Climate change: Evidence of human causes and arguments for emissions reduction

A response to skepticism about climate change as part of a broader review of climate change science and ethics.

Seth D. Baum, Jacob D. Haqq-Misra, and Chris Karmosky, 2012. Climate change: Evidence of human causes and arguments for emissions reduction. Science and Engineering Ethics, vol. 18, no. 2 (June), pages 393-410.

Pre-print: Click here to view a full pre-print of the article (pdf).

Note: This article was written as a response to an editorial published in 2008. The article was submitted in April 2009 but, due mainly to frustrating delays at Science and Engineering Ethics, the article was not accepted for publication until February 2011. The article was updated prior to acceptance.

In a recent editorial, Raymond Spier expresses skepticism over claims that climate change is driven by human actions and that humanity should act to avoid climate change. This paper responds to this skepticism as part of a broader review of the science and ethics of climate change. While much remains uncertain about the climate, research indicates that observed temperature increases are human-driven. Although opinions vary regarding what should be done, prominent arguments against action are based on dubious factual and ethical positions. Thus, the skepticisms in the recent editorial are unwarranted. This does not diminish the general merits of skeptical intellectual inquiry.

Non-Technical Summary: pdf version

Background: Skepticism About Climate Change
This article was written in response to an editorial by Raymond Spier, editor of Science and Engineering Ethics. The editorial expressed skepticism about the importance of climate change as an ethical issue. The article addresses Spier's skepticisms as part of a broader review of the science and ethics of climate change. The article is suitable for researchers from any discipline as well as for students at the advanced undergraduate level or higher.

Climate Research
The article begins with a discussion of the nature of research on climate change. Climate change research also does not fit neatly into conventional academic disciplinary divisions. The research is highly interdisciplinary, incorporating research from many disciplines, and transdisciplinary, transcending traditional disciplinary boundaries towards new forms of knowledge. Because climate change is such an important societal issue, researchers often strive to make their research relevant to public policy, so that policy makers can make better informed policy decisions. But researchers often insist that the policy decisions should be made by elected representatives and not by the researchers themselves.

Climate Science
The article then reviews the science of climate change, i.e. our understanding of how the climate is changing. The crucial role of greenhouse gas emissions is demonstrated through a simple climate model. Then, Spier's skepticisms are addressed. These concern (1) a temperature decline from 1943 to 1975; (2) ice core data; (3) the role of clouds. Upon closer inspection, each of these skepticisms turns out to be unfounded. Finally, noting that the climate system is too complex to understand fully, the article discusses some key remaining uncertainties in climate change science, including (1) how sensitive the climate is to greenhouse gas emissions; (2) the role of ice melt in causing sea level to rise; (3) possible changes in El-Nino Southern Oscillation; (4) how climate will change in specific local regions. These uncertainties are of major parts of the climate system and are thus important to address in future research. However, they do not diminish our overall understanding that the climate is changing due to human activity.

Climate Ethics
Finally, the article reviews the ethics of climate change. What society should do about climate change is fundamentally an ethical question. The answer to this question depends on our ethics, i.e. on what we think is right and wrong, or good and bad. Research on climate change ethics comes from a variety of disciplines, including philosophy, law, and economics. The article then responds to several ethical claims made by Spier: (1) that climate change brings benefits in addition to costs (it does, but the costs are larger); (2) that society has better uses of its resources than addressing climate change (this is true only if we don't care about the future); and (3) that climate change is best addressed mainly through investment in new technology (this is a risky and indefensible strategy). Overall, a strong ethical argument can be made that society should prioritize reducing greenhouse gas emissions to reduce how much the climate will change.

Created 20 Apr 2011 * Updated 29 Jul 2013