Last week, 164 people died from extreme heat in California. This week's heat wave has caused fatalities and power outages in the eastern states of America. Though a cold wave might push temperatures down into the 80's tonight, increased demand for electricity means that energy supplies will be strained for a long time to come. Climatologists warn about global warming, and many energy experts say that America's way of life will increase demand for electricity. The world's biggest retailer shocked its critics by welcoming Al Gore to lecture about the environment. Wal-Mart is going green. Is conservation good business for big companies that depend on increased consumption? Is America's current lifestyle sustainable? We speak with journalists, and sustainability and energy experts, including a former Energy Department official. Making News: Generals Testify before Senate on Threat of Iraqi Civil WarAt a Senate committee hearing today, Defense Secretary Donald Rumsfeld heard bitter criticism from New York's Democratic Senator Hillary Clinton. She asked why Americans should believe him now when he's been wrong in the past, making reference to his "track record" of "many assurances that have proven to be unfulfilled." John Donnelly, who covers defense and foreign policy, attended the hearings for Congressional Quarterly. Reporter's Notebook: Tackling Hezbollah in LebanonHezbollah rockets killed seven Israelis today, the most in a single day since July's last month's strike on Haifa. Israel's current stated objective is to establish a buffer zone until a multinational combat force can move in along the border. At the UN, there's still no consensus on if that could be accomplished. We look at the long-term challenge posed by Hezbollah with Joel Greenberg, who's on the border between Israel and Lebanon for the Chicago Tribune and political scientist Robert Pape at the University of Chicago.