Modern sea-level change
Tide gauges are used to measure sea level. William Bell Dawson began measuring tides in Atlantic Canada in 1895, when the Halifax gauge was established. The network of gauges (today managed by the Canadian Hydrographic Service) was used to produce better tidal predictions for mariners.
- Water levels and currents - Canadian tide tables (Canadian Hydrographic Service)
Dawson decided that tide tables needed to be circulated more widely, and accordingly, in 1896 the predictions were made available in The Canadian Almanac (shown here) and other publications. Interestingly, at that time the almanac featured a debate on a future Canadian flag!
Although the tide gauges were established to improve the quality of tide predictions, they have become extremely useful in other ways. A plot of annual mean sea levels shows how sea level has been rising in Atlantic Canada. Similar trends can be seen in the data from Charlottetown, Saint John, and St. Johns. The sea-level rise is mostly due to crustal subsidence, a lingering effect from the last ice age.
