2010
Blue Planet Prize
Dr. James Hansen (USA)

Sir Bob Watson (UK)

Director at Goddard Institute for Space Studies( NASA )Adjunct professor in the Department of Earthand Environmental Sciences at Columbia
University

Chief Scientific Adviser of the UK Department
for Environment, Food and Rural Affairs(DEFRA)
Chair of Environmental Science and Science
Director at Tyndall Centre for Climate Change
Research, the University of East Anglia

PRAY:
This blue planet where we live
Does not belong to us only
All the children to be born on thisplanet,All living beings on the planet,
All have the holy right
To rejoice in the happiness
Of being born on this planet
We as one of those given life on thisplanet,By rendering thoughts to all the life
rejoicing in their lives
In the future of this planet,
Can recreate our linkage
Between all of those lives and us.
If the film helps to allow you
To refresh you to rejoice in the happinessOf passing this blue planet to the future
generations,
By rendering thoughts to the blessingsof the Earth,
The Planet of LifeWe are more than delighted

Selected from the Slide Show Presented at the Openingof the Awards Ceremony
207

Their Imperial Highnesses Prince andPrincess Akishino at the Awards Ceremony
His Imperial Highness Prince Akishino congratulates
the laureates
The prizewinners receive their trophies from Chairman Tanaka

Tetsuji Tanaka, Chairmanof the Foundation delivers
the opening address

Dr. James Hansen

Dr. Hiroyuki
Yoshikawa, Chairmanof the Selection
Committee explains
the rationale for thedetermination of the
year's winners

Mr. James P. Zumwalt, Deputy Chief of Mission of theUnited States of America (left) and Mr. David Warren,
United Kingdom Ambassador to Japan, congratulate thelaureates

Blue Planet Prize Commemorative Lectures208

Sir Bob Watson

Profile

Dr. James Hansen
Director at Goddard Institute for Space Studies ( NASA )Adjunct professor in the Department of Earth and Environmental Sciences at Columbia
University
Education and Academic and Professional Activities
1941
Born in USA
1963
Receives a bachelor’s degree in physics and mathematics at the University of
Iowa
1965, 1967 Receives a master’s degree in astronomy and a doctorate in physics at the
University of Iowa
1967-1969 A researcher at Goddard Institute for Space Studies (New York)
1969
Post-doctoral fellow at Leiden Observatory (Netherlands)
1969-1972 Researcher at Columbia University (New York)1972-1981 Manager of the planetary atmospheres program at Goddard Institute for SpaceStudies
1978-1985 Adjunct professor in the Department of Earth Sciences at Columbia University
1981-present Director at Goddard Institute for Space Studies
1985-present Adjunct professor in the Department of Earth and Environmental Sciences atColumbia University
1996
Elected to United States National Academy of Sciences
2001
John Heinz Environment Award
Roger Revelle Medal, American Geophysical Union
2006
Duke of Edinburgh Conservation Medal, World Wildlife Fund (WWF)2007
Laureate, Dan David Prize for Outstanding Achievements & Impacts in Quest
for Energy
Leo Szilard Award, American Physical Society for Outstanding Promotion &Use of Physics for the Benefit of Society
Haagen-Smit Clean Air Award
American Association for the Advancement of Science Award for Scientific
Freedom and Responsibility
2009Carl-Gustaf Rossby Research Medal, highest award of American MeteorologicalSociety
2010
Sophie Prize(As of June, 2010)209

Based on the concept of radiative forcing to indicate the flow of radiation energy in theatmosphere, Dr. Hansen et al. succeeded in developing a practical climate model that wasproven by tests such as the Pinatubuo volcanic eruption – they predicted global cooling tofollow, which proved quite accurate – there are other verifications, and pioneered understanding
and forecasting of the climate system. At a time when there was a noticeable temperaturedecline because of the impact of the sun and volcanic activity, Dr. Hansen predicted global
warming in the future based on the climate model. In 1988, he got more attention with strong
statements at an appropriate time to testify before committees and subcommittees in the US
Senate and House of Representatives and provided the public with an early alert to the dangers
of global warming and to call for actions. Later he claimed that the climate had a “tipping
point,” and warned that an average temperature increase of even a few degrees would very
probably cause irreversible and unrecoverable climate change and produce destructive results
for life on Earth. Dr. Hansen called on the governments and the public to take immediate action
to reduce and mitigate the impact of climate change. He has consistently emphasized the needfor unprecedented international cooperation and significantly contributed to enlightening thewhole world about global environment issues.
From Astronomy to Climate Science
Study of Planetary Atmosphere
Dr. Hansen was born on a farm, located in Charter Oak township, Iowa in 1941. Attracted to
the renowned space science program of Professor James Van Allen of the University of Iowa,
he received a master’s degree in astronomy and a doctorate in physics at the university. Whileattending the University of Iowa, he came to Japan and did researches on astrophysics andastronomy at the University of Kyoto and the University of Tokyo, respectively. Professor Sueo
Ueno of Univ. of Kyoto kindly introduced Dr. Hansen to his methods of computation called“invariant imbedding”, which is one of the techniques Dr. Hansen used for radiative transfer inplanetary atmospheres.
In 1967, he analyzed the data on Venusian temperature and published a thesis arguingthat the high temperature of Venus was attributable to a trap of thermal energy caused byaerosol in the atmosphere. In 1974 and 1975, he studied the composition of clouds in the
Venusian atmosphere, which completely veil the planet so that its surface cannot be seen. He
reported that the clouds consisted of very small spherical droplets of nearly uniform size – healso was able to measure the index of refraction of these droplets and how this index changed
from ultraviolet to green to red and infrared wavelengths – this precise information was usedby others to conclude that the hazy veil shrouding Venus must be sulfuric acid. The Pioneer
Venus spacecraft launched in 1978 confirmed the properties that Dr. Hansen had inferred fromtelescopic observations and confirmed that the haze was sulfuric acid. The validity of thefinding was proven by the Pioneer Venus Orbiter in 1978. In 1981, Dr. Hansen reported that theclouds consisted of sulfuric acid airborne droplets and sulfur dioxide.
Other researchers reported that Venus had been rich in water until several billion years
before and that the water had disappeared from the surface of the planet due to the runaway
greenhouse effect that subsequently occurred.1 Later, Dr. Hansen warned that an occurrence of210this kind of runaways warming could expose Earth to a harsh environment like it did to Venus,
through the evaporation of water.2
Then Dr. Hansen shifted the focus of his study to climate change that is caused byhuman activities which change the composition of Earth’s atmosphere. He utilized NASA’ssatellite observation data in studying the thermal radiation of Earth’s atmosphere, which led tothe development of a global-scale atmospheric circulation model and significantly contributed
to a detailed understanding, analyses and predictions of climate change that included the impact
of human activities.
Study of the Earth’s Climate
In 1987, Dr. Hansen et al. summarized and published the data on the atmospheric temperatureof Earth mainly during the period between 1880 and 1985 obtained from global weather
stations. Accurate data on atmospheric temperature from the last 100 years showed a rise of 0.5- 0.7 degrees in the average temperature. The recorded figures of average temperature increase,
updated in 2006, reached 0.8 degrees/100 years, showing that the tendency toward global
warming was an undeniable fact and was not merely a result of urbanization.
In a thesis published with Dr. Menon et al., Dr. Hansen argued that there is the existenceof atmospheric black carbon effects in the climate of some local regions. He showed that black
carbon in the atmosphere brought convection and rain by heating the atmosphere and would
ultimately lower temperatures over large areas by reducing the amount of sunlight reaching the
ground. As an example, he explained a climatic abnormality observed in northern China in 1988.
Then Dr. Hansen joined Dr. Makiko Sato in conducting a study using the solar photometer of
AERONET (AErosol RObotic NET work) and showed that the impact of black carbon doubled
the value that would normally be estimated from it. Black carbon in the atmosphere rapidly
increased in the 1880s when the Industrial Revolution was at its peak. The increase slowed
down from the 1900s to the 1950s and leveled off. Even at present, the emissions of black
carbon are increasing in China and India, which are in the midst of their rapid economic growth.
Impact of Human Activities on Climate Change
In 2003, Dr. Hansen published an essay titled “Can We Defuse the Global Warming Time
Bomb?” He warned that the climate change resultant from human activities has currently
overcome natural climate change and, if this persists for extended periods, could grow to anenormous level causing great disasters. He also said that actions to prevent or mitigate global
warming and other undesirable climate change phenomena need to be taken immediately, andthat unprecedented kinds of international cooperation would be called for. He also stressed thatsuch mitigating actions would be feasible and would benefit the health of humankind as well
as agriculture and the environment.
In 2006, Dr. Hansen et al. suggested that the average temperature of Earth should be
regarded as a yardstick of the degree of impact of human activities on the Earth’s atmosphericsystem. He emphasized that the rise of the average temperature was inevitably accompanied by“a rise in the sea level” and “extinction of species” and that an increase in the average temperature of even one degree would produce highly destructive results for life on Earth. According211

