Of all major world regions, Europe has worked the hardest to implement policies aimed at countering human-caused climate change. Yet the cornerstone of Europe’s approach — a continent-wide emissions trading system for the greenhouse gases that cause climate change — is in trouble. That experience suggests a better strategy for both Europe and the rest of the world.
The basic story of human-caused climate change is becoming clearer to the global public. Several gases, including carbon dioxide, methane and nitrous oxide, warm the planet as their concentrations in the atmosphere increase. As the world economy grows, so do emissions of these gases, accelerating the pace of human-caused climate change.
The main greenhouse gas is carbon dioxide. Most carbon emissions result from the burning of fossil fuels — coal, oil and natural gas — for energy, global consumption of which is rising as the world economy grows. As a result, we are on a path to very dangerous levels of carbon dioxide in the atmosphere.
Twenty years ago, the world agreed to reduce sharply emissions of carbon dioxide and other greenhouse gases, but little progress has been made. Instead, the rapid growth of the emerging economies, especially coal-burning China, has caused global carbon dioxide emissions to soar.
Dangerous changes in climate have already begun. If the world continues on its current trajectory, global temperatures will eventually rise by several degrees centigrade, causing higher sea levels, mega storms, severe heat waves, massive crop failures, extreme droughts, heavy flooding and a sharp loss of biodiversity.
Yet changing the world’s energy system is a daunting challenge, because fossil fuels are so deeply embedded in the workings of the global economy. Oil provides the main fuel for transportation worldwide. Coal and gas are burned in huge and growing amounts to produce electricity and to provide energy for industry. How, then, can we sustain worldwide economic progress while cutting back sharply on carbon emissions?
There are essentially two solutions, but neither has been deployed on a large scale.
The first is to shift massively from fossil fuels to renewable energy sources, especially wind power and solar power. A number of countries will also continue to use nuclear power. (Hydroelectric power generation emits no carbon dioxide, but there are only a few remaining places in the world where it can be expanded without major environmental or social costs.)
The second solution is to capture carbon dioxide emissions for storage underground. However, this technology, called carbon capture and sequestration (CCS), is not yet proven on a large scale. One approach is to capture the carbon dioxide at the power plant as the coal or gas is burned. Another is to capture it directly from the air using specially designed chemical processes. Either way, CCS will require significant investment in further research and development before it becomes a viable technology.
The big problem is time. If we had a century to change the world’s energy system, we could feel reasonably secure.
Yet we must complete most of the transformation to low-carbon energy by mid-century. This is extraordinarily difficult given the long transition period needed to overhaul the world’s energy infrastructure, including not only power plants, transmission lines and transport systems, but also homes and commercial buildings.