The heady days of early 2009, when advocates for global action on climate change anticipated world leaders gathering later that year around a conference table in Copenhagen to reach a global agreement, are but a distant memory. Today, with many of these same leaders focusing their attention on jumpstarting economic growth, environmental issues have taken a back seat. For environmentalists, it may seem that climate policy has dropped from the political agenda altogether.
They're right. The world's biggest emitters have reached a consensus of sorts, but not the one hoped for in Copenhagen. In the United States, President Barack Obama has borrowed his energy policy -- "all of the above" -- from the Republicans. Europe has dithered on any further commitments to emissions reductions as governments have been completely consumed by the euro crisis. China and India have used the follow-on conferences to Copenhagen, held in Durban and Cancun, to decisively push international climate negotiations into the long weeds. Leaders' attention to climate policy is not coming back -- at least not in any form comparable to the plans being discussed just a few years ago.
Copenhagen will likely be remembered as the moment when advocates for action lost their innocence. For more than a decade, expectations had been raised for a grand global bargain to put a price on carbon that would compel a major reduction in greenhouse-gas emissions -- notably carbon dioxide -- over the coming decades. To understand why this bargain failed requires a basic understanding of where carbon dioxide comes from and how it is reduced. A very simple but powerful framework for such an understanding was proposed in the 1980s by Japanese scientist Yoichi Kaya. Kaya explained that future carbon dioxide emissions would be the product of four factors: population, economic activity, how we obtain our energy, and how we use that energy.
We can simplify these four factors even further. Population and income together are simply GDP, or aggregate economic activity, and the production and consumption of energy reflect the technologies of energy supply and demand. The resulting Kaya Identity -- as his equation has come to be called -- simply says:
Emissions = GDP x Technology
With this simple equation before us, we can see the fundamental challenge to reducing emissions: A rising GDP, all else equal, leads to more emissions. But if there is one ideological commitment that unites nations and people around the world in the early 21st century, it is that GDP growth is non-negotiable. Right now, leaders on six different continents are focused on efforts to grow GDP, and with it jobs and wealth. They're not as worried about emissions.
If you spend any time in the midst of the climate debate, it won't be long before you will be assailed by those who would like to argue that economic growth is unnecessary or even wrong, and stopping it is a key to reducing emissions. I hear these arguments mostly from wealthy liberal academics in posh university towns across the richer parts of the world. Noted environmental activist Bill McKibben, for example, frequently makes the case that "growth may be the one big habit we finally must break," and he is far from a lone voice. But of course, no candidate has ever secured political office on an anti-growth platform. One has to live in a thickly insulated bubble to think that stopping or reversing growth could ever be a feasible way to reduce emissions.
So what's the solution, then? The Kaya Identity tells us that instead of GDP, the focus must be on technology, and here the math is surprisingly simple. Stabilizing the level of carbon dioxide in the atmosphere would require more than 90 percent of the energy we consume to come from carbon-free sources like nuclear, wind, or solar. Policymakers often discuss reducing annual emissions by 80 percent from 1990 levels. But emissions today are already more than 45 percent higher than in 1990, so that higher level implies a need to cut by more than 90 percent from today's levels. Put another way, in round numbers, we could keep at most 10 percent of our current energy supply, and 90 percent or more would have to be replaced with a carbon-free alternative. Today, about 10 percent of the energy that we consume globally comes from carbon-free sources -- leaving a long way to go.
Frustratingly, this 90 percent threshold for carbon-free energy supply is largely independent of how much energy the world consumes. Every major projection of future energy consumption foresees growth in energy demand around the world, which makes sense when you consider that today 2 billion people or more lack basic access to energy. Energy demand is skyrocketing in China and India, and eventually will in Africa. But even letting your imagination go wild and envisioning a future world that consumes half of the energy we do today would still require that more than 80 percent of our energy supply be carbon-free. This isn't a statement about the feasibility or desirability of improved energy efficiency; it's just math.
Consider this: If the goal is to stabilize the amount of carbon dioxide in the atmosphere at a low level by 2050 (in precise terms, at 450 parts per million or less), then the world would need to deploy a nuclear power plant worth of carbon free energy every day between now and 2050. For wind or solar, the figures are even more daunting.