• James Hansen, an early outspoken leader in warning about the risks of global climate change, delivers the 13th annual David Rose Lecture at MIT’s Wong Auditorium.

    James Hansen, an early outspoken leader in warning about the risks of global climate change, delivers the 13th annual David Rose Lecture at MIT’s Wong Auditorium.

    Photo: Russ Campbell

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  • Richard Lester, head of MIT’s Department of Nuclear Science and Engineering, introduces Hansen.

    Richard Lester, head of MIT’s Department of Nuclear Science and Engineering, introduces Hansen.

    Photo: Russ Campbell

    Full Screen

James Hansen: We should look at all energy options

James Hansen, an early outspoken leader in warning about the risks of global climate change, delivers the 13th annual David Rose Lecture at MIT’s Wong Auditorium.

Former NASA scientist says we need to develop all carbon-free energy sources to avoid disaster.

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James Hansen, a former head of NASA’s Goddard Institute for Space Studies who was one of the first scientists to raise concerns about global climate change, spoke at MIT Tuesday in the biennial David J. Rose Lecture, sponsored by the Department of Nuclear Science and Engineering (NSE).

Richard Lester, the Japan Steel Industry Professor at MIT and department head of NSE, said in introductory remarks that Hansen “may well be the world’s best-known climate scientist.” Hansen came to prominence in the late 1980s, when he first testified before Congress about the perils of accumulating carbon dioxide in the atmosphere — testimony that “had a galvanizing effect,” Lester said.

“I think it’s really important that young people understand the situation that we older people are leaving them with,” said Hansen, currently an adjunct professor at Columbia University’s Earth Institute. “It’s going to be extraordinarily difficult to deal with … and I’ve become frustrated with governments that don’t recognize their responsibilities to future generations.”

He said that while it may not have been apparent during this year’s harsh winter in the Boston area, “the planet was actually extremely warm in January, February, and March” — in fact, he added, the readings for those months were the warmest for that season in recorded history. That wasn’t obvious locally, Hansen said, merely because, “We’re stuck in this pattern where the eastern part of North America has been extremely cold.”

That pattern, Hansen suggested, may be related to a cold patch in the North Atlantic, generated by increasing meltwater from Greenland, that may portend a slowdown of the present Atlantic circulation system. Overall, he said, 2014 was the warmest on record, and 2015 is on track to exceed it.

Delayed responses

“We have an emergency,” Hansen said. He pointed out that there is a lag in the climate system, so the planet has not yet finished warming from the greenhouse gases that are already in the atmosphere. “And we’re adding more all the time,” he added.

What’s more, the response to this increase in greenhouse gases is likely to be extremely nonlinear, he said: “It just turns out that our climate system is dominated by amplifying feedbacks … so there’s a danger that the system is going to run out of control.”

“The things that we need to do actually make sense for other reasons,” Hansen stressed, “but they’re not being pursued, and frankly they’re not even being proposed by governments.”

Some effects of climate change, he said, are simply irreversible. For example, the Intergovernmental Panel on Climate Change has projected that 25 to 50 percent of all species on Earth could be extinct by 2100 if energy use continues on its current trajectory. The loss of ice sheets is essentially also irreversible, since it takes thousands of years for these sheets to accumulate.

While most policy recommendations have focused on trying to limit greenhouse gas emissions to a level that would produce warming of no more than 2 degrees Celsius, that is “actually a disaster scenario, in my opinion,” Hansen said: It would likely cause so much melting of ice sheets that the resulting sea-level rise would render most of the world’s coastal cities uninhabitable.

Rebalancing the system

“We have to rebalance the planet’s energy balance,” Hansen said. Earlier calculations, he said, had indicated that would require a sustained reduction of 6 percent annually in global carbon emissions — a very difficult target to meet — but more recent measurements have shown that the planet is absorbing more carbon dioxide than scientists had expected, so the actual needed reduction may be less.

“The science is crystal clear,” Hansen said: We can’t afford to burn even the already known reserves of fossil fuel. And avoiding that, he said, will require a substantial increase in the use of nuclear power.

“We need to be realistic in looking at the available energy sources,” he said, pointing out that solar and wind energy still represent only about 3 percent of global energy supply.

“If we could decarbonize electricity, then we could solve the problem,” Hansen added: Even liquid fuels for transportation can be manufactured using alternative sources of electricity. Sweden, he noted, has already achieved essentially carbon-free electricity, thanks to a combination of nuclear power and abundant hydropower; France is nearing this goal, thanks mostly to its extensive use of nuclear power. Both countries, he said, produced most of their nuclear infrastructure within a decade, “so that has been the fastest way to decarbonize that has been demonstrated so far.”

