This week we continue our trek toward New Normal by looking at No. 11 on Donella Meadows' 12 Places to Intervene in a System: The Size of Buffers/Stocks Relative to Flows.

Ugh. This sounds terribly academic and . . . it kind of is at the beginning, but I'm hoping it's worth it.

Soooo, we need to digress a bit into Systems Dynamics here to discuss this leverage point. I just hope I remember what Dana taught me all those years ago!

Pretty much everything in nature can be discussed in terms of stocks and flows. In its hopelessly simplified usage here, stocks are accumulations or levels of things that can be physical (e.g. carbon dioxide in the atmosphere, water in a bathtub) or non-physical (personal satisfaction or fulfillment). Flows are, well, flows. They go both in and out, and the rate of flow is governed by the difference between actual state (or stock) and the desired, or allowed state.

Indoor comfort provides a good example of how this works: The indoor temperature is the "stock" of heat/cooling. Hot or cold "flows" in to adjust the temperature happens when there is a difference between the thermostat setting (desired state) and the actual temperature. The flow of temperature out and in is governed by how tight the building envelope is. A building-related example of increasing a stock relative to a flow to stabilize the system is adding thermal mass to a building. Energy is stored in mass and the more mass a building has, the more stable its temperature.

Although very effective, this strategy is hard to implement, which is why it's down at No. 11 instead of higher.

In the context of New Normal, I'll look at buffer-related options for avoiding unmanageable climate change. Astute readers will notice that the construct of Leverage Point No. 11 involves the relative size of stock buffers to flows, which means that if we reduce flows (most obviously: reducing carbon-intensive energy use) then the size of current buffers in relation to excess carbon flows increases. But discussion of the leverage point that involves energy and water efficiency comes later because it's a higher-impact opportunity.

In pre-industrial times, the global carbon balance was more or less stable with the amount of CO2 absorbed in biomass growth and the oceans approximately equal to emissions from fires, volcanoes and decay. Industrial activity began to push this system out of balance, and we're now waiting for the inevitable adjustment. [Yes, CO2 levels have been as high or higher than 450 parts per million (ppm), but never have they moved this quickly. Think of the difference between taking the elevator down from the 10th floor and jumping out the window: The end-state is the same, but arguably the voyager is in a different condition upon arrival.]

Net deforestation contributes to about 20 percent of humans' total contribution to excess carbon pollution, so eliminating net deforestation can increase the buffer stock that forests represent. However, we still have 60 percent to go to reach scientists' assessment that an 80 percent reduction by 2050 is necessary to keep CO2 levels below 450 ppm, which is considered to be the threshold of unmanageable climate change. So, as important as this step is, it is still not nearly enough.

Oceans also are mentioned as another potential buffer. Currently there is a great deal of concern that CO2 dissolving into the ocean is increasing its acidity, which in turn is leading to decreased growth in plankton and increased coral reef mortality, which in turn could imperil fish stocks, which are the only source of protein for a huge chunk of the world's population. The leading concept about using oceans as a buffer involves growing plants, grinding them up and dumping them in the sea where they won't decay in conventional fashion. Hmmm. The other idea is to pumping CO2 into the deepest reaches where pressure and temperature keep it in liquid form. Hmmmm. Researchers at Lawrence Livermore and Berkeley National Laboratories estimate that on balance about 15 percent of U.S. emissions might be sequestered by the "plant-meal" method.

Our final "conventional" option in the enlarging stocks arena involves carbon capture and storage or "CCS" for acronym junkies. CCS is the underground sequestration of carbon dioxide in various geological formations, particularly (and perhaps poetically) coal and oil and gas formations. In terms of the theoretical capacity of these formations in North America, both the U.S. Department of Energy and Battelle Memorial Lab studies of the total carbon sequestration potential peg it at approximately 900 years of emissions.

This is exactly the kind of large buffer relative to flows that could make a huge difference in mitigating unmanageable climate change. In reality, little more than half of our CO2 emissions -- those from electricity production -- are actually storable by this means at present. This potential would increase relative to the total electrification of our economy. Then the decision becomes whether to add dirty production and store the effluents underground or to go directly to clean production.

For this measure to be remotely practical, carbon must be emitted reasonably near to where it can be stored. A strong and effective (translation for our Beltway English-speaking audience: "infeasible") policy step would be to require siting new powerplants within a reasonable distance of an appropriate geological formation and to include CCS technology as part of the design. Needless to say, this would have serious ramifications for certain communities, both positive and negative, as well as issues related to electricity transmission. In addition, the Ego-nomic cost of carbon capture and sequestration is an extra 3 to 5 cents per kWh, which, during the current economic situation, essentially precludes this option politically, even if the other issues could be resolved.

We can only hope in the short run that we get some CCS examples up soon to prove out the technology as a "both-and" in conjunction with efforts to change the structure of our energy system to one that is more decentralized and renewably based, which will be the subject of Leverage Point No. 10: Changing the Structure of Material Stocks and Flows and Their Intersections.

Rob Watson
Executive Editor, GreenerBuildings.com
You can reach Rob at rob.watson@greenerworldmedia.com

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