to him, a CO2 level of 450ppm or greater in the atmosphere would pose a great deal of danger
and powerful measures to reduce CO2 and other greenhouse gases are important and must be
taken immediately.
Advocating Conservation of the Global Environment
In 1988, Dr. Hansen published a thesis on climate predictions using a general atmosphericcirculation model based on some scenarios of greenhouse gas emissions. He concluded that the
global warming caused by human activities would grow to a level well above the level ofnatural climate variability within the next few decades. In the same year, Dr. Hansen testified
before committees and subcommittees in the U.S. Senate and House of Representatives andprovided the public with an extensive alert to the dangers of global warming.
In 2007, he used his knowledge of paleoclimatology to show that the sea level of 35
million years ago (when the average temperature of Earth was two or three degrees higher than
today) was 25 meters higher than the current level and that the IPCC’s estimate, 59 centimeters,
was far from correct. In 2008, he gave a lecture and explained the definition of a tipping point,a threshold of climate change that humankind must not exceed, as 1) a tipping level: the levelat which a large climate change occurs even when greenhouse gases do not increase any further;and 2) a point of no return: the point at which the climate system causes an uncontrollable andirreversible change on the climate. According to paleoclimatology, ice in the polar areas would
dissolve suddenly instead of dissolving gradually. This can be interpreted as an example of atipping point. Dr. Hansen uses multiple lines of evidence to conclude that the world has alreadyreached a dangerous level of atmospheric greenhouse gases, but he admits that it is difficult todetermine how long the world can be in the dangerous zone before the effects become large andirreversible. However, he argues further that if emissions continue at current or increased levels
for a few decades large climate changes and impacts will proceed out of humanity’s control.
Dr. Hansen recommends that all nations should determine their responsibilities forgreenhouse gas emissions based on a historical viewpoint, more specifically, the cumulative
amount of their CO2 emissions. According to this yardstick, United Kingdom would be thelargest cause of greenhouse gas emissions followed by the United States and Germany. He
urges nations to base their actions on the extent of their responsibilities.
Last year, Dr. Hansen urged the US government to set an example and lead the world intaking actions against climate change, because humankind should no longer postpone theimplementation of anti-global warming measures. To ensure the next generations a better
future, Dr. Hansen continues to explain to government officials and the public about the dangerof global warming and to advocate early actions for reduction of greenhouse gases with theaim of conserving the global environment.
Notes
1. Kasting J.F. (1988) “Runaway and moist greenhouse atmospheres and the evolution of earth and Venus” Icarus
74 (3): 472–494.
2. Climate Threat to the Planet: Implication for Energy Policy and Intergenerational Justice Jim Hansen December
17, 2008 Lecture at AGU

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EssayEnvironment and Development Challenges:
The Imperative of a Carbon Fee and Dividend
Dr. James E. Hansen
Most governments have paid little attention to the threat of human-made climate change.
They have acknowledged its likely existence, notably in the Framework Convention on Climate
Change (1), in which 195 nations agreed to avoid "dangerous anthropogenic interference"with climate. However, the instrument chosen to implement the Framework Convention, theKyoto Protocol, is so ineffectual that global fossil fuel CO2 emissions have increased by about
3 percent/year since its adoption in 1997, as opposed to a growth rate of 1.5 percent/year in thedecades preceding the Kyoto Protocol [http://www.columbia.edu/~mhs119/Emissions/, which
is an update of a graph in (2)].
This feckless path cannot continue much longer, if there is to be hope of preserving aplanet resembling the one on which civilization developed, a world that avoids the economic
devastation of continually receding shorelines and the moral nightmare of having exterminateda large fraction of the species on Earth. The science is clear enough: burning most fossil fuels
would invoke such consequences (3).
At least a moderate overshoot of climate change into the dangerous zone is unavoidable
now, but, fortunately, prompt actions initiating a change of directions this decade could
minimize the impacts on humanity and nature. The policies needed to produce a rapid phaseout of fossil fuel emissions would have a wide range of other benefits for the public, especiallyin those nations that recognize the advantages in being early adoptors of effective policies. So
there is some basis for optimism that the political will necessary to enact effective policies
could be marshaled.
However, for this to happen it is essential that the next approach not repeat thefundamental mistakes that doomed the Kyoto Protocol. If another 15 years is wasted on an
ineffectual approach, it will be too late to avoid catastrophic consequences for today's young
people and future generations. Therefore it is important to clarify the principal flaws in the
Kyoto approach from the standpoint of climate science.
Kyoto Protocol
A fundamental flaw of the Kyoto approach is that it was based on a "cap" mechanism. Thisapproach embodies two ineluctable problems. First, it made it impossible to find a formula foremission caps that was equitable among nations and also reduced carbon emissions at the raterequired to stabilize climate. Second, it failed to provide clear price signals that would rewardbusinesses, individuals and nations that led the way in reducing emissions.
The validity of the first assertion can be proven by comparing national responsibilities
213

