In 1968, UCSB professor Garrett Hardin published an essay "The Tragedy of the Commons" in the journal Science, which became a call to action for the environmental movement of the 1970's. The "tragedy" is that depletion or pollution of a shared resource by individuals, each acting independently and rationally according to their own self interest, acts contrary to the group's long-term best interests.
Today we are faced with the ultimate tragedy of the commons - pollution of the atmosphere with "greenhouse gases", mainly carbon dioxide, methane, and nitrous oxide, which absorb heat radiation escaping into space from the earth, causing global warming. This is unlike any threat ever experienced by humanity, other than possibly the threat of a global nuclear war. However nuclear weapons are controlled by governments and their use is suicidal, whereas global warming is caused by our modern way of life, by civilization itself.
Serious scientific concern about climate change due to atmospheric pollution began in the 60's and 70's, and the scientific consensus about global warming began forming in the 80's. To address the issue on a global basis, the Intergovernmental Panel on Climate Change (IPCC) was established by member governments of the United Nations, and endorsed by the United Nations General assembly in 1988. Thousands of climate scientists and other experts contribute on a voluntary basis, without payment from the IPCC, to writing and reviewing reports. These
are reviewed by representatives from all the governments, who produce a “Summary for Policy Makers.” Finally, this summary is subjected to line-by-line approval by all participating governments. This involves the
governments of more than 120 countries. Never before has there been such an ongoing international scientific evaluation on a crucial
problem for civilization.
The IPCC has published four comprehensive assessment reports (1990, 1995, 2001, and 2007) reviewing the latest climate science, as well as a number of special reports on particular topics. Drafts of these reports are made available for comment in open review processes to which anyone may contribute. People from over 130 countries contributed to the Fourth Assessment Report. The contributors included more than 450 lead
authors, 800 contributing authors, and 2500 scientific expert reviewers.
As in the past, the Fifth Assessment Report will consist of four separate reports issued by four different Working Groups: "Physical Science Basis"; "Impacts, Adaptation, and Vulnerability"; "Mitigation"; and "Synthesis.” The reports are published at different times depending on when they are finished by the different groups. The fifth "Physical Science Basis" report was published in September 2013, and the other three Fifth Assessment Reports are due to be published this year. When "the IPCC report" is cited in the media, it usually refers to the "Physical Science Basis" report, which is the key report covering the basic science of climate change.
The main conclusions of the fifth "Physical Science Basis" report (205 pages) are summarized below:
• Warming of the climate system is unequivocal, and since the 1950’s, many of the observed changes are unprecedented over decades to millennia.
• Atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years.
• Human influence on the climate system is clear. It is extremely likely (95-100% probability) that human influence was the dominant cause of global warming between 1951-2010.
• Continued emissions of greenhouse gases will cause further global warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.
• Most aspects of climate change will persist for many centuries even if
emissions of CO2 are stopped. In his 1968 essay and after, Garrett Hardin discussed problems such as population growth and depletion of natural resources that cannot be solved by science and technology alone, but which require a change in human values. That is the case with global warming. It is clear that there are no known technical fixes that can
save us from global warming. Alternative energy sources such wind, wave, solar, biofuel, geothermal, hydroelectric, and nuclear power can help, but all have their own problems and limitations, and they cannot reasonably be expected to replace more than a fraction of the energy produced by fossil fuels. On the other hand, energy conservation has the potential to reduce greenhouse emissions as much as all alternative energy sources combined. It is clear that "substantial and sustained reductions of greenhouse gas emissions" will require major changes in global civilization.
Global warming is an existential problem. It has emerged as a result of activities that have been essential in producing our global civilization, such as exploration and exploitation of natural resources, scientific advancement and technological innovation, and unlimited growth of the world population and the world economy. We all contribute to global warming every day, some much more than others. In the words of Pogo in Walt Kelly's comic strip, "We have met the enemy and he is us." However, we cannot expect people to altruistically and radically change their life style and lower their standard of living unless they believe that global warming is a very serious and immediate threat to civilization, and that everyone will share in the deprivation that will be required to limit it.
Today there is rampant science denialism about global warming in the US. We need much more education to teach people how science works as a system, and why it works. Science is the only subject I can think of that is truly universal. There are no distinctions between the principles and practice of American science, Chinese science, Icelandic science, et cetera. International scientific conventions attract scientists from all over the globe and they all speak the same scientific "language" and follow the same scientific methods for finding the truth. That is why it is possible for thousands of climate scientists from more than 120 countries to reach a "95-100%" consensus that human activities are the dominant cause of global warming.
For my February column, I ran the essay by Sam Harris on “Our Narrow Definition of Science.” He concludes that "We must abandon the idea that science is distinct from the rest of human rationality. When you are adhering to the highest standards of logic and evidence, you are thinking scientifically. And when you’re not, you’re not." The problem is that most people have not learned how to find information that adheres to the highest standards of evidence and logic, and to form their opinions based on that information. We need more educational programs to teach people how to do that, and to instill the values of critical thinking.
I got a new ankle joint four years ago, and when I am asked how my ankle is doing, I reply “Not as good as I hoped, or as bad as I feared.” With global warming, I hope that there soon will be a major coordinated worldwide movement to drastically reduce greenhouse gas emissions,
and I fear that already it may be too little too late for my grandchildren