Great Lakes in a Changing Climate. Lucinda B. Johnson University of Minnesota Duluth Natural Resources Research Institute

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1 Great Lakes in a Changing Climate Lucinda B. Johnson University of Minnesota Duluth Natural Resources Research Institute

2 What is climate change?

3 What is climate change? How do we know it is happening?

4 Emissions of Heat Trapping Gases Where do they come from? Organic waste (2%) Agriculture (20%) deforestation, nitrogen fertilizers, cows, rice Burning coal, oil and natural gas: energy for industrial processes (32%) Heating buildings (12%) Transportation (14%) Electricity generation (20%)

5 Concentrations of Heat Trapping Gases in the Atmosphere Have they increased?

6 The Impact of GHGs on Climate Increase in Global Air Temperature This century shows the warmest temperatures in 1000 yrs (Mann et al., 1999) 1.3 F warming since 1860s 1990s is the warmest decade on record Top Three: 1998, 2002, 2001 (Jones et al., 2001)

7 Simulations and proxy data Tools of the trade Ice cores, corals, tree rings, lake sediments used to reconstruct past climate. Instrument record used to verify reconstructions. Simulations forecast and hindcast climate. From Mann, Science, Vol 297, Issue 5586,

8 Further Evidence for Global Warming Worldwide Glacier Melt Blomstrandbrennen Glacier, Spitsbergen (Svalbard) Norway

9 Further Evidence for Global Warming Worldwide Glacier Melt Franz Josef Glacier, New Zealand

10 RECENT SIGNIFICANT CLIMATE TRENDS IN THE UPPER MIDWEST WARMER WINTERS; HIGHER MINIMUM TEMPERATURES EARLIER SPRING SHORTER DURATION OF ICE COVER GREATER FREQUENCY OF TROPICAL DEW POINTS GREATER ANNUAL PRECIPITATION o MORE DAYS WITH RAIN o MORE FREQUENT HEAVY RAINS o TREND OF INCREASING WINTER SNOWFALL From Seeley, 2003

11 Local Evidence for Global Warming Minnesota Temperature Increases MN Temperature Trends ( ) Winter o F Summer +1.0 o F NCDC Climate at a Glance (

12 Increasing Mean Annual Precipitation

13 1990s wettest decade of the 20 th Century in Minnesota

14 Increasing Mean Annual Runoff

15 Declining Ice Cover (Days) Lake Mendota, WI Corresponds to ca. 1 C in Air Temperature per 100 Years

16 Natural Forcing Natural (solar + volcanic) forcing alone does not account for warming in the past 50 years. Why is this happening? Anthropogenic Forcing Only Global changes are much larger than can be explained by natural climate variability Human influences alone (greenhouse gases and sulfate aerosols) brings the models and observations into pretty good agreement. Natural and Anthropogenic Forcing

17 Climate Change Impacts: Key Findings* Human activities produce heat trapping gas emissions that cause climate change Climate change magnifies existing health and environmental problems Climate change is changing the character of the Great Lakes region Common sense solutions are available now * From: Kling, et al., Confronting Climate Change in the Great Lakes Region.

18 What might the future look like? Global Temperature Change

19 Temperature What might the future look like? Precipitation Regional Temperature Change Change in Annual Temperature and Precipitation for relative to

20 Temperature Change in Minnesota Historical Data Lower Emissions Higher Emissions Steady increases 6 10 o F in winter 7 16 o F in summer Growing season 3 6 weeks longer

21 Precipitation Change in Minnesota Historical Data Lower Emissions Higher Emissions Seasonal shifts More precip in winter & spring (planting time) Less rain during the summer and fall growing seasons

22 Precipitation Change in Minnesota Historical Data Lower Emissions Higher Emissions Changes in rainfall distribution Doubling of heavy rain events since 1900 s Doubling again by 2100

23 Hurricanes (not in Minnesota!) Intensity of the strongest hurricanes is projected to increase due to the higher sea surface temperatures. Precipitation is likely to increase appreciably, leading to flooding and mudslides. Hurricane storm surges will be larger due to sea level rise from melting ice and snow and the thermal expansion of ocean waters. At greatest risk are low lying coastal areas along the Gulf Coast, such as Florida's Panhandle, Alabama's Gulf shores, and southern Louisiana.

24 Where could Minnesota move to? Note: Based on average temperature and precipitation for mid range emissions. Does not account for variability or regional characteristics.

25 Abrupt Climate Change Describes changes in climate that occur over the span of years to decades, compared to the human caused changes in climate that are occurring over the time span of decades to centuries. From ice cores, ocean sediments, tree rings, and other records of Earth's past climate, scientists have found that changes in climate have occurred quickly in the past over the course of a decade. E.g., Younger Dryas (~12,000 years ago), a period of abrupt cooling that interrupted a general warming trend as Earth emerged from the last Ice Age. During the Younger Dryas period, average summertime temperatures in New England cooled by about 5 7 F (3 4 C). This and other abrupt events have been linked to changes in an ocean circulation pattern known as thermohaline circulation.

