CHICAGO (AP) -- Barack Obama is scheduled to speak today at the Chicago Council on Global Affairs.
The Illinois Democrat was supposed to address that forum last week. But his speech was rescheduled after the killings of more than 30 people at Virginia Tech.
The presidential candidate marked Earth Day over the weekend in Iowa.
He told an Iowa City rally not to wait for their political leaders to tackle issues like climate change.
He says change won't happen because bills are introduced in Congress. Instead, he says change will happen once American people mobilize around the issue.