If you live in a coastal area, you know how highly dynamic it is and the types of harsh conditions it creates, such as wind, waves, and extreme temperatures. Flooding, storm surge, and erosion are examples of natural processes occurring in the coastal area that can threaten our coastal communities. Rising temperatures and unpredictable precipitation events are compounding these threats in many areas. From major urban centers to small towns, these conditions pose risks to public safety and private property.
Yet, the coastal area also provides the Great Lakes’ most diverse and productive ecosystem for fish, wildlife, and human inhabitants. Just like the city provides services for its citizens like water and sewer, nature provides services for people, which include absorbing floodwater and filtering pollutants, thus creating a need to protect these natural resources so they can continue to protect us.
We live in a changing world, however. The Great Lakes-St. Lawrence River Basin is a dynamic and continually evolving environment. Climate variability is the norm for the region, not the exception. This vast region is continuously affected by hydrologic and climate forces and has been, and will continue to be, a major indicator of global climate change. Yet, the increasing rate of change that we are experiencing is unprecedented and beyond any historic records.
Ever since the last glaciers retreated more than 10,000 years ago, Great Lakes water levels have varied dramatically. This is also true of the flows of water between these five massive lakes and their combined outflow to the Atlantic Ocean. The Great Lakes affect human activities and all aspects of the natural environment, from weather and climate to wildlife and habitat. Our knowledge of the geophysical, ecological, and socioeconomic characteristics of the system are improving over time but we will continue to be challenged by uncertainty and the randomness of nature.
Through the tools, information and resources provided in this Planning Guide, coastal communities will have a better understanding of how Great Lakes ecosystems and populations will be impacted by hazards in a changing climate.
There are numerous efforts underway to refine predictions of future climate conditions and to predict impacts on the Great Lakes-St. Lawrence River Basin. An array of Global Circulation Models (GCMs) has been created over the last decade, all differing in assumptions, scale and structure to predict global climate change. Output from some of these global models has been “down-scaled” or regionalized to help predict future Great Lakes climate conditions. Further detail on this work is contained in this section of the guidebook.
The Nature Conservancy has created a powerful online tool that helps visualize recent and predicted temperature and precipitation conditions over the continental United States. An example of predicted temperatures over the U.S. by 2050 is shown here, based on an ensemble average of GCM output with medium-level anticipated carbon emissions. Further details and other examples of the TNC Climate Wizard are shown within this section of the guidebook.
Climate Wizard from The Nature Conservancy
Global warming and a phenomenon known as the greenhouse effect could cause significant changes in long-term lake levels. Although debatable, most predictions indicate that global warming would cause prolonged declines in average lake levels into the future. These declines could create large-scale economic concern for virtually every user group in the Great Lakes Basin. Dramatic lake level declines also could compromise the ecological health of the Great Lakes, particularly in the highly productive nearshore areas.
The National Weather Service’s Climate Prediction Center provides near-term climate prediction, monitoring, and diagnostic products for timescales ranging from weeks to years. Their mission is to provide these products to the nation and the global community for the protection of life and property and the enhancement of the economy.
For further reference, the National Oceanic and Atmospheric Administration (NOAA) in conjunction with Environment Canada, the Midwest Regional Climate Center (MRCC), and other keystone partners, produces the NOAA Great Lakes Quarterly Climate Impacts and Outlook. Released on a quarterly basis, this tool provides an overview of the significant weather and climate trends from the last three months, their related impacts on industry, and a projection as to what can be expected in the next three months.
Long-term Models, Temperature, Precipitation
The Climate Wizard, developed through collaboration between The Nature Conservancy, The University of Washington, and The University of Southern Mississippi, enables technical and non-technical audiences alike to easily and intuitively access leading climate change information and visualize the impacts anywhere on Earth. The Climate Wizard allows the user to choose a state or country and see both the climate change that has occurred to date and the climate change that is predicted to occur.
