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Dr. James E. Hansen (born March 29, 1941 in Denison, Iowa) heads the NASA Institute for Space Studies in New York City, a division of Goddard Space Flight Center in Greenbelt, MD, Earth Sciences Directorate. Dr. Hansen is currently an adjunct professor in the Earth and Environmental Sciences department at Columbia University. He is best known for his testimony on climate change to congressional committees in the 1980s that helped raise broad awareness of the global warming issue. He is a vocal critic of the Bush Administration's ideology on climate change.

Education

Hansen was trained in physics and astronomy in the space science program of Dr. James Van Allen at the University of Iowa. He obtained a B.A. in Physics and Mathematics with highest distinction in 1963, an M.S. in Astronomy in 1965 and a Ph.D. in Physics, in 1967, all three degrees from the University of Iowa. He participated in the NASA graduate traineeship from 1962 to 1966 and, at the same time, between 1965 and 1966, he was a visiting student at the Institute of Astrophysics at the University of Kyoto and in the Department of Astronomy at the University of Tokyo.

Dr. Hansen was elected to the National Academy of Sciences in 1996 and he received the Heinz Environment Award for his research on global warming in 2001.National Academy of Sciences Membership Directory List of members of the National Academy of Sciences

Field of research and interests

As a college student in the University of Iowa, Hansen was attracted to science and research by James Van Allen's space science program in the physics and astronomy department. A decade later, he started focusing on planetary research that involved trying to understand the climate change on earth that will result from anthropogenic changes of the atmospheric composition.

One of Hansen’s research interests is radiative transfer in planetary atmospheres, especially interpreting remote sounding of the earth's atmosphere and surface from satellites. Such data, appropriately analyzed, may provide one of the most effective ways to monitor and study global change on the earth.

Dr. Hansen is also interested in the development and application of global numerical models for the purpose of understanding current climate trends and projecting humans' potential impacts on climate.

Statements

• A global tipping point will be reached in 10 years (counting from 2006, and if levels of greenhouse gases like methane and CO₂ are not reduced. Global warming at this point becomes unstoppable.
• Global warming is 0.5–0.75 °C in the past century, and about 0.3 °C or more in the last 25 years
• Climate sensitivity to CO₂ doubling is 3±1 °C
• The dangerous level of CO2 can be no more than approximately 450 ppm; a feasible strategy for planetary rescue almost surely requires a means of extracting GHGs from the air.

Publications

In 2000 he authored a paper called Global warming in the twenty-first century: an alternative scenario in which he presents a more optimistic way of dealing with global warming focusing on non-CO₂ gases and black carbon in the short run, giving more time to make reductions in fossil fuel emissions. He notes that warming observed to date is largely due to non-CO₂ gases. This is because CO₂ warming is offset by climate-cooling aerosols emitted with fossil fuel burning and because non-CO₂ gases, taken together, are responsible for roughly 50% of greenhouse gas warming.

Fig. 1: Estimated climate forcings between 1850 and 2000.

Climate forcing by CO2 is the largest forcing, but it does not dwarf the others. Forcing by CH4 (0.7 W/m2) is half as large as that of CO2 and the total forcing by non-CO2 GHGs (1.4 W/m2) equals that of CO2. Moreover, in comparing forcings due to different activities, note that the fossil fuels producing most of the CO2 are also the main source of atmospheric aerosols, especially sulfates, black carbon, and organic aerosols.

Aerosols cause a climate forcing directly by reflecting sunlight and indirectly by modifying cloud properties. Forcing by atmospheric aerosols is uncertain, but research of the past decade indicates that it is substantial (IPCC 1996). The aerosol forcing that we estimate (4) has the same magnitude (1.4 W/m2) but opposite sign of the CO2 forcing. Fossil fuel use is the main source of both CO2 and aerosols, with land conversion and biomass burning also contributing to both forcings. Although fossil fuels contribute to growth of some of the other GHGs, it follows that the net global climate forcing due to processes that produced CO2 in the past century probably is much less than 1.4 W/m2.

