pounds of CO2 a year." The bad news, of course, is that you have to live in Phoenix.
This data point jives with that recent study showing that the citizens of Honolulu and Los Angeles emit the least amount of carbon dioxide per capita. At first glance, you might be surprised to learn that LA, the capital of car culture, is so atmospherically friendly. But a history of strict emission standards, coupled with urban density (LA county is the densest county in the country) and a temperate climate translates into a low CO2 footprint. As I noted in a Seed article from last year:
When most of us think about environmentally friendly places, we imagine rural landscapes and bucolic open spaces. We picture a terrain untouched by concrete. Cities, in contrast, seem like ecological nightmares. They are densities of pollution, artificial environments where nature consists of cockroaches, pigeons and florist shops. But, according to Bettencourt and West, the conventional wisdom is exactly backwards. Cities are bastions of environmentalism. People who live in densely populated places lead environmentally friendly lives. They consume fewer resources per person and take up less space. (On average, city dwellers use about half as much electricity as people living outside the city limits.) The typical Manhattanite generates 30 percent less CO2 than the typical American.
Environment
Comments (13)
Not sure about your math on A/C. Most houses act a bit like a greenhouse, sunlight enters through the windows, and heats the roof to excruciatingly high temperatures. If a house used no heat or A/C its average temperature would be 10-20 degrees warmer than the average outside. That is probably made up for by the fact that A/C is a heat pump (like your refrigerator), and more than 1 unit of heat can be pumped at the expenditure of 1 unit of energy. Heat pumps are slowly coming into use for heating however.
Posted by: bigTom | June 3, 2008 4:13 PM