A Moving Target
November - December 2007
Let’s see. . . What do we know about exotic species? They’re bad. They crowd out and out-compete native species. They often have no predators in their new environment. They’re invasive and hard-to-get rid of.
If you’re reading this, you’re probably fond of our native species. We love our cattails and milkweed, our monarchs and maples. We love our mature upland broadleaf forests and our closed-canopy lowland needleleaf forests, even if we don’t know these terms and can’t tell a fen from a bog or sedge from a grass. The point is, we’re used to seeing certain animals and plants, we’re alarmed to see exotic invaders, and we want to protect our native species.
But there’s a catch. All of the species of plants and animals that we think of as having been here forever are here—are what they are—in part because of climate. Opossums have been limited to southern Michigan because in colder winters, they lose appendages to frostbite. However, as winters get warmer, they are able to survive further north. White-footed mice were formerly found only in Lower Michigan. Now they are found in the Upper Peninsula and seem to be displacing the woodland deer mice. Bluebirds have in recent years been observed year-round in Lower Michigan, whereas they used to migrate south in the winter.
It was 92 today as I wrote this on October 7. Do you remember another year this hot, with August temperatures lasting through mid-October? Of course it is impossible to attribute any single weather event to climate change. Trends, however, are in line with scientific projections on the impacts of increased carbon dioxide in the atmosphere. Based upon actual temperature measurements since the Civil War, 20 of the 21 hottest years on record have been in the last 25 years.
Last summer, the National Arbor Day Foundation released a new Hardiness Zone map reflecting rising temperatures. Plants which grew in more southerly states are now gaining a foothold in Michigan. That’s true for wild plants as well as ornamentals.
There is no scientific debate about whether human actions are causing global warming. Dr. Naomi Oreskes of the University of California published a study in the peer-reviewed journal Science which reported that of 928 peer-reviewed articles about climate over a 10-year period, none expressed doubt that humans were accelerating climate change. Over the same period, however, 53 percent of the articles about climate change in the popular press expressed doubt. So while the scientific community moves on to study how best to cope with the climate change that is already occurring, the media is still presenting the cause of climate change as a matter of debate.
The Union of Concerned Scientists issued a state-by-state report entitled “Confronting Climate Change in the Great Lakes Region.” According to that report, by the end of this century, southern Michigan is expected to have summers like northern Arkansas and winters like northern Kentucky. There may be 30 to 50 days per year over 90 degrees in Detroit. The growing season could be eight to ten weeks longer. Average annual temperature may not change much, but the timing of hot and cool periods is expected to change. Summers may be drier, with more droughts. Heavy rainstorms will increase and could be 50 to 100 percent higher than today.
This is not the climate with which our current flora and fauna evolved. How will they cope? Some species will extend their ranges northward. Mammals and birds will be most successful at this. Some trees will not be able to advance their ranges quickly and will die out. Sugar maples are expected to only survive in a tiny portion of Canada, according to U.S. Environmental Protection Agency. Some migratory creatures may get out of sync with the plants they depend upon. If a bird’s migration is temperature dependent, but its food source is light dependent, the bird may arrive before there is enough food to support reproduction. And clearly, other species from the south will be extending their ranges north to Michigan.
What will the children of 2070 think of as native species? They won’t even know what they’re missing, just as we don’t have any real sense of “missing” passenger pigeons. And they will be used to exotic species like loosestrife and Phragmites grass, just as we are used to Queen Anne’s lace and dandelions.
Set against a backdrop of climate change, eliminating exotic species is like trying to shoot a moving target. Something will be growing in Michigan in the year 3000, but what will it be?
If you would like to envision a future where your children’s children enjoy the same wildlife legacy you inherited, it’s time to curb your carbon use.
The four most important ways to curb your greenhouse gas pollution
Let’s see. . . What do we know about exotic species? They’re bad. They crowd out and out-compete native species. They often have no predators in their new environment. They’re invasive and hard-to-get rid of.