A corollary following from Figure 1 is that climate forcing by non-CO2 GHGs (1.4 W/m2) is nearly equal to the net value of all known forcings for the period 1850-2000 (1.6 W/m2). Thus, assuming only that our estimates are approximately correct, we assert that the processes producing the non-CO2 GHGs have been the primary drive for climate change in the past century.

In 2004 he wrote a paper called Can We Defuse the Global Warming Time Bomb , containing:

At present, our most accurate knowledge about climate sensitivity is based on data from the earth’s history, and this evidence reveals that small forces, maintained long enough, can cause large climate change.

Human-made forces, especially greenhouse gases, soot and other small particles, now exceed natural forces, and the world has begun to warm at a rate predicted by climate models.

The stability of the great ice sheets on Greenland and Antarctica and the need to preserve global coastlines set a low limit on the global warming that will constitute “dangerous anthropogenic interference” with climate.

Halting global warming requires urgent, unprecedented international cooperation, but the needed actions are feasible and have additional benefits for human health, agriculture and the environment.

He also commented on the past usefulness of extreme warming scenarios to obtain political and policy actions on page 30 in Can We Defuse the Global Warming Time Bomb?

Emphasis on extreme scenarios may have been appropriate at one time, when the public and decision-makers were relatively unaware of the global warming issue, and energy sources such as “synfuels”, shale oil and tar sands were receiving strong consideration. Now, however, the need is for demonstrably objective climate forcing scenarios consistent with what is realistic under current conditions. Scenarios that accurately fit recent and near-future observations have the best chance of bringing all of the important players into the discussion, and they also are what is needed for the purpose of providing policy-makers the most effective and efficient options to stop global warming.

Rewriting The Science

In 2005 and 2006, Hansen claimed in interviews with the Washington Post and the New York Times that NASA administrators have tried to influence his public statements about the causes of climate change. Hansen claims that NASA public relations staff were ordered to review his public statements and interviews after a December 2005 lecture at the American Geophysical Union in San Francisco.

James Hansen has also appeared on 60 Minutes claiming that the White House edited climate-related press releases reported by federal agencies to make global warming seem less threatening. He is unable to speak "freely", without the backlash of other government officials. "In my more than three decades in the government I've never witnessed such restrictions on the ability of scientists to communicate with the public," he said in one of his many public appearances.

Hansen has said that the tipping point (also known as the runaway effect) is upon us, and that if by 2016 the human population is unable to reduce greenhouse gases, that the oceans might rise as much as 10 feet by 2100.

There is a short clip in the 2006 documentary An Inconvenient Truth that shows Hansen being questioned by Al Gore on May 8, 1989, at what appears to be a Congress meeting. Gore criticizes Hansen for apparently contradicting himself in a written testimony on global warming. At that point, Hansen reveals that the last paragraph in the testimony was not written by him, but added by someone else.

Who is responsible for climate change?

Ranking of the world's countries by per capita fossil-fuel CO2 emission rates.

My final chart shows another uncomfortable truth, uncomfortable for me and

my compatriots. Some politicians like to point out that China will soon exceed the U.S. in CO2 emissions. That is true, as indicated by the first pie chart and the fact that Chinese power plants and vehicles are increasing rapidly. However, the climate effect is not determined by current emissions, but rather by time-integrated emissions, the second pie chart. The third pie chart corrects for the lifetime of CO2, but that makes little difference.

For many decades to come, the U.S. will be the largest single cause of climate change.

I am concerned about the burden that we will leave for our children and grandchildren, if we do not take a leadership role in addressing global warming. A moral burden, as species disappear from the planet, as people are displaced by rising seas, or impoverished by increased droughts in the subtropics and by increased floods and climate variability in other regions. Perhaps also a legal burden: will not people driven from their land seek reparation from countries most responsible? Science does not leave the opportunity for us to claim ignorance of the consequences of greenhouse gas emissions.

