http://www.guardian.co.uk/weather/St...282372,00.html

Heatwaves here to stay

Tim Radford, science editor
Friday August 13, 2004
The Guardian

Heatwaves of the kind that killed 30,000 people in Europe last year
will become more frequent, more intense and longer-lasting, according
to reports by US scientists today.

Gerald Meehl and Claudia Tebaldi of the US national centre for
atmosphere research (NCAR) report in the journal Science that the
predicted increase in heat-absorbing greenhouse gases over the next
hundred years is likely to intensify the pattern of heatwaves
established in Europe and North America.

Computer models show that heatwaves will become more severe in the
south and west of the US and the Mediterranean.

"It's the extreme weather and climate events that will have some of
the most severe impacts on society as climate changes," said Dr Meehl.

The study backs up a prediction made by Swiss scientists, earlier this
year that 2003 was a "summer of the future" for Europe.

Without some relief from the sweltering conditions, the elderly and
the ill become increasingly at risk of heatstroke, heat exhaustion and
dehydration. The team focused on Paris and Chicago be cause both had
experienced lethal heatwaves in recent years.

The researchers predict that without worldwide cuts in greenhouse gas
emissions, the average number of heatwaves in Chicago would increase
by 25% to about two a year. The increase in Paris will be even
greater, to an average of 2.15 a year.

The hot spells will also last longer. Heat waves in Chicago now tend
to last for between five and eight days. Computer models predict that
they could extend to eight or nine days.