If you’re reading this, you’re probably fond of our native species. We love our cattails and milkweed, our monarchs and maples. We love our mature upland broadleaf forests and our closed-canopy lowland needleleaf forests, even if we don’t know these terms and can’t tell a fen from a bog or sedge from a grass. The point is, we’re used to seeing certain animals and plants, we’re alarmed to see exotic invaders, and we want to protect our native species.
But there’s a catch. All of the species of plants and animals that we think of as having been here forever are here—are what they are—in part because of climate. Opossums have been limited to southern Michigan because in colder winters, they lose appendages to frostbite. However, as winters get warmer, they are able to survive further north. White-footed mice were formerly found only in Lower Michigan. Now they are found in the Upper Peninsula and seem to be displacing the woodland deer mice. Bluebirds have in recent years been observed year-round in Lower Michigan, whereas they used to migrate south in the winter.
It was 92 today as I wrote this on October 7. Do you remember another year this hot, with August temperatures lasting through mid-October? Of course it is impossible to attribute any single weather event to climate change. Trends, however, are in line with scientific projections on the impacts of increased carbon dioxide in the atmosphere. Based upon actual temperature measurements since the Civil War, 20 of the 21 hottest years on record have been in the last 25 years.
Last summer, the National Arbor Day Foundation released a new Hardiness Zone map reflecting rising temperatures. Plants which grew in more southerly states are now gaining a foothold in Michigan. That’s true for wild plants as well as ornamentals.
There is no scientific debate about whether human actions are causing global warming. Dr. Naomi Oreskes of the University of California published a study in the peer-reviewed journal Science which reported that of 928 peer-reviewed articles about climate over a 10-year period, none expressed doubt that humans were accelerating climate change. Over the same period, however, 53 percent of the articles about climate change in the popular press expressed doubt. So while the scientific community moves on to study how best to cope with the climate change that is already occurring, the media is still presenting the cause of climate change as a matter of debate.
The Union of Concerned Scientists issued a state-by-state report entitled “Confronting Climate Change in the Great Lakes Region.” According to that report, by the end of this century, southern Michigan is expected to have summers like northern Arkansas and winters like northern Kentucky. There may be 30 to 50 days per year over 90 degrees in Detroit. The growing season could be eight to ten weeks longer. Average annual temperature may not change much, but the timing of hot and cool periods is expected to change. Summers may be drier, with more droughts. Heavy rainstorms will increase and could be 50 to 100 percent higher than today.
This is not the climate with which our current flora and fauna evolved. How will they cope? Some species will extend their ranges northward. Mammals and birds will be most successful at this. Some trees will not be able to advance their ranges quickly and will die out. Sugar maples are expected to only survive in a tiny portion of Canada, according to U.S. Environmental Protection Agency. Some migratory creatures may get out of sync with the plants they depend upon. If a bird’s migration is temperature dependent, but its food source is light dependent, the bird may arrive before there is enough food to support reproduction. And clearly, other species from the south will be extending their ranges north to Michigan.
What will the children of 2070 think of as native species? They won’t even know what they’re missing, just as we don’t have any real sense of “missing” passenger pigeons. And they will be used to exotic species like loosestrife and Phragmites grass, just as we are used to Queen Anne’s lace and dandelions.
Set against a backdrop of climate change, eliminating exotic species is like trying to shoot a moving target. Something will be growing in Michigan in the year 3000, but what will it be?
If you would like to envision a future where your children’s children enjoy the same wildlife legacy you inherited, it’s time to curb your carbon use.
The four most important ways to curb your greenhouse gas pollution
- Drive less. Walk, ride your bike, carpool, buy a car that gets more miles per gallon.
- Eat less red meat.
- Conserve energy at home. Air condition less in the summer and dress more warmly in the winter. Buy EnergyStar appliances.
- Inform yourself. Read The Consumer’s Guide to Effective Environmental Choices by the Union of Concerned Scientists. If we take action now, we can keep green house gas emissions at their current level and minimize climate change.