for climate change, which are proportional to cumulative historical emissions (4, 5). The
United Kingdom, United States, and Germany have per capita responsibilities exceeding the
responsibilities of China and India by almost a factor of ten (4). Even if the UK, US andGermany terminated emissions tomorrow, by the time China, India and other developing
nations reached comparable responsibility for climate change the world would be on a course
headed to certain climate disasters.
Key Points: Why a Carbon Fee and Dividend is Imperative
1. There is a limit on fossil fuel carbon dioxide that we can pour into the atmospherewithout guaranteeing unacceptably tragic, immoral climatic consequences for young
people and nature.
2. It is clear that we will soon pass the limit on carbon emissions, because it requires
decades to replace fossil fuel energy infrastructure with carbon-neutral and carbonnegative energies.
3. Climate system inertia, which delays full climate response to human-made changes ofatmospheric composition, is both our friend and foe. The delay allows moderate
overshoot of the sustainable carbon load, but it also brings the danger of passing a
climatic point of no return that sets in motion a series of catastrophic events out ofhumanity's control.
4. The ineffectual paradigm of prior efforts to reign in carbon emissions must be replacedby one in which an across-the-board rising carbon fee is collected from fossil fuelcompanies at the place where the fossil fuel enters a domestic market, i.e., at thedomestic mine or port-of-entry.
5. All funds collected from fossil fuel companies should be distributed to the public. Thisis needed for the public to endorse a substantial continually rising carbon price and toprovide individuals the wherewithal to phase in needed changes in energy-use choices.
It is unrealistic to think that a "cap" approach can be made global or near-global.
Nations less responsible for the world's climate predicament believe, with considerable
justification, that they should not have to adhere to caps on CO2 emissions (much less steadily
shrinking caps) that are comparable to caps on industrialized countries. At the same time,some industrialized countries, including the United States, refuse to bind themselves to capsthat are more stringent than those imposed on developing countries. This impasse cannot be
resolved under a cap approach. Indeed, the targets adopted to date with a cap approach havebeen but a drop in the bucket compared to the reductions required to stabilize climate.
A secondary, but important, flaw of the Kyoto approach is its introduction of "offsets".
Nations are allowed to limit reduction of fossil fuel emissions by means of alternative actions
such as tree planting or reduced emissions of non-CO2 climate forcings such as methane orchlorofluorocarbons. However, these offsets are not equivalent to fossil fuel emissions,214because the fossil fuel carbon will stay in surface carbon reservoirs (atmosphere, ocean, soil,
biosphere) for millennia. Rapid phase-out of fossil fuel emissions, as required to stabilize
climate, becomes implausible if leakage is permitted via offsets. Leakage is avoided via theflat across-the-board carbon fee on fossil fuels in the fee-and-dividend approach. Incentives
to reduce non-CO2 climate forcings will be useful, but such programs should not be allowed
to interfere with the more fundamental requirement of phasing out fossil fuel CO2 emissions.
Fee and Dividend
Fee-and-dividend (5) has a flat fee (a single number specified in $ per ton of CO2) collectedfrom fossil fuel companies covering domestic sales of all fossil fuels. Collection cost is trivial,
as there are only a small number of collection points: the first sale at domestic mines and at the
port-of-entry for imported fossil fuels. All funds collected from the fee are distri-buted
electronically (to bank account or debit card) monthly to legal residents of the country in equal
per capita amounts. Citizens using less than average fossil fuels (more than sixty percent of
the public with current distribution of energy use) will therefore receive more in their monthly
dividend than they pay in increased prices. But all individuals will have a strong incentive to
reduce their carbon footprint in order to stay on the positive side of the ledger or improve theirposition.
The carbon fee would start small and rise at a rate that sows benefits of economic
stimulation while minimizing economic disruptions from sudden change. Economic efficiency requires the price of fossil fuels to rise toward a level that matches their cost tosociety. At present fossil fuels are the dominant energy only because the environmental andsocial costs are externalized onto society as a whole rather than being internalized into theirprices (6). Human health costs due to air and water pollution from mining and burning of fossil
fuels are borne by the public, as are costs of climate change that have been estimated at$100-1000/tCO2 (7).
International Implementation
When the reality and consequences of the climate threat become clear enough the international
community should recognize that all nations are in the same boat and that the fruitless capand-trade-with-offsets approach must be abandoned. The reality is that the Kyoto Protocol andproposed replacements are "indulgences" schemes (5), which allow aggressive developmentof fossil fuels to continue worldwide. Developing countries acquiesce if sufficient paymentsfor offsets and adaptation are provided. This works fine for adults in developed and developing
countries today, but this abuse of young people and future genera-tions must eventually end as
the facts become widely apparent.
A fundamental fact is that as long as fossil fuels are allowed to be cheap, via subsidies
and failure to pay their costs to society, they will be burned. Even ostensibly successful caps
have no significant benefit. They simply reduce demand for the fuel, thus lowering its priceand creating incentives for it to be burned somewhere by somebody. What is required is anapproach that results in economically efficient phase-out of fossil fuels, with replacement byenergy efficiency and carbon-free energy sources such as renewable energy and nuclear power.

215

Specifically, there must be a flat (across-the-board) rising fee (tax) on carbon emissions.
With such a flat fee, collected by the energy-using nation at its domestic mines and ports ofentry, there is no need for trading carbon permits or financial derivatives based on them.
Indeed the price oscillations inherent in carbon trading drown out the price signals. The
required rapid phase-out of fossil fuels and phase-in of alternatives requires that businesses
and consumers be confident that the fee will continue to rise. Another flaw of trading is thefact that it necessarily brings big banks into the matter – and all of the bank profits are extracted
from the public via increased energy prices.
A carbon fee (tax) approach can be made global much more readily than cap-and-trade(8). For example, say a substantial economic block (e.g., Europe and the U.S. or Europe andChina) agrees to have a carbon tax. They would place border duties on products from nations
without an equivalent carbon tax, based on a standard estimates of fossil fuels used in
production of the product. Such a border tax is allowed by rules of the World Trade
Organization, with the proviso that exporters who can document that their production uses lessfossil fuels than the standard will be assigned an appropriately adjusted border duty. Borderduties will create a strong incentive for exporting nations to impose their own carbon tax, sothey can collect the funds rather than have them collected by the importing country.
Once the inevitability of a rising carbon price is recognized, the economic advantagesof being an early adopter of fee-and-dividend will spur its implementation. These include improved economic efficiency of honest energy pricing and a head-start in development ofenergy-efficient and low-carbon products. The potential economic gains to middle and lower
income citizens who minimize their carbon footprint will address concerns of people in manynations where citizens are becoming restive about growing wealth disparities. Note that theeffect of a carbon price on upper class citizens is modest and non-threatening except to ahandful of fossil fuel moguls who extract obscene profits from the public's dependence on
fossil fuels. An added social benefit of fee-and-dividend is its impact on illegal immigration– by providing a strong economic incentive for immigrants to become legal, it provides anapproach for slowing and even reversing illegal immigration that will be more effective thanborder patrols.
National Implementation
The greatest barriers to solution of fossil fuel addiction in most nations are the influence of thefossil fuel industry on politicians and the media and the short-term view of politicians. Thus
it is possible that leadership moving the world to sustainable energy policies may arise in
China (9), where the leaders are rich in technical and scientific training and rule a nation thathas a history of taking the long view. Although China's CO2 emissions have skyrocketed
above those of other nations, China has reasons to move off the fossil fuel track as rapidly aspractical. China has several hundred million people living within 25 meter elevation of sea
level, and the country stands to suffer grievously from intensification of droughts, floods, andstorms that will accompany continued global warming (3, 5, 10). China also recognizes the
merits of avoiding a fossil fuel addiction comparable to that of the United States. Thus China
has already become the global leader in development of energy efficiency, renewable energies,216

