4.8 The Bay of Fundy and the tides of climate change

1.6 What does climate change mean for the Bay of Fundy?

Climate change will influence, and to some extent already does, temperatures, rainfall, storm frequency and amplitude, seasonal patterns and sea level. In New Brunswick, average annual temperatures have increased by 1.5°C over the past century and may increase by another 3-3.5°C by the end of this century (NB, 2014). The frequency of intense rainfalls has already increased, especially in the decade 2000, and under a future climate, precipitations will increase on average, and especially extreme precipitation events (NB, 2014). Recent sea level rise is apparent in the record of the Saint John tidal gauge (figure 8). In parallel, severe storms have become more frequent, especially in the decade 2000 (Daigle, 2006; NB, 2014).

Records from the Saint John tidal gauge from 1939 to 2011.

Figure 8. Records from the Saint John tidal gauge from 1939 to 2011..

Source: Lieske and Bornemann (2011)

In the future, sea levels will increase further. Based on IPCC projections, maximum observed storms, and local isostatic adjustment, Daigle Enviro (2011) estimated sea levels for 1:10, 1:25, 1:50 and 1:100 year events for current (2000) and future (2025, 2050, 2085) conditions in the Tantramar region (table 2).

Table 2: Maximum sea levels for storms of various return times as a function of future sea level rise.

Maximum sea levels for storms of various return times as a function of future sea level rise.

Source: Daigle Enviro (2011)

In a wider temporal perspective, it can be noted that sea levels have historically fluctuated as a result of the post-glacial sea-level and continental isostatic readjustments (Figure 9). Towards present day, the rise in relative sea level asymptotically approached zero, until climate change caused an acceleration in sea level rise over the 20th and beginning of the 21st centuries.

Post-glacial sea level variations in the Gulf of Maine from 14 000 ybp to today based on 14C dated shells and salt marsh peat, interpretation of former shorelines on seismic reflection data and paleodeltas.

Figure 9. Post-glacial sea level variations in the Gulf of Maine from 14 000 ybp to today based on 14C dated shells and salt marsh peat, interpretation of former shorelines on seismic reflection data and paleodeltas.

Source: Belknap et al. (1987)

Important storms have occurred in the past. Arguably, the best remembered of those historic storms is the Saxby gale of October 4-5, 1869. The hurricane, which traveled northwards from the eastern Caribbean, and made landfall in the Gulf of Maine, combined with an extratropical storm off the eastern seaboard, which increased its strength to a probably category 2 hurricane, with wind speed of up to 166 km/h (Heidorn, 2010). The 2 m high storm surge coinciding with a spring tide produced a high water mark of 21.6 m. The Minas basin and the Tantramar marshes were flooded by waves overtopping the dykes, causing the destruction of agricultural land and the death of many cattle. Overall, over 100 people were killed, several hundred vessels stranded or sunk. On the island of Grand Manan alone, over eighty buildings were destroyed. In Moncton, Main street was flooded up to nowadays’ City Hall’s location. The Windsor and Annapolis railway destroyed.

Another notable storm was the 1976 Groundhog Day storm, February 2nd. This extratropical storm originated in the South-West of the United States and moved eastwards across Canada, producing winds of up to 164 km/h. In the Bay of Fundy, it led to coastal flooding of up to 1.6 m. Damages were all the more significant as it coincided with exceptionally high tides resulting from a 1 in an 18-year event.

Erosion is a well-documented problem on the majority of coastal segments in New Brunswick and Nova Scotia and has been accelerating (Bérubé, n.d.; Daigle, 2006). The coastal vulnerability map established after Owen’s classification of the physical sensitivity of coastal environments (Figure 10) shows that due to its geological constitution, the coast of the Bay of Fundy is somewhat less sensitive than other coasts in the are, such as the southern coast of Nova Scotia, the south-eastern coast of New Brunswick or Prince Edward Island. The most sensitive area is the low lying land at the south-eastern end of the Bay of Fundy.

