In previous
blogs, I have advocated particular approaches to fisheries and suggested an
analogy with climate change. This week, I will describe the analogy more
explicitly and make the case for its broad applicability, using water
management as an example.
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| The Pineapple Express |
I can talk with at least a little authority on water management
systems. While working for the National Oceanic and Atmospheric Administration
(NOAA), I had the great fortune to be selected for its Leadership Competencies
Development Program. Though I worked for NOAA’s Fisheries Service, the program
assigned me to work details in the agency’s Office of Oceanic and Atmospheric
Research (OAR), which provides national leadership in climate science and gave
me some early exposure to issues I wrote about the last couple of weeks.
OAR also develops
new weather forecasting technologies. My mentor for the Leadership Program was
Marty Ralph, a meteorological researcher who has played a major role in
identifying and describing atmospheric rivers, which rapidly carry warm moist
air from the tropics to temperate regions and are responsible for many of the major
winter storms that batter the U.S. West Coast. I explained my ideas on managing
uncertainty to Marty, and he was interested in having me look at the potential
benefits that his research might provide to society. We focused on the Folsom
Reservoir, a man-made lake above Sacramento, California.
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| The Folsom Dam, California |
This reservoir
is a key water source for central California but also protects Sacramento from
floods. Visitors to California’s capital will notice that the buildings of old
town are raised above street level, an old technology to confront Sacramento’s great
flood risk (second only to New Orleans in the U.S. even with the current
dam/reservoir). Managing the reservoir is tricky. The water it contains is
extremely valuable from mid-spring through mid-fall, when central California
gets virtually no rain or snow. However, warm wet storms have the potential to
bring vast quantities of water rushing down from the snow-covered Sierra
Mountains. The dam has only so much capacity to release water safely, and so
reservoir operators must plan ahead. They risk a flood if they do not release
enough water and provide space in anticipation of a storm. However, they risk a
water shortage during the dry season if they release too much water. Marty
recognized that more accurate weather forecasts could result in better information
to guide the choices the dam operators face.
To me, the dam
operator challenge sounded strikingly familiar. The water in the reservoir is
like fish in the ocean. Let’s call this phenomenon the stock. The decisions
about releases are like catch quotas. Let’s call this phenomenon the flow. The
dam operator faces two fundamental choices: a target stock level, and rules
that govern flow. Both involve trade-offs. Larger stocks of water are good for
water supply but bad for floods, just as larger stocks of fish are good for
ecosystems but may dampen the productivity of fisheries. More responsive flows
will keep reservoirs closer to target water levels and can reduce the chances
of a flood, but are more costly in terms of required technology on the dam,
greater stress on the riverbed and low-lying development downstream, and lost
opportunity to generate electricity (which is done using turbines with
carefully controlled water flows). Similarly, more responsive fisheries
policies will keep fish stocks closer to target levels and reduce the chance of
a stock collapse, but require more management infrastructure and impose economic
and social costs of unpredictable incomes for fishing operations and their
distribution chains.
Climate change
can also be thought of in terms of stock—greenhouse gases in the atmosphere;
and flows—production of greenhouse gases. In this context, our current policy
can be interpreted in one of two ways. One interpretation is that we have a
target stock level that is much higher than current greenhouse gas levels and
we are willing to accept the possible consequences of those higher levels. The
other interpretation is that we have a target that is somewhere near current
levels, but unresponsive flow policies that will allow the stock to grow a fair
amount before we gradually adjust it downward. Since we do not fully understand
the consequences of much higher greenhouse gas levels, the most accurate
depiction of current policies might be one of waiting and seeing. The problem
is, if it turns out that high stock levels are as bad as several models
predict, we will then be forced into a tough decision between adapting to the
new conditions versus enacting expensive or risky responsive policies to bring
greenhouse gas levels down quickly.
With all three
of these systems—water management, fisheries, and climate—we can make smarter
policies by considering stock and flows following a common formula. It involves
only a few steps, but each requires specialized knowledge. We need three
interconnected models: one of the environmental system of concern, another of
the management system, and finally one of the socioeconomic system. The
environmental model must describe how stock size will change under various flow
rules and consider scientific uncertainties. Similarly, the management model must
take into consideration choices managers can make and the degree to which these
choices will change flows, including implementation uncertainties. The
socioeconomic model must translate uncertainties into risks, and be capable of
predictions about stock and flows related to the set of objectives (sometimes
conflicting) that various user groups have. In combination, this set of models
can then be used to evaluate various policy options and give advice on their
relative strengths and weaknesses. This advice can be instrumental in helping
people to rationally navigate uncertainties by giving them concrete advice
about what options they have to reduce future risks and what they would have to
give up to achieve these reductions.
Not all
environmental issues have stock and flow properties, but many do. Recognizing
this commonality should help us to devise means to use science more effectively
when crafting environmental policies.
Next week, I
plan to switch gears somewhat. Feel free to suggest topics either by commenting
here or by contacting me directly.
Wishing you a
Happy 2013,
Josh
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