Precautionary Principle: a Rational Approach to Climate Change

New York Law Journal

October 23, 2014
by Christine A. Fazio and Ethan I. Strell

On Sept. 22, 2014—the day after an estimated 300,000 persons attended the Climate Change march in New York City[1]—the New York City Bar Association held a program Leading by Example: State and Local Governments as Catalysts for Action on Climate Change. Because of ongoing disagreement among federal lawmakers on whether to regulate greenhouse gases (or in some cases to even acknowledge that climate change is caused, in part, by humans), many state and local governments have initiated their own programs to address climate change. One of the themes raised by the New York State Attorney General Eric Schneiderman at the city bar program is the need to explain how climate change impacts the public personally to help garner support for additional programs to regulate greenhouse gases.

New Yorkers have generally embraced the bulk of scientific evidence that supports the view that the Earth’s climate is warming faster than expected due primarily to human activity. Climate change is contributing to extreme weather events, such as heat waves in the western United States and heavy storms in the Northeast. However, especially after a very cold winter and cooler summer, there are still many people who are unsure that climate change is occurring at all or, if occurring, question whether it is due to man-made greenhouse gas emissions, and lack enthusiasm for policies that may raise energy prices. Therefore, examples of real-world, local experiences from those adversely impacted by climate change is an important method to engage New Yorkers to support climate change mitigation policies.

Science of Climate Change

Earth’s climate is changing. Since 1895, the average temperature in the United States has increased by 1.3°F to 1.9°F, and most of this increase has occurred since 1970. Indeed, the last decade was the nation’s and the world’s hottest on record, and 2012 set the record for hottest year in the continental United States. This warming is believed to be largely the result of human activity, namely deforestation and burning of fossil fuels.[2]  At least four lines of evidence support the scientific consensus on this point.

First is a basic understanding of the greenhouse effect. Gases such as water vapor, carbon dioxide, ozone, and methane, absorb some of the heat given off by Earth’s surface and lower atmosphere, and then re-radiate energy back toward the surface. This process traps some of the heat inside the climate system. Increasing atmospheric levels of greenhouse gases intensifies this process. And human activities have increased the concentration of carbon dioxide in the atmosphere by more than 40 percent since the beginning of the Industrial Revolution. Most scientists agree that this human-caused intensification of the greenhouse effect is the primary cause of observed warming in recent decades.

Second, scientists have reconstructed past climates by investigating ancient ice cores and tree rings. Their results show that global surface temperatures over the last several decades are clearly unusual, with the last decade (2000-2009) warmer than any time in at least the last 1,300 years. The third and fourth lines of evidence establish that human activity, rather than natural factors, is responsible for the unusual warming over the past century. Climate simulations show that natural factors have either slightly cooled the earth or caused little change at all. The models can reproduce the recent warming only by accounting for human influences.

Similar studies dispute the idea that changes in solar activity are responsible for the increasing speed of the recent global warming. They reveal that the Earth’s upper atmosphere is cooling while its surface and lower atmosphere are warming. This can only be explained if the warming is due to increases in heat-trapping gases, rather than increased solar output.[3]  The models cited by the National Climate Assessment predict that even under a lower emissions scenario—which assumes large reductions in emissions from today’s levels—global average temperatures will rise 3°F to 5°F over the next century. But if emissions continue to increase, the models predict temperature will rise 5°F to 10°F over the same period.[4]

Nonetheless, some scientists challenge these projections, and a portion of the public, media, and politicians latch on to those ideas to bolster their denial of climate change. Some suggest that the Earth is not getting warmer by referring to changes in federal reporting in temperature change over the years with differing results.[5]  Others recognize climate change but question whether it is caused by man-made greenhouse gas emissions. For example, some scientists question the theory that sustained additional water vapor concentrations (resulting from higher average temperatures) will trap additional heat and result in additional warming.[6]  Others question whether climate sensitivity is due to solar cycles as opposed to greenhouse gases.[7]

