Effects of a Changing Climate on the Lake Champlain Ecosystem

The Goal

Identify potential changes in climate and develop appropriate adaptation strategies to minimize adverse impacts on Lake Champlain’s ecosystem and its natural, heritage, and socioeconomic resources.

// In This Section //

• Introduction
• Role of the LCBP in Addressing Climate Change in the Lake Champlain Basin
• Citations
• Additional Reading

Introduction

Large-scale changes in environmental conditions are not new for the Lake Champlain Basin. Less than 15,000 years ago much of the Adirondacks and Green Mountains were covered by ice more than a mile thick, and less than 10,000 years ago, the Champlain Valley contained the Champlain Sea, a salt-water extension of the Atlantic Ocean and the Gulf of St. Lawrence. When viewed in geological time, the natural ecosystems of this region are relatively young. While our regional ecosystems have been shaped by incremental environmental changes of the last 15,000 years, the effects of global climate change during the last several decades are greater than at any other time in the period of record documented to date. Much of this change is driven by increasing levels of atmospheric greenhouse gases associated with fossil fuel use and by land-use changes attributed to increasing global human impact and economic activity (IPCC 2007).

Climate data collected within the Lake Champlain Basin provide strong evidence that accelerated climate changes have occurred here for decades. Many of these changes are irreversible in the time scale of human lives. Resource managers must plan for ongoing changes and take action to minimize changes that are likely to occur in the future. In particular, resource management strategies must adapt to changing climate and work to ensure that public investments in Lake stewardship remain effective. The following trends have already been recognized within the Basin and are almost certain to continue.

• The average annual air temperature in the region increased by 2.1° F (1.2° C) from 1976 to 2005 (Stager and Thill 2010).
• The number of days of annual ice cover on Lake Champlain has decreased. The date that freeze-up occurs on the Lake is about two weeks later than it was in the early 1800s, and the Lake has not frozen at all more often in recent decades. There were only three times in the 1800s that the Main Lake did not freeze over; it has frozen over in fewer than half of the winters since 1975 (Stager and Thill 2010). An extended period of open water during winter increases water loss by evaporation and produces local lake-effect snow. Ice cover also provides protection for some species and helps to moderate water temperature.

• More winter precipitation now falls as rain instead of snow, which decreases the spring Lake and ground-water levels needed to maintain wetlands that support spring spawning of some fish and many amphibians (Stager and Thill 2010).
• Since 1976, total annual precipitation has increased about 3 inches over the previous 80 years. Recent climate data also indicate that more summer rain falls during intense storms, which can cause flash floods in rivers and streams, thereby increasing nutrient and contaminant inputs to Lake Champlain from erosion and from municipal combined sewer overflows (Stager and Thill 2010).
• Fish community structure has changed in many parts of North America because of decreased spawning and recruitment success of cold-water fishes, such as salmon and trout, and cool-water fishes, such as walleye and northern pike. Simultaneously, populations of warm-water species, such as bass and the invasive white perch, have increased. Some of these prey on juveniles of the cold-water species. Similar trends are apparent in Lake Champlain (Casselman 2010).
• Lake surface temperatures have increased throughout the northeastern United States and Great Lakes. This can contribute to intense and potentially toxic algal blooms. It may also result in longer periods of summer stratification and increased risk of low benthic oxygen levels (UCS 2006; Kling et al. 2003).

Climate change analyses for both the northeastern United States and the Great Lakes highlight trends that will have a significant impact on our aquatic ecosystems and indicate that these changes are already occurring. These analyses provide specific predictions for “high carbon emission” scenarios (if there is a continuation of the current emission trends) and “low carbon emission” scenarios (if significant economic, social, and political changes result in rapid and sustained reductions in carbon emissions). Some predicted outcomes based on these two scenarios are provided in the table below.

Although there are no large cities in the Lake Champlain Basin, it is worth noting that climate changes in large cities in the northeastern United States will likely be even more extreme. Some major US cities are expected to average twenty to thirty days each summer with temperatures over 100° F by 2100 (UCS 2006). These heat waves would increase regional demand for electricity, which could affect the Lake Champlain region. Higher temperatures could result in both additional economic opportunity and increasing environmental pressures as people visit the Lake Champlain region to escape the heat in warmer urban areas.

The economic, social, and political choices that are made, both locally and globally, in the coming years will determine whether the climate of the Lake Champlain Basin will more closely resemble those of Pennsylvania or northern Virginia 60 years from now. Predicted climate change outcomes based on published emission scenarios describe a compelling need for policies targeted at reducing regional and global emissions of greenhouse gases. Responsible stewardship of the Lake Champlain Basin requires management and policy planning to address likely outcomes of each of the different future scenarios in order to mitigate increasing environmental pressures and protect Lake water quality and ecosystem integrity.

Predicted climatic changes will continue to affect the regional physical infrastructure, particularly transportation and public works. The governmental agencies involved need to research and adopt new standards to accommodate increases in storm events and subsequent tributary flows and impacts to roads, bridges, and culverts. Increased storm flows will affect wastewater treatment plants that are not disconnected from stormwater systems. Designs for aquatic organism passageways and flood control systems must be informed by these predicted changes.

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Role of the LCBP in Addressing Climate Change in the Lake Champlain Basin

The LCBP acknowledges that many organizations are working locally and globally to implement carbon emission reduction programs to slow predicted impacts on global climate. The LCBP will primarily work with partners and stakeholders to adapt to a changing climate in the Lake Champlain Basin. These climate-change tasks are highlighted in the tables below, and are cross-referenced in relevant Opportunities for Action (OFA) chapters.

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Citations

Casselman, J. 2010. Effects of a changing climate on freshwater fish and fisheries: Driving environmental factors and shifting baselines - what to expect, how to adapt. Presented at the Lake Champlain 2010 Conference, 7-8 June, Burlington, Vermont.

IPCC. 2007. Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and A. Reisinger, eds.]. Geneva: IPCC.

Kling, G.W., K. Hayhoe, L.B. Johnson, J.J. Magnuson, S. Polasky, S.K. Robinson, B.J. Shuter, M.M. Wander, D.J. Wuebbles, D.R. Zak, R.L. Lindroth, S.C. Moser, and M.L. Wilson. 2003. Confronting Climate Change in the Great Lakes Region: Impacts on our Communities and Ecosystems. Cambridge, Mass: Union of Concerned Scientists and Washington, DC: Ecological Society of America.

Stager, C. and M. Thill. 2010. Climate Change in the Lake Champlain Basin: What natural resource managers can expect and do. Keene Valley, NY and Montpelier, VT: The Nature Conservancy.

UCS. 2006. The Changing Northeast Climate: Our choices, our legacy. Cambridge, Mass: Union of Concerned Scientists.

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Additional Reading

Jenkins, J. 2010. Climate Change in the Adirondacks: The path to sustainability. Ithaca, NY: Cornell University Press.

• NYS DEC Climate Change
• EPA Climate Change
• VT Climate Collaborative
• Québec Climate Change: English | French

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