Climate Alarmism and the Snowshoe Hare in Michigan

A report in the Detroit Free Press cites a study claiming that climate change is reducing the population of Michigan's snowshoe hare – a favorite of hunters in the state:

The rabbits have coats that adapt with the seasons to camouflage them with their environment. They turn white during the snow season and brown the rest of the year. With last winter an obvious exception, data show a decreasing number of days with snow on the ground is leading toward an 'alarming' decline in snowhoe hare sightings, according to recent Michigan State University study.

There are many influences on wildlife populations, and determining unequivocal causation from a single factor is often nearly impossible.  Thus, the statement that “a decreasing number of days with snow on the ground is leading toward an 'alarming' decline in snowshoe hare sightings” requires some testing.

Using data from the NOAA National Weather Service database, here are the trends in number of days with snow on the ground since records began in each climate sub-region within the state, as well as any trends since 1970 and over the past three decades.

It looks like there is no solid evidence that the number of days with snow on the ground has been declining anywhere in Michigan over the past several decades.  If we look back to the start of climate records in the 1800s and early 1900s, the evidence suggests that the number of days with snow on the ground has actually increased substantially over time.

The Lansing area has the longest climate record, and here is a plot of the number of days with snow on the ground for each season (i.e., 1863 represents the 1863-1864 winter season, 2013 is the 2013-2014 winter season, and so on).

For this area, the number of days with snow on the ground increased between the 1860s and the early 1900s and has been constant (i.e., no significant trend) over the past century.

The snowshoe hare population may be declining in Michigan, but the evidence doesn't suggest this is due to a declining number of days with snow on the ground.

A report in the Detroit Free Press cites a study claiming that climate change is reducing the population of Michigan's snowshoe hare – a favorite of hunters in the state:

The rabbits have coats that adapt with the seasons to camouflage them with their environment. They turn white during the snow season and brown the rest of the year. With last winter an obvious exception, data show a decreasing number of days with snow on the ground is leading toward an 'alarming' decline in snowhoe hare sightings, according to recent Michigan State University study.

There are many influences on wildlife populations, and determining unequivocal causation from a single factor is often nearly impossible.  Thus, the statement that “a decreasing number of days with snow on the ground is leading toward an 'alarming' decline in snowshoe hare sightings” requires some testing.

Using data from the NOAA National Weather Service database, here are the trends in number of days with snow on the ground since records began in each climate sub-region within the state, as well as any trends since 1970 and over the past three decades.

It looks like there is no solid evidence that the number of days with snow on the ground has been declining anywhere in Michigan over the past several decades.  If we look back to the start of climate records in the 1800s and early 1900s, the evidence suggests that the number of days with snow on the ground has actually increased substantially over time.

The Lansing area has the longest climate record, and here is a plot of the number of days with snow on the ground for each season (i.e., 1863 represents the 1863-1864 winter season, 2013 is the 2013-2014 winter season, and so on).

For this area, the number of days with snow on the ground increased between the 1860s and the early 1900s and has been constant (i.e., no significant trend) over the past century.

The snowshoe hare population may be declining in Michigan, but the evidence doesn't suggest this is due to a declining number of days with snow on the ground.