A recent update to the five-year moving average of the Actuaries Climate Index (ACI), which tracks changes in climate extremes and sea level, showed a slight increase in data collected through February 2024 (Winter 2024) compared to the last update in November 2023. 

The five-year moving average now stands at 1.22, relative to an average of zero during the reference period from 1961 to 1990. 

In the last update for data collected through November 2023, the ACI was at 1.20.  

“The increase is primarily due to changes in frequency of high and low daily temperatures,” states the update, which was released on August 14. 

Comparison with Winter 2019 

The five-year moving average of the ACI was updated following the inclusion of Winter 2024 seasonal data, which is recorded at 1.58 for Canada and the United States. 

Since the moving average is calculated over five years and revised every quarter, the Winter 2024 data replaces the Winter 2019 data, which was recorded at 1.21. 

When the ACI averages are above zero, it indicates an increase in extreme weather events and a more significant rise in sea levels. 

Combination 

Quarterly seasonal data is collected to determine this index, using variables with the most significant impact on the population and the economy: high and low temperatures, heavy rainfall, droughts, high wind, and sea levels. 

The ACI was launched in 2016 by four organizations associated with the actuarial profession in Canada and the United States. The index aims to “inform actuaries, public policymakers, and the general public about climate trends and some of the potential impacts of a changing climate on the United States and Canada,” explains the executive summary on the index's website.