and nuclear power.
Conceivably the threat of impending second-class economic status could stir the UnitedStates into action, but it is imperative that the action contain no remnant of prior cap-and-trade
fiascos, which were loaded with giveaways to big banks, big utilities, big coal and big oil. The
approach must be simple and clear, with the fee rising steadily and 100 percent of the collected
revenue distributed to legal residents on a per capita basis.
The fee-and-dividend approach allows the market place to select technology winners.
The government should not choose favorites, i.e., subsidies should be eliminated for allenergies, not just fossil fuels. This approach will spur innovation, stimulating the economy as
price signals encourage the public to adopt energy efficiency and clean energies. All materials
and services will naturally incorporate fossil fuel costs. For example, sustainable food products
from nearby farms will gain an advantage over highly fertilized products from halfway aroundthe world.
The carbon price will need to start small, growing as the public gains confidence thatthey are receiving 100 percent of the proceeds. If the fee begins at $15/tCO2 and rises $10 per
year, the rate after 10 years would be equivalent to about $1 per gallon of gasoline. Giventoday's fossil fuel use in the United States, that tax rate would generate about $600B per year,
thus providing dividends of about $2000 per legal adult resident or about $6000 per year for afamily with two or more children, with half a share for each child up to two children perfamily.
The proposal for a gradually rising fee on carbon emissions collected from fossil fuelcompanies with proceeds fully distributed to the public was praised in the United States by thepolicy director of Republicans for Environmental Protection (11) as: "Transparent. Marketbased. Does not enlarge government. Leaves energy decisions to individual choices… Sounds
like a conservative climate plan."
A grassroots organization, Citizens Climate Lobby (12), has been formed in the UnitedStates and Canada with the objective of promoting fee-and-dividend. My advice to thisorganization is adoption of a motto "100 percent or fight", because politicians are certain to try
to tap such a large revenue stream. Already there are suggestions that part of the proceeds
should be used "to pay down the national debt", a euphemism for the fact that it would become
just another tax thrown into the pot. Supporters of young people and climate stabilization willneed to have the determination and discipline shown by the "Tea Party" movement if they areto successfully overcome the forces for fossil fuel business-as-usual.
Global Strategic Situation
Europe is the region where citizens and political leaders have been most aware of the urgencyof slowing fossil fuel emissions. Given the stranglehold that the fossil fuel industry has
achieved on energy policies in the United States, it is natural to look to Europe for leadership.
Yet Europe, despite dismal experience with cap-and-trade-with-offsets, continues to push thisfeckless approach, perhaps because of bureaucratic inertia and vested interests of individuals.
China, at least in the short run, likely would be only too happy to continue such a framework,as the "offsets" have proven to be a cash cow for China.

217

The cap-and-trade-with-offsets framework, set up with the best of intentions, fails to
make fossil fuels pay their costs to society, thus allowing fossil fuel addiction to continue andencouraging “drill, baby, drill” policies to extract every fossil fuel that can be found. There isa desperate need for global political leaders who can see through special financial interests andunderstand the actions required to achieve a bright future for young people and the planet.
Perhaps such leaders exist – the problem is really not that difficult.
Acknowledgements. I thank Shi-Ling Hsu and Charles Komanoff for useful reviews andsuggestions.
References
1. United Nations Framework Convention on Climate Change (FCCC), 1992: United Nations, http://www.
unfccc.int.
2. Hansen, J. and Sato, M., 2001: Trends of measured climate forcing agents. Proc Nat Acad Sci USA, 98,
14778-14783.
3. Hansen, J., et al., 2012 (submitted): Scientific case for avoiding dangerous climate change to protect young
people and nature Proc Natl Acad Sci USA.
4. Hansen, J., et al., 2007: Dangerous human-made interference with climate: a GISS modelE study. Atmos
Chem Phys, 7, 2287-2312.
5. Hansen, J., 2009: Storms of My Grandchildren. Bloomsbury, New York, 304 pp.
6. G20 Summit Team, 2010: Analysis of the Scope of Energy Subsidies and Suggestions for the G-20 Initiative.
7. Ackerman, F., DeCanio, S., Howarth, R., and Sheeran, K., 2009: Limitations of integrated assessment
models of climate change. Climatic Change, 95, 297-315.
8. Hsu, S.-L., 2011: The Case for a Carbon Tax. Island Press, Washington.
9. Hansen, J.E., 2010: China and the Barbarians: Part 1:
http://www.columbia.edu/~jeh1/mailings/20101124_ChinaBarbarians1.pdf accessed.
10. Intergovernmental Panel on Climate Change (IPCC), 2007: Climate Change 2007,
Impacts, Adaptation and Vulnerability, Parry, M. L., Canziani, O. F., Palutikof, J. P., Van Der Linden, P. J.,
and Hanson, C. E. eds., Cambridge Univ Press, 996 pp.
11. Dipeso, J., 2010: Jim Hansen’s conservative climate plan, blog post at Republican’s for Environmental
Protection, October 11, 2010.
http://www.rep.org/opinions/weblog/weblog10-10-11.html accessed August 26, 2011.
12. Citizens Climate Lobby: http://citizensclimatelobby.org/ accessed.

218

Lecture

Human-Made Climate Change:
A Moral, Political and Legal Issue
Dr. James Hansen
Summary of the Situation
Human-made climate change is a moral issue. It pits the rich and the powerful against the
young and the unborn, against the defenseless and against nature.
Climate change is a political issue. But politics fails when there is a revolving door
between government and the fossil fuel-industrial complex.
Climate change is a legal issue. The judiciary provides the possibility of holding ourgovernments accountable for their duty to protect the public interest.
Slide 1* - There is a huge gap between what is understood about global warming, by therelevant scientific community, and what is known about global warming by the people whoneed to know, the public.
It is difficult for the public to recognize that we have a crisis, because human-madeglobal warming, so far, is small compared to day-to-day weather fluctuations. Yet the fact is:
we have an emergency. Because of the great inertia of the ocean, which is 4 kilometers deep,
and the ice sheets, which are 2 to 3 kilometers thick, the climate system responds slowly to
climate forcings such as increasing greenhouse gases. But this inertia is not our friend, because
it increases the danger that we may pass tipping points, beyond which the dynamics of theclimate system takes over and rapid changes occur out of humanity’s control.
The bad news is that atmospheric carbon dioxide (CO2) has already reached a dangerous
level, having increased from 280 parts per million (ppm) 200 years ago to 389 ppm today. The
good news is that it is still possible to get CO2 back below 350 ppm, if we act promptly, andthere would be many benefits of taking the actions that are needed.
Slide 2 - The great ice sheets on Greenland and Antarctica provide examples of tipping points,
especially the West Antarctic ice sheet, which sits on bedrock below sea level. If an ice sheet
is weakened to the point that it begins to collapse, the dynamics of the process takes over. It
will be out of our control – we cannot tie a rope around an ice sheet that is two kilometers
thick.
Extermination of species is another non-linear problem that can accelerate, because of
the interdependencies among species. Multiple stresses may cause enough extinctions that
ecosystems collapse.
Methane hydrates are essentially frozen methane. If they begin to disintegrate rapidly,
it could become a self-sustaining process.

219* There are supplement slides at the back of the section.

These tipping points all have occurred during Earth’s history in conjunction withwarming climates. Following mass extinctions new species evolved, but it required hundredsof thousands of years. We will leave a much more desolate planet for future generations, if we
destroy many species.
Slide 3 - Climate inertia and tipping points give rise to potential intergenerational injustice.
Today’s adults enjoy the benefits of fossil fuel use, but the impacts will be borne by young
people and future generations. Our parents did not know that their actions would affect future
generations. We do not have that excuse. We can only feign ignorance. It is called denial.
I showed this photo of our first grandchild in 2000, because newspapers had called me
the grandfather of global warming. It was amusing to show that I really was a grandfather.
After I testified to Congress in the 1980s I had decided to stick to research and leave
public communication to others. But by 2004 we had two grandchildren and the gap between
what was understood about the science and what was known by the public had become huge.
I decided to give one carefully prepared public talk in 2004.
Slide 4 - The talk was titled “Dangerous anthropogenic interference: a discussion of humanity’s
Faustian climate bargain and the payments coming due.” I began with this chart comparing
Mars, Earth and Venus. Mars has a thin atmosphere of carbon dioxide, Earth an intermediate
amount, and Venus has a very thick carbon dioxide atmosphere. The greenhouse effect ofcarbon dioxide – the fact that it allows sunlight to penetrate to the planetary surface, butpartially traps the planet’s infrared (heat) radiation – causes each planet to be warmer than it
would otherwise be, given the amount of sunlight that it absorbs – Mars by a few degrees,
Earth by a few tens of degrees, and Venus by several hundred degrees.
Mars is too cold – its water is all frozen. Venus is too hot – the water has boiled into theatmosphere. Earth is just right for life to exist.
Slide 5 - The habitable zone around a star is the zone where liquid water can exist on a planet.
Our sun is an ordinary star, “burning” hydrogen in its core, producing helium by nuclear
fusion, slowly getting brighter. When the solar system was young the sun was 30 percent
dimmer than today and the habitable zone was closer to the sun. Venus was cool enough tohave an ocean. Earth was near the cold limit of the habitable zone. On several occasions Earthfroze all the way to the equator. The most recent “snowball Earth” occurred about 700 million
years ago.
As the sun brightened, Venus experienced a runaway greenhouse effect. The ocean
evaporated, boiling into the atmosphere. Carbon dioxide baked from the Venus crust into theatmosphere. There is no going-back. Venus is permanently outside the habitable zone, locked
forever in a hellish greenhouse with a surface hot enough to melt lead.
Earth is now near the middle of the habitable zone. Earth can never freeze over again.
The sun is now too bright and humans have added greenhouse gases to the atmosphere. A
runaway greenhouse effect will not occur naturally on Earth for several billion years. But if
we burn all fossil fuels, including tar sands and oil shale, it is conceivable that we will hasten

