Climate Change Signals

Climate Change is coming to Chandos. The mean annual temperature is increasing; the ice on deeper lakes is coming in later; the ice on shallow lakes is going out earlier; and overall ice cover days are decreasing. The hummingbirds are leaving later in the season, and certain changes in the diatom record and limnological profile are believed attributable to climate warming.

 Peterborough Annual Mean Temperatures  1866-2015

Dr Peter Lafleur graciously supplied the following temperature records for  Peterborough from 1866-2015.

Delayed Ice-In

We do not have a long data record for ice-in and ice-out on Chandos Lake.

Chandos lake is a relatively deep lake, and before it can freeze up, a lot of heat has to be extracted. With the warmer summers and the delayed onset of winter, the result is a later freeze up. over the last 35 years it has shifted about a week.

See the Ice-in and Ice-Out tab for more discussion on the above graph. (data courtesy of C. Burgess)

Early Ice-Out

Shallow lakes will tend to warm up much quicker and are more sensitive to shifts in temperature. We do have fairly long Ice-Out data sets for two shallow flow through area lakes, namely Scugog and Chemong.

Lake Scugog Ice-Out data

The Scugog data set (1884- 2015) comes from the Port Perry Star, courtesy of P. Hvidsten. The following graph shows the Scugog Ice-Out plotted against the Peterborough annual mean temperatures, and there is a striking inverse correlation.

The correlation between the ice-out date and the annual mean temp is -0.49, which is pretty strong (-ve sign means an inverse relationship).  As one might expect, the highest correlation is with the mean temp for the month of March, rising to -0.75.    However, plotting against the annual mean is likely a better overall signal of climate change.

Chemong Lake Ice-Out data

In April 2020 Steve Kirton supplied historical Ice-Out data for Chemong Lake from 1877- 2020.  Chemong Lake is a similar lake to Scugog, in that it is shallow and a flow-through lake.  The Ice comes out of Scugog approximately 5 days ahead of Chemong, on average. After adjusting for this offset, we overlaid the ice-out dates and there was a remarkable similarity.

Hummingbird Arrivals and Departures, since 1986

Cathy Burgess has been recording the (Ruby-Throated) Hummingbird season at her Chandos Lake feeder since 1986.
The 2020 trend-line indicates that the birds arrive around May 9, and depart around September 15, for a season about 129 days long.  (So they are out-of-country quite a bit longer than they are in Canada) 

The data relating to their arrival is “shaky” in that it depends on when the feeder gets out; how difficult the flight north is; and how long it takes any bird to actually find this feeder. So, the departure date is likely a more reliable indicator on what is happening with the climate. Over the last 35 years the hummers on average are leaving 7 days later.

Paleo indicators of Climate Change

Please refer to the 2019 Paleolimnology Investigation in Gilmour Bay for a thorough discussion of changes to the lake that are believed to be climate change induced.

Also see Rühland et al paper, Lake diatom responses to warming: reviewing the evidence