MARSHALL SHEPHERD: When I heard about the agreement, I said boy, what a great birthday present. It gets us halfway there, but one of the really interesting things if you read through the details of this new agreement, it really, in five years out it requires countries to be more aggressive about some of their targets as we move forward. And that's very important for us.
JOHN DICKERSON (HOST): But if it's only halfway there, how do we get to the other half?
SHEPHERD: Well I think that's where we see this cascading, or rolling, or building in terms of the targets that the 195-plus countries agreed to. And I want to make the point that this is very different from previous agreements like Kyoto, which left some of the big-emitting countries like China out. What's important about this particular agreement is it really brings everybody into the tent and gets a commitment from everyone to reduce their emission levels. It's a part of this mitigation of climate change. It also has key provisions in there for adapting, suggesting that some things are already going to happen and we need to adapt to them.
DICKERSON: So it's not just though, in terms of meeting this crucial tipping point, or avoiding the tipping point, meeting the crucial goals, it's not just that they all got together in a room and made an agreement, there needs to be constant vigilance in terms of keeping these goals.
SHEPHERD: That is correct. This is really the start of something that will cascade or roll through the next several decades. It requires countries, and there's a counting of these reductions, and it also requires these countries to actually, in the next reporting period out three, five years, to actually produce more aggressive targets as well, and that will be key to keeping us at that two-degree level.