Policy Response

Even if some scientists or policymakers question the cause and effect of man-made greenhouse gas emissions on climate change, this does not justify avoiding or delaying policy action. Policymakers should be guided by the precautionary principle, which states that “when possibly dangerous, irreversible, or catastrophic effects are identified,” precautionary actions should be taken, even if “scientific evaluation of the potential damage is not sufficiently certain.”[8]  The strong version of this principle says that the mere existence of risk is enough to justify regulation. But such extreme risk-aversion is not needed to justify climate change mitigation policies. The potential costs of climate change damaging our ecosystem and economy are substantial enough to justify regulation even if we are only slightly risk-averse.

In this sense, “climate policy can be thought of as ‘climate insurance’ taken out against the most severe and irreversible potential consequences of climate change.”[9]  The White House urges this view in a paper released over the summer. The paper argues that “just as the…threat of a fire justifies purchasing homeowners insurance, the threat of large-scale losses from climate change justifies purchasing ‘climate insurance’ in the form of mitigation policies.” Viewed this way, investment in climate change mitigation, despite its costs, is an economically efficient approach to dealing with a catastrophic risk.[10]

Therefore, as discussed at the city bar program, state and local governments can provide public support for investing in climate change mitigation by exposing the public to real-life examples of the impacts of climate change. For instance, a new report by the New York State Attorney General documents the effects of extreme rainfall in New York State. By releasing this report, the Attorney General’s office hopes that New York State residents understand the specific environmental and public health impacts they are already facing and will continue to face unless regulation of greenhouse gases proceeds.[11]

The report draws on the National Climate Assessment and other research to show that across New York the frequency and intensity of extreme rainfall is increasing and is damaging communities throughout the state. According to the Attorney General Report, data show a substantial increase in frequency of heavy rainfall events (two inches over a 24-hour period) in New York since the mid-1990s.[12]  Moreover, the recurrence intervals of climate phenomena, such as extreme rainfall and stream flows, have shortened dramatically in the past few decades.

According to the best available data, if emissions remain high, extreme storms that are currently expected to occur every 20 years will occur every five to seven years. The Attorney General Report points out that these statistics are consistent with the experiences of many New Yorkers in recent years. The impact is widespread: New York’s top 10 rainstorms of the past five years have affected many different regions throughout the state.

The Attorney General Report includes three case studies to illustrate the impact these events are having on New Yorkers. These are concrete examples of how climate change already affects our infrastructure, economy, and health. The first case study describes a stalled weather front on Long Island this past summer, when 13.57 inches of rain fell in just a few hours, resulting in New York’s heaviest downpour on record. That storm overwhelmed drainage systems, caused massive flooding and evacuations, and forced many drivers to abandon their vehicles on flooded roadways. It caused $30 million of damage—including damage to 1,000 homes—and power loss in 6,200 homes and businesses.

The second case study details a series of storms that produced nearly six inches of rain in less than two hours across parts of Western New York in August 2009. The storm caused extensive flash flooding. For example, the stream gauge on Cattaraugus Creek in Gowanda showed a rise from six feet to nearly 13 feet in less than an hour. The third case study recounts Hurricane Irene, which in August 2011 dropped 11.6 inches of rain on parts of New York in a 24-hour period. The heavy rainfall caused catastrophic flooding in many locations upstate, and 31 counties were declared disaster areas. The storm caused 10 deaths and $1.3 billion in damage, including $300 million damage to transportation infrastructure, and forced 33,000 New Yorkers to seek disaster assistance.[13]

Not mentioned in the Attorney General Report is Hurricane Sandy, which in October 2012 caused massive coastal damage from storm surge and flooding along the Northeast coast. The second most costly Atlantic hurricane in history behind Katrina, Sandy caused $60 to $80 billion in damage, mostly in New York, New Jersey, and Connecticut. It caused approximately 150 deaths, damaged or destroyed 650,000 homes, flooded much of New York City’s subway system, and caused significant damage to the electrical grid and overwhelmed sewage treatment plants.[14]

