The five-year moving average of the Actuaries Climate Index (ACI), which tracks changes in climate extremes and sea levels, has been updated. The index increased in summer 2024 compared to spring 2024.
The five-year average now stands at 1.31, up from the baseline average of zero recorded during the reference period from 1961 to 1990.
In the last update released in November, covering the spring period, the ACI was reported at 1.26.
“The increase is due to changes in frequency of high daily temperatures, precipitation and consecutive dry days, sea level changes, and wind speed,” says a statement published on Feb. 27.
Comparison with summer 2019
The addition of summer 2024 data updates the ACI’s five-year moving average, which reached 2.10 for Canada and the United States.
Since the moving average is calculated over five years and updated quarterly, the summer 2024 data replaces that of summer 2019, which stood at 1.21.
When ACI averages rise above the baseline of zero, it indicates an increase in extreme weather events and ongoing sea level rise.
Data components
The index is based on various seasonal and quarterly data points, focusing on factors that have the most significant impact on populations and the economy: high and low temperatures, heavy precipitation, droughts, strong winds, and sea level changes.
For the sea level sub-index, the five-year moving average for Canada and the United States was 3.15 in summer 2024, down slightly from 3.20 in the previous quarter. In summer 2019, the same sub-index stood at 3.27.