Regional Climate Projections: Impact Assessment and Historical Trends Analysis
The NOAA Great Lakes Environmental Research Lab’s research on regional climate projections is based on atmospheric and coupled hydrodynamics-ice-ecosystem models. Results are used to predict the physical and ecological conditions of the Great Lakes over the course of yearly seasonal changes to that over decades. GLERL’s research tools are designed to examine the effects of climate on regional air temperature, precipitation, water levels, lake temperature and thermal structure, ice cover, and ecological changes and trends.
In addition, Great Lakes Integrated Sciences and Assessments (GLISA) in partnership with MRCC and the Office of the Michigan State Climatologist developed two page summaries of the observed historical climate for each of the NOAA U.S. Climatic Divisions within the Great Lakes Region. This Great Lakes Climatic Divisions tool allows users to select each summary from a map of the climatic divisions in the basin. Historic trends captured in each document include changes in temperature and precipitation trends from the early nineteen hundreds to the year two thousand and ten.
Multi-sector interests are affected by rising temperatures and more unpredictable precipitation events, and decision-makers need to know how future climate will impact the local area, the natural resources, and the infrastructure they manage. We need to understand and quantify the changes that we are already experiencing as well as what is vulnerable, or at risk, in the future. This information can help us shape our decisions and our community to lessen these threats.
Along with threats to storm water, waste water, and drinking water infrastructure, adaptive responses must consider how climate change will impact coastal wetland connectivity – a natural and cost-effective remedy to reducing impacts of many of these threats — as well as how it will affect invasive species introductions and hydrologic modifications.
There is a high level of scientific certainty that the climate has changed in significant ways in recent decades, and that it will continue to change in the future. Compiled by the Great Lakes Integrated Sciences and Assessments (GLISA), the following is a summary of the potential changes and impacts on climate in the Great Lakes region from the best research available across many scientific disciplines (GLISA, 2012).
- Water levels in the Great Lakes have been decreasing since a record high was reached in 1980.
- Lake levels are rising and falling a month earlier than during the 19th century.
- Other factors such as land use and lake regulations also affect lake level, however, and it is still unclear how much of the recent trend in lake levels may be attributed to climate change.
- Future projections of lake levels for the Great Lakes vary, though most indicate a greater decline in lake levels with increasing greenhouse gas emissions.
- For additional information on the many drivers and impacts of lake level changes in the Great Lakes please reference the following video.
"Great Lakes Water Level Changes: Addressing Risks and Impacts on Coastal Assets," courtesy of: The Nature Conservancy.
- Projections of future precipitation vary widely.
- Annual average precipitation will likely increase or remain nearly stable.
- Winter and spring precipitation may increase more significantly.
- Warmer temperatures will lead to less precipitation falling as snow, and more falling as rain.
- Lake-effect precipitation may increase in some areas.
- The intensity of precipitation is predicted to increase despite relatively stable projections for total averaged annual rainfall; 9 of the top 10 years on record for one-day extreme precipitation events have be observed since 1990 (Melilo et al., 2014; EPA, 2014).
Extreme Weather Events
- The frequency and intensity of severe storms has increased, and current models suggest that this trend will continue as the effects of climate change become more pronounced.
- More severe storms may have a negative economic impact due to resulting damages and increased costs of preparation, clean-up, and business disruption.
- Average temperatures increased by 2.3°F (1.3°C) from 1968 to 2002 in the Great Lakes region.
- By 2050, an average air temperature increase of 1.8 to 5.4°F (1 to 3°C) is projected.
- By 2100, an average air temperature increase of 3.6 to 11.2 °F (2 to 6.2°C) is projected.
- Winter temperatures will likely experience a greater increase than the summer months.
- Lake temperatures have been increasing faster than surrounding air temperatures.
- Both inland lakes and the Great Lakes will likely experience longer warm seasons.
- Warmer water surface temperatures may increase the stratification of the lakes, decrease vertical mixing in the spring-winter, and lead to more low-oxygen “dead zones” and toxic algal blooms.
- Warmer surface water temperatures may increase the rate of contaminant mercury uptake into the food chain, resulting in increased levels of mercury contamination in fish (Mackey, 2012).
Water Quality and Stormwater Management
- Increased risk of droughts, severe storms, and flooding events may increase the risk of erosion, sewage overflow, lead to more interference with transportation, and more flood damage.
