As the climate changes, it’s important that we understand how Michigan’s environment will change and what will be affected. Something we don’t often think about is how climate change does and will impact the health of our native plant and animal species. To learn more, I spoke with Dr. Sarah Green, professor of chemistry at Michigan Technological University and vice co-chair of the United Nation’s Global Environmental Outlook advisory committee.
Adrian de Novato: Ecologists at the University of British Columbia found that non-native species better adapt to changing flowering seasons than native plant species. How do you project Michigan’s growing and flowering seasons to be impacted by climate change as we move forward?
Dr. Sarah Green: Michigan already has an average of 9 more frost-free days every year than it did before 1960. By the end of the century our frost-free growing season could be a month longer than it was in the early 1990’s. The change will be even more drastic if carbon emissions are not reduced.
Longer growing seasons will let some plants expand their ranges. And my vegetable garden will do better. We expect species that like warm weather to thrive further north than they do now. Some of our red and white pine forests that cannot tolerate high heat may become replaced with deciduous species of trees. The range of eastern white cedar, an important food for deer, could be reduced by heat and drought.
Longer growing seasons have some other negative consequences. For example, the ragweed pollination season is about two weeks longer now than it was in 1995. Increased CO2 levels make poison ivy grow faster and produce more of its toxin, urushiol.
As the climate shifts, we are also seeing much more variability in the weather. For example, unusually warm weather in spring can be followed by a big cold snap. These extremes can be bad for fruit production. Blueberry bushes and cherry, peach and apple trees might flower early, and then be damaged by frost. But big temperature swings in spring might improve yields of maple syrup.
Adrian de Novato: Invasive species are often those that are highly flexible and resilient to environmental changes. Will they be better suited in the Michigan of tomorrow?
Dr. Sarah Green: Species that can adapt to rapid changes will be able to outcompete species that rely on a more predictable climate. Some invasive plants might be able to quickly move into an area where plants have been killed by drought or fire. Insect pests can take advantage of plants weakened by heat or drought stress.
In some cases we should consider new species in an area to be migrants rather than invaders. If white pines no longer thrive in an area we should welcome oak trees. Within the next decade or two there will probably be “native” species that can no longer live in their historic ranges. They will be replaced by species that are better adapted to the new climate in that place.
Adrian de Novato: What kind of changes can we expect to Michigan’s lakes and waterways that will inhibit or prohibit invasive species?
Dr. Sarah Green: Any big change in the local climate will be an opportunity to some species and a disadvantage to others. Most invasive species move from warm areas to places with a similar or warmer climate. So, it’s hard to think of a change that will inhibit invaders. Many species are transported by humans, so a change that makes a lake less attractive to boaters would inhibit their spread.
Adrian de Novato: What native Michigan species, either plant or animal, do you think is most at risk from the impacts of climate change?
Dr. Sarah Green: That would be pure speculation. Ecosystems are complex. The loss of one species or the addition of an invader can have ripple effects that are unpredictable.
In the past ecosystems in Michigan underwent huge changes when its original forests were cleared for farming and timber. That certainly had an effect on the animals that lived here (where are the wolverines). The changing climate will also have large scale consequences.
Adrian de Novato: So many of our native plant and animal species rely on delicate food webs in Michigan’s varied aquatic and terrestrial ecosystems. How will these environments be impacted by climate change and are they resilient enough to withstand the changes?
Dr. Sarah Green: We are certain of some environmental changes that are already happening: more very hot days, longer warm season, less lake ice, more dry periods, more variability in weather, more extreme downpours.
Plants and animals have different capacities to adapt to changes. Animals may move to a better environment; birds can easily move, but a salamander may not be able to find a better pond if his dries up. Plants can’t move, but they can send their seeds far away to search out better digs. Some plants and animals are more resistant to heat or drought than others.
We can study individual plants and animals to guess how they will adapt, which gives clues about how a whole ecosystem might change. Right now humans are doing a giant global experiment by adding carbon dioxide to the air and over the next 100 years we will see how heating the planet changes its ecosystems.
Adrian de Novato: How can people help protect Michigan’s native species from the impacts of climate change? What do they need to know?
Dr. Sarah Green: We must act to limit carbon emissions to prevent drastic impacts in the future. Locally, we can make efforts to use less energy in driving, electricity, and heating, because carbon dioxide is emitted by burning gasoline, coal, natural gas, and oil. This is a global problem that individual actions cannot solve. So, it is just as important to press businesses to act responsibly. Most importantly people should demand that elected officials commit to climate action, such as supporting the recent Paris Agreement on Climate.
Locally, we also need to adapt to climate changes that are happening now. “Green infrastructure” such as planned wetlands, can help protect communities from flooding while also providing homes for native species.
About Dr. Sarah A. Green
Dr. Green has been a member of the Chemistry Department at Michigan Tech since 1994 and served as Department Chair from 2004 to 2013. She was awarded a Jefferson Science Fellowship to serve in the Bureau of East Asia-Pacific Affairs in the U.S. Department of State (2013-14). Dr. Green currently serves as co-vice chair for the Scientific Advisory Panel on the Sixth Global Environmental Outlook (GEO-6), United Nations Environment Programme.
Learn more about how climate change is impacting Michigan and the Midwest from the National Climate Assessment Report and by reading my recent article on Medium covering how Michigan’s climate has already changed.
Image Credit: Observed Increase in Frost-Free Season Length, NOAA NCDC / CICS-NC