03 Jun 2008: Opinion

The Ethics of Climate Change

When it comes to setting climate change policy, science can only tell us so much. Ultimately, a lead report author for the Intergovernmental Panel on Climate Change writes, it comes down to making judgments about what is fair, equitable, and just.

by richard c. j. somerville

A world in which all human beings were equal, rational, and perfectly governed, when confronted with the prospect of global warming, might reach an optimal decision based on compelling climate science. That ideal world would then find effective international agreements to restrict greenhouse gas emissions and avoid harmful climate change.

We do not live in such a world. In reality, the science of climate change, no matter how advanced, will never be sufficient to tell humanity what to do. Science may be able to inform policy by forecasting how severe climate change will be, given different greenhouse gas levels. However, experience teaches that science alone is never enough. When confronting environmental challenges, considerations of fairness, equity, and justice must also inform any successful international agreement.

This is certainly true of three major ethical dilemmas now complicating the climate change debate: how to balance the rights and responsibilities of the developed and developing world; how to evaluate geo-engineering schemes designed to reverse or slow climate change; and how to assess our responsibility to future generations who must live with a climate we are shaping today.

The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, together with subsequent agreements, is often hailed as a model environmental treaty. Although replacing chlorofluorocarbons (CFCs) clearly is much easier than weaning the world off fossil fuels, the ethical dimension of the ozone treaty holds lessons for tackling global warming. In dealing with CFCs, governments, industry, and science — realizing that CFCs and related manmade chemicals caused ozone depletion — quickly developed ozone-safe substitutes. And recognizing that developed and developing countries had differing legitimate concerns, the international ozone agreements called for developed countries to take the lead in addressing the issue, because these nations had produced most of the substances implicated in destroying stratospheric ozone. A fund was established to help developing countries phase out ozone-destroying chemicals. Technology transfer was addressed.

Many different segments of society now recognize that an effective climate agreement must also have such an ethical dimension. Religious organizations have contributed to the dialogue, addressing such fundamental questions as the rights of poor people and developing nations. “Action to mitigate global climate change,” the United States Conference of Catholic Bishops has declared in a statement, “must be built upon a foundation of social and economic justice that does not put the poor at greater risk or place disproportionate and unfair burdens on developing nations.”

Nearly all the nations of the world now agree that atmospheric greenhouse gases should be kept below a level that would produce dangerous human-caused climate change. However, exactly what level is “dangerous”?

The Intergovernmental Panel on Climate Change (IPCC) is required by its mandate to be policy-neutral. As one of the authors of its 2007 Fourth Assessment Report, I can testify that IPCC scrupulously avoided all forms of policy advocacy. Its task was simply to assess the scientific research literature in a way that was policy-relevant but not policy-prescriptive.

In any case, dangerous climate change is a subjective concept, depending on one’s values and risk tolerance, among other factors. Science cannot say that a given atmospheric level of greenhouse gases is safe, and another slightly higher one is not. Expecting that degree of precision from climate science is as unrealistic as expecting medical science to declare that one level of cholesterol is surely tolerable, and any higher level is certain to lead to a heart attack. Climate is complex. Einstein once remarked that everything should be made as simple as possible, but not more simple than that.

However, science, speaking through the IPCC, can provide guidance by suggesting what degree of severity of climate change is likely to be associated with any specific amount of greenhouse gases in the atmosphere. This information is found in great detail in the IPCC reports. Mainstream climate scientists like me regard these reports as the gold standard in our field. We use IPCC reports as textbooks for our graduate students, and they have been recognized as authoritative by national academies of science, by scientific professional societies, and most recently by the award of the 2007 Nobel Peace Prize. The IPCC reports have guided the European Union in formally adopting a specific goal of holding global warming to no more than 2 degrees Celsius (3.6 degrees Fahrenheit) above the average pre-industrial temperature of the mid-19th century.

