If you live in a flood-prone area, you may be familiar with a term like 500-year flood, which is a description engineers, planners, and emergency agencies use to predict the likelihood, frequency, and scale of flooding events. A 500-year flood, which has a 0.2% chance of happening any year, would be expected to be large and significant. As Hurricane Harvey descended on southeast Texas, UW–Madison’s Space Science and Engineering Center, one of the world’s leading centers on weather and satellite information, described the flooding as a 1,000-year flood, which is, well, unprecedented in American history. And then, on its heels came one of the largest hurricanes ever observed by humans.
How do we know these are extraordinary historical events? Because we have data that tells us so.
Here in Wisconsin we’ve experienced multiple floods over the last few decades, many at the 500-year scale. These recurring floods, often in the same areas, tell us that perhaps the conditions that influence how and when these areas flood are changing. What this observation also tells us is that we may need to adjust our assumptions and projections.
It turns out that our understanding of how things “are” or “should be” is shifting, and rapidly. As a changing climate increases the scale and frequency of extreme storms, it looks like we’re going to need a bigger scale. But if in creating a new scale we throw out the original baseline, we will lose the critical perspective of just how rapid and significant these changes are. From the standpoints of human health and safety, economics, and environmental protection, understanding our baseline is extremely important.
Earlier this year there were forecasts about the scale of predicted dead zones in Green Bay and Lake Erie. While it is good to have this information, these predictions also trouble me because they remind me that algal blooms, fish kills, and beach closures are now part of normal life in the Great Lakes region. “Normal,” however, should not be confused with “acceptable.”
Humans manage change in many ways, and one is to define a new normal when the old one seems to no longer fit. But when we normalize new conditions and don’t consider the cause or consequence of change, we blind ourselves to the capacity to learn, respond, and adapt.
We can’t all personally experience all the important changes happening in our world. Moreover, the “sample of one” (our own experience and perspective) is clearly not sufficient to understand global and ecosystem-scale change. This is where science comes in. Thousands of data points from consistent monitoring and a thorough understanding of the baseline by which we track change can help us see the bigger picture. Science can help us to better understand change and navigate it wisely. Measuring change can provide insights that can help us determine whether changed conditions are indeed acceptable as “the new normal,” and, if they are, what the impact might be of normalizing these changes.
Science enables us to see trends that are larger than our personal experience. With this bigger picture we can identify risks and opportunities to society and, in many cases, also to specific communities and individuals.
That is, if we’re willing to see and accept what the bigger picture shows us.
