James Hansen

The case for a sustainability emergency

The pressure to soft-pedal is very, very high. I know because I feel it. I'm tempted. I do not wish to be dismissed as an apocalyptic. So when I read, in this fine and even astonishing report, that "politics as usual" must be cast aside, and quickly, there's something in me that balks.

After all, the mainline debate at Bali was about a "25-40% cut by 2020" for the developed countries. Isn't this enough? Doesn't it tell us that we're already moving as quickly as we can? Must we call for emergency mobilization? Must we seek to put all "available and necessary resources" at the service of a global crash program to stabilize the climate?

Carbon is forever — so ban new traditional coal plants now

Another clear statement (PDF) from the nation's top climate scientist on the scientific need for a dramatic change in global coal policy -- this time addressed to the German chancellor, a fellow physicist. He points out that:

Hansen v. coal

PRE-PUBLISHING UPDATE: After I wrote this but before I posted it, I got an email from Grist reader CD notifying me of the sad news that Mass.’s gov approved the coal gasification plant. Decisions like this are going to look awfully stupid in a few years. —– I meant to mention this last week, but […]

What is the safe upper limit for atmospheric CO2?

The nation's top climate scientist, NASA's James Hansen, apparently now believes "the safe upper limit for atmospheric CO2 is no more than 350 ppm," according to an op-ed by the great environmental writer Bill McKibben. Yet while preindustrial levels were 280, we're now already at more than 380 and rising 2 ppm a year!

Like many people, in the 1990s I believed 550 was the target needed to avoid climate catastrophe -- but now it's clear that:

1. 550 ppm would lead to the greatest disaster ever experienced by human civilization -- returning us to temperatures last seen when sea levels were some 80 feet higher. This is especially true because ...
2. long before we hit 550, major carbon cycle feedbacks -- the loss of carbon from the tundra and the Amazon, the saturation of the ocean sink (already beginning) would almost certainly kick into high gear, inevitably pushing us to much, much higher CO2 levels (see here, here, and my book).

Exactly when those feedbacks seriously kick in is the rub. No one knows for sure, but based on my review of the literature and interviews of leading climate scientists, somewhere between 400 and 500 ppm seems most likely. It could be lower, but it probably couldn't be much higher.

So I, like the Center for American Progress and the world's top climate scientists, now believe 450 ppm is the upper bound. That said, I have spent two decades managing, analyzing, researching, and writing about climate solutions and can state with some confidence that:

1. Staying below 450 ppm is technologically doable, but would be the greatest achievement in the history of the human race, by far. It would require a global effort sustained for decades, comparable to what the U.S. did for just the few years of World War II (the biggest obstacle is not technological, but political -- conservatives currently would never let progressives and moderates pursue such a strategy).
2. If 350 ppm is needed (and I'm not at all sure it is) then the deniers and delayers have won, since such a target is hopeless.

In 2008, I will devote a fair amount of ink bits to laying out the solution (there really is only one), but to understand why 450 is so hard, and 350 all but inconceivable, let's look at the odd way McKibben describes the solution:

James Hansen talks about what to do now that we’ve passed the ‘tipping point’

For the last few years, James Hansen, the man who first warned Congress of global warming in testimony last century, and the man considered NASA's "top scientist" on climate questions, has been giving talks around the country asking can we avoid dangerous climate change (PDF)?

But Hansen has changed his tune: no longer does he ask if we have passed the tipping points of climate change. In a press conference Thursday morning at the American Geophysical Union, he stated that we have passed several tipping points. He said scientists now know that soon the Arctic will be ice-free in the summer, that huge ice sheets will melt, and the climactic zones will shift towards the poles of the earth, among other consequences.

A letter from James Hansen pleads for action on coal-fired power plants

The following is a draft letter to UK Prime Minister Gordon Brown, on the subject of proposed new coal-fired power plants. (A similar letter is in the works to German Chancellor Angela Merkel.) The author would appreciate feedback.

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Dear Prime Minister Brown,

Your leadership is needed on a matter concerning coal-fired power plants in your country, a matter with global ramifications, as I will clarify.

For the sake of identification, I am a United States citizen, director of the NASA Goddard Institute for Space Studies and Adjunct Professor at the Columbia University Earth Institute. I write, however, as a private citizen, a resident of Kintnersville, Pennsylvania, on behalf of the planet and life on Earth, including all species.

I recognize that you strongly support policies aimed at reducing the danger of global warming. Also Great Britain has been a leader in pressing for appropriate international actions.

Yet there are plans for construction of new coal-fired power plants in Great Britain. Consummation of those plans would contribute to foreseeable adverse consequences of global warming. Conversely, a choice not to build could be a tipping point that seeds a transition that is needed to solve the global warming problem.

Basic Fossil Fuel Facts

The role of coal in global warming is clarified by a small number of well-documented facts. Figure 1 shows the fraction of fossil fuel carbon dioxide (CO2) emissions that remains in the air over time. One-third of the CO2 is still in the air after 100 years, and one-fifth is still in the air after 1000 years.

Is the analogy between climate change and Hitler’s atrocities appropriate?

Andy Revkin has an interesting post on Dot Earth about global warming and Holocaust analogies. On Oct. 22, climate scientist James Hansen testified before the utilities board in his home state of Iowa. He said, among 59 pages of other stuff, this: If we cannot stop the building of more coal-fired power plants, those coal […]

Hansen’s response to a claim that he accepted money from George Soros

I don't know how NASA's James Hansen keeps up his pace of writing -- or how he puts up with the steady stream of disinformation launched against him. I am not trying to create a cult of personality around him, but I do feel under some obligation to give his writing as much attention as possible -- as I think he has done more than any other scientist to raise awareness on climate change, and deserves our thanks, not slander.

"The latest swift-boating," Hansen explains in a new post (PDF), "is the whacko claim that I received $720,000.00 from George Soros." Here is a smear from Investors Business Daily, of all places -- I have no idea why investors would be interested in such drivel -- which migrated over to the conservative websight NewsBusters in an article titled, "Is Global Warming Alarmist James Hansen a Shill for George Soros?"

Hansen explains, "Here is the real deal, with the order of things, as well as I can remember without wasting even more time digging into papers and records":

‘Long-term’ climate sensitivity of 6 degrees C for doubled CO2

The nation's top climate scientist is prolific: He has co-authored another important article: "Global Warming: East-West Connections" (PDF). And I'm not just saying that because he cites one of my articles. In fact, we've been having an email exchange and he strongly disagrees with me that it is too late, in a practical sense, to save the Arctic (and hence the polar bear). He believes strong and smart action now could work -- whereas I believe we need such action now to save the Greenland ice sheet, but doubt we can or will act in time to stop the total loss of Arctic summer ice.

I have previously written about the crucial climate variable -- the equilibrium climate sensitivity (typically estimated at about 3°C for double CO2) -- and how it only includes fast feedbacks, such as water vapor. Now Hansen has a draft article that looks at both current climate forcings and the paleoclimate record to conclude that "long-term" sensitivity is a stunning 6°C for doubled CO2. Here is what Hansen says on the subject (though when you read it you may wonder why Hansen is more optimistic than I am, rather than less):