We often hear about climate change and its implications, but what does it actually mean for Lake Champlain and the communities around it?
Lake Champlain has already seen drastic increases in lake temperature. According to the Lake Champlain Basin Program (LCBP), the main lake adjacent to Charlotte has seen a 6.8 degrees Fahrenheit increase in temperature since 1964. Higher surface temperatures have had a substantial effect on lake ice. In fact, Lake Champlain froze over only 26 times in the last 50 years, while it froze over 39 times in the 50 years prior. Even when it does freeze over, data from the LCBP 2015 State of the Lake report shows it freezes later in the year and thaws earlier.
In addition, there has been an increase in precipitation of 45.8mm (1.8 inches) per decade on the Vermont side of the Champlain Basin since 1941. The additional precipitation along with more energy from warming temperatures yields stronger storms and flash floods, which increases erosion, releases sediments and nutrients, and threatens infrastructure.
Warmer and wetter conditions affect lake ecology and human uses. The species profile of fish in the lake is expected to change. Cold water species like trout and salmon may not be able to survive due to decreasing surface water temperatures. Warmer surface temperatures could affect spawning times of cool water species like walleye and therefore affect reproductive success. We may see an increase in warm water species like perch and bass.
Beyond fish, warmer lake temperatures are an open invitation to invasive species, many of which are on our doorstep in the Great Lakes and the St. Lawrence River, both connected to Lake Champlain through rivers and canals. Species that may not have been able to survive winter temperatures and freeze-over are now starting to be able to thrive here. Invasive species outcompete native species for resources and have no natural predators, so are able to thrive. Besides the intrinsic value of a natural, balanced ecosystem, this could have implications for anglers and boaters.
Blue-green algae has been a hot topic in recent years as a threat to health and scenic beauty, but climate change could enhance growing conditions. More stormwater runoff (carrying nutrients that the algae need) plus hotter conditions will likely lead to an increase in blooms. Algae blooms reduce dissolved oxygen in the lake and deprive fish and aquatic life of oxygen. Blue-green algae can be toxic, and some studies suggest these algae are associated with higher instances of neurodegenerative diseases. And according to the Gund Institute at the University of Vermont, blue-green algae on lake-front property is causing a drop in property values.
It is critical that we take steps to manage stormwater and prevent the spread of invasive species to the extent possible.
The Conservation Commission meets the fourth Tuesday of the month. All are welcome.
Krista Hoffsis is a member of the Charlotte Conservation Commission