26 Heavy rainfall events

27 Impacts of Changing Climate Hydrology water quantity Lakes Rivers Wetlands Forests Ecosystems Water quality Productivity Biodiversity Infrastructure Roads, bridges Property CLIMATE CHANGE WILL NOT OCCUR IN A VACUUM! pollution shipping flooding winter survival biodiversity

28 Change in monthly averaged hydrological variables projected by HadCM3 mid range scenarios in relative to seasonal average. Winter Spring Summer Autumn Precipitation Evaporation Surface Runoff Sub Surface Runoff Soil Moisture Bold arrows indicate a larger and uniform change over the Midwest region projected by both scenarios; thin arrows indicate a smaller, non uniform change; while a negligible or a net zero change over the region is indicated by a line. From: Wuebbles & Hayhoe 2003.

29 Declining Water Levels Shorter duration of ice cover will increase evaporation in winter Warmer air temperatures will increase evapotranspiration Lower precipitation in summer will decrease soil moisture and draw down water tables

30 Great Lakes Water Levels* Future water level scenarios for the Great Lakes (Sousonius and Bisanz 2000; Lofgren et al. 2002) Lake 2X CO 2 (range of 3 4 simulations) 2030 ( range of 2 simulations) 2090 (range of 2 simulations) Lake Superior 0.23 m to 0.47 m 0.01 m to 0.22 m 0.42 m to m Lake Huron Michigan 0.99 m to 2.48 m 0.72 m to m 1.38 m to m * High degree of uncertainty in these predictions

31 Increased Incidence of Flooding Earlier snowmelt (esp when corresponding with frozen soils) Increased incidence of intense rain events, interacting with increased urbanization and decrease in flood storage capacity (i.e., wetlands) Results: Increased soil erosion Degraded water quality Economic impacts

32 The Changing Character of the Great Lakes Region Lakes Greater penetration of UV B radiation through water column in summer as water clears. Mobilization of mercury and other contaminants, uptake in aquatic food chain.

33 Lakes Productivity Nutrient availability could limit or reverse the increases in primary production due to increased temperature. Reduced runoff and drying of watersheds likely to reduce nutrients (e.g., phosphorus) and other dissolved material inputs (Magnuson et al. 1997; Schindler et al. 1996; Webster et al. 1996, 2000).

34 Lakes Summer stratification Earlier and longer summer lake stratification will cause higher risk of dead zones and fish kills. Anoxic sediments release redox sensitive metals (Hesslein et al. 1980). In acidic sediments, mobility of metals (e.g., Al, Cd) is increased, and bioaccumulates in the food chain.

35 The Changing Character of Great Lakes Rivers & Streams Longer ice free periods, Earlier spring flows, Great variability in flow overall Earlier & more intense spring floods More severe summer droughts More possibilities of flash floods Red River 1988 drought Red River 1997 flood

36 Rivers & Streams Intermittent and some smaller perennial streams will dry Aquatic ecosystem disruptions will be compounded by invasions of non native species

37 Rivers & Streams Food Quality Elevated CO 2 levels appear to change plant leaf chemistry (increased phenolics & decreased nitrogen) (Lindroth 1996). This may lower microbial colonization and decomposition rates of organic matter (Tuchman et al. 2003a; Rier et al. 2002; Ostrofsky 1997; Cotrufo and Ineson 1996; Meson and Cotrufo 1997). These changes have been linked to reduced growth and survival in some stream insects (Tuchman et al. 2002, 2003b).

38 The Changing Character of Great Lakes Fish Range expansions and contractions are expected Cold water species ranges will contract; warm and cool water species will expand Non native species will expand ranges. Zebra mussels Carp Increased stress due to floods, acidification, contaminants

39 Fish Habitat Thermal habitat is defined by both maximum and minimum temperature tolerances; Under 2xCO 2 climate scenarios (Mohseni, Stefan & Eaton 2003) Warmwater fish communities expand thermal habitat by 31% Cool water habitat contracts by 15% Cold water habitat shrinks by 36%

40 Fish Communities

41 The Changing Character of Great Lakes Wetlands Earlier spring runoff and more intense flooding increase challenges for species Reduced summer water levels result in poorer water quality and fewer safe breeding sites for amphibians, shorebirds and waterfowl Shrinking wetland size and drying of prairie potholes and temporary wetlands will reduce groundwater recharge and habitat

42 Wetlands & Shorebirds The availability of seasonal mudflats for migratory shorebirds and endangered, beach nesting species such as the Piping Plover (Great Lakes population of about 20 pairs) will be affected with the drying or loss of wetlands.