In December 2007, at a major United Nations-sponsored climate conference in Bali, I joined other climate scientists to help publicize a statement signed by more than 200 climate scientists from more than 20 countries. Many of these scientists were also IPCC authors, but all of us signed the statement strictly as individuals. Our statement declared that by 2050 global greenhouse gas emissions should be cut by at least 50 percent below 1990 levels. The goal, we scientists said, should be to stabilize greenhouse gas concentrations at a CO2-equivalent level well below 450 parts per million.

Not surprisingly, the Bali negotiators failed to reach an agreement in which nations accepted binding commitments with firm timetables and quantitative targets for greenhouse gas reductions. The problem was not that the science was unreliable or that the negotiators were incompetent. The major obstacle was that nations, like individuals, do not take major decisions solely on the basis of scientific results. This realization may seem obvious, but we scientists are often politically naïve.

It is now increasingly clear that meaningful international action to limit climate change not only requires compelling scientific evidence and recognition of legitimate national interests, but also must focus on considerations of equity and ethics. The climate system is a global commons. Yet the consequences and costs of climate change do not fall equally on all nations and all parts of the globe. And with fossil fuels now supplying 80 percent of global energy, and thus enabling much of modern economic progress, nations will accept constraints on their freedom to emit greenhouse gases only when they are satisfied they are being treated fairly as part of a global response.

The differing perspectives of developed and developing nations — and the contrast between past and future actions — remain a key issue. Today, more than one out of every four molecules of carbon dioxide in the atmosphere has been put there by human actions, chiefly burning coal, oil, and natural gas. If we ask which nations are responsible for this dramatic increase in greenhouse gases, the answer is obvious — the developed nations. The United States, currently with about 5 percent of global population, has produced about a quarter of all the carbon dioxide that humankind has added to the atmosphere.

On the other hand, if we ask where the future growth in carbon dioxide emissions will originate, the answer is that the developing nations will largely be responsible. The developing nations with large populations — China foremost, followed by India, Brazil, Russia and others — are rapidly exploiting fossil fuels to power economic development. China, which now builds a new large coal-fired power plant every week or so, has already passed the United States as the nation that emits the most carbon dioxide. Is this fair? Ethical concerns demand a principled understanding of the differing rights and obligations of both developed and developing countries.

The sobering prospect of using geo-engineering to counter human-caused climate change also raises profound ethical issues. Many geo-engineering approaches are conceivable. For example, it is relatively easy to propose ways to make the Earth more reflective, in the hope that reduced absorption of sunlight might compensate for a strengthened greenhouse effect. Large mirrors might be placed in space. Sulfate particles or their chemical predecessors might be launched into the stratosphere. As the consequences of human-caused climate change become more severe and apparent, the temptation to seek a relatively simple technological remedy will surely increase.

I believe this temptation should be resisted. At best, if it worked well, geo-engineering would be addictive, committing future generations to continue it and encouraging further reliance on fossil fuels. More probably, geo-engineering would create additional problems while exacerbating existing ones. Artificially increasing the Earth’s reflectivity, for example, does nothing about the ongoing acidification of the oceans resulting from carbon dioxide being added to the atmosphere.

Research is far preferable to ignorance, and I feel about geo-engineering exactly as I do about nuclear war: Study it, by all means, but never try it. It would be highly irresponsible to conduct a massive international intervention on our planet without being virtually certain there would be no side effects making the cure worse than the disease. Such certainty is highly unlikely. Even relatively simple, small-scale plans can go wrong. If geo-engineering is the last resort in a worst-case scenario, let us do all we can to avoid that scenario. Who has the moral — and legal — right, on behalf of all nations, to tinker with the entire global environment?

Finally, the issue of intergenerational equity requires agreement on how decisions taken now may affect people not yet born. The climate system has several built-in delaying mechanisms. The consequences of a heightened greenhouse effect appear after a time lag, often decades or more. Oceans, as well as ice and snow, react slowly to the increasing burden of greenhouse gases. We have already committed our descendants to many centuries of sea-level rise. We benefit now from using cheap and abundant fossil fuels, and we use the atmosphere as a free dump for the waste products. In doing so, however, we sentence our children and grandchildren to cope with the resulting climate change.