In addition to damaging our economy and infrastructure, climate change is impacting our health as well. This summer the White House released a report, The Health Impacts of Climate Change on Americans, that details a number of ways climate change is harming human health. For example, climate change worsens asthma as rising temperature increases the amount of ground-level ozone.[15]  Somewhat related is the increase in particle pollution from wildfires in the West and Southwest, which can lead to respiratory and cardiovascular hospitalizations, medical and emergency room visits for lung illnesses, and increased episodes of asthma, bronchitis, chest pain and respiratory infections. The White House report also raises concern about infectious diseases. It notes that the distribution of diseases spread by pests is influenced by climate change and that the incidence and distribution of reported cases of Lyme disease appears to be increasing over time.

Government thus needs to continue to educate the public with real-world examples of how climate change continues to impact their lives in order to ensure that the public supports programs, based on the precautionary principle, to regulate greenhouse gas emissions.

Christine A. Fazio is a partner and co-director in the environmental practice group at Carter Ledyard & Milburn.  Ethan I. Strell is counsel at Shamberg Marwell Hollis Andreycak & Laidlaw.  Adam B. Shamah, an associate at Carter Ledyard, assisted in the preparation of this article.

Reprinted with permission from the October 23, 2014 edition of the New York Law Journal © 2014 ALM media Properties, LLC. All rights reserved. Further duplication without permission is prohibited. For information, contact 877-257-3382, or visit


[1] Lisa W. Foderaro, “Taking a Call for Climate Change to the Streets,” New York Times (Sept. 21, 2014).

[2] Third National Climate Assessment, United States Global Change Research Program (USGCRP) (2014) [Hereinafter NCA], at 8. Established by Congress in 1990, USGCRP coordinates the federal government’s climate change research. Its most recent quadrennial report, released in May 2014, “draws from a large body of scientific peer-reviewed research, technical input reports, and other publicly available sources” to document climate change-related impacts and potential responses.

[3] Id. at 23-24.

[4] Id. at 8.

[5] Real Science Blog, “NOAA/NASA Dramatically Altered US Temperatures After the Year 2000” (June 23, 2014), available at; see generally Environmental Protection Agency, “Climate Change Indicators in the United States,” available at (providing U.S. annual heat wave index, 1895 -2013, that shows the highest heat wave index occurred in the 1930s).

[6] See, e.g., Richard S. Lindzen, “The Climate Science Isn’t Settled,” Wall St. J. (Nov. 30, 2009); Zeke Hausfather, “The Water Vapor Feedback, Yale Climate Connections,” (Feb. 4, 2008), available at; Statement of Dr. William Gray, U.S. Senate Committee on Environment & Public Works Hearing Statements (Sept. 28, 2005).

[7] See, e.g., Hermann Harde, “Advanced Two-Layer Climate Model for the Assessment of Global Warming by CO2,” Open Journal of Atmospheric and Climate Change Abstract (in press) (different and counteracting processes control the climate and it not clear what individual contribution they each have).

[8] “A Report of Working Group III of the Intergovernmental Panel on Climate Change, Climate Change 2001: Mitigation,” Section “Precautionary Considerations,” available at

[9] White House, “The Cost of Delaying Action to Stem Climate Change” (June 2014), at 24, available at

[10] See generally Richard A. Posner, “Efficient Responses to Catastrophic Risk,” 6 Chi. J. Int’l L. 511 (2006).

[11] “Current & Future Trends in Extreme Rainfall Across New York State: A Report from the Environmental Protection Bureau of New York State Attorney General Eric T. Schneiderman” (Sept. 2014).

[12] Id. at 4 (citing Dr. Art DeGaetano of the NOAA Northeast Regional Climate Center and Cornell University).

[13] Id. at 5 to 13.

[14] NCA at 375.

[15] White House, “The Health Impacts of Climate Change on Americans” (June 2014), available at

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