220a runaway greenhouse effect.
How will climate change this century? It depends. It depends mainly on how muchcarbon dioxide humans put into the atmosphere.
Slide 6 - Our understanding of climate change is based most of all on Earth’s history – how
the climate responded in the past to changing boundary conditions such as atmosphericcomposition surface properties. Ongoing global observations are also valuable, showing how
climate is responding to rapid changes of atmospheric composition. Climate models andtheory are helpful in interpreting what is happening and they are needed to predict futurechanges.
Slide 7 - Why should we be concerned about human-made climate change? There have beenhuge climate changes in the past. Is today’s climate the best one? These are reasonable
questions. Indeed, they were statements made on National Public Radio in 2008 by my thenboss’s, boss’s, boss’s boss, the NASA Administrator. Earth’s climate history helps answer suchquestions.
Slide 8 - This is the deep ocean temperature over the past 65 million years. 50 million years
ago Earth was so warm that there were alligators in Alaska – the Arctic was tropical-like.
There were no ice sheets and sea level was about 75 meters (250 feet) higher than today. Earthcooled over the past 50 million years. About 34 million years ago it became cool enough foran ice sheet to form on Antarctica. What caused the great warmth in the first half of thisCenozoic Era, and why did Earth then become cooler?
Slide 9 - The climate change was due mainly to change of atmospheric carbon dioxide (CO2).
Climate forcings, perturbations of the planet’s energy balance, must be due to changes of theenergy coming into the planet, changes within the atmosphere, or changes on the surface. The
sun’s luminosity increased 0.4 percent over this era, which is a forcing of 1 watt per square
meter. The continents at the beginning of the Cenozoic were already close to their present
latitudes, so the surface forcing was only about 1 watt. But atmospheric CO2 varied from as
little as 170 ppm to more than 1000 ppm, a forcing of more than 10 watts per square meter.
The amount of CO2 naturally in the atmosphere-ocean system depends on the balance
between the source and sink of CO2. The balance changes over time, depending mainly on
continental drift. The source of CO2 is volcanic eruptions, which occur at moving continents
subduct ocean floor. The metamorphosis of carbonates on the ocean floor into denser rocks,
due to high pressure and temperature as the continent rides over the ocean floor, releases CO2
via volcanoes. The main sink of atmospheric CO2 is the weathering process as sediments arecarried by rivers to the ocean and deposited as carbonates on the ocean floor.
Between 60 and 50 million years ago atmospheric CO2 increased rapidly because India
was moving at high speed, about 20 centimeters per year, through the Tethys (Indian) Ocean,which had long been the depocenter for major rivers and thus had a carbonate-rich ocean floor.
When India crashed into Asia, pushing up the Himalayas and Tibetan Plateau, this source of221CO2 diminished and the weathering sink increased. So atmospheric CO2 decreased and theplanet cooled over the past 50 million years.
Slide 10 - The lesson from the Cenozoic is that the amount of CO2 in the atmosphere-oceansystem changes naturally via exchange with the Earth’s crust. The imbalance between thesource and sink of CO2 yields a change of atmospheric CO2 of the order of 100 ppm in one
million years, or 1 ten-thousandths of a ppm per year. Humans are now increasing atmospheric
CO2 by about 2 ppm per year, 10,000 times faster than the natural geological change.
The Cenozoic also allows us to estimate that an ice sheet began to form on Antarctica
when CO2 had declined to about 450 ppm. Some scientists estimate a higher amount of
CO2 at the transition. But it is clear that burning all the fossil fuels would produce enoughCO2 to head Earth back toward the ice-free state, a different planet than the one that humans
know.
Slide 11 - Climate also fluctuates on shorter time scales, as shown by this record of Antarctic
temperature for the past 400,000 years. Civilization developed during the Holocene, therelatively stable warm period, now almost 12,000 years long. During the last ice age New Yorkwas under a kilometer of ice and sea level was 350 feet lower.
The glacial to interglacial climate swings are caused by perturbations of Earth’s orbit.
As Jupiter, Saturn and Venus tug at our planet, Earth’s spin axis tilts successively slightly more
toward or away from the sun. Also Earth’s orbit becomes more or less eccentric. Thesechanges alter the amount of sunlight striking the ice sheets in the summer.
As ice sheets melt they expose a darker surface that absorbs more sunlight, causing
Earth to become slightly warmer. The warming ocean releases CO2 to the atmosphere and thegreenhouse effect of this CO2 causes additional warming. Changing ice sheet size andchanging atmospheric CO2 are slow feedbacks that amplify the climate change.
Slide 12 - Indeed, these feedbacks cause almost the entire temperature change. The sea level
record in the top curve tells us how large the ice sheets were. Greenhouse gas amount is
known from bubbles of air trapped in the Antarctic ice sheet as snow piled up.
Multiplying the ice sheet plus greenhouse gas forcings by a climate sensitivity of ¾
degrees Celsius for each watt of forcing yields good agreement with the actual climate change,
as sown by the lower curves. This empirical climate sensitivity includes all fast feedback
processes such as changes of water vapor, clouds, sea ice and aerosols – and it is much moreaccurate than can be obtained from climate models. The climate sensitivity for a specified
greenhouse gas change becomes twice as large if we wait long enough for ice sheets to
respond.
Slide 13 - The climate sensitivity and response time of the climate system are important,because humans have caused greenhouse gases to increase in the past century far outside therange of the past several million years, as shown by the expanded time scale on the right.
Earth has begun to warm, as shown by the lower curve, but much of the warming is still in the222pipeline, due to the long climate response time.
Slide 14 - To understand modern climate change we must know all climate forcings, that is,perturbations to Earth’s energy balance. Greenhouse gases are accurately measured – theycause a large positive (warming) forcing. Human-made fine particles in the air (aerosols)reflect sunlight and thus cause cooling, but it is very uncertain, because it is not measured.
Natural forcings, due to the sun and volcanoes, are probably larger now than in the eighteenth
century, when the sun is believed to have been slightly dimmer and volcanic eruptions weregreater. But the natural forcings are small compared to present human-made forcings.
The net climate forcing is probably between +1 and +2 watts per square meter. Carbon
dioxide is the largest forcing, and as time goes on it will be more and more dominant becauseof its long lifetime in the atmosphere.
Slide 15 - In my University of Iowa talk in 2004 I used this photo of my daughter’s children to
discuss climate forcing. Sophie explains that the net forcing is about 2 watts, equivalent to twotiny light bulbs over each square meter of Earth’s surface. But Connor could only count 1 watt.
Connor may be right. We are not measuring aerosol forcing well enough to know for sure.
So I went back to Sophie and Connor a few years later, when they were older and wiser.
I asked them “what is the net climate forcing?” They said that they don’t know. Well, we can’t
blame them if we adults fail to make the measurements.
But my grandchildren were useful in another way. They forced me to keep speaking
out. I decided that I didn’t want my grandchildren in the future to say “Opa understood what
was happening, but he never made it clear.”
Slide 16 - The upper graph shows estimates of changing climate forcings over the past
century. Greenhouse gas forcing becomes increasingly dominant. Aerosol forcing is very
uncertain, because it is not well measured.
If we use these forcings in a climate model with equilibrium sensitivity ¾°C per watt offorcing, we find good agreement with observed global temperature, as shown in the lower
graph. This agreement could be partly accidental: if we used a model with greater sensitivity
and a smaller climate forcing, or vice versa, we might also get agreement. However, themodel’s sensitivity agrees with the fast-feedback climate sensitivity implied by paleoclimate
data.
Slide 17 - The most fundamental check of the physics is the planet’s energy imbalance. We
anticipate that the planet is out of balance, more energy coming in than emitted to space. That
imbalance is the signature of the greenhouse effect, the smoking gun that can confirm climatechange is being driven by a forcing. Imbalance is expected because greenhouse gases reduce
the planet’s heat radiation to space.
How can we measure Earth’s energy imbalance? Small amounts of energy go into
warming the atmosphere, melting ice, and warming the upper tens of meters of the ground, but223most of the excess energy must go into the ocean, which has enormous heat capacity.
Measuring the ocean’s heat content accurately has been a great challenge, but the data are
improving as more than 2000 ARGO floats have been distributed around the world ocean.
Each float regularly yoyos an instrument package to a depth as great as 2000 meters.
The best data, covering the past 6 years, indicate that the planet is out of energy balanceby at least ½ watt per square meter. These data are for the time of minimum solar irradiancein the 10-12 year solar cycle. Our climate model yields an imbalance of ¾ of a watt averaged
over the solar cycle. I expect we will find close agreement with the model as the observations
extend over the full solar cycle and the entire ocean. The data already show that the planet isout of energy balance, confirming the expected effect of human-made greenhouse gases.
Slide 18 - Global observations reveal effects of Earth’s energy imbalance. The area of Arctic
sea ice began to be measured by satellites in the late 1970s. The area of sea ice at the end of
the melt season has decreased about 30 percent. There are large year-to-year fluctuations
because of weather variations that affect the wind direction and ocean currents. But, becauseof the planet’s energy imbalance, the area of sea ice will continue to decrease on decadal timescales. Unless we restore the planet’s energy balance, we can expect to lose all late-summer
sea ice within the next few decades.
Slide 19 - The area on Greenland that has summer snow melt, shown in red, fluctuates fromyear-to-year, depending on the weather. But the melt area has increased about 50 percent overthe past few decades.
Slide 20 - Meltwater runs to a low spot on the ice sheet and burrows a hole, a vertical shaftthat goes all the way to the base of the ice sheet. This water lubricates the base of the ice sheet.
Slide 21 - Increased meltwater is one of the processes speeding up discharge of giant icebergs
to the ocean. The net effect was once uncertain, because global warming also increases theamount of water vapor in the air, so snowfall over the center of the ice sheet is increasing.
Slide 22 - But beginning in 2002 the gravity satellite, GRACE, began making measurementsof the Earth’s gravitational field with such high precision that we can measure the change ofice sheet mass. The Greenland ice sheet gets heavier in the winter as snowfall piles up andloses mass in the melting season. But overall Greenland is now losing more than 200 cubic
kilometers of ice per year. Antarctica is losing more than 100 cubic kilometers per year. The
data suggest that the rate of mass loss may be increasing.
Slide 23 - Another expected effect of global warming is expansion of subtropical dry regions.
The overturning circulation, rising air in the tropics with subsidence in the subtropics, which
gives rise to the dry subtropics, is expected to expand poleward as the planet warms.
Observations show that expansion by 4 degrees of latitude, averaged over all longitudes, has
occurred already.

