More extreme weather on the way?

>>> it's brutally hot in the american southwest today. fires are still blazing in the rockies, and all the places where there isn't flash flooding . the midwest is struggling with with drought conditions , and the memory of last week's extreme heat wave is still fresh in the minds of millions of americans. and the word tonight from federal government weather experts, get used to it. our chief environmental affairs correspondent anne thompson is with us now from a fire charred section of colorado springs . anne, good evening.

>> reporter: good evening, brian. just consider this, june's extreme weather cost the u.s. almost $2 million. that's including the massive wildfire that happened here in colorado springs . that estimate comes from the insurance giant aon. and tonight we also have a warning from noaa, the national oceanic and atmospheric administration that once unusual weather is going to become more and more common. heat, fire and drought are familiar elements of most summers, but events in each case this summer are record breakers , due to climate change .

>> the intensity and frequency is caused -- not in every case, but many cases by human activity, increasing greenhouse gas concentrations in the atmosphere.

>> reporter: gases like carbon dioxide created when we burn fossil fuel. in the state of the climate report released today no, one noted significant changes at the ends of the earth in 2011 . the south pole hitting an all time high of 9.9 degrees on christmas day . the arctic continued to warm at almost twice the rate of lower latitu latitudes, further is rinking the sea ice .

>> all the ice reflects sunlight back to space. when the ice is gone, the sunlight that had been reflected back to space now is available to heat the earth even further.

>> reporter: climate challenge scientists say is increasing the odds of such extreme weather , can't be blamed for every event. looking at some last year's extremes, researchers found no evidence climate change caused the defb statie devastating floods in thailand. however, they say, our warming earth did play a role in the severity of the texas drought, caused in part by the cooler pacific waters of la nina , bringing dry conditions to the south.

>> we should get used to these la nina related heat waves , today they're 20 times more likely to occur than 50 years ago.

>> reporter: now, government scientists say 2011 was cooler than 2010 , but it was still warm enough to be one of the warmest 15 years on record. and with concentrations of greenhouse gases increasing, scientists say we should get ready for more extreme events. brian?

>> anne thompson , colorado springs tonight, thanks for that. another example of extreme weather just this morning, just outside austin texas , ten inches of rain fell in a matter of just a few hours, touching off some nasty flash floods , leaving more than a dozen homes totally sur rounded by water. it was a good sides mess to clean up later in the day, luckily nobody was hurt.