Magazine Article - John F. Kennedy School of Government Bulletin

Global Warning

  • Robert O'Neill
| Winter 2008

The Opportunity to Stop Climate Change is Evaporating Quickly Says Environmental Scientist John Holdren

A car with bad brakes is driving toward a cliff in the fog. The cliff is the severe or irreversible disruption of the world’s climate. The fog is the lack of scientific certainty about where that cliff is. The car with the bad brakes is, well, us.

John Holdren could be delivering this scary analogy to the United Nations General Assembly, the American Academy of Arts and Sciences, or a corporate board. He has spoken to all, and as one of the foremost experts on the science and policy of climate change, he is in constant demand on the subject.

Usually he illustrates his points with slides, showing statistics on emissions, deforestation, rising temperatures, storm activity, and dozens of other markers of environmental degradation. The maps and charts zip by quickly, keeping pace with his rapid, precise delivery, building a case that has gone from controversial to unassailable.

Since the beginning of the industrial age, the concentration of carbon dioxide in the atmosphere has increased by about 35 percent, mostly due to the burning of fossil fuels by humans. Carbon dioxide, with other greenhouse gases, has trapped more heat inside the world’s atmosphere. Over the last century, the world’s temperature has increased by 0.75 degrees centigrade, with 11 of the 12 warmest years on record occurring since 1995. Ergo, we’re changing the climate.

Someone usually asks Holdren why we should be worried about it. Holdren, who has been thinking about climate change since the late 1960s, has a prepared list: “Heat waves, drought, wildfires, rising sea level, reduced agricultural productivity, damage to ocean fisheries, loss of coral reefs,” he says. “I mean, I have a much longer litany,” he reminds his audience. This isn’t just about beach erosion on Cape Cod or warmer summers in Europe, it’s about trying to preserve the conditions for our economic, social, and political well-being.

Holdren manages to balance the obvious urgency of the subject with an optimism that we can make the changes if we choose to. But, he makes clear, that window of opportunity will close soon. Nobody knows with certainty when or what the precise consequences will be if we don’t (and this is where much of the argument resides now), but the emerging scientific consensus is that we will not have time to change things if carbon emission levels do not start leveling off by about 2015 and start dropping sharply soon after.

The choices we have are mitigation, adaptation, and suffering, he is fond of saying. It’s up to us what that mix will be.

Holdren is Teresa and John Heinz Professor of Environmental Policy and director of the Program on Science, Technology, and Public Policy at the Kennedy School.

He is also Professor of Environmental Science and Public Policy in the Department of Earth and Planetary Sciences at Harvard University and director of the Woods Hole Research Center. He is the immediate past president and current chair of the Board of the American Association for the Advancement of Science. He has authored more than 300 papers and 20 books in subjects ranging from population growth to plasma physics.

If his portfolio seems a little full, perhaps even haphazard, to Holdren himself it is pretty much exactly what, as a teenager, he had hoped it would be.

Born in Pittsburgh and raised in San Mateo, CA, Holdren had always combined a huge appetite for knowledge with a natural fondness for human interaction. As a child he read the World Book Encyclopedia his parents got him from A-Z (“I was interested in all of it,” he says), but he also fished, hunted, hiked, and loved to talk.

In his sophomore year of high school in 1958 he stumbled on two books: C.P. Snow’s The Two Cultures and Harrison Brown’s Challenge of Man’s Future.

Taken together, the books argued that the main problems of the human condition (security, environment, health, prosperity) were interconnected, and man could only help to address them significantly if the gulf between science and the humanities were bridged. They were life-changing insights, Holdren says. “I thought, ‘What could be more interesting and important than working on these great problems of the human condition?’”

Holdren went to MIT to study aeronautics and aerospace engineering (he thought science “would be much harder to get on the side”), before going on to a doctorate in plasma physics at Stanford. He worked at Lawrence Livermore National Laboratory, then at CalTech (lured by Harrison Brown, the scientist whose book had such an influence on Holdren as a teenager) before creating the energy and resources program at the University of California at Berkeley and then arriving at Harvard in 1996.

His academic resume is of course only a small part of it. He has also spent nearly four decades in the thick of policy and practice. He was at the fulcrum of science and policy on nuclear weapons for decades, accepting the 1995 Nobel Peace Prize on behalf of the Pugwash Conference for its work on reducing the nuclear threat. He has advised world leaders and CEOs. He has headed countless committees and commissions, including the 2004 National Commission on Energy Policy.

“I’ve always had this interest in practice, as long as I can remember, in changing things,” he says.

For a man who has spent his life conversing in both the language of science and policy, helping to change the way the world understands and acts on climate change seems, then, a natural part of the purposeful arc of his career.

In a recent paper Holdren cowrote with several other Belfer Center colleagues on the domestic transportation system, the scale of the problem becomes apparent.

Motor vehicles consume more than 9 million barrels of oil a day (to put that into perspective, the Japanese economy consumes 5.2 million barrels a day) and account for about 20 percent of U.S. carbon dioxide emissions. Replacing them with more fuel-efficient cars will take time, as about 40 percent of passenger vehicles on the road, like SUVs, are subject to weaker fuel-economy standards. But even a 2.5 percent per year increase in fuel efficiency would not prompt a decline in oil needs if the distances Americans drive continue to increase as they have been.

Now multiply those problems by a whole planet, and it is easy to see why Holdren argues that climate change is “the most dangerous and intractable of all the environmental problems caused by human activity.”

Dangerous, because the climate is the envelope within which all the environment operates, and distorting it impacts everything from oceanic currents down to Midwest corn production. Intractable, because there is no easy fix to changing the way we get about 80 percent of our energy.

Even if greenhouse gas concentrations could be frozen at the current levels, which they can’t, the average global temperature would continue to increase to about 1.5 degrees centigrade above the preindustrial average. An increase of two degrees is what many scientists believe is the highest tolerable level, and to limit ourselves to that it is estimated that the use of carbon-free energy would need to increase sixfold over the next four decades.

That means fundamental changes to an economy that may quadruple in that period, powered in part by a population set to increase by about three billion people. It means acting quickly to help redirect the estimated $17 trillion dollars the energy industry will invest in the next 25 years. It means enormous investment in research and development of new technologies (see story, page 20). It means balancing the needs of developing countries, which will contribute more to the problem as they strive to raise their populations out of poverty, but who will also be more vulnerable to the changes brought about. It will also mean political courage, as countries begin to draft a new global regime when the first Kyoto Protocol expires in 2012 (see story, page 24).

It means no less than resolving what Holdren describes as the energy-economy-environment dilemma at the core of the problem of sustainable well-being. A tall order. But as Holdren reminds us, the options are adaptation, mitigation, and suffering, and the mix is up to us.

For more information on this publication: Please contact Science, Technology, and Public Policy
For Academic Citation: O'Neill, Robert. “Global Warning.” John F. Kennedy School of Government Bulletin, Winter 2008,

The Author


John P. Holdren