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The expanding subtropics affects the southern United States, the Mediterranean region,
and Australia, for example. It is one of the reasons that Lake Mead and Lake Powell are only
half full.
Slide 24 - The expanding subtropics is also one of the reasons for the increase in fires in thewestern United States, Greece and Australia. With the changing climate the fires burn hotter,making it more difficult for forests to recover.
Slide 25 - Another impact of global warming is the world-wide recession of mountain glaciers.
Glaciers are receding in the Rocky Mountains, the Andes, the Alps, the Himalayas. Glacier
National Park in the United States will need a new name within 25 years, because it will haveno glaciers if greenhouse gases continue to increase.
Loss of glaciers has a practical impact, because in the driest months more than half of
the water in major rivers, such as the Indus and Brahmaputra, is provided by glacier melt
water. Without glaciers, floods from spring snowmelt will be greater and rivers will tend torun dry in the driest months.
Slide 26 - Coral reefs are the rainforests of the ocean, home to more than a quarter of ocean
species. Coral reefs are under stress for several reasons. Two of the most important stresses
are the warming waters and ocean acidification. Warming can cause coral bleaching and deathas the coral expel their symbiotic algae. The ocean becomes relatively more acid as it takes up
carbon dioxide, which is a problem for animals with carbonate shells or skeletons – if thewater becomes too acid it can dissolve carbonates.
Slide 27 - Such phenomena help us assess the atmospheric carbon dioxide amount required
to maintain life on our planet as we know it. Each of these phenomena, including their responses to current levels of atmospheric CO2, lead to the conclusion that the target atmospheric
CO2 amount that we must aim for is less than the current amount, which is 389 ppm in 2010.
The best, most quantitative, assessment is the need to restore planetary energy balance.
Stabilizing climate, stopping global warming, requires restoration of Earth’s energy balance– as long as there is more energy coming in than going out, the planet will keep getting
warmer. The present imbalance is at least ½ watt per square meter. A ½ watt increase ofthermal emission to space can be achieved by reducing atmospheric CO2 by 35-40 ppm.
The optimum CO2 may be somewhat less than 350 ppm, especially if there are future
reductions in atmospheric aerosols. However, adjustments of other forcings such as methaneand black soot can help balance such effects.
For policy purposes all we need to know for the foreseeable future is that the CO2 target
must be “<350 ppm”, if we wish to preserve creation, the planet on which civilization
developed. Bill McKibben and the young people who form the backbone of the organization
350.org have done a remarkable job of publicizing the need for this target. They have succeededin getting more than 100 nations to agree to this target.

