At a recent news conference, scientists announced some good news about renewable energy: "We've got solar, wind, geothermal - we're all set to move forward with this stuff whenever everyone else is." Unfortunately, representatives from the world's leading economies signaled that "they would continue to heavily rely on fossil fuels until they had something more than an overwhelming scientific consensus to go on". (The Onion, May 21, 2014, Scientists Politely Remind World That Clean Energy Technology Ready To Go Whenever
In all seriousness, we do not need to wait for some new miracle technology to save us from climate change. The existing renewable energy sources of solar, wind, and geothermal have been tested and put into service. We just need to ramp up the deployment of these energy sources on a huge scale. It won't be easy, it won't happen overnight, and it won't be cheap. But the consequences of not
doing it will be even more expensive. And the longer we wait to deploy these technologies, the harder it will be for us to make the necessary changes to stave off the worsening effects of climate change.
Ten years ago, Princeton University scientists, Steve Pacala and Robert Socolow, wrote a seminal paper outlining the magnitude of the problem before us.* They introduced the concepts of a "Stabilization Triangle" and "Stabilization Wedges". Figure 1 graphs our emissions of CO2 (as billions of tons, or Gigatons (Gt), of carbon (C) per year) since 1950 and shows that they have been steadily ramping upwards. The dotted black line represents an extension of our current path into the future, or "business as usual" (BAU), with ever higher CO2 emissions year after year, which leads to a doubling of our emissions (from about 8 to 16 GtC/yr) in about 50 years. The flat path is an idealized path were we keep our emissions at the same level every year for 50 years. We need to move from the upper path to the lower path to slow down climate change. The area between these two paths is the "Stabilization Triangle" which represents the emissons reductions we need to implement in order to change paths.
Figure 1: Emissions pathways and the "Stabilization Triangle".
Figure 2: "Stabilization Wedges"
Carbon Mitigation Initiative, Princeton University
Figure 2 illustrates the numerous "Stabilization Wedges" which represent the individual activities/approaches/strategies that reduce emissions of CO2, slowly at first but growing year after year until each wedge accounts for 1 GtC/year of reduced emissions 50 years from now. For example, one wedge might be incresing our use of wind power (already happening) by ten times relative to today. Other wedges would be solar power, energy efficiency improvements, reforestation, etc.
In 2004, when Pacala and Socolow wrote their paper, we were emitting about 7 GtC/yr. Figures 1 and 2 are from some years later at which time we had increased emissions to about 8 GtC/yr. In 2011, Socolow updated
the charts to the latest emissions amount of 9 GtC/yr. In other words, we are still following the BAU path - more and more CO2 emitted each year, rather than leveling off. Which means we need to drive more wedges into the triangle to meet our goals.
Yes, the task is onerous, but the good thing is we don't have to do it all at once. The point to remember about the Stabilization Wedges is that they start at zero and grow from there. It would be nice if, like the islanders on Tokelau
, we could switch from diesel to 100% solar power all at once, but that is unrealistic and not neccssary. Every ton of coal, barrel of oil, or cubic foot of gas replaced by some other energy source, which doesn't release CO2, helps us solve the problem. Every home with newly installed solar panels adds to the solar power wedge, every wind farm built adds to the wind power wedge, etc. Will it be enough, will we ramp up the necessary solutions fast enough? No one knows. But what do we have to lose?
*PDF - Pacala, S., & Socolow, R. (2004). Stabilization wedges: solving the climate problem for the next 50 years with current technologies. science, 305(5686), 968-972.