43 The Changing Character of Great Lakes Forests Grasslands expand north & east; Maple & oak will expand their ranges northward; Boreal forests likely to disappear; Higher CO 2 and N could increase short term forest productivity, but

44 Higher ozone, more frequent droughts, forest fires, lower soil moisture will stress forest species Greater risk from insect pests could damage longterm forest health Forest species composition will change, impacting paper and saw timber industries Forests Forestry

45 The Changing Character of Great Lakes Wildlife Loons and other water birds are nesting earlier in the season. Resident bird species may benefit; migratory species will likely suffer. Raccoons, skunks, and white tailed deer may benefit increased encounters with cars likely. Moose, elk likely to decline.

46 Wildlife Bird Migration Migration is initiated by photoperiod cues. Insect emergence regulated by temperature. Insectivorous birds may be out of sync with food supply. Changes in the timing of the spring melt will alter migratory pathways and timing. Canada Geese formerly wintered in Southern Illinois (~1.4 million birds through the mid 90s) now mainly winter in Wisconsin and further north in Illinois.

47 The Changing Character of Great Lakes Biodiversity Estimated rates of extinctions are very large (Thomas et al. 2004) Migration rates of vegetation will not keep up with the rate of climate change (Malcolm et al. 2002). Compared to post glacial times. Mid range climate scenario for % of taxa committed to extinction From 3 regions around the globe Extinctions due to habitat loss range 1 29%

48 The Changing Character of Great Lakes Recreation & Tourism Millions of anglers affected by impacts on fish Bird watchers and hunters affected by impacts on birds Summer season expanding, but more extreme heat, heavy, higher ozone, and increased risk of infectious diseases

49 Climate Change Impacts Will Not Occur in a Vacuum Population growth Increasing urbanization and sprawl Landscape fragmentation Industrial pollution of air and water Social challenges Geographic variability and limits

50 Surface Geology & Land Use Impervious and thin soils limit agriculture, other land use activities Although climate may warm, corn and soybeans will not grow on bedrock and in thin soils Alter hydrologic responses to floods and drought

51 Exacerbation of Existing Problems Water Resources Reduced groundwater recharge, small streams and temporary wetlands likely to dry up Average lake levels are expected to decline Pressure to increase water extraction from the Great Lakes Increased flooding and erosion from intense storms

52 Exacerbation of Existing Problems Agriculture Benefits: Warmer temperatures, Longer growing season, CO 2 fertilization Constraints: Declining soil moisture; Higher ozone; More pests; Storms & floods during planting and harvesting; Extreme heat

53 Exacerbating Existing Problems Property & Infrastructure More frequent extreme storms and floods greater property damage heavier burden on emergency management increase clean up and rebuilding costs financial toll on businesses and homeowners Damage of water related infrastructure Lake level drops will require more dredging and other shipping and boating related infrastructure adjustments

54 Cascading Impacts from Water Changes Infrastructure & Industry Changes in water levels and increased flooding will also: Reduce the amount of available water for hydroelectric generation Degrade water quality Require costly & environmentally harmful dredging operations for shipping

55 Exacerbating Existing Problems Human Health Cold related health problems will decline while heat related morbidity and mortality will increase Extreme heat more likely: 40+ days exceeding 90 F days exceeding 97 F Higher ground level ozone concentrations Waterborne and other vector borne infectious diseases may become more frequent and widespread (lyme; West Nile virus)

56 Worst Impacts Are Not Inevitable No regrets solutions available now A three pronged approach to deal with climate change: 1. Reduce our emissions 2. Minimize pressure on the environment 3. Plan and prepare to manage the impacts of a changing climate

57 Reducing Emissions Energy Transportation Agricultural Forestry Integrated Strategies

58 Minimizing Pressure on Our Environment Air quality improvements Water resource protection Habitat protection Riparian management & restoration Urban and land use planning

59 Managing Climate Impacts Emergency Preparedness Agricultural and Forestry Adaptations Public Health Improvements Infrastructure Adjustments Education

60 George Kling (U Mich, lead) Katharine Hayhoe (U IL) Lucinda Johnson (U MN) John Magnuson (U WI) Steve Polasky (U MN) Scott Robinson (U IL) Brian Shuter (U of Toronto) Michelle Wander (U IL) Donald Wuebbles (U IL) Donald Zak (U Mich) Richard Lindroth (U WI) Susanne Moser (UCS) Mark Wilson (U MI)

61 Acknowledgments This presentation was is based on Confronting Climate Change in the Great Lakes Region: Impacts on our Communities and Ecosystems (Kling et al., 2003). The project was jointly sponsored by Union of Concerned Scientists and the Ecological Society of America (ESA).