In May of this year, the measurement station atop the Mauna Loa volcano in Hawaii detected in the atmosphere, over the course of 24 hours, an average carbon dioxide concentration of 400 parts per million. Carbon levels have probably not been as high as that in the past 3 million years—since before human beings existed.

Human activity is responsible for the high levels of carbon dioxide, but the majority of humans burn relatively little carbon. According to the UN Development Programme, the planet's poorest 1 billion people are responsible for only 3 percent of carbon emissions. (Many of them, however, live in rural areas and urban slums that are highly vulnerable to threats associated with climate change.) Meanwhile, the 1.26 billion people who live in nations that belong to the Organisation for Economic Co-operation and Development are responsible for 42 percent of the carbon added to the atmosphere each year, and their nations are overwhelmingly responsible for the carbon that has been added in the past.

Basic values such as justice and respect for human dignity make it obvious that the people most responsible for carbon in the atmosphere—the richest one-seventh of them—should both burn less carbon and pay most to address the problems that use of fossil fuels has created. But burning fossil fuels is highly addictive. People who are hooked on it will try every trick they can think of to avoid withdrawal symptoms.

One such trick is to burn carbon derived from Earth's surface (biomass) instead of carbon deposits extracted from underground (fossil fuels). The idea appears at first to make sense, as biomass when burned emits the same amount of carbon as has been stored during the biomass's growth phase; this should result in no net increase of atmospheric carbon. But things are not so simple when the idea is applied on an industrial scale and all inputs and indirect effects are taken into account.

The European Environment Agency Scientific Committee argues that bioenergy "is meant to reduce [emissions of greenhouse gases] but … increases the amount of carbon in the air … if harvesting the biomass decreases the amount of carbon stored in plants and soils, or reduces ongoing carbon sequestration." And many have argued that biofuels in particular actually use more energy than they produce. Moreover, replacing fossil fuels with bioenergy implies that an enormous amount of agricultural or forest land will be diverted to the purpose. Massive deforestation and land clearing—which eliminate carbon sinks and add to total carbon concentrations—are already occurring in Indonesia and other countries due to the increasing cultivation of commodities like palm oil.

Various sensible approaches for mitigating climate change are available. Modern agricultural practices, which are responsible for 14 percent of global greenhouse gas emissions, could be replaced with organic agriculture, which can be carried out in a carbon-neutral manner and might even store large amounts of carbon in the soil. But this would require the world's wealthy to change their consumption habits, for instance by eating less meat. Forests can be regrown so they can function as carbon sinks—though this has a net effect only as long as forests are expanding. Europe's forests, which have been recovering since the 1950s after centuries of deforestation, have functioned as carbon sinks over recent decades but are showing early signs of saturation.

What's really necessary, however, is for people—especially in the wealthy world—to reduce their carbon emissions. To achieve this, it is probably necessary to introduce carbon taxes in wealthy countries. But the developed world's big emitters continue to seek other solutions. It is as if a cigarette smoker, rather than giving up tobacco, decided to move to the suburbs to breathe cleaner air. This is a fake form of compensation, and bioenergy is similar. It creates the illusion of a greener economy. It allows people to postpone tough decisions. But whereas smokers who don't give up cigarettes mainly harm themselves, wealthy countries that consume massive amounts of fossil fuels pass the harm to innocent people.

If nothing changes, it may be just as well to abandon any pretense of respect for values such as justice and human dignity. Those values have suffered for a long time in any case, as nations have failed to live up to the "common but differentiated responsibilities" that are discussed in the UN Framework Convention on Climate Change.