Medicine For People!

September 2016

Climate Wedges

Figuring It Out

When the subject of climate change comes up in my neighborhood, which isn't often enough, it's usually dismissed with "Well, if only our politicians would get behind wind and solar." But google this issue and you'll find that wind and solar aren't going to be nearly enough, not in anyone's book. At least, not anyone who does the math. If you've got a calculator handy–or a pencil and piece of paper–here's the concept.

Climate Wedges


Ignore that this graph starts in the year 2000; this has been a "new" problem for at least 20 years and the principles have not changed.

The light green-blue area at the bottom represents how much carbon would be going into the atmosphere had emissions remained at the 2003 level. But of course they did not. Each year we emit more carbon dioxide than we did the previous year. Those emissions make up the yellow area. If this trend continues, there will be twice as many emissions per year by 2050 as we had in 2010.

Imagine that you are trained as an engineer and you ask yourself how to eliminate that yellow triangle. An engineering professor at Princeton, Robert Socolow, asked that question and came up with the diagram above and the list of remedies you can see below. He listed 15 actions, each of which would eliminate one wedge from the yellow triangle. For example, if every motor vehicle in the world required only half the fossil fuel per mile that it does now, then we could whittle away one yellow wedge.

In fact, he made a game out of this, which you can find here. Below is the list of possible actions from the game. His abbreviations include CCS for "carbon capture and storage" and PV for "photovoltaic."

Stabilization Wedges Table

As you check the math, some caveats:

  1. Some sources estimate by weight of carbon emitted, which was at 10 GtC (Gt = gigatons, C = carbon) per year in 2010, and other sources calculate by carbon dioxide, which computes to about 36 GtCO2 (gigatons of carbon dioxide).
  2. Some sources list methane and other greenhouse gases separately, and some translate them into "greenhouse gas equivalents" and adjust the carbon or carbon dioxide number up commensurately.
  3. Some sources measure greenhouse gases from energy production only. Other analyses include other greenhouse gases such as methane, ozone, carbon dioxide from cement production, gas flaring from petroleum producers, etc.
  4. Emissions listed in this newsletter are global figures, not U.S. figures.
  5. There are millions of smokestacks and billions of tailpipes in this world. The only people with exact numbers are conning you. In actuality, we are still learning how to measure our emissions and their dangers. 

Let us return to solar and wind, my neighbors' solution. If we expand our use of solar energy by a factor of 100 and wind energy by a factor of 10 (after solving the energy transport and storage problems unique to these energy sources), we can remove two wedges from the eight required to prevent increased carbon output. God willing, we can do better and perhaps take out another wedge with solar and wind. We can build facilities closer to where the energy will be used and discover methods to store electricity between the time of generation and the time of use. Yet, as you can see from the list above, we still face major and disruptive engineering, financial, and political struggles to remove all the yellow wedges.

Look back at the yellow wedges above. Notice that the vertical axis starts at about 7 Gt of carbon emissions per year and that the blue area indicating those emissions greatly understates our baseline emissions. In other words, even after removing every yellow wedge, we will still be pouring into the atmosphere some 8 Gt of carbon or 36 Gt of carbon dioxide each year. That is our current baseline; removing eight wedges through great effort basically prevents us from making the baseline worse. We will still be adding carbon dioxide to the atmosphere at the current dangerous rate. If we actually wish to push carbon dioxide emissions down to zero within the next 50 years, we will need to start work today on another eight wedges, the eight wedges necessary to eliminate today's baseline emissions. We will need to succeed at every one of them.

And if we do, even though we are emitting no significant carbon dioxide at that point, we will still face global warming from:

  1. An atmosphere that still contains the excess carbon dioxide we've already emitted
  2. Reduced ice and snow cover in the polar regions, so that those regions no longer reflect heat into space from their white surfaces, but instead absorb heat from newly exposed seawater and earth
  3. Methane releases from melting permafrost
  4. Climate alterations from changing ocean currents, such as the Gulf Stream and our own Humboldt current
  5. Increased human energy needs as we adjust to social and economic challenges of climate change, such as mass migration, increased energy inputs for agriculture, air conditioning, etc.
  6. And other factors,  most of them unpredictable

In other words, if we can carry out every remedy in the list of stabilization wedges, we still face unprecedented problems.

Personally, I think we can do it.  Some wedges will be difficult, such as carbon capture and storage. Yet each has been chosen because it seems to be, however challenging, technologically and socially possible. 

We Can Succeed

In the late 1930s, President Roosevelt gently prepared us for war with Germany, even though much of the country was in denial. Then, as now, if you wished to oppose national preparation for disaster, you had to deny that there was any threat. In the late 1930s, isolationists opposed to the United States spending money on what they saw as a European problem had no choice but to say, no matter what they actually believed, that the Nazis were not a threat. Today those with an economic interest in the status quo have no choice but to say, whatever they actually believe, that the global temperature is not increasing or that if it is, our carbon emissions are not responsible.

Isolationists in the 1930s did not threaten every human being on the planet. Today, climate change deniers do threaten every human being on the planet.

Fortunately, those delusions are becoming more difficult to maintain. And, history shows that once we put our hands to the plow, or Rosie puts her hands to that rivet gun, we can achieve what seemed inconceivable.

Earth Rising

The image of the earth rising above the edge of the moon can never be erased from the mind of any human being who has seen it. What seemed to be a limitless flat world over which the sun traveled each day from East to West has become a space ship. Whatever problems come up from our reckless endangerment of our space ship, we can and must solve. Working together, facing the common enemy of our carbon emissions and the still unfolding and yet to be revealed consequences, we will only be exercising the human cooperation and ingenuity which long ago made us master of the woolly mammoth and the great whale.

We were not wise enough in those battles to know how to keep those food and oil sources sustainable. Let us be wise now!


Credit to Jody Bower, now on a book tour for Jane Eyre's Sisters: How Women Live and Write the Heroine Story (Quest Books 2015), for taking the time to provide thoughtful editorial assistance.


Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington.