. >> i'm command sergeant major armando saldana. >> and we and the troopers of 4- 9 cav, dark horse,swietoszow, poland, want to wish our families a happy thanksgiving. >> happy thanksgiving! >> begnaud: welcome back. you know, thanksgiving means turkey for a lot of people, but what about the bubbly? there's a world of sparkling choices, and prosecco from italy is a bestseller. seth doane take us there tonight. in our "eye on earth," he is going to tell us how heat, drought, and erratic weather are threatening the grapes used to make it. >> reporter: climate change are threatening centuries of italian tradition. paolo tomasella says extreme weather is posing new challenges at his vineyard, tenute tomasella. >> climate change is a big problem, when it's very hot, when it's raining, it rains very much. >> reporter: prosecco, he explains, should have low alcohol and high acidity, but high temperatures and earlier ripening produce the opposite effect. >> it's our prosecco. >> reporter: so tomasella is testing new techniques and letting italian government scientist, diego tomasi, use the v