Michigan’s Changing Climate: Recent Past and Projected Future Trends Jeffrey A. Andresen Dept. of Geography Michigan State University.

Michigan’s Changing Climate: Recent Past and Projected Future Trends

Jeffrey A. AndresenDept. of Geography

Michigan State University

Mean Temperatures vs. Year, Michigan1895-2010

Mean Winter Temperatures vs. YearIronwood, MI1902-2008

Grand Traverse Bay - Years Frozen by Decade 1851-2006

0

1

2

3

4

5

6

7

8

9

10

Year

s of

Fre

ezin

g

Yrs. BayFroze

Great Lakes Region (32°F threshold)

-10

-5

0

5

10

1895 1915 1935 1955 1975 1995

Year

Fro

st-

Fre

e S

ea

so

n (

da

ys

fro

m n

orm

al)

Length Spring FallSource: K. Kunkel, Midwest. Reg. Clim. Center

Great Lakes Region (1-yr, 1-week)

-100

0

100

200

300

1895 1915 1935 1955 1975 1995

Year

He

at

Wa

ve

Ind

ex

(%

de

via

tio

n)

INTENSE HEAT WAVES

Source: K. Kunkel, Midwest. Reg. Clim. Center

Annual Precipitation vs. Year, Michigan1895-2010

Frequency of Wet Days and Wet/Wet DaysCaro, MI

1930-2008

Great Lakes Region (1-yr, 1-week)

-60

-40

-20

0

20

40

60

1895 1915 1935 1955 1975 1995

Year

He

av

y P

rec

ipit

ati

on

Ind

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(%

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FREQUENT HEAVY RAINS FREQUENT HEAVY RAINS

Source: K. Kunkel, Midwest. Reg. Clim. Center

Total Seasonal Snowfall vs. YearBay City, MI1897-2008

Total Seasonal Snowfall vs. YearChatham, MI1901-2008

Annual Number of Days with Snowcover >= 1” vs. Year, Chatham, MI1895-2008

Projecting the Future: Global Climate Models (GCMs)

Natural Variability or Anthropogenic Signal?

(Source: IPCC, 2007)

Source: (IPCC, 2007)

Source: (IPCC, 2007)

Source: (IPCC, 2007)

Model-Projected Mean Temperature DifferencesPontiac, MI 1990-2099

Model-Projected Precipitation RatiosPontiac, MI 1990-2099

Historical and Projected Wheat Yields by Year With and Without CO2 EnrichmentHadCM3 A2 ZS Scenario

Owosso/Pontiac, MI

Impacts of Climatic Variability

• Past history suggests that society will be able to cope/adapt with steady climatic changes, but possibly not with changes in variability (e.g. changes in extremes, storminess)

Summary• Overall, mean average temperatures in Michigan rose

approximately 1.0ºF during the past century. Warming of about 2.0ºF has occurred between 1980 and the present, much of it concentrated during the winter season and at night.

• Milder winter temperatures have led to less ice cover on the Great Lakes and the seasonal spring warm-up is occurring earlier than in the past.

• Annual precipitation rates increased from the 1930’s through the 1990’s but have leveled off recently.

• Most recent GCM simulations of the Great Lakes region suggest a warmer and wetter climate in the distant future, with much of the additional precipitation coming during the cold season months.

• Projections of future climate change in Michigan suggest a mix of beneficial and adverse impacts.

• A changing climate leads to many potential challenges for dependent human and natural systems, especially with respect to climate variability.

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