The document summarizes a Senate hearing where four of President Bush's advisors defended his decision to withdraw from the Kyoto Protocol and implement voluntary programs to reduce greenhouse gas emissions instead. They argued this approach would save billions of dollars compared to the costs of the Kyoto Protocol. However, Democratic senators criticized the plan as inadequate given the warnings about climate change impacts in a recent administration report. The debate centered on whether voluntary programs or mandatory caps on emissions were needed to sufficiently address climate change risks.