Sensitivity of the coast of Canada to sea level rise (excerpt). Vulnerability index red=high, yellow=moderate, green=low.

Figure 10. Sensitivity of the coast of Canada to sea level rise (excerpt). Vulnerability index red=high, yellow=moderate, green=low.

Source: Geological Survey of Canada (1994)

In a survey of 37 communities in the Bay of Fundy, undertaken by the Gulf of Maine Climate Council, respondents identified five main climate-related areas of concern: 1) extreme weather, 2) hurricanes and high winds, 3) inland/freshwater flooding, 4) sea-level rise, and 5) storm surges (Schauffler, 2014). The areas of municipal functioning deemed most vulnerable to these impacts were transportation infrastructure and accessibility, stormwater management, wastewater infrastructure, and emergency management. Adaptation to climate change is an emerging topic for provincial and municipal authorities, but mostly still at the information and planning stage rather than implementation. According to Schauffler (2014), less than one fifth of surveyed municipalities are actively implementing climate adaptation plans. Flood management, mapping and zoning are the most common activities undertaken by municipalities (Schauffler, 2014). Federal and provincial programs, such as Atlantic Climate Adaptation Solutions Association or the Regional Adaptation Collaborative are essential for municipalities, since about three quarters of the municipalities cite lack of funds and lack of staff as main obstacles to climate change adaptation (Merrill and Zwicker, 2010; Schauffler, 2014). Those programs can provide guidance, scientific information and planning tools such as LiDAR surveys. Associations and NGOs play an important role in mobilizing and engaging citizen.

There is a significant difference in adaptation capacity between large municipalities and smaller municipalities. Large municipalities like Moncton, Dieppe, Saint John or Fredericton are capable of establishing comprehensive climate adaptation plans, with dedicated funds and personnel. Thus, Moncton and Dieppe have reviewed all their emergency planning with regards to anticipated flood risks; detailed flood risk maps have been produced in order to assist with that task; specialized emergency management software has been set up (Waban-Aki, 2016). In contrast, smaller municipalities rely on part-time volunteer personnel and staff with numerous other responsibilities for the preparation and implementation of emergency plans. Those plans are often not up to date due to lack of time and personnel. Emergency plans of small municipalities are usually generic “all-hazard” plans which do not specifically take into account climate change (Waban-Aki, 2015). In this context, the role of regional service commissions (RSC) in assisting with emergency and rural planning becomes an important one and several municipalities, for example the newly founded municipality of Cocagne, work in close collaboration with the RSC (Waban-Aki, 2015).

Floods and storms have a catalyzing effect on climate adaptation action. As in many communities in New Brunswick and Quebec, the two major storms of 2010, causing extensive flooding and property damage, were a wake-up call to the reality of climate change and climate risks, especially occurring at the end of a decade characterized by a number of large storms. It persuaded the municipality to spend 185,000 $ on a stormwater management plan and examine in detail the risks caused by storm surges, sea level rise, climate change and coastal erosion. In Grand Bay-Westfield, it was two storms in 2005 and 2007 that prompted the municipality to participate in a Regional Adaptation Collaborative (RAC) project with three other communities along the southern St. John River, in order to assess the the need for strict zoning setbacks from water bodies. Colchester, NS, updated its flood zoning using LiDAR data after a rainstorm flooded through existing berms in 2012. In the absence of recent floods, budgets for flood protection and climate change adaptation are often hard to find, as is the case of Sackville (Schauffler, 2014).

Dykes, historical dykes under the responsibility of the ministry of agriculture, but being transferred to the ministry of transport. Privately owned dams, lack of jurisdiction (Schauffer, 2014). Lack of jurisdiction or expertise to investigate options for restoring saltmarshes in historically dyked areas (or to assess their capacity relative to dykes for buffering inland areas from storm surge) lack of jurisdiction over a shoreland zone that increasingly needs erosion control measures (and where poorly engineered shoreline hardening measures can exacerbate both ecological and management problems).