I am convinced that a scientific community that aspires to be helpful to society must include ethics and equity as an integral part of its research agenda. We should place greater emphasis on providing quantitative information relevant to the ethical consequences of different policy options. For example, policymakers urgently need to know how climate change will affect different regions of the world and different economic sectors. The coming temperature change labeled “global warming” is simply a symptom of climate disruption. Research is required to generate specific forecasts of effects on water supply, on hurricanes and other storms, and on droughts, floods, and many other phenomena. Consequences for ecosystems and biodiversity worldwide are among the unknowns. Options and costs of adaptation to climate change will vary greatly around the globe and among developed and developing nations, and science has much to contribute to understanding these factors.

Incorporating such considerations into international negotiations on climate change is not fanciful or unrealistic. Indeed, experience in other domains teaches us that an ethical basis is essential in order to reach effective solutions. The historical development of the Montreal Protocol and follow-on agreements to deal with human-caused damage to stratospheric ozone illustrates clearly the benefits of taking ethics into account.

Let us recognize the damage we have already done to the climate system and resolve to minimize the additional damage we threaten to cause in the future. That is our moral and ethical responsibility to our neighbors on this small planet, to our descendants, and to all life on Earth.

POSTED ON 03 Jun 2008 IN Business & Innovation Climate Climate Science & Technology Africa Antarctica and the Arctic Asia Central & South America Europe Middle East North America North America 


A very smart and humane way of looking at the
challenges posed by global warming. We are part
of the world community, and the burdens of
dealing with all this are not evenly distributed. Our
policy makers need to take heed.
Posted by Alan Freund on 06 Jun 2008

The e360.yale.edu is cool site, tnks, webmaster.
Posted by ringtonesblasledolycle on 29 Jul 2008

Well, in our country Himalayan glaciers are melting at the rate of 10 meters every year. This is horrible. Our main 3 rivers are originating from these glaciers.

At this rate in year 2030 30% of Indian population will strive for water.

We will shortly start a marathon cycling from delhi to Himalaya to protest against pollution.

We should seriously start looking at climate change now.

Posted by Jilesh Patadiya on 27 Jan 2010

Comments have been closed on this feature.
richard c. j. somervilleABOUT THE AUTHOR
Richard C. J. Somerville, a theoretical meteorologist and expert on computer atmospheric simulations, is Distinguished Professor Emeritus at Scripps Institution of Oceanography, University of California, San Diego. He was a coordinating lead author for the 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change.



As Himalayan Glaciers Melt,
Two Towns Face the Fallout

For two towns in northern India, melting glaciers have had very different impacts — one town has benefited from flowing streams and bountiful harvests; but the other has seen its water supplies dry up and now is being forced to relocate.

Why Ocean Health Is Better
And Worse Than You Think

The good news is the world’s oceans have not experienced the extinctions that have occurred on land. But as ecologist Douglas McCauley explains in a Yale Environment 360 interview, marine life now face numerous threats even more serious than overfishing.

As Extreme Weather Increases,
A Push for Advanced Forecasts

With a warmer atmosphere expected to spur an increase in major storms, floods, and other wild weather events, scientists and meteorologists worldwide are harnessing advanced computing power to devise more accurate, medium-range forecasts that could save lives and property.

Climate Consensus: Signs of
New Hope on Road to Paris

After years of frustration and failure, a more flexible approach to reaching an international strategy on climate action is emerging – and it could finally lead to a meaningful agreement at climate talks in Paris later this year.

Wood Pellets: Green Energy or
New Source of CO2 Emissions?

Burning wood pellets to produce electricity is on the rise in Europe, where the pellets are classified as a form of renewable energy. But in the U.S., where pellet facilities are rapidly being built, concerns are growing about logging and the carbon released by the combustion of wood biomass.


MORE IN Opinion

Why U.S. East Coast Should
Stay Off-Limits to Oil Drilling

by carl safina
It’s not just the potential for a catastrophic spill that makes President Obama’s proposal to open Atlantic Ocean waters to oil exploration such a bad idea. What’s worse is the cumulative impact on coastal ecosystems that an active oil industry would bring.

