Great Lakes Water Levels Shoreline Dilemmas : Report on a Colloquium (1989) / Chapter Skim
Currently Skimming:
PANEL DISCUSSION: GLOBAL CLIMATE CHANGE
PANEL DISCUSSION: GLOBAL CLIMATE CHANGE
Pages 115-134
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 115... ...
Climate changes determine natural changes in that portion of the total water supply to a lake that is generated within the lake basin itself (the sum of lake precipitation plus runoff minus lake evaporation) -- referred to as "net basin supplies." Changes in precipitation onto the basin will result in changes in lake precipitation 115
|
From page 116... ...
; and it is this that makes Lake Superior useful as a reservoir -- one of the bases of current lake level management. Extreme net basin supply events have, however, been basin-wide at times, and these have led to the low waters of the 1930s and 1960s, and the high waters of the 1950s, 1970s, and 1980s.
|
From page 117... ...
Obviously, we know that the earth without human influences has experienced some extremely wide shifts in climate; here where Chicago stands there have been past epochs with tropical forests and others with glaciers nearly a mile thick; hence, people and their waste products are not needed to change the climate dramatically. Natural forces, as yet poorly understood, have made and are making the climate change.
|
From page 118... ...
In fact, during the last 2,000 years climate conditions have been both much wetter/cooler and warmer/drier than anything we have experienced since 1860. Interestingly, if one uses Larson's historical lake level reconstructions, one can project that the Great Lakes Basin is in a period that will be wetter and cooler over the next 100 to 200 years.
|
From page 119... ...
I believe that those who predict a man-induced climate change of severe proportions over the next 25 to 75 years must provide more compelling evidence than exists now and must become much more definitive about the spatial and temporal features of change before climate change will become a major regional issue leading to action. When will the change occur?
|
From page 120... ...
The ultimate aim is to evaluate policy choices. Three frameworks, or models, have been developed that continue to be actively studied and that have potential application to a study of changing climate implications for hydrologic systems such as the Great Lakes.
|
From page 121... ...
To projections of economic activity of these economic models must be added environmental quality submodels indicating how trace gases accumulate, how this leads to changing climate, and how changing climate affects the Great Lakes, among other systems. Finally, an environmenta1 damage submodel must be added to permit benefit-cost calcuations and policy appraisal.
|
From page 122... ...
A particularly difficult hydrological issue is the variability question of changing climate and its relationship to fluctuating water levels. The variance rather than the level of these variables may be important, and it will be challenging to estimate changes of variances within our projection framework.
|
From page 123... ...
was for the Donner Canadian Foundation on future lake levels and the hydrologic, environmental, and political impacts. In the first study, the Canadian Climate Centre of Environment Canada provided to the researchers a projection of climate conditions in the Great Lakes Basin with an atmospheric carbon dioxide (CO2)
|
From page 124... ...
A third set of data gave lake level and flow data for 2 x CO2 climate plus the impact of increased consumptive use of Great Lakes water as projected by the International Joint Commission in 1981 for the year 2035. In this scenario, average lake levels decreased by an additional 10 to 20 cm.
|
From page 125... ...
1950 1960 1970 1980 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC FIGURE 2 Lake Erie net basin supply. Monthly averages, 1958-1983.
|
From page 126... ...
We found that a diversion of 1560 m3s 1 into Lake Huron from James Bay would increase Lake Erie levels and compensate for the lowering of the levels under the GISS scenario. Under the GFDL scenario, Lake Erie levels would be raised 45 cm above historic levels, thus introducing the possibility of the export of water southward.
|
From page 127... ...
This study should include, but not be limited to, the potential impacts on agriculture, forest, wetlands, human health, rivers, lakes and estuaries as well as other ecosystems and societal impacts." My presentation to the Colloquium on Great Lakes Water Levels will review some of the preliminary results from the Effects Report relevant to the Great Lakes Basin. Since the results have not been peer reviewed, they will not be available for citation or quotation.
|
From page 128... ...
In addition, we are conducting national studies on agriculture, sea level rise, energy demand, human health, and other issues. The Environmental Protection Agency (EPA)
|
From page 129... ...
Changes will be estimated for the lake levels for all lakes and for ice cover on Lakes Superior and Erie. The potential effects on the thermal structure of Lakes Erie and Michigan will be examined and results will be used to study possible impacts on Great Lakes fish.
|
From page 130... ...
PROJECTS The specific projects in support of this case study are as follows: Title Researcher Institution Changes in Lake Levels Croley Changes in Ice Cover Assel Thermal Structure of McCormick Lake Michigan Thermal Structure of Blumberg Lake Erie Great Lakes Fisheries Magnuson Regier Impacts on Shorelines Changnon Impacts on Shipping Keith Crop Yields Ritchie Farm Level Response Easterling Stand Simulation Botkin Modeling Pollen Response Surfaces Overpeck Seedling Distribution Davis Policy Implications Brah Great Lakes Environmental Research Lab Great Lakes Environmental Research Lab Great Lakes Environmental Research Lab Hydroqual, Inc. University of Wisconsin University of Toronto Illnois State Water Survey Engineering Computer Optecnomics Michigan State University Illnois State Water Survey University of California, Santa Barbara Lamont-Doherty Geological Observatory University of Minnesota Center for the Great Lakes
|
From page 131... ...
IMPACTS OF GLOBAL WARMING 131 NOTE 1. The GCMs simulate the physics and dynamics of the global atmosphere.
|
From page 133... ...
Panel Discussion: State Coastal Erosion Management Programs
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.