Wisconsin Climate Impacts

Climate impacts various sectors of Wisconsin's ecosystems, economy and society. These impacts are reflected in the statistics of climate variables, in particularly their extreme values, which are illustrated in this section..

Introduction: How Climate Affects Our World and Our State

Climate impacts our life on earth. Normal seasonal variations leave changing imprints upon vegetation, animals, and humans. Applied climatology is the science of understanding how climate, particularly temperature and precipitation, affects agriculture, water resources, ecosystems, energy supply, and the health of humans and animals. The probable irreversible climate change during the course of this new century implies permanent changes in impacts as well. Estimating these changes is an important  new challenge for applied climatology.

Extremes & Impacts
We study these impacts by first analyzing the complete record of climate and its fluctuations lasting from decades down to days. These fluctuations are combinations of both complex climate systems and chaotic weather; they are best described by probability distributions. Climate impacts on the environment commonly involve extreme events (e.g. unusually cold conditions where the temperature is at the extreme low end of a temperature probability distribution).
Impact events are often found at threshold values, such as 32 degrees F, a threshold state that may have a damaging impact (e.g. freezing).  Such events occur when a combination of normal climate, a variable climate situation (e.g. El Niño), and a particular weather pattern (e.g. cold surge) "add up" to a temporary extreme state (e.g. record sub-freezing temperature).

Changing Impacts
In a changing climate, the probabilities of extreme events will shift because of:
(a) a trend  in "normal climate" (e.g. "climate warming"), (b) a trend in climate variability (e.g. El Niño years), or (c) change in weather types (e.g. cold surges diminishing). Climate change science aims at understanding and predicting changes in the probabilities of  both  "changing normals" and extreme events. Research on changing climate impacts (e.g. WICCI)  will follow these steps:
(1) attribution of past climate/probability changes;
(2) assessment of predicted climate/probability changes;
(3) risk assessment of environmental vulnerabilities to changing extremes;
(4) policy guidance for adaptation in order to minimize future negative impacts.

Collaborations with Wisconsin Initiative on Climate Change Impacts (WICCI) research on climate impacts are now underway.