- Future changes in land use could have a far greater impact on water quality than climate change. The coupling of climate change and land use change could therefore result in even stronger effects in some areas.
- Since 1940 persistent low stream flows have increased, in some areas, by more than 50%. These increases are placing additional strain on stormwater infrastructure (EPA, 2014).
In May of 2013, northern Minnesota communities recorded the latest lake ice-out dates in more than sixty years. As a consequence of the late lake ice-out, many Minnesotans chose to forego the 2013 opener.
Snow and Ice Cover
- Since 1975, the number of days with land snow cover has decreased by 5 days per decade, and the average snow depth has decreased by 1.7 cm per decade.
- From 1973 to 2010, annual average ice coverage on the Great Lakes declined by 71%.
- Snow and ice levels on the Great Lakes and on land will likely continue to decrease.
- Reduced lake freezing will result in more exposed water that could increase lake-effect precipitation.
- Earlier spring warming may decrease the length of the snow season and cause precipitation in some lake-effect events to fall as rain rather than snow.
Recreation, Tourism, and Ports
- Winter recreation and tourism are likely to suffer due to reduced snow cover.
- Changes in climatic patterns may alter shoreline wetlands which are vital habitats for breeding and migrating waterfowl, overtime this could have significant impacts on bird watching and hunting of these species (Nicholls, 2012).
- Changes in land-use and climatic patterns have driven average North American bird wintering ranges more than 40 miles northward since 1966. Fifteen percent of North American birds have moved their wintering ranges more than 200 miles northward (EPA, 2014). These alterations in bird migratory patterns may limit the wildlife viewing opportunities afforded to birders in the Great Lakes region.
- Many species of fish important to recreation are likely to decline while the populations of some warmwater species may grow.
- Decreases in Great Lakes water levels may force ships to carry less cargo, require the redesign of vessels, or increase dredging rates (IFC International, 2008).
- Strong wave action and storm surges resulting from increasingly severe storms could damage critical infrastructure of ports, harbors, and marinas (IFC International, 2008).
- Since 1950 the Midwest's growing season has increased by nearly 2 weeks due to increasingly early occurrences of the last spring freeze, this trend is expected to continue and is predicted to have minor benefits in terms of agricultural productivity for certain crops (EPA, 2014).
- Simultaneous increases in anomalous weather events (post plant-budding freezing events, heat waves, etc.) are predicted to negate any benefits accrued by having an extended growing season due to the stress they place on crops. In the long term, it is predicted that these weather events will decrease agricultural productivity overall (Melilo et al., 2014).
In September of 2013, Carroll Township's municipal water treatment plant was shut down and flushed when microcystin was found in the treated water supply. Microcystin is a potentially deadly chemical that is produced by microcystis, a type of blue-green algae that blooms annually in Lake Erie.
- Increased risk of heat waves and increased humidity may increase the number of heat-related deaths and illnesses.
- Increased frequency of flooding events may lead to watershed contamination, while warmer surface waters could mobilize pollutants in sediment and contaminate fish.
- Heavy rainfall may lead to increased incidences of sewer systems or treatment plants capacities' being exceeded, facilitating the release of untreated water containing pathogens like e-coli and fecal coliform into surface water bodies like the Great Lakes (Patz et al. 2008).
- West Nile virus may become more widespread since carrier insects will be more likely to survive milder winters.
- Lyme disease infection rates have doubled nationwide since 1910, the most concentrated increases have been observed in the Midwest and Northeastern regions of the United States where ticks are more common. Climate driven increases in temperature have increased the range of Lyme disease carrying deer ticks, and this is thought to be the driver for the observed increase in infection rates (EPA, 2014).
- Increases in temperature and nutrient rich runoff may increase the severity and frequency of algal blooms, especially potentially life threatening Microcystis (Davis et al. 2009).
- Six of the fifteen species of Great Lakes fishes consumed by people have average mercury concentrations in their fillets above the U.S. EPA human health criterion. (Great Lakes Commission, 2011).
- In the Upper Midwest ragweed pollen season has increased between 13-21 days, placing additional strain on allergy sufferers (EPA, 2014).