After the Flood – “Doomsday” Climate Change Scenario Looks a Little Less Alarmist

In 2014, the Water, Sustainability and Climate Project at the University of Wisconsin-Madison published “Yahara 2070” a series of stories about potential futures for the Madison area and the Yahara watershed.

Using a combination of published scientific research, computer modeling and a dose of science fiction, a team of researchers attempted to answer the following question – what could our community look like in 50-60 years?

The result was four “climate change scenarios” exploring how our current actions and policies around land use and water quality might shape the future. One of the four was a “doomsday” scenario based on the assumption that we basically did nothing to try to mitigate climate change impacts on the community.

And, tucked into that scenario was a fictional flood.

Illustrations from the Yahara 2070 scenarios. 

Here’s an excerpt:

The 2020s and 2030s were exceptionally
warm and wet. Frequent and ferocious storms
caused the Yahara lakes to repeatedly breach
their banks, and flooding was a recurrent
problem. A devastating storm put the summer
of 2031 in the history books. The storm caused
Lakes Waubesa and Kegonsa to overflow and
converge, flooding the towns of Dunn and
McFarland in the southern part of the
watershed. Many of the existing control structures
could not withstand the floodwaters,
which consequently inundated most low-lying
areas, destroying homes and property, drowning
roads, and causing incalculable damage.
Water management officials struggled with
where to put the excess water, and most of the
watershed was declared a disaster area.

“We wanted rain events to be part of the narrative” recalls Eric Booth, a hydrologist and research scientist in the UW-Madison department of civil and environmental engineering.  “We needed to simulate the hydrology and water quality component. It wasn’t something we really chose to refine, but I was confident in the lake level predictions we made it terms of predicting big rain events.”

But, says Booth, some stakeholders who were helping review the scenarios weren’t so sure.

“There were definitely some people who thought it was a little too out there,” he says. “I never really got to the root of the problem, but I think it came down to a lot of people having a hard time with the scenarios in general.”

But, Booth says, it’s important to remember that the goal of scenario building is to look at what’s possible, not necessarily what’s plausible. While the “doomsday” scenario is a very unlikely future – involving epic flooding, air-borne toxic algal events and escaped elephants – hard science underlies the science fiction.

Which is a point that the current flooding in Madison has underscored.

LEFT: Map released by city of Madison 8/24/18. RIGHT: Map of area inundated during largest flood of Yahara 2070 scenarios (released to workshop on 5/2/2017). Courtesy: Eric Booth

“I think the way our models simulated that big flood event was fairly realistic,” Booth says. “Now we have a huge event that just happened (Editor’s Note: Is STILL happening) and some of these flood maps the city is putting out look really similar to our projections.”

These similarities, Booth says, show how useful scenarios can be. By taking what we currently know about the hydrology and ecology of the systems we live in, we can ask “what if” questions and use modeling to see how the answers to those questions lead to all sorts of different futures – futures we will get to based on what we choose to do now.

Or, as Steve Carpenter, emeritus director of the CFL and one of the scenarios’ lead authors told Wisconsin Public Television during an interview back in 2014, “Every element of the scenarios is true and exists today. What is fiction is the way we put the elements together. And so the question for the public is, as we go into the future, what parts of the present do we want to take with us and what parts should we leave behind?”