The Abuse of Scientific Uncertainty
October 7, 2010
This essay is in response to: How can we set science-based policies in the face of scientific uncertainty?
The present moment is a gloomy one for
attention to urgency of climate change. In July of 2009, cap and trade
legislation failed definitively in the US Congress. The Kyoto Protocol of the
United Nations Framework Convention on Climate Change, the initiative of 187
nations to control greenhouse gas emissions, died in Copenhagen in December of
2009. The opponents of action on climate change have successfully abused the
notion of scientific uncertainty to create doubt and justify inaction.
How can we proceed? I believe that there are lessons
from work in other contested policy fields such as the regulation of tobacco
that might help us in the pursuit of urgently needed policies in climate change
and toxic chemicals.
Experimental science is a process of
approximation. Few studies are
definitive and most are not. Progress in scientific understanding relies
heavily on the weight of evidence. Over time evidence accumulates from different
types of studies by scientists of differing disciplines creating, finally, a
In the late 1950s Roger Revelle of Scripps
Institution of Oceanography wrote of the potential impacts of carbon dioxide-caused
global warming and hired Charles Keeling to begin measurements of atmospheric
carbon dioxide. Over fifty years data has accumulated from thousands of studies
of temperature, weather events, arctic ice, glaciers, and ocean chemistry. The
task of the IPCC has been to evaluate and assemble this huge body of science.
In each subsequent IPCC Assessment - there
have been four over twenty years - the evidence of human influence on climate
has been more firmly established. Today all but a tiny handful of scientists
believe that the globe is heating and that anthropogenic greenhouse gas
emissions are the major cause. Similarly in 1950s the health effects of smoking
began to be studied. Today it is universally accepted that cigarette smoking
causes cancer and that nicotine is addictive.
But why did it take so many decades to
develop scientific and public consensus? One answer is that this is the way
science works. It takes time to develop the weight of evidence sufficient to
convince. Experts may differ in their judgment of the weight. The second more
important answer is that in contested fields, opponents of policy may
deliberately create doubt about science to obfusticate the facts and delay
decision-making. The deliberate creation and marketing of doubt, the abuse of
scientific uncertainly, has been a prominent feature of both the tobacco and
climate change struggles.
How can we make sound, rational policies in
the face of scientific uncertainty? The answer is that we do it all the time.
We make decisions about public health, security, and agriculture policy
commonly before the science base for these decisions is in. Genetically
modified crops and farmed fish were introduced to use before we knew their
effects on wild populations. Policy-making and scientific study typically
proceed in parallel.
In the 1960s good evidence was available that
cigarette smoking causes cancer. This conclusion was actively contested by the
tobacco industries in a well-funded long-term campaign of denial well described
in Orestes and Conway’s recent book, Merchants
of Doubt (2010). Many thousands of lives would have been saved if the
industry had not abused scientific uncertainty and manufactured doubt so
What is interesting about the campaigns of
manufactured doubt is that the same cast of contrarian scientists and corporate-funded
public relations firms has been involved in opposition to precautionary
policy-making in tobacco, most recently second-hand smoke, the ozone hole,
toxic chemicals, and climate change. David Michaels in his book Doubt Is Their Product: How industry’s
assault on science threatens your health (2008), amply makes the case that
industry has turned what should be a debate over policy into a debate over
science. The abuse of scientific uncertainty is a clear endangerment of the
public’s health. In Dr. Michaels’ words, “It is time to return to first
principles: use the best science available, do not demand certainty where it
does not and cannot exist.”
The tobacco story has obvious lessons for
current efforts to reduce exposure to toxic industrial chemicals and to control
greenhouse gas emissions. I would suggest that scientists and health
professionals in particular seek to actively:
and defend sound science.
and expose the deliberate manufacture of doubt.
the use of the precautionary principle in policy and regulatory decision-making.
in improving science education in elementary and high schools.
socially responsible actions (including 1-4 above) of scientists and health
professionals including themselves.
Study of the nature of science and the
scientific process is an academic sub-specialty. In Return to Reason (2001), a recent essay by philosopher and
historian Stephen Toulmin provides a useful introduction. A few of the
practical elements of sound science can be readily identified: peer review and
confirmation, expert review and compilation, full acknowledgement of sources of
funding and other potential conflicts of interest. Sound science is peer
reviewed, fully assessed by authorities in the field, and confirmed by
Peer review is the process of judgment
conducted independently by fellow scientists. In the US peer review occurs at
three points in the conduct of a particular study: first when a scientist’s
proposal is submitted to a government agency, philanthropy, or corporation for
funding. Corporations do conduct high quality research but the suspicion exists
that corporate review of proposals and topics chosen for study in new research
is potentially less objective than review by independent funders.
Peer review occurs next when completed
research is submitted for publication. Editors now require but commonly do not
get full disclosure of funding sources and potential conflicts of interest e.g.
ownership of stock in the company manufacturing the drug or device being
studied. Corporate funded research published in non-peer-reviewed journals
should be viewed with suspicion of unacknowledged bias.
Sound science is a self-correcting process in
which studies are confirmed by repetition and by related studies with
alternative methods and design. Studies not subjected to these review processes
and confirmed by continued study must be viewed with some degree of suspicion.
Review articles published in peer reviewed or
authoritative journals provide yet another independent peer analysis of a body
of science. The Annual Review series is a good example. Reviews are a useful
guide to sound science in a particular science topic. Reviews are also
conducted by expert organizations such as the US National Academy of Science
and the Institute of Medicine. The IPCC is the review body for climate science.
The IPCC does not conduct research but rather assembles, analyzes and draws
conclusions from thousands of science journals from around the world.
It is only the most extreme doubters and
deniers who find it possible to believe that all these processes are a hoax.
Events like “climate-gate” actually reveal the strength of the process by
identifying one or two instances in which non- peer-reviewed publications with
erroneous conclusions made it through the IPCC process.
With some of the criteria of sound science in
mind, manufactured doubt is not difficult to recognize. Science that is not
independently funded after a review process, not published in peer review
journals, not cited in review articles or included in publications of national
and international scientific bodies is likely not sound science. Because of
their training and knowledge, scientists have a special responsibility to
publically critique opinion based on such sources.
Use of the precautionary principle is a sound
and widely accepted approach to the question of scientific uncertainty. The
precautionary principle says that decision-makers have a duty to take
preventive action to avoid harm before scientific certainty has been
established. The principle is commonly invoked in international environmental
and public health treaties and agreements. Essays in Raffensperger, Tickner,
and Jackson’s book, Protecting Public
Health and the Environment: Implementing the precautionary principle (1999)
offers many examples of the use of the principle.
Finally, the whole scientific enterprise will
suffer if we do not raise the level of public understanding of science and
better train future generations of scientists. President Obama’s Council of
Advisors on Science and Technology (PCAST) has very recently released a report
on urgency of the problems of science, technology, engineering, and math (STEM)
education and a plan to address them. We in the health sciences are
particularly able to contribute example and inspiration to students at many
levels. Our participation in the science preparation of citizens and future
scientists is a critical contribution to the future of sound environmental and
Toulmin, Return to Reason. Harvard University Press, Cambridge MA 2001
Michael, Doubt Is Their Product. Oxford University Press, Oxford 2008
Oreskes and Erik M. Conway, Merchants of Doubt. Bloomsbury Press, New York 2010
Raffensperger, Joel Tickner, and Wes Jackson, Protecting Public Health and the
Environment: Implementing the precautionary principle. Island Press, Washington