A series of events is putting climate change back in the public eye. The Intergovernmental Panel on Climate Change (I.P.C.C.) has issued three reports this year as groundwork for negotiations planned for Stockholm, Sweden, in 2015. President Barack Obama’s Environmental Protection Agency (E.P.A.) has issued a rule that would require states to meet targets designed to reduce carbon emissions from power plants by 30% from their 2005 level by 2030. Some in southern Florida want to break away from northern Florida to put more effort into climate change mitigation and adaptation. And a bipartisan report entitled “Risky Business” that is financed by wealthy climate-change advocates projects some far-reaching harms from the phenomenon.

While much of this sounds like a replay of past debates, there also have been some meaningful changes in the climate-change landscape. Three stand out: (1) the rising role of middle-income countries; (2) more attention to cost-effectiveness; and (3) more pro-growth strategies.

Middle income countries

When the Kyoto Treaty was developed, its emission-reduction commitments were only to apply to developed (i.e., Annex I) countries; developing (non-Annex I) countries were not subject to any binding obligations. This exemption caused the U.S. Senate to reject the treaty on a 95-0 vote.

Fifteen years later, the carbon-emissions landscape has changed. In 2011, the United States emitted 5.5 billion tons of carbon, according to the U.S. Energy Information Agency. But China emitted 8.7 billion tons, with its total rising rapidly. And India, the Middle East, Latin America and Africa combined exceeded U.S. emissions by 10%, with this gap also steadily widening.

In some ways the picture is even more striking for agriculture. A recent article by Caro, Davis, Bastianoni and Caldeira found that, using I.P.C.C. guidelines, in 2010 methane and nitrous oxide emissions by the global livestock industry accounted for about 9% of total greenhouse gas (G.H.G.) emissions and were up 50% over the past 50 years. But Annex I emissions fell 23% in that period while non-Annex I emissions more than doubled. Seven of the eight largest emitters by 2010 were developing countries, and the most rapid percentage increases were in African and Middle Eastern countries. A strategy with non-Annex I exemptions looks increasingly unhelpful.


Many of the strongest advocates of aggressive climate-change mitigation strategies have relied on worst-case scenarios or understated costs. Both have tended to undermine their credibility over time. For example, Richard Tol, a member of the I.P.C.C. since 1994, wrote in a recent Financial Times comment: “Climate change is not, then, the biggest problem facing humankind. It is not even its biggest environmental problem. The World Health Organization estimates that about 7 million people are now dying each year as a result of air pollution.”

Mr. Tol does not favor doing nothing about climate change. But he criticizes the I.P.C.C. for missing the opportunity to offer cost-effective ideas.

Similarly, The Economist recently assessed the cost-effectiveness of various carbon-reduction strategies. Four had carbon-emission reductions above one billion tons annually; none of them was undertaken for climate-change reasons. The four were: the 1987 Montreal Protocol to phase out chlorofluorocarbons; global hydropower; nuclear power worldwide; and China’s one-child policy.

All renewables worldwide together save only 600 million tons of carbon emissions annually, and those savings come at a very high cost. Charles Frank of Brookings Institution estimates that the costs of avoided carbon emissions exceed the benefits (compared to coal-fired power plants) for wind and solar, even at a carbon price of $50 per ton (compared to about $10 per ton in Europe today). Carbon would require a price of $185 per ton to make solar a net benefit.

Nuclear plants, in spite of their high capital costs, have a positive benefit-to-cost ratio. The big winner: replacing coal with natural gas in power generation, which requires no extra standby capacity and cuts carbon emissions by at least half. Yet Germany is spending $21 billion per year to convert to renewables, slowing its and the European Union’s growth.

Integrating mitigation with growth

Recognizing the importance of bringing the developing world on board and of pursuing cost-effective strategies, a group of political leaders, economists and development experts has issued a report entitled “Better growth, better climate.” It starts with two fundamental facts: that virtually all future population growth will be in the developing world; and that virtually all of that population growth will be in urban areas.

By their calculations, better urban design, improved infrastructure, more energy-efficient buildings, etc. combined would cut the capital costs of urbanization over the next 15 years by $3 trillion. At the same time, it would enhance productivity from clustering talent. And, it would reduce carbon emissions by 1.5 billion tons per year.

The same report urges developing country governments to double their agricultural research and development budgets (currently $16 billion per year) and eliminate their fertilizer subsidies, which lead to overuse. Combined, this would enhance global food security while reducing global G.H.G. emissions by “the equivalent of 4.2 billion to 10.4 billion tons” of CO2 by 2030.

All of these strategies meet demands for better living standards while slowing carbon emissions and making future adaptation costs lower and more affordable. They might win more converts than previously tried pathways.