Earth Day 2009: Obama Energy Chief Lays Out Climate Doomsday Scenario

Days before Earth Day 2009, President Obama's Energy Secretary Steven Chu gave a press briefing at the "Summit of the Americas" in Trinidad and Tobago where he laid out the potentially disastrous consequences if the world community doesn't unite to combat climate change.

Chu, who won the Nobel Prize for Physics in 1997, detailed several of the most dramatic impacts that global warming could have, such as several island nations being submerged.

We've posted the transcript below -- take a look:

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SECRETARY CHU: Well, I had no discussions in this summit meeting on the issue as to whether the climate is really changing or what are potential economic consequences. Now, in full candor, I haven't talked with representatives from Venezuela yet, but I think they're -- in terms of discussing whether the climate is changing or whether humans have caused it, I think for the most part this debate is over. It's something -- yes, it's changing; that's a demonstrable fact. If one looks at the latest IPCC reports, there's very, very convincing evidence -- very high probability it was caused predominantly by greenhouse gas emissions. And what is not known with certainty is what are the range of effects that might happen, and -- because that, quite frankly, also depends on what the world does.

But let me just say that there are certainly a reasonable probability that -- I'm sure the people in this room have heard this -- that in the last IPCC report, the 2007 report, they said that it's going to be somewhere between two and four -- two and a half, four and a half -- I'm not sure of the exact numbers -- degrees Centigrade change.

And so let me remind you that the Earth has already warmed up by about 0.8 degrees Centigrade; that the experts acknowledge that there is another 1 degree Centigrade already built into the system, even if humans stopped carbon emissions today flat. That's because we put enough greenhouse gases up into the atmosphere, the sun continues to warm up the Earth, and until you reach a new equilibrium or the heat from the Earth then reaches the equilibrium -- what's coming in and what's getting reflected back -- there's 1 degree change already; that there's a reasonable probability we can go above 4 degrees Centigrade to 5 and 6 more. That means we have a -- there's a reasonable probability, and certainly in business-as-usual scenario, we can go to 5 or 6 degrees Centigrade.

Now, what does that mean? The last ice age, we were 6 degrees Centigrade colder than we are today -- a very different world. Okay, only 6 degrees Centigrade means, in North America, ice sheet from Canada down to Pennsylvania, Ohio -- year round in ice. So imagine a world 6 degrees warmer. It's not going to recognize geographical boundaries. It's not going to recognize anything. So agriculture regions today will be wiped out. Yes, there are parts of Canada will be -- can grow more food, but, you know, the other thing is, the Earth is spherical and the sun hits at an angle up north. So there are going to be huge consequences if we go up to that 4, 5, 6 degrees.

Q How long would it take?

SECRETARY CHU: We're talking about that temperature in -- by the end of this century. And the other thing is, you stick that carbon in the atmosphere, it cycles around, but it's up there for a couple hundred years. Okay, so you've just bought a couple hundred years of this effect. So -- and that could have dramatic consequences on the world, but especially the more vulnerable people in the world.

Q Secretary Chu, so did any of the leaders, especially from this part of the world, talk about the specific concerns about rising ocean levels?

SECRETARY CHU: Yes, very much so. I think the Caribbean countries face rising oceans and they face increase in the severity of hurricanes. This is something that is very, very scary to all of us; that if you consider what has been happening, especially in the polar regions in the north, and you look at the predictions of the IPCC beginning in 1990, this is something they didn't do so well. It's melting considerably faster than anyone predicted ten years ago.

So we are terribly afraid there will be an increase in temperature if the ice in the Antarctica and Greenland melt. This is bad news. If Greenland melts -- it's two or three kilometers thick -- we're looking at a seven-meter sea level rise around the world. Some island states will disappear.

So there was specific -- at the lunch today, there was specific discussion represented from the island states that this is of great concern, and the island states in the world represent -- I remember this number -- one-half of 1 percent of the carbon emissions in the world. And they will -- some of them will disappear. So this is pretty serious business.