We are not alone. Australia and Canada stand almost shoulder-to-shoulder with the

United States in per capita emissions, and they have also refused to participate effectively

in international attempts to reduce emissions. Some countries are doing better, yet change so far has been small, and almost nowhere does action match rhetoric. What can be done? The public is concerned about jobs, the economy, health care, schools, crime, terrorism. The planet’s problems seem remote, stress on animal and plant species, future sea level rise, even increasing climate extremes. There is a connection among climate change, energy policies, and other public problems, yet it will not be easy to achieve fundamental changes in the face of opposition by special interests.

The best hope for saving the planet, for preserving creation, rests with the younger generation, I believe. They are the ones who will be most affected by climate change. My advice to them is that it may be time to act up, not in a destructive way, but to forcefully and effectively make their concerns known.

When a fossil fuel company refuses to become an energy company and bamboozles the

public with advertisements such as “you call CO2 pollution, we call it life”, it is time to

stop patronizing that company. When a politician accepts money from fossil fuel interests and then describes global warming as “a great hoax”, it is time to draw attention to that and help vote him out. When our government stands on the side of polluters in court and connives with industries to continue pollution, characterizing it as a “clear skies” policy, it is time to help draw attention to the truth. In this era of the internet and instant global communication, young people may be capable of finding ways to galvanize stewardship for our planet that has so far been lacking.

Finally, I emphasize that the changes needed do not require hardship or reduction in the quality of life. Quite the contrary. They will result in a cleaner environment, healthier air and cleaner water, good-paying jobs in high-tech industries in our own countries, certainly better than mining coal, although coal may continue as one source of energy. The only losers will be those special interests who do not adapt, who prefer to spread misinformation and buy off politicians, to the detriment of life on Earth. We must be on the lookout for them and point them out for what they are.

Of course, although I am a government employee, these are just my opinions as a private citizen. They do not represent government policy. Thank you.

Climate Change Controversy

The topic is wrought with seemingly contradictory views on the role of human's involvement and contribution to climate change. As a result fierce debate on the issue continues to persist. There are a number of notable critics who challenge the interpretation of data used in modeling future climate changes and consequences. Two notable critics are:

Michael Crichton: Crichton spoke on issues such as the role of science in policy making, criticisms of climate-change researcher Michael Mann and what Crichton claimed was the deliberate obstruction of research into the subject by some in the scientific community.

Bjorn Lomborg: (born January 6, 1965) is an Adjunct Professor at the Copenhagen Business School and a former director of the Environmental Assessment Institute in Copenhagen. He became internationally-known for his best-selling and controversial book The Skeptical Environmentalist.

Global Warming Controversy :The global warming controversy is a debate about the specific causes of the increase in global average air temperature since the mid-1800s, the prediction of additional warming, and the consequences of that warming. An additional issue is whether the current warming trend is unprecedented or within normal climatic variations over the last 1,000 years.

References

• 29 Jan 2006 Hansen in the New York Times
• 13 Feb 2006 Time Magazine Cover Story: The Political Science Test
• Sequence of stories in The New York Times, from January to July 2006, exposing political interference with climate scientists at NASA"

External links

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• Dr. James E Hansen's Homepage
• NASA GISS Biography
• James E Hansen timeline at the History Commons
• The Global Warming Debate by James Hansen
• "Scientist Inspires Anger, Awe for Challenges on Global Warming" Washington Post
• "Climate Expert Says NASA Tried to Silence Him" New York Times
• "NASA and Global Warming" Audio Interview with WBUR OnPoint
• Soviet style "minder(s)" are being used on American scientists

• 1941 births
• American physicists
• Living people
• Members and associates of the United States National Academy of Sciences
• NASA personnel
• Sustainability advocates
• Action on climate change
• Climate change feedbacks and causes
• Climate change policies
• Energy policy
• Global warming
• Climatologists