Fossil fuels have been artificially cheap because their true costs to society, including pollution and climate change, have been ignored, Hansen said. To counter that, he added, what’s needed is “to put a rising fee, a tax, on carbon emissions,” which would be collected at the source, and then returned directly to the public.

“That would be a huge incentive for entrepreneurs to develop no-carbon and low-carbon energy and products,” Hansen said. And by returning the money to the people, he said, those who achieve the greatest reductions in carbon use would reap the greatest profit. Projections show that such an approach could reduce U.S. carbon emissions by more than half within 20 years — and create 3 million new jobs in the process.

“I think you need to be open-minded,” Hansen said. “We should be looking at all the carbon-free energy sources, and figuring out what their contribution should be — and frankly, the market should be helping us do it. … We should have a carbon-free energy portfolio, and let the market find what is the least expensive way. We should be doing [research and development] on all the good candidates, and certainly nuclear is one of them.”

Topics: Special events and guest speakers, Nuclear science and engineering, School of Engineering, Climate change, Sustainability, Environment, Energy, Nuclear power and reactors


And by returning the money to the people, he said, those who achieve the greatest reductions in carbon use would reap the greatest profit. "
Really ??? I'd like to see the actual math behind that statement. Give me an example with some actual numbers of how that would work.
At best, it sounds like income redistribution, at worst, just double speak.
...and while you are doing that, how about providing an example of a time when a government actually returned the money that they collected from a Tax on an industry to "the people". ( we will just ignore the fact that the Carbon Tax is paid by the Customers of the industry ( the "people") in the first place)
.... and promises of returns that take the form of vague payments in the future while the government spends the collection now don't count. We've seen that movie before.

If you believe we have to transition away from carbon based energy sources then I would say a universal emissions tax is the way to do it. It's nonintrusive, less political than current tax incentives, and leaves markets to find the best way to adapt. As for "redistribution", if Congress ever gets working again you might be able to trade a new carbon tax for across the board rate cuts elsewhere. Possibly even make it budget neutral.

I am all for the government correcting externalities and the science seems to say carbon is imposing huge costs on society.
The devil would be in the details however. To gauge the cost of a pound of CO2 you need to calculate its warming effect as well as how that temperature increase's affects the economy and environment. Both these calculations are at best hazy. The climate behaves chaotically, so it is very difficult to predict its behavior. The current "pause" in warming is a perfect example.

This instability is part of what make human CO2 emissions so scary. The climate is in balance right now, but a sufficient push could dramatically alter it (e.i. Another ice age or tropics at the poles). It is up to us as a society to decide how seriously we will take that risk.

Hansen is right, nuclear is the way to go and has been demonstrated in France (eliminating coal as an energy source for electricity). Once nuclear provides the base, now solar and wind can be supplemental to further suppress carbon emissions. People who call for more research are missing the point, we already have the power to get rid of fossil fuels in electricity generation. Waiting for solutions is folly in fighting climate change, we do not have the time. Once fossil fuels have been deterred to a large degree then there may be other options out there, but nuclear fission is the only option right now. Replacing the internal combustion engine is another matter, but the electric car only makes sense if the power company is using carbon free energy.

Hansen base himself on absurd low estimations regarding the deaths caused by nuclear. E.g. that Chernobyl caused 40 deaths, while the Annals of the New York Academy of Sciences show that more than a million would be a far better estimation.

How did nuclear kill all those people? Where are your facts? "UN and other international agencies such as the Chernobyl Forum and the World Health Organization
state that such numbers are wildly over-estimated, stressing a need for
hard documentation of deaths. It is thought that the principal
long-term adverse health outcomes are anxiety and depression among the
general public across Eastern Europe as a result of irresponsible
reporting and exaggerated statements by anti-nuclear power activists."
Your statement about the "absurd" level of deaths is absurd in your mind only

According to you the New York Academy of Sciences agrees with your viewpoint which is in itself is absurd. Here is their quote on the subject

"Annals of the New York Academy of Sciences issue “Chernobyl:
Consequences of the Catastrophe for People and the Environment”,
therefore, does not present new, unpublished work, nor is it a work
commissioned by the New York Academy of Sciences. The expressed views of
the authors, or by advocacy groups or individuals with specific
opinions about the Chernobyl volume, are their own. Although the New
York Academy of Sciences believes it has a responsibility to provide
open forums for discussion of scientific questions, the Academy has no
intent to influence legislation by providing such forums. The Academy is
committed to publishing content deemed scientifically valid by the
general scientific community, from whom the Academy carefully monitors

So you have no facts and should not comment upon a subject of which you are offering your viewpoint which is slanted anti-nuclear.

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