How much will strawberry harvests shrink when extreme heat harms pollinators? How much will timber production decline when windstorms flatten forests? How much will recreational value disappear when large wildfires sweep through mountain towns?

These are some critical questions that a new computer simulation is helping answer. Researchers, including Peter Reich of the University of Michigan, presented a model that aims to understand how extreme weather events, worsened by climate change, will affect ecosystems and the benefits they provide to humans.

“We’re not the first people to try this and we won’t be the last, but it’s an attempt to holistically connect climate disturbances and natural processes,” said Reich, a professor at the U-M School for Environment and Sustainability. “It’s linking biodiversity and different kinds of ecological responses, some of which are services to people, and answering how we might go about trying to put dollar values on those services.”

Based on the model, a Minnesota forest could lose up to 50% of its timber revenue if a severe windstorm hits. But even if all trees are flattened, Reich said, the exact value of the economic loss will vary markedly depending on the mix of species and the size of the trees.

“With climate change, there’s an urgent need to incorporate the impacts of extreme events like mega-fires and hurricanes on the benefits nature provides,” said Laura Dee, first author of the new report published in Nature Ecology and Evolution and associate professor of ecology and evolutionary biology at the University of Colorado.

“This research is an important step toward anticipating impacts to ecosystem services so that we can adapt management strategies accordingly.”

Scientists use the term “ecosystem services” to refer to the essential functions that nature provides to support human life and well-being. Tree roots purify water, insects pollinate crops and forests lock away carbon, helping to stabilize the climate. In addition to these tangible benefits, mountains, lakes and oceans offer recreational enjoyment for people and hold cultural significance for communities.

Previous models for predicting how ecosystems respond to climate change tend to assume that changes are steady. For example, a gradual increase in global temperatures of up to 1.5°C. But as climate change makes extreme weather events like wildfires and floods more frequent and severe, the impacts from rapid disturbances have become significant. 

Dee, Reich and the team developed a new mathematical model that tracks how the probability of an extreme weather event affects certain species and the ecosystem services they provide. The model also incorporates how people value these services.

To show the model’s potential, the team applied it to calculate the possible consequences of extreme windstorms in a mid-latitude forest in northern Minnesota. The model considered how winds have different effects on different tree species, each of which has distinct economic value. For example, white cedar trees are more resilient to windstorms than pine or spruce trees, but the latter can sell at a higher price.

The model suggested that a windstorm, depending on its intensity, can slash the total timber value of the forest by 23% to 50%. Recreational opportunities like hiking and camping would also take a hit.

“We know that all aspects of ecological health are important, but monetizing the services we get from nature is illuminating,” Reich said.

Study: Quantifying disturbance effects on ecosystem services in a changing climate

Read the full press release on the Michigan News website.