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Slide 28 - What is the practical implication of the “<350 ppm” target? This chart shows theamount of carbon in fossil fuel reservoirs, dark purple areas being the portion that has alreadybeen burned and released into the air. There is a range of estimates for the remaining reserves,which depend in part on whether we will go after “every last drop.”
In order to stop growth of atmospheric CO2 and return to a level below 350 ppm, wemust phase out coal emissions rapidly and leave most of the “other” fossil fuels, the unconventional fuels such as tar sands, in the ground. In that case atmospheric CO2 could peak at avalue between 400 and 425 ppm, depending upon how much of the remaining oil and gas we
exploit.
If we do not go after every last drop of oil and gas, it will be possible to get CO2 backbelow 350 ppm within several decades, provided that we also adopt improved agricultural andforestry practices that cause more CO2 to be stored in the vegetation and soil.
Slide 29 - So it is possible to achieve the 350 ppm CO2 target, but there are 3 essential actions.
First, coal emissions need to be phased out rapidly. Second, the unconventional fossil fuels
should be left in the ground. Third, we should not pursue every last drop of oil and gas.
In other words, we must move on to the clean energy future now, rather than using all
the remaining fossil fuels.
Slide 30 - But what is really happening? The United States has signed an agreement with
Canada for a pipeline to carry tar sands oil to Texas. New coal plants are being built all aroundthe world, some being financed by the World Bank. Environmentally destructive mountaintop
removal continues. Oil is pursued in pristine places. The environmentally destructive practiceof shale fracturing is being developed and implemented to find the last bits of gas.
Slide 31 - There is a huge gap between government rhetoric and policy reality. Leaders saythat we have a “planet in peril,” yet their proposed policies barely differ from business-asusual.
Greenwash is plentiful, but the leaders follow a path of appeasement of fossil fuelspecial interests. There is no Winston Churchill willing to stand up and tell the truth about
what is needed.
International agreements are jury-rigged to allow continued business-as-usual. For
example, the World Bank is allowed to finance new higher efficiency coal plants in developing
countries and count these as a “clean development mechanism”, which allows dirty plants indeveloped countries to continue. Total CO2 emissions actually increase. The science
requirement is that the coal be left in the ground, because fossil fuel CO2 stays in theatmosphere-ocean system for millennia. It does not help to burn it more efficiently.
Slide 32 - CO2 emissions were increasing 1.5 percent per year prior to the Kyoto Protocol.
Subsequently emissions have increased 2.5 percent per year, even with the recent economic
downturn.

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Slide 33 - Fossil fuel use continues to increase because fossil fuels are the cheapest energy. It
is as certain as the law of gravity: as long as fossil fuels are the cheapest energy their use willcontinue. Fossil fuels are cheapest in part because they are subsidized, but mainly because they
are not made to pay their cost to society – caused by their impact on human health, on theenvironment, and on the future of young people.
The solution is obvious: remove subsidies and put a rising price on carbon – a fee
collected domestically from the fossil fuel companies at the mine or port of entry.
Of course efficiency regulations are also needed, as is technology development – but thesuccess of these depends on having a rising carbon price.
Slide 34 - The public will accept a substantial rising carbon fee only if the money is distributed
to the public. Put the money in the hands of consumers and let the market place choose
technology winners. Those citizens who do not use their resources to reduce their carbon
emissions will soon be paying more in increased energy prices than they get in their green
check.
A carbon fee or tax is the only viable global approach. It requires mainly that theUnited States and China agree upon a carbon price. Europe and Japan would surely thenconsent. Any country not agreeing would have a duty placed on its products made with helpof fossil fuels.
Slide 35 - Cap-and-trade, in contrast, is favored by big banks and fossil fuel interests. In a
multi-trillion dollar carbon market it is impossible to avoid bank involvement. Their highly
skilled, secretive, trading units would make billions, without providing any added value.
Cap-and-trade is proven to be ineffectual in reducing emissions and it cannot be madeglobal. India and China would never accept caps on their economies, nor should they.
Slide 36 - Fee-and-green-check puts money in the public’s hands, a lot of money, stimulating
the economy and stimulating innovation. It is the fastest route to a clean energy future. It
would quickly bring mountaintop removal and tar sands development to an end – it may be theonly way to do that, surely the least painful way.
Slide 37 - Back to the basic issue: stabilizing climate is a matter of intergenerational justice.
Jake, my son’s first child, recently was excited to have a baby sister, who was 2½ days old inthis photo. My parents lived about 90 years, so Jake and Lauren Emma are likely to be aroundmost of this century and feel the full force of climate change.
Jake likes to protect his baby sister, even though she is sometimes a nuisance. Jake is agentle giant, for his age. If you believe long extrapolations, the charts suggest that he may bealmost 2 meters tall eventually. But here is the problem: protecting Lauren Emma may be outof Jake’s control, no matter how big and strong he is.
Today we have pushed the planet close to tipping points. Ice is melting in the Arctic, on
Greenland and Antarctica, and on mountain glaciers worldwide. Many species are stressed by227

environmental destruction and climate change. If fossil fuel emissions continue unabated, sealevel rise and species extinction will accelerate out of humanity’s control. Increasing temperature and atmospheric water vapor will magnify climate extremes, both droughts and floods,
and the storms of our grandchildren will be much more devastating.
Slide 38 - Such intergenerational injustice is foreign to all nations, cultures and religions. Yet
we are saddled with governments who do nothing effective. They think they can set emissions
at whatever level they choose, and they choose it with the help of the fossil fuel industry.
This situation is likely to continue until the public demands that governments do theirjob. But prospects for pressure from the public have been diminished by an effective campaign
to discredit science by those who prefer business-as-usual.
Slide 39 - Yet I see 2 reasons for some optimism. First, China seems capable of making
rational decisions and taking action. China has several incentives to move as rapidly aspractical into clean energies: (1) their high levels of local air and water pollution, (2) the factthat they will suffer more from global warming than most nations, and (3) the economic
advantage that they can gain by being out front in clean energy technologies. Indeed, China isaggressively investing in clean energy technologies.
Will this action by China stimulate the United States and other nations to get moving?
Maybe. But, because of the undue influence of money in Washington and other capitals, I
believe it is essential to involve the judicial branch of governments. As in the case of civilrights, achievement of justice probably requires people standing up for their rights and courts
enforcing them.
Slide 40 - Legal scholars point out that governments have a fiduciary responsibility to manage
the atmospheric trust. The executive and legislative branches of our governments are turninga deaf ear to the science, but the courts have the ability to require the government to makeemission reductions that the science shows to be necessary. Stabilizing climate is a matter ofintergenerational justice that can be enforced.
Young people, and older people who support them, must unite in demanding an effective
approach that preserves our planet. I look forward to working with young people and theirsupporters in developing the scientific and legal case for young people and the planet.
To the young people I say: Stand up for your rights. Demand that the government takethe actions needed to assure a future for you and your children. To the old people I say: we are
not too old to fight. Let us gird up our loins and prepare to fight on the side of young people
for protection of the world that they will inherit.

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Slide 1
Global Warming Status

Slide 2
Climate Tipping Points

Slide 3First Grandchild, Sophie — at Age Almost Two Years229

Slide 4Goldilocks Planets

Slide 5
Habitable Zone

Slide 6
Basis of Understanding230

Slide 7
Why be concerned about human-made climate change?

Slide 8Global Deep Ocean Temperature

Slide 9Cenozoic Era

231

Slide 10
Summary: Cenozoic Era

Slide 11
Antarctic (Vostok) Temperature

Slide 12
Kyr Before Present

232

Slide 13
Kyr Before 1850

Slide 14
Climate Forcings

Slide 15
Sophie explains 2 watts of forcing to brother Connor.

233

Slide 16
Global Climate Forcings and Temperature Change

Slide 17
Heat Storage in Upper 2000 Meters of Ocean

Slide 18
Arctic Sea Ice Area at Warm Season Minimum234

Slide 19
Greenland Total Melt Area

Slide 20
Surface Melt on Greenland

Slide 21
Jakobshavn Ice Stream in Greenland

235

Slide 22
Gravity Satellite Ice Sheet Mass Measurements

Slide 23
Pier on Lake Mead

Slide 24
Fires are increasing world-wide

236

Slide 25
Himalayan (Rongbuk) Glacier

Slide 26
Stresses on Coral Reefs

Slide 27
Assessment of Target CO2

237

Slide 28
Fossil Fuel Reservoirs & CO2 Scenarios

Slide 29<350 ppm is possible, but…

Slide 30
What's really happening.

