James Hansen

James E. Hansen heads the NASA Goddard Institute for Space Studies in New York City. He has held this position since 1981. He is also an adjunct professor in the Department of Earth and Environmental Sciences at Columbia University.

After graduate school, Hansen continued his work with radiative transfer models and attempting to understand the Venusian atmosphere. This naturally led to the same computer codes being used to understand the Earth's atmosphere. He used these codes to study the effects that aerosols and trace gases have on the climate. Hansen has also contributed to the further understanding of the Earth's climate through the development and use of global climate models.

Hansen is best known for his research in the field of climatology, his testimony on climate change to congressional committees in 1988 that helped raise broad awareness of global warming, and his advocacy of action to limit the impacts of climate change.

In the wake of President Donald Trump’s announcement that he was withdrawing the United States from the international climate agreement, governors from over a dozen states immediately announced they would take climate action on their own.

There is much that governors and state legislators can do, but study after study finds that keeping existing nuclear plants—our largest and most reliable source of clean energy—operating is one of the most important and cost-effective ways to prevent carbon emissions from increasing.


Mounting evidence of climate change is growing too strong to ignore. While the extent to which climate change is due to man-made causes can be questioned, the risks associated with future warming are too big and should be hedged. At least we need an insurance policy. For too long, many Republicans have looked the other way, forfeiting command-and-control regulations, and fostering a needless climate divide between the GOP and the scientific, business, military, religious, civic and international mainstream.

Now that the Republican Party controls the White House and Congress, it has the opportunity and responsibility to promote a climate plan that showcases the full power of enduring conservative convictions. Any climate solution should be based on sound economic analysis and embody the principles of free markets and limited government. As this paper argues, such a plan could strengthen our economy, benefit working-class Americans, reduce regulations, protect our natural heritage and consolidate a new era of Republican leadership. These benefits accrue regardless of one’s views on climate science.


by James Hansen, 02 December 2016


Sophie, my oldest grandchild, and I made a video concerning the crucial issue of how the climate matter can be solved in democracies.  See video.

Stopping human-made climate change is inherently difficult, because of the nature of the climate system: it is massive, so it responds only slowly to forcings; and, unfortunately, the feedbacks in the climate system are predominately amplifying on time scales of decades-centuries. The upshot is that there is already much more climate change “in the pipeline” without any further increase of atmospheric greenhouse gases (GHGs).  That does not mean the problem is unsolvable, but it does mean that we will need to decrease the amount of GHGs in the relatively near future.

Without 'negative emissions' to help return atmospheric CO2 to 350 ppm, future generations could face costs that 'may become too heavy to bear,' says James Hansen, lead author of a new study urgently calling for removal of carbon dioxide from the atmosphere.

If global temperatures on our planet continue to go up, ferocious super-storms could become more frequent and sea levels could rise several meters over the next century, drowning coastal cities along the way.

That’s the ominous warning put forth in a new, peer-reviewed paper penned by former top NASA scientist Dr. James Hansen and 18 co-authors, which was published in the journal Atmospheric Chemistry & Physics on Tuesday.

The paper builds from controversial research released last year before the study was peer reviewed, a process that gives other scientists an opportunity to critique the work.

In this interview (James Hansen, former Head of the NASA Goddard Institute for Space Studies and currently professor at Columbia University) talks about the role of nuclear in climate change mitigation.

I’m James Hansen. I’m from Columbia University’s Earth Institute where I had programmes on climate science awareness and solutions. First we have to educate the public because there’s a lot of misunderstanding about nuclear power.
There are problems with every energy source including nuclear power, but if you look at fossil fuels, 10,000 of people a day are dying from pollution from fossil fuels. Nuclear power has been much safer than that over its lifetime, but we can make it much better with new technologies, much better nuclear power. So it really has the potential of being a substantial part of the solution to climate change.

James Hansena, Makiko Satoa,b, Reto Ruedyc, Gavin A. Schmidtb, Ken Loc
16 January 2015
Abstract.  Global surface temperature in 2014 was +0.68°C (~1.2°F) warmer than the 1951-1980 base period in the GISTEMP analysis, making 2014 the warmest year in the period of instrumental data, but the difference from the prior warmest year (2010), less than 0.02°C, is within uncertainty of measurement.  The eastern two-thirds of the contiguous United States was persistently cool in 2014, cooler than the 1951-1980 average in all seasons.  Record warmth at a time of only marginal El Niño conditions confirms that there is no “hiatus” of global warming, only a moderate slowdown since 2000.  Global temperature in 2015 may further alter perceptions. We discuss the prospects for the 2015 global temperature in view of the seeming waning of the current weak El Niño.

James Hansen, 04 October 2014

In The Wheels of Justice I argued that a multi-front strategy is essential in the fight to stabilize climate and preserve our planet for young people and future generations.  One front is provided by our legal system.

Questions for the Record
Submitted by Senator Robert Menendez to
Dr. James Hansen
Senate Foreign Relations Committee Hearing
Keystone XL and the National Interest Determination
March 13, 2014

Menendez question #1:
Given that a new nuclear power plant would probably cost more than $12 billion, it seems few companies are willing to take the risk to build new plants here.  This reluctance occurs despite the fact that new nuclear plants receive a production tax credit, and that the federal government has agreed to foot some of the bill in the case of a catastrophic accident.  What makes you so bullish on nuclear power when other technologies, with less carbon emissions, are attracting much more investment in the United States than nuclear power?

by James Hansen, November 3, 2010

South China Morning Post

Chinese leadership can save humanity in the fight against global warming. But fossil-fuel companies must be forced to pay for their carbon emissions writes James Hansen.
The climate crystal ball is clear-the physics undeniable. Burning all fossil fuels (coal, oil, gas) would have staggering consequences, even threatening humanity's survival.

prof-james-hansen-001Dr. JAMES HANSEN, director of the NASA Goddard Institute for Space Studies, and one of the leading voices on global warming, joins Marty to discuss his research, advocacy and his new book, Storms of My Grandchildren. It tells the story of why Hansen boycotted the Copenhagen climate talks and has turned to a new degree of advocacy in the race to alleviate the effects of global climate change. Dr. Hansen will also discuss the new Kerry-Lieberman climate bill and what he thinks it will take for the United States and the world to align our carbon output with the Earth’s ability to absorb it without devastating disruptions.


