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Is heat wave a result of global warming?

We’ve had heat waves before. The worst was in the 1930s when 50 million acres turned to dust. NBC's Tom Costello reports

The debate over global warming has been raging for years.

So, is our current heat wave a symptom of global warming?

Here’s what most scientists say is certain:

  • The Earth is warming, by 1.4-degrees Fahrenheit since 1920
  • The ice caps are melting and sea levels are rising
  • 10 of the last 12 years were the warmest since 1850
  • The first six months of 2006 were the hottest since they started keeping records in 1890.

"This heat wave and other extreme events we've seen in recent years are completely consistent with what we expect to become more common as a result of global warming, even though we can't be definitive on any single event,” says Jay Gulledge with Pew Climate Change.

We’ve had heat waves before. The worst was in the 1930s when 50 million acres turned to dust. In 1972, 891 people died in New York over a 14-day stretch. And in 1995, 733 people died in record heat in Chicago.

But experts say our current heat wave is unique.

"So far, we've had about 80 daily high temperature records broken and in the month of July there were about 50 all-time records for the month of July broken -- that's phenomenal for any air mass, any heat wave that's going on right now," says Dennis Feltgen, a meteorologist with the National Oceanic and Atmospheric Administration.

But scientists want to see whether this heat wave is part of a longer, more intense pattern of heat waves before declaring it all part of the bigger global warming phenomenon.

Still, the movement to curb greenhouse gas emissions is gaining traction, with 22 cities worldwide signing on to former President Bill Clinton’s initiative to cut carbon dioxide emissions.

"We know what needs to be done, we have to use less energy and find cleaner sources," Clinton says.

The concern now is that, in the coming decades, 100 degrees may be the new norm.