238

Slide 31
Global Action Status

Slide 32
Global Fossil Fuel CO2 Annual Emissions

Slide 33
Problem & Solution239

Slide 34
Fee & Green Check (Dividend)

Slide 35
Cap-and-Trade Flaws

Slide 36
Fee & Green Check Addresses

240

Slide 37
Lauren Emma (age 2½ days) and Jake (age 2½ years)

Slide 38
Intergenerational JusticeSlide 39
Notes of Optimism

241

Slide 40
Atmospheric Trust Litigation*242

Major Publications
Dr. James E. Hansen
Selected Publications:
Hansen, J., M. Sato: Paleoclimate Implications for Human-Made Climate Change. arXiv:1105.0968v1.
Hansen, J., M. Sato, P. Kharecha, and K. von Schuckmann, 2011: Earth's energy imbalance and implications.
Atmos. Chem. Phys., 11, 13421-13449, doi:10.5194/acp-11-13421-2011.
Kharecha, P.A., C.F. Kutscher, J.E. Hansen, and E. Mazria, 2010: Options for near-term phaseout of CO2 emissions
from coal use in the United States. Environ. Sci. Technol., 44, 4050-4062, doi:10.1021/es903884a.
Hansen, J., R. Ruedy, Mki. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., 48, RG4004,
doi:10.1029/2010RG000345.
Rockström, J., W. Steffen, K. Noone, Å. Persson, F.S. Chapin, III, E. Lambin, T.M. Lenton, M. Scheffer, C. Folke,
H. Schellnhuber, B. Nykvist, C.A. De Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P.K. Snyder, R.
Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R.W. Corell, V.J. Fabry, J. Hansen, B. Walker, D. Liverman,
K. Richardson, P. Crutzen, and J. Foley, 2009: Planetary boundaries: Exploring the safe operating space forhumanity. Ecol. Soc., 14 (2), 32.
Rockström, J., W. Steffen, K. Noone, Å. Persson, F.S. Chapin, III, E.F. Lambin, T.M. Lenton, M. Scheffer, C. Folke,
H.J. Schellnhuber, B. Nykvist, C.A. de Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P.K. Snyder, R.
Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R.W. Corell, V.J. Fabry, J. Hansen, B. Walker, D. Liverman,
K. Richardson, P. Crutzen, and J.A. Foley, 2009: A safe operating space for humanity. Nature, 461, 472-475,
doi:10.1038/461472a.
Xu, B., J. Cao, J. Hansen, T. Yao, D.J. Joswia, N. Wang, G. Wu, M. Wang, H. Zhao, W. Yang, X. Liu, and J. He, 2009:Black soot and the survival of Tibetan glaciers. Proc. Natl. Acad. Sci., 106 , 22114-22118, doi:10.1073/pnas.
0910444106.
Hansen, J., Mki. Sato, P. Kharecha, D. Beerling, R. Berner, V. Masson-Delmotte, M. Pagani, M. Raymo, D.L.
Royer, and J.C. Zachos, 2008: Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J., 2,
217-231, doi:10.2174/1874282300802010217.
Kharecha, P.A., and J.E. Hansen, 2008: Implications of "peak oil" for atmospheric CO2 and climate. Global
Biogeochem. Cycles, 22, GB3012, doi:10.1029/2007GB003142.
Hansen, J., 2008: Tipping Point: Perspective of a Climatologist. In The State of the Wild: A Global Portrait ofWildlife, Wild Lands, and Oceans. E. Fearn, Ed. Wildlife Conservation Society/Island Press, pp. 6-15.
Hansen, J., Mki. Sato, R. Ruedy, and 44 co-authors, 2007: Climate simulations for 1880-2003 with GISS modelE.
Clim. Dynam., 29, 661-696, doi:10.1007/s00382-007-0255-8.
Hansen, J., 2007: Climate catastrophe. New Scientist, 195, no. 2614 (July 28), 30-34.
Hansen, J., Mki. Sato, P. Kharecha, G. Russell, D.W. Lea, and M. Siddall, 2007: Climate change and trace gases.
Phil. Trans. Royal. Soc. A, 365, 1925-1954, doi:10.1098/rsta.2007.2052.
Hansen, J., Mki. Sato, R. Ruedy, and 44 co-authors, 2007: Dangerous human-made interference with climate: A
GISS modelE study. Atmos. Chem. Phys., 7, 2287-2312.
Hansen, J.E., 2007: Scientific reticence and sea level rise. Environ. Res. Lett., 2, 024002, doi:10.1088/17489326/2/2/024002.
Nazarenko, L., N. Tausnev, and J. Hansen, 2007: The North Atlantic thermohaline circulation simulated by the
GISS climate model during 1970-99. Atmos.-Ocean, 45, 81-92, doi:10.3137/ao.450202.
Mishchenko, M.I., B. Cairns, G. Kopp, C.F. Schueler, B.A. Fafaul, J.E. Hansen, R.J. Hooker, T. Itchkawich, H.B.
Maring, and L.D. Travis, 2007: Precise and accurate monitoring of terrestrial aerosols and total solar irradiance:
Introducing the Glory mission. Bull. Amer. Meteorol. Soc., 88, 677-691, doi:10.1175/BAMS-88-5-677.
Novakov, T., S. Menon, T.W. Kirchstetter, D. Koch, and J.E. Hansen, 2007: Reply to comment by R. L. Tanner and
D. J. Eatough on "Aerosol organic carbon to black carbon ratios: Analysis of published data and implications
for climate forcing". J. Geophys. Res., 112, D02203, doi:10.1029/2006JD007941.
Rahmstorf, S., A. Cazenave, J.A. Church, J.E. Hansen, R.F. Keeling, D.E. Parker, and R.C.J. Somerville, 2007:
Recent climate observations compared to projections. Science, 316, 709, doi:10.1126/science.1136843.
Hansen, J., 2006: The threat to the planet. New York Rev. Books, 53, no. 12 (July 13, 2006), 12-16.
Hansen, J., Mki. Sato, R. Ruedy, K. Lo, D.W. Lea, and M. Medina-Elizade, 2006: Global temperature change. Proc.

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Quirk, and J. Tenenbaum, 1974: The GISS model of the global atmosphere. J. Atmos. Sci., 31, 84-117,
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Whitehill, L.P., and J.E. Hansen, 1973: On the interpretation of the "inverse phase effect" for CO2 equivalent widths
on Venus. Icarus, 20, 146-152, doi:10.1016/0019-1035(73)90047-X.
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Hansen, J.E., 1971: Multiple scattering of polarized light in planetary atmospheres. Part II. Sunlight reflected byterrestrial water clouds. J. Astmos. Sci., 28, 1400-1426, doi:10.1175/1520-0469(1971)028<1400:MSOPLI>2.
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Liou, K.-N., and J.E Hansen, 1971: Intensity and polarization for single scattering by polydisperse spheres: A
comparison of ray optics and Mie theory. J. Atmos. Sci., 28, 995-1004,
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Hansen, J.E., and J.B. Pollack, 1970: Near-infrared light scattering by terrestrial clouds. J. Atmos. Sci., 27, 265-281,
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Hansen, J.E., 1969: Absorption-line formation in a scattering planetary atmosphere: A test of Van de Hulst's
similarity relations. Astrophys. J., 158, 337-349.
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Hansen, J.E., 1969: Radiative transfer by doubling very thin layers. Astrophys. J., 155, 565-573, doi:10.1086/149892.
Hansen, J.E., and H. Cheyney, 1969: Theoretical spectral scattering of ice clouds in the near infrared. J. Geophys.
Res., 74, 3337-3346.
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doi:10.1175/1520-0469(1968)025<0629:NIROVA>2.0.CO;2.
Hansen, J.E., and S. Matsushima, 1967: The atmosphere and surface temperature of Venus: A dust insulation
model. Astrophys. J., 150, 1139-1157.
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