RENEWABLE energy won't save the planet so it's time to go nuclear, according to one of world's most high-profile climate scientists.

"We should undertake urgent focused research and development programs in next generation nuclear power," said atmospheric physicist James Hansen, head of NASA's Goddard Institute for Space Studies and adjunct professor at Columbia University's Earth Institute in New York.

While renewable energies such as solar and wind were gaining in economic competition with coal-fired plants, Professor Hansen said they wouldn't be able to provide baseload power for years to come.

An essay delivered to the chairperson of the Carbon Trading Summit in New York on 12 January 2010.

Houston Chronicle 1/5/2010

NASA climatologist James Hansen's research into global warming has brought him fame — and put him in the big fat middle of controversy on more than one occasion.

The intellectual journey that first led Hansen to warn against the imminent perils to our planet of continuing to burn fossil fuels, particularly coal, began in the 1980s. Over the years it has also led him to another, somewhat surprising conclusion: Nuclear power could offer an environmentally acceptable way out of the problems caused by heavy reliance on coal.

Specifically, Hansen says, the Generation IV nuclear power plants now under development offer an alternative to burning coal that ought to be pursued, in this country and globally.


My experience with global temperature data over 30 years provides insight about how the science and its public perception have changed. In the late 1970s I became curious about well known analyzes of global temperature change published by climatologist J. Murray Mitchell: why were his estimates for large-scale temperature change restricted to northern latitudes? As a planetary scientist, it seemed to me there were enough data points in the Southern Hemisphere to allow useful estimates both for that hemisphere and for the global average. So I requested a tape of meteorological station data from Roy Jenne of the National Center for Atmospheric Research, who obtained the data from records of the World Meteorological Organization, and I made my own analysis.

Fast forward to December 2009, when I gave a talk at the Progressive Forum in Houston Texas. The organizers there felt it necessary that I have a police escort between my hotel and the forum where I spoke. Days earlier bloggers reported that I was probably the hacker who broke into East Anglia computers and stole e-mails. Their rationale: I was not implicated in any of the pirated e-mails, so I must have eliminated incriminating messages before releasing the hacked emails. The next day another popular blog concluded that I deserved capital punishment. Web chatter on this topic, including indignation that I was coming to Texas, led to a police escort.

Storms of our Grandchildren an urgent and provocative call to action from the world's leading climatologist.  Dr. Hansen’s background in both space and earth sciences allows a broad perspective on the status and prospects of our home planet.

Get the book.

Published in The Observer on 29 November, 2009

Never-Give-Up Fighting Spirit: Lessons From a Grandchild

Such negative questions and attitudes are increasing. How refreshing, on cold, windy Thanksgiving Plus One Day, which we spend with our children and grandchildren, when I went outside to shoot baskets with 5-year-old Connor. Connor is very bright, but needs work on his hand-to-eye coordination. I set the basket at a convenient height for him, but his first several shots banged off the backboard off-target. Then he said, very brightly and bravely, “I don’t quit, because I have never-give-up fighting spirit.” It seems his karate lessons are paying off.

Some adults need Connor’s help. A Scientific American article by Michael Lemonick, “Beyond the Tipping Point”, described our 2008 paper “Target Atmospheric CO2: Where Should Humanity Aim?” Lemonick concluded with the almost-obligatory “fair and balanced” opinion, delivered by Steve Schneider. In response to our conclusion that we must get atmospheric CO2 to peak during the next few decades, and then decline back to 350 ppm or less, Schneider opines “It has no chance in hell. None. Zero. The best we can do is to overshoot, reach 450 or 550 parts per million, then come back as quickly as possible on the back end.”

The scientific method requires that we keep an open mind and change our conclusions when new evidence indicates that we should.  Climate change is the new evidence affecting the nuclear debate -- we need low-carbon energy.  Current (2nd generation) nuclear reactors are not as fail-safe as possible and they burn less than one percent of the energy in uranium ore.  Next (3rd) generation reactors are safer, shutting down automatically in case of anomalies, and are ready to go, but they still leave 99 percent of the energy in long-lived waste piles.  4th generation reactors, tested but not commercially available, can extract all of the energy in the nuclear fuel and burn nuclear waste.  We urgently need R&D to make the combination of 3rd and 4th generation reactors available with comprehensive international controls.

"It would be great if energy efficiency, renewable energies, and an improved (”smart”) electric grid could satisfy all energy needs. However, the future of our children should not rest on that gamble. The danger is that the minority of vehement antinuclear “environmentalists” could cause development of advanced safe nuclear power to be slowed such that utilities are forced to continue coal-burning in order to keep the lights on. That is a prescription for disaster.

"There is no need for a decision to deploy nuclear power on a large scale. What is needed is rapid development of the potential, including prototypes, so that options are available. We have to avoid a “FutureGen” sort of drag-out. It seems to me that it is time to get fed-up with those people who think they can impose their will on everybody, and all the consequences that might imply for the planet, by putting this R&D on a slow boat to nowhere instead of on the fast-track that it deserves.”