Democratic presidential candidate Barack Obama says America is ready for a change. But speaking before a crowd of nearly ten-thousand Sunday at an Earth Day rally in downtown Iowa City, the Illinois Senator said people shouldn’t stand for future leaders who lack a sense of urgency.

"We know what to do. The problem is not a lack of plans and a lack of policies. The problem is a lack of will and a lack of a sense of urgency on the part of our government," Obama said. "That’s what’s going to have to change." Obama has drawn large crowds in cities around the country as well as in Iowa, and Obama sounded some of the same themes he’s used in speeches since February.

"The reason the people have been gathering all across the country is that they sense it is time to turn the page," Obama said. "They sense that it is time to write a new chapter in American history. They want a different kind of politics." In tribute to Earth Day, Obama told the crowd that if he’s elected president, he’d seek policies that reduce carbon dioxide emissions and he’s raise the federal fuel efficiency requirements for America’s cars and trucks. Also on Sunday, New York Senator Hillary Clinton — another Democratic presidential hopeful — met with nurses who’re striking at a hospital in Dubuque.