Air conditioning turns up city heat

Tim Radford in the Daily Climate: Researchers in the United States have identified how city-dwellers inadvertently stoke the heat of the night: By installing air conditioners. At night, heat from air conditioning systems now raises some urban temperatures by more than 1ºC.

Because the cities are getting hotter as the climate changes, residents are increasingly investing in air conditioning systems − which discharge heat from offices and apartment blocks into the city air. The vicious circle effect is that cities get still warmer, making air conditioning all the more attractive.

According to scientists at Arizona State University, the air conditioning feedback loop is now having a measurable effect. During the days, the systems emit waste heat, but because the days are hot anyway, the difference is negligible. At night, heat from air conditioning systems now raises some urban temperatures by more than 1 degree Celsius, they report in the Journal of Geophysical Research Atmospheres.

The team focused on the role of air conditioning systems in the Phoenix metropolitan area in Arizona's Sonora Desert, where summer conditions are harsh there anyway. But worldwide, normally warm countries are experiencing increasing extremes of heat, and conditions in cities have on occasion become lethal.

To cap this, cities are inevitably hotspots – and not just because of global warming. The concentration of traffic, pavement, lighting, central heating, industry, buildings and activity associated with millions of people can raise temperatures as much as 5°C above the surrounding countryside.

At present, 87 percent of U.S. households have air conditioning, and the United States – which is not one of the warmer nations – uses more electricity to keep cool than all other countries of the world combined. To keep Phoenix residents cool during periods of extreme heat, air conditioning systems can consume more than half of the region's total electricity needs, straining power grids....

Airconditioning units atop the Fairmont Hotel in Dallas, Texas, shot by Joe Mabel, Wikimedia Commons, under the Creative Commons license 3.0

Texas grid expects to set June power record again in baking heat

Reuters: The Texas power grid expected demand Tuesday to break the June peak record for a second day in a row and urged consumers to continue cutting back on power use to avoid straining the system as much of the state broils under triple-digit temperatures.

The Electric Reliability Council of Texas (ERCOT), the grid operator for most of Texas, forecast peak demand Tuesday would reach 66,415 megawatts (MW), easily surpassing the June record set Monday of 65,047 MW. Before Monday, the June record was 63,102 MW set last year.

The state's all-time peak use was 68,379 MW set in August last summer during a protracted heat wave and drought. Real-time power prices briefly exceeded $100 per megawatt-hour Monday afternoon. Next-day power prices for Tuesday traded between $165 and $175 per MWh.

The extreme heat hit Sunday when the mercury reached 100 degrees Fahrenheit (38 Celsius) in Houston, San Antonio and Dallas, the three biggest cities in the Lone Star State, prompting residents to crank up air conditioners. Triple-digit highs were forecast for several more days this week, with several high enough to set records, AccuWeather.com forecast...

A road sign in Notrees, Texas, public domain

Air conditioning -- threat or menace?

Britt Harvey in the Winnipeg Free Press: It’s become the wonder drug for heat waves. Ice cubes, Super Soakers, Popsicles and pools -- whatever method you're using to keep cool these hot summer days just can't compete with the antidote of central air.

A new book by American scientist Stan Cox called Losing Our Cool: Uncomfortable Truths About Our Air-conditioned World (and Finding New Ways to Get Through the Summer), covers the health risks and political consequences of a society of air-conditioner addicts.

Everything from the election of George W. Bush to our sexual habits has been affected by air conditioners, Cox argues. For instance, he says the population boom of the southern U.S. states was made possible by air conditioning. And without that vote-rich electoral base in Florida, and Texas, Bush might have lost the 2000 election. As for our sexual proclivities, Cox argues that as the heat turns up outside, it goes down in the bedroom. But turning on air conditioners has led to more summer loving.

But much like any drug, there are side-effects to cranking up the air conditioner, and Winnipeg environmentalists say we need to kick this habit cold turkey. "We have to realize there is a greenhouse gas outcome to our consumption," said Curtis Hull, Manitoba's Climate Change Connection project manager. "The more electricity we use, the less we export to places that use dirtier forms of energy like coal."…

Industrial air conditioning unit outside Durham Regional Hospital in Durham, North Carolina, shot by Ildar Sagdejev (Specious), Wikimedia Commons, under the Creative Commons3.0 Unported Attribution-Share Alike