Earth & Sky

Expert: global warming to increase heat waves

Heat waves in cities are generally caused by stagnant air and the urban heat island effect.

Scientists say heat waves are already increasing as Earth’s climate warms.

Linda Mearns: One of the most dramatic effects it has had is indeed in terms of increased frequency of heat waves and the effect that has on human health.

That was Linda Mearns, a climate scientist with the National Center for Atmospheric Research in Boulder, Colorado and an author on a recent report by scientists from around the globe who are working with the IPCC, or Intergovernmental Panel on Climate Change. Mearns spoke of a coast-to-coast heat wave in the U.S. in 2006, in which over 200 people died of heat stroke.

Linda Mearns: At one point, all of the lower U.S. was basically in a condition of thermal stress. And that’s something that’s very interesting and important, because if you have a very large extent of the population under heat stress, you want to pump up the air conditioning, but it’s much more difficult to borrow energy from adjacent areas if they are also under heat stress.

Since 1990, the U.S. has had its 10 hottest years on record.

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