If Sterl's predictions hold true, what might the impact be?  Looking at historical records, a good comparison point would be the French heat wave of 2003, in which temperatures hit 104° F, killing nearly 15,000, with mortality rates especially high among the elderly.  A similar heat wave in Chicago in 1995 raised temperatures to 106° F killing about 600 people.

Mr. Sterl remarks jokingly that in the future we will look back on these heat waves, "And we will laugh.  We will find (those temperatures) lovely and cool."

The computer model developed by Sterl is cutting edge and draws on his team's sizable climatological experience to model the past, present, and future.  While the study does not disagree with the international scientific consensus on the more moderate standard temperature rises, it reveals an interesting previously unconsidered aspect of the warming process -- its effect on heat waves.

The new study found that for normal temperature rises, heat wave temperature rises will increase twice as fast.  Once-in-a-generation heat waves in Chicago will reach 115° F according to the model, in Paris 109° F, and Lyon 114° F.

When these heat waves hit, according to Sterl they will be particularly damaging due to their drying effects.  They will do much more damage than daily temperatures, he indicates.

He finds that LA will be at 117° F during a heat wave and Atlanta may seem temperatures of 110° F; in each case, this is 5 degrees higher than either city has ever seen.  Kansas City could get as hot as 116° F, 7 degrees hotter than the current high of 109° F, according to the National Climactic Data Center.

New York will have a more modest jump from an all time high of 104° F to 106° F.  Some cities will not get much hotter, but will just see highs more frequently, such as Phoenix, Arizona, which has hit 122° F, and will be regularly hitting in the 120s.

Worldwide, other countries will be hit much harder.  Delhi, India will reach 120, Belem, Brazil 121, and Baghdad a toasty 122. Ken Kunkel, a top Midwestern climate scientist and interim director of the Illinois Water Survey, says that the figures derived from the study check out.

University of Wisconsin environmental health professor Dr. Jonathan Patz comments that the results disturb him as those temperatures are extremely dangerous to the human body.  Said Patz, "Extreme temperature puts a huge demand on the body, especially anyone with heart problems.  The elderly are the most vulnerable because they don't sense temperature as well."

Even before the end of the century, we should be seeing similar effects says Sterl.  By 2050, heat waves will rise 3 to 5 degrees in temperature and will "probably be longer lasting", according to his findings.

Sterl used France as a benchmark for the increases.  In the 1950s, the worst heat wave expected was 91° F, by 1990s it rose to 104° F.  By 2050 he expects the worst heat wave to be at 111° F, and by the end of the century southern France will likely hit 118° F during a heat wave.

As human body temperatures of 104° F are considered life threatening and 113° F typically fatal, if such heat waves occur the human body will likely sweat excessively to try to exhaust heat.  This can lead to dehydration and drops in blood pressure.  Many medications taken for common illnesses interfere with the body's ability to perspire, which could yield death under such extreme conditions.

There have also been numerous studies linking heat wave temperatures to crime sprees; as it appears abnormally high temperatures have psychological effects, increasing the rate of criminal acts.

The study will soon be published in the Geophysical Research Letters journal.