The greenhouse gas problem is far more intractable than most people think, and although there is a solution in sight, we will need a technological revolution to implement it. To be more specific:
- Most people believe that cutting CO2 emissions in half would reduce CO2 levels, but this is wrong: Levels would still rise.
- In the most optimistic conventional scenarios — even with swift, innovative, and successful efforts to remake the human world — CO2 levels climb higher and stay higher through the end of this century.
- Nonetheless, molecular manufacturing capabilities based on advanced nanotechnology will make it possible to reduce CO2 concentrations to pre-industrial levels within a short time span.
- This can resolve the dilemma of economic development and climate change.
I wrote a brief essay on this in response to The Edge Foundation’s 2009 Annual Question: “WHAT WILL CHANGE EVERYTHING? What game-changing scientific ideas and developments do you expect to live to see?” Last year’s question was “WHAT HAVE YOU CHANGED YOUR MIND ABOUT? WHY?”; respondents, answers, and press comments are presented here. I found it difficult to answer this one (too many possibilities!), but I did better this time.
The 2009 answers are under a press embargo until midnight, Eastern Standard Time, so I’ll keep my finger off the publish button for another hour or so…. And here’s the link:
Below are a few excerpts with added links and commentary:
Carbon stays in the atmosphere for a long time.
To many readers, this is nothing new, yet most who know this make a simple mistake [see below]. They think of carbon as if it were sulfur, with pollution levels that rise and fall with the rate of emission: Cap sulfur emissions, and pollution levels stabilize; cut emissions in half, cut the problem in half. But carbon is different. It stays aloft for about a century, practically forever. It accumulates. Cap the rate of emissions, and the levels keep rising; cut emissions in half, and levels will still keep rising. Even deep cuts won’t reduce the problem, but only the rate of growth of the problem.
In the bland words of the Intergovernmental Panel on Climate Change, “only in the case of essentially complete elimination of emissions can the atmospheric concentration of CO2 ultimately be stabilised at a constant [far higher!] level.” This heroic feat would require new technologies and the replacement of today’s installed infrastructure for power generation, transportation, and manufacturing. This seems impossible. In the real world, Asia is industrializing, most new power plants burn coal, and emissions are accelerating, increasing the rate of increase of the problem.
In fact, the mistaken idea that CO2 behaves like a typical pollutant seems deeply entrenched in people’s thinking (if you find it in your thinking, please make an effort to dig it out). I was disturbed to read a recent article in Science (here, if you’re a subscriber) in which John Sterman describes a study in which a group of MIT students (from my own school!) flubbed this completely. After reading a description excerpted from the IPCC‘s “Summary for Policymakers”, they still misunderstood the problem, mistakenly thinking that limiting emissions would limit CO2 levels. From the Science article, with emphasis added:
The dynamics are easily understood using a bathtub analogy in which the water level represents the stock of atmospheric CO2. Like any stock, atmospheric CO2 rises when the inflow to the tub (emissions) exceeds the outflow (net removal), is unchanging when inflow equals outflow, and falls when outflow exceeds inflow. Participants were informed that anthropogenic CO2 emissions are now roughly double net removal, so the tub is filling.
Yet, 84% drew patterns [graphs of emission control policies and their effects] that violated the principles of accumulation…. Nearly two-thirds of the participants asserted that atmospheric GHGs [greenhouse gases] can stabilize even though emissions continuously exceed removal–analogous to arguing a bathtub continuously filled faster than it drains will never overflow. Most believe that stopping the growth of emissions stops the growth of GHG concentrations. The erroneous belief that stabilizing emissions would quickly stabilize the climate supports wait-and-see policies but violates basic laws of physics.
Training in science does not prevent these errors. Three-fifths of the participants have degrees in science, technology, engineering, or mathematics (STEM); most others were trained in economics. Over 30% hold a prior graduate degree, 70% of these in STEM. These individuals are demographically similar to influential leaders in business, government, and the media, though with more STEM training than most.
The way to remove CO2 quickly is to pump it, but this is a project too large to undertake with today’s manufacturing infrastructure. However, as I note in the Edge essay,
If we were good at making things, we could make efficient devices able to collect, compress, and store carbon dioxide from the atmosphere, and we could make solar arrays large enough to generate enough power to do this on a scale that matters. A solar array area, that if aggregated, would fit in a corner of Texas, could generate 3 terawatts. In the course of 10 years, 3 terawatts would provide enough energy remove all the excess carbon the human race has added to the atmosphere since the Industrial Revolution began. So far as carbon emissions are concerned, this would fix the problem.
A few specifics:
- Nanosystems provides a physical analysis of a class of selective, thermodynamically efficient molecular pumps. Devices like these provide one option for satisfying the first condition I mentioned.
- Excess atmospheric CO2 is expected to be about 1 trillion tons in the time frame of interest, and the amount of energy required to collect and compress this to liquid density is about 1021 Joules.
- This is equivalent to 3 terawatts of electric power for 10 years, comparable to the total world electric generating capacity today.
- Solar arrays with an aggregate area equivalent to a 250-km square would provide ample power (assuming cells of mediocre photovoltaic efficiency, but placed in sunny locations).
- Advanced molecular manufacturing capabilities will make it practical to produce the necessary hardware to solve the greenhouse gas problem by removing the excess greenhouse gases, reversing net emissions.
Regarding molecular manufacturing, as I note in the Edge essay:
The U.S. National Academies has issued a report on molecular manufacturing, and it calls for funding experimental research. A roadmap prepared by Battelle with several U.S. National Laboratories has studied paths forward, and suggests research directions. This knowledge will spread, and will change the game.