air conditioning and environment

Here’s the good news: Over the past decade, as summers became hotter, air conditioning became 30% more efficient.

Bad news? Air conditioning usage doubled, which canceled out any gains in moderating climate change.

The world is getting warmer. People are having fewer children, but living in larger homes. The population is growing fastest in hot places like India or the American sunbelt. What does this mean for the average person who wants to be cool?

Cultural and personal

AC is a fairly new phenomenon. Before World War II, many areas were considered uninhabitable– at least to people from industrialized societies.

In the olden days, bodies adjusted physiologically to a hot environment. We moved more slowly. We took afternoon siestas and worked in the twilight hours. We wore loose-fitting clothes and blocked the sun from our homes.

Today it’s almost unthinkable to live in a hot place without AC. Modern high-rise buildings have windows that don’t open. Nobody is allowed to take the day off because it’s too hot. (In 2011, Dallas had an unprecedented 70 consecutive 100-degree days.)

And once people discover how to control their indoor climate, they don’t look back. One study showed that workers in Bangkok were comfortable until they were exposed to air conditioning. After that, they found the same office with natural ventilation unbearable.

World-wide air

The United States is the undisputed AC leader. The number of U.S. homes with air conditioning increased from 64 million to 100 million between 1993 and 2009.

But China is gaining on the U.S.; 50 million air-conditioning units were sold in China in 2010 alone.

It’s no secret that the great surge of air conditioning has paralleled global warming.

Scientists call this a feedback loop: The world is warmer so there’s more demand for AC, which in turn increases the warming trend which again spikes demand for AC . . . . and on and on.

Problem? There is no ‘off’ switch.

Technology shifts gears

Air conditioning is especially problematic in developing nations because the electricity to run the AC is produced by burning fossil fuels, generally coal. Coal is a major contributor to greenhouse gases.

In addition, while refrigerants such as R-22 that destroy the ozone layer are being phased out, newer substitutes contribute to the greenhouse effect.

In any case, the exploding popularity of air conditioning will offset the benefits of using more ozone-friendly chemicals. So why bother to improve the situation? We’re all doomed, right?

A light at the end of the . . . . shaft?

Well, for starters, air conditioning has made it possible for more people in more places to live comfortably and productively. If you are pro-human race, that’s a good thing.

Plus, the demand for AC, as well as its negative impact on the environment, have created a strong incentive for entrepreneurs, government, and industry to do something.

So we are. Here are a few of the technologies in development:

✓  Solar-powered AC may use a desiccant (like silica gel or calcium chloride) which sucks moisture out of the air instead of a coolant. This is considered cost-effective and energy-efficient. It’s a few years away from mass production.

✓  Chillers are thermal collectors that are heated and then used to cool the air. The technology, which is being implemented in Portugal, China, and Singapore, has been used for 150 years to make ice in the summer.

✓  Underground heat exchangers use the earth’s stable temperature to cool air or fluid. (Water is a more efficient conductor than air.) Called ‘earth tubes,’ this technology is well-suited to temperature zones where the earth doesn’t heat up much in the summer.

✓  For sure, all of these solutions are a bit of pie-in-the-sky. But while we’re waiting for new technology to save our bacon, we can do our part– by investing in the most energy-efficient system we can afford, by using AC wisely and monitoring its use (installing programmable thermostats and closing curtains during the heat of the day, for instance).

After all, no technological boon comes without its cost. We just need to keep working to make the world a cool place to live.