The Climate is Changing . . .
So What?
Overview
• The “worldview” on climate change
• Zoom in on Michigan
• Will it affect ME?
WORLDWIDE
General trends
• Temperature increases: 4°F to 7°F by 2100
• Precipitation will increase in some places, and
decrease in others
• Sea levels will rise
• Extreme weather events will be more frequent
WORLDWIDE
IPCC says:
• increasing ground instability in permafrost regions, and rock
avalanches in mountain regions
• warming of lakes and rivers in many regions, with effects on
thermal structure and water quality
• earlier timing of spring events, such as leaf-unfolding, bird
migration and egg-laying poleward and upward shifts in ranges in
plant and animal species
• range changes and earlier migrations of fish in rivers
http://www.ipcc.ch/publications_and_data/ar4/wg2/en/contents.html
WORLDWIDE
IPCC says:
• Most of the observed increase in the globally averaged
temperature since the mid-20th century is very likely due to the
observed increase in anthropogenic greenhouse gas
concentrations.
• Of the more than 29,000 observational data series, from 75
studies, that show significant change in many physical and
biological systems, more than 89% are consistent with the
direction of change expected as a response to warming.
http://www.ipcc.ch/publications_and_data/ar4/wg2/en/contents.html
WORLDWIDE
Socioeconomic Effects
• effects on agricultural and forestry management at Northern Hemisphere higher
latitudes, such as earlier spring planting of crops, and alterations in disturbance
regimes of forests due to fires and pests
•
some aspects of human health, such as heat-related mortality in Europe,
infectious disease vectors in some areas, and allergenic pollen in Northern
Hemisphere high and mid-latitudes
• In the Sahelian region of Africa, warmer and drier conditions have led to a reduced
length of growing season with detrimental effects on crops. In southern Africa,
longer dry seasons and more uncertain rainfall are prompting adaptation measures
• Sea-level rise and human development are together contributing to losses of
coastal wetlands and mangroves and increasing damage from coastal flooding in
many areas
WORLDWIDE
Third World bears brunt of global warming impacts
• coastlines along the Pacific and Indian oceans and sub-Saharan Africa
• large sprawling cities, with their urban "heat island" effect
http://www.news.wisc.edu/11878
So . . .
• Michigan is OK, then . . .
Right?
What climatic changes have YOU noticed?
MICHGAN
General Trends
• Warmer
– Extreme heat will be more common
– Nighttime temperatures are expected to warm more than
daytime temperatures
• Drier overall
– Average precipitation levels are unlikely to change, but the
seasonal patterns of precipitation will vary greatly
• increasing in winter
• decreasing in the summer
http://www.ucsusa.org/sites/default/files/legacy/assets/documents/global_warming/climatechange-michigan.pdf
MICHGAN
Some Details
Warmer Temperatures
A 5-10oF rise in winter and a 7-13oF rise in summer temperatures by the end of the century is
projected.
Precipitation Changes
Although average annual precipitation may not change much, an overall drier climate is
expected because rainfall cannot compensate for the increase in evaporation resulting from
greater temperatures. Thus Michigan may see drier soils and more droughts. Seasonally,
winter precipitation is expected to increase by 5-25% while summer precipition is expected to
remain the same.
Extreme Events
Extreme heat will be more common, and the frequency of heavy rainstorms will increase and
could be 50-100% higher than today.
Growing Season
The growing season could be 8-10 weeks longer.
Ice Cover
Declines in ice cover on the Great Lakes and inland lakes have been recorded over the past
100-150 years and are expected to continue.
But will it affect ME?
What is a Cooling Degree Day?
• Unit relating temperature to energy demand
• Used for comparisons, weather derivatives
• Every degree Fahrenheit the average daily
temperature increases above 65˚F
– Let’s see an example…
M
T
W
T
F
S
S
Avg.
Temp
70˚F
88˚F
90˚F
95˚F
84˚F
87˚F
90˚F
#
Degrees
Above
65˚F
70 –
65 =
5
88 –
65 =
23
90 –
65 =
25
95 –
65 =
30
84 –
65 =
19
87 –
65 =
22
90 –
65 =
25
Cooling
Degree
Days
5
23
25
30
19
22
25
5 + 23 + 25 + 30 + 19 + 22 + 25 =
149 total cooling degree days for this week
Discussion Questions
• Briefly describe the patterns you see in each
scenario. How are conditions predicted to change
over time?
• Are the predicted changes consistent with
patterns you observed this summer? Why might
there be differences?
• What are some ways you might be affected (both
directly and indirectly) by the predicted changes?
• Will longer growing seasons automatically mean
more crops? What other changes could affect
productivity?
http://www.pileus.msu.edu