John Holdren

Any objective look at what science has to say about climate change ought to be sufficient to persuade reasonable people that the climate is changing and that humans are responsible for a substantial part of that - and that these changes are doing harm and will continue to do more harm unless we start to reduce our emissions.

Issues of energy, climate change, nuclear arms control and non-proliferation are all big deals. These are problems that we have to get right globally, not just nationally, and there are big benefits in cooperating, in terms of sharing costs, in terms of sharing risks, in terms of propagating the best answers.

Iran's continued drive to develop nuclear capabilities, including troubling enrichment activities and past work on weaponization documented by the IAEA, and its continued support to groups like Hezbollah, Hamas and other terrorist organizations make clear that the regime in Tehran is a very grave threat to all of us.

Well, there's no question that the law passed in 1996 was flawed. It deregulated the wholesale market, meaning the price that the utilities had to pay energy companies for power, but not the retail market.