"These are the times when the far north has to have air conditioners now to function," said Sheila Watt-Cloutier, a leading campaigner for the rights of 155,000 Inuit in Canada, Alaska, Russia and Greenland.

"Our Arctic homes are made to be airtight for the cold and do not 'breathe' well in the heat with this warming trend," she said. Temperatures in Kuujjuaq, home to 2,000 people, hit 31 Celsius (88 Fahrenheit) in late July.

If the Inuit are feeling the heat, chances are that people further south are sweltering too.

Billion-dollar shifts in lifestyles in rich nations are likely as people adapt to what most scientists say is a warming stoked by use of fossil fuels -- affecting demand for everything from soft drinks or foods to architecture and tourism.

Scientists who advise the United Nations say a build-up of heat-trapping gases emitted by power plants, factories and cars are likely to spur more heatwaves, droughts, floods and raise sea levels by up to a metre in the 21st century.

"Lifestyles will change ... but businesses have to be flexible," said Manfred Stock of the Potsdam Institute for Climate Impact Research in Germany. He noted the climate is also likely to have bigger swings in a warmer world.

FLOODS, HEATWAVES

"For instance in making ice creams you may have a bad year and you have to stand that," he said. "A winner one year can be a loser the next." In Europe, searing heatwaves in 2003 followed widespread floods in 2002.

"Today we've sold almost nothing," said Miriam Eid Bergan, 20, working at an ice cream parlour in Oslo's main street and looking out the window as people hurried past in the rain. "When it's sunny the queue can stretch down the street."

Most studies of global warming focus on businesses' opportunities to save energy or to shift to wind or solar power from fossil fuels, especially with oil prices around US$75 a barrel.

Lifestyle often gets less attention, even though a rising temperature will affect sectors as diverse as producers of beer, suntan lotion, lightweight clothing, air conditioning, swimwear and open-top cars.

Farmers may be able to grow new crops closer to the poles, changing the range of choice, and tourists may shun low-altitude Alpine ski resorts which could lack snow or traditional beach resorts that get too hot.

People in Florida might become wary of living by the ocean, especially if they have to pay higher insurance premiums linked to rising seas. In cold climates, houses may have to be designed to lose heat in summer as well as trap it in winter.

The 1990s were probably the warmest decade of the past 1,000 years, with 1998 the warmest year, according to UN data. Temperatures have risen by 0.6 C since the late 1800s and may gain 1.4-5.8 C by 2100.

David Viner, a senior climate scientist at the University of East Anglia in England, said tourism could shift dramatically in the 21st century -- Mediterranean beaches might get too scorching for northern Europeans who would instead stay at home.

"People in northern Europe go to the Mediterranean because they have unpredictable summers at home. But the summers in the north will become warmer," he said.

HOTTER, THIRSTIER

With hotter, thirstier populations, air conditioner makers such as United Technologies Corp. or Japan's Daikin Industries seem obvious winners along with brewers such as Anheuser-Busch or Heineken.

But it is often hard to disentangle how climate affects demand -- fashion, health or other concerns are at play.

Analysts are unsure how far the share price of brewers, for instance, reflects expectations that warm years will continue.

Larry Watt, mayor of Kuujjuaq, said one reason for ordering air conditioners was to stop dust from outside blowing into computers. Before the municipality owned computers, the windows could be kept open in hot weather.

And Bergan in the ice cream shop in Oslo said: "People are buying fewer ice creams here than five years ago ... Maybe they're buying somewhere else or they worry about eating so much sugar."