The event includes Rajendra Pachauri, chairman of the United Nations' Intergovernmental Panel on Climate Change, and billionaire Sir Richard Branson. Former Gov. Arnold Schwarzenegger also is expected to attend Thursday afternoon.
Brown vowed to continue investing in renewable energy and infrastructure projects to protect coastlines from sea-level rise and homes from increased flooding from faster snow melts and longer wildfire seasons.
Brown opened the conference by calling for people to wake up to these threats, and called skeptics of global warming a well-funded "cult."
