TODAY | April 05, 2014
>>> this week, the united nations released a sobering report about climate change and the impact it's having around the world, and some experts say we could be going from bad to worse. ann curry takes a look.
>> reporter: for the last year and a half, it seems mother nature has thrown everything at us.
>> look at the cold air that is surging into the upper midwest .
>> reporter: a bone-chilling deep freeze, searing heat, drought and fire, floods gushing through the u.s., europe and asia. and superstorms devastating entire regions. what on earth is going on? for more than a year, we traveled the far corners of our planet searching for answers to what's causing these weather extremes.
>> this is the storm of the century .
>> reporter: we met ordinary people who have seen changes up close and asked some of the world's brightest scientists, is the weird weather a coincidence or a sign that fundamental change is here?
>> the planet is not just changing, it's changed.
>> reporter: just this past week, an influential group of the world's climate scientists named the intergovernmental panel on climate change , issued a groundbreaking report, saying climate change is already sweeping all the continents and oceans of our planet . their position, there is no doubt the planet is getting warmer. over the years, you've probably heard debate about whether man or nature is to blame, but now, for most climate scientists, that debate is over. 97% of them agree, as humans burn fossil fuels like coal, oil and gas , pumping carbon dioxide or co2 into the atmosphere, the planet warms. you're saying it's impossible for it not to have something to do with the warming of the planet , just because of simple physics.
>> literally impossible. there is no argument that mankind's activities have caused the planet to warm.
>> reporter: even so, we wondered, is there anything we can do to stop climate change altogether?
>> in the next hundred years, it's really tough to deal with the changes that are coming. we probably can't affect a lot of those. on the longer time scales , though, we can have dramatic effects.
>> reporter: for "today," ann curry , nbc news.
>> you can see much more of ann's reporting in an nbc news special "our year of extremes" on sunday night at 7:00/6:00 central on nbc .