Researchers at the Naval Postgraduate School have told us that the entire Arctic ice cap may totally disappear in summer in as little as five years if nothing is done to curb emissions of greenhouse gas pollution.

Any child born into the hugely consumptionist way of life so common in the industrial world will have an impact that is, on average, many times more destructive than that of a child born in the developing world.

If you allow someone like Saddam Hussein to get nuclear weapons, ballistic missiles, chemical weapons, biological weapons, how many people is he going to kill with such weapons? He's already demonstrated a willingness to use these weapons. He poison-gassed his own people. He used poison gas and other weapons of mass destruction against his neighbors. This man has no compunction about killing lots and lots of people. So this is a way to save lives and to save the stability and peace of a region of the world that is important to the peace and security of the entire world.

As human beings, we are vulnerable to confusing the unprecedented with the improbable. In our everyday experience, if something has never happened before, we are generally safe in assuming it is not going to happen in the future, but the exceptions can kill you and climate change is one of those exceptions.

Making consumer choices that reward eco-friendly products and companies is a great way to start.

There's such a wide variation in tax systems around the world, it's difficult to imagine a harmonized CO2 tax that every country agrees to. That's not in the cards in the near term. But the countries that are doing the best job, like Sweden, are already doing both of these. I think that eventually we'll use both of them but we need to get started right away and the cap-and-trade is a proven and effective tool.

American democracy has been hacked.