The Impact of Climate on Changes in the Seasonal Timing of Life Cycle Events of Eastern Canada from 1901 to 1923

From 1900 to 1923, an influential supervisor of schools in Nova Scotia, Canada, Dr. A. H. MacKay, recruited a number of knowledgeable teachers around the province to use their students to observe 100 natural occurrences each year, and report them in a standardized way. These observations included the appearance of blooming wildflowers, cultivated plants, migratory birds, mammals, amphibians plus the freezing of lakes and rivers, appearance of frost and snow, number and severity of thunderstorms, hurricanes, among others. In addition, the timing of human agricultural practices was also recorded, including calving, seeding, potato planting, and haying. Tracking the timing of naturally occurring events helps show trends in the effects on biota and human activities as a result of climate change and weather variability. Analysis has shown that earlier springs can be linked to El Nino events, and a trend has been observed towards earlier plant development over the last 40 years in the Edmonton, Alberta area  a trend that matches trends in warmer January to June temperatures in Western Canada. Some plant and animal life cycle events integrate the effects of various climate factors and can be used to detect subtle trends against the noisy background of normal weather variability. Many centuries of plant phenology records from Europe show us that plants and animals are sensitive weather instruments: they can be used for recording climate variables (heat, precipitation, wind) and for forecasting the best time for planting, harvesting, treating for pests, avoiding pollen or planning your holidays. MacKay was an acclaimed botanist whose lichen collection and publications are part of the Nova Scotia Museum of Natural History resources. The records from his environmental observation project are also part of the Nova Scotia Museum collection, and are a valuable source of data. With over 1500 Nova Scotian schools participating, MacKay filled 20 thick volumes with meticulous records of the natural environment. In 1998, these records were digitized, put into a database, and have recently been examined. This paper will detail the results of examining the 20 years of MacKay data identifying trends in phenology and human activity, and its possible messages for climate change in eastern Canada during the first quarter of the 20th century.