Climate Consensus: Signs of
New Hope on Road to Paris

by david victor
After years of frustration and failure, a more flexible approach to reaching an international strategy on climate action is emerging – and it could finally lead to a meaningful agreement at climate talks in Paris later this year.

How Falling Oil Prices Could
Help Stop the Keystone Project

by jacques leslie
The U.S. Congress is preparing to vote on expediting the Keystone XL pipeline. But plummeting oil prices and opposition to other proposed pipelines for tar sands oil are upending the rationale for this controversial project.

A Conservationist Sees Signs of Hope for the World’s Rainforests
by rhett butler
After decades of sobering news, a prominent conservationist says he is finally finding reason to be optimistic about the future of tropical forests. Consumer pressure on international corporations and new monitoring technology, he says, are helping turn the tide in efforts to save forests from Brazil to Indonesia.

True Altruism: Can Humans
Change To Save Other Species?

by verlyn klinkenborg
A grim new census of the world’s dwindling wildlife populations should force us to confront a troubling question: Are humans capable of acting in ways that help other species at a cost to themselves?

A Blueprint to End Paralysis
Over Global Action on Climate

by timothy e. wirth and thomas a. daschle
The international community should stop chasing the chimera of a binding treaty to limit CO2 emissions. Instead, it should pursue an approach that encourages countries to engage in a “race to the top” in low-carbon energy solutions.

Animal ‘Personhood’: Muddled
Alternative to Real Protection

by verlyn klinkenborg
A new strategy of granting animals “personhood” under the law is being advanced by some in academia and the animal rights movement. But this approach fails to address the fundamental truth that all species have an equal right to their own existence.

A Year After Sandy, The Wrong
Policy on Rebuilding the Coast

by rob young
One year after Hurricane Sandy devastated parts of the U.S. East Coast, the government is spending billions to replenish beaches that will only be swallowed again by rising seas and future storms. It’s time to develop coastal policies that take into account new climate realities.

Why Pushing Alternate Fuels
Makes for Bad Public Policy

by john decicco
Every U.S. president since Ronald Reagan has backed programs to develop alternative transportation fuels. But there are better ways to foster energy independence and reduce greenhouse gas emissions than using subsidies and mandates to promote politically favored fuels.

Should Wolves Stay Protected
Under Endangered Species Act?

by ted williams
The U.S. Fish and Wildlife Service has stirred controversy with its proposal to remove endangered species protection for wolves, noting the animals’ strong comeback in the northern Rockies and the Midwest. It’s the latest in the long, contentious saga of wolf recovery in the U.S.

e360 digest
Yale Environment 360 is
a publication of the
Yale School of Forestry
& Environmental Studies


Donate to Yale Environment 360
Yale Environment 360 Newsletter



About e360
Submission Guidelines

E360 en Español

Universia partnership
Yale Environment 360 articles are now available in Spanish and Portuguese on Universia, the online educational network.
Visit the site.


e360 Digest
Video Reports


Business & Innovation
Policy & Politics
Pollution & Health
Science & Technology


Antarctica and the Arctic
Central & South America
Middle East
North America


A three-part series Tainted Harvest looks at the soil pollution crisis in China, the threat it poses to the food supply, and the complexity of any cleanup.
Read the series.


The latest
from Yale
Environment 360
is now available for mobile devices at e360.yale.edu/mobile.

e360 VIDEO

Warriors of Qiugang
The Warriors of Qiugang, a Yale Environment 360 video, chronicles a Chinese village’s fight against a polluting chemical plant. It was nominated for a 2011 Academy Award for Best Documentary Short.
Watch the video.

header image
Top Image: aerial view of Iceland. © Google & TerraMetrics.

e360 VIDEO

Badru's Story
Badru’s Story, winner of the Yale Environment 360 Video Contest, documents the work of African researchers monitoring wildlife in Uganda's remote Bwindi Impenetrable National Park.
Watch the video.