“Hot fun in the summertime”
-Sly and the Family Stone
In case you still need more evidence that the climate is changing, aside from all the forest fires, summer heat waves, record ocean temperatures, and loss of sea ice, our local lakes have given us additional confirmation of this global trend.
On July 16, 2024, our automated buoys logged instantaneous, near-surface temperatures of 87°F (30.6°C). That is the highest reading ever recorded in the ten years the buoys have been operating on Long Lake and Highland Lake. And it was not just a blip in the record. In the 24 hours leading up to that event, the surface temperature never went below 84°F (28.9°C). On several lakes, landowners reported 90°F readings at the surface near the shore. During this hot spell, we heard many people lamenting that a dip in the lake was no longer refreshing. After July, the water cooled to levels comparable to previous years, bringing some relief.
We saw a similar peak in surface water temperature in our regular water testing program data. On several lakes during the heat wave, July temperatures were the highest on record. We collect data every two weeks for about half of our monitored lakes, so the extreme temperatures of mid-July may have been missed on some of the lakes because of our staggered schedule. Once we retrieve all 16 of our HOBO temperature logger buoy arrays, we will have a better idea of the conditions based on the continuous temperature records.
Not only did we have record temperatures this year, but lake surface temperatures show a gradual increase over time based on our long-term data. For a selection of our service area lakes, average summer surface water temperatures have risen about 3.7°F (2°C) since 1980, depending on which months are included in the trend analysis. That is smaller than rates published in a satellite-based study of New England lakes and a report by the Maine Climate Council. Yet, this is still a significant increase. If it continues, it will likely lead to increased algal and cyanobacterial blooms, increased beach closures, more invasive plant growth, and other water quality issues.
LEA’s water testing program helps capture trends and events like the record water temperatures we saw this past summer. This helps us better understand climate change which is critical to making small and large steps to combat and mitigate its effects. Your generous support ensures that we can continue to collect and analyze this kind of data, as well as all of our other lake and watershed-based programs that help keep lakes out of hot water, even as the water heats up.
-Ben Peierls, LEA Research Director
