Wisconsin's Role in Great Lakes Restoration - American Water ...

Using Risk Calculations to Support Climate Change Adaptation in Wisconsin
**Zachary Schuster, University of Wisconsin-Madison, Madison, WI, zschuster@wisc.edu
Kenneth Potter, University of Wisconsin-Madison, Madison, WI, kwpotter@engr.wsic.edu
Many studies of the impacts of climate change on precipitation have found that it is very likely
that the magnitude and frequency of intense precipitation events will increase for the
Midwestern United States over the next century. With a consensus coalescing around these
projected changes, the task for water resource decision-makers now becomes to use that
knowledge to help states and communities prepare adaptation strategies for flooding caused
by a changing climate.
The goal of this study is to use both climate model precipitation projections and historical
precipitation data to develop a framework for assessing how the precipitation regimes for
Wisconsin’s communities are projected to change over the next half-century and how these
projected changes can be used in the climate change adaptation process.
The damages caused by intense precipitation events frequently behave non-linearly, with the
most intense events causing a majority of the total damage calculated for a given precipitation
distribution. One method of accounting for this non-linearity is by multiplying a damage
function and a precipitation threshold exceedance probability distribution to obtain a value of
total risk for a given precipitation record.
This study applies damage functions to statistically-downscaled and de-biased General
Circulation Model (GCM) precipitation data for the state of Wisconsin to determine the
magnitude of projected changes in total risk over the next half-century due to climate change.
We then seek to put the model changes into perspective by comparing the total risk
calculated based on Wisconsin historical records from 1950-2007 with those calculated for
the other Midwestern states of Illinois, Iowa, Minnesota, and Missouri.
The future temperature regimes for Wisconsin are projected to resemble those that currently
occur in locations to the south and west of the state. This total risk method allows us to
determine if similar shifts in Wisconsin’s precipitation patterns are expected to occur. It also
provides a framework for using known historical precipitation records from other locations as
the basis for preparing climate change adaptation strategies for Wisconsin’s communities.
** Graduate student presentation
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