CLIMATE CHANGE IMPACTS

Sea-Level Rise

Atlantic Canada is expecting a 1 metre increase in sea level by 2100 and 2 metres or more by 2150. According to the Intergovernmental Panel on Climate Change (IPCC) 2021 AR6 report, global mean sea level rise could be approaching 2 metres by 2100 and 5 metres by 2150, under a very high GHG emissions scenario (SSP5-8.5), which cannot be ruled out due to deep uncertainty in ice sheet processes. There are regional variations to sea-level rise and it will affect communities in different ways, for example, First Nation communities are particularly affected by these threats due to their limited infrastructure funding and land base. Coastal ecosystems are already impacted by the combination of sea-level rise, other climate-related ocean changes, and adverse effects from human activities on ocean and land.

Coastal ecosystems, including salt marshes, vegetated dunes, and sandy beaches, can build vertically and expand laterally in response to sea-level rise, though this capacity varies across sites. These ecosystems provide important services that include coastal protection and habitat for diverse plant and animal lives. However, as a consequence of human actions that fragment wetland habitats and restrict landward migration, coastal ecosystems lose their ability to adapt to climate-induced changes and no longer act as protective barriers.

A diversity of adaptation responses to coastal impacts and risks have been implemented around the world, but mostly as a reaction to current coastal risk or experienced disasters. Hard coastal protection measures (dikes, embankments, sea walls and surge barriers) are widespread, providing predictable levels of safety in many coastal cities and towns. 

 

Figure Notes: Mean Sea Level data represented in these graphs is measured relative to Chart Datum (CD), the plane of vertical reference to which all charted depths on navigation charts are related and is selected so that the water level will seldom fall below it. Predicted Tide Tables are referenced to CD.  Mean annual sea level data points were calculated as annual means from daily mean water levels downloaded from the Marine Environmental Data Section of Fisheries and Oceans Canada: https://www.meds-sdmm.dfo-mpo.gc.ca/isdm-gdsi/twl-mne/inventory-inventaire/index-eng.htm.

 

Further Reading:

Daigle, R. (2020). Sea-level rise and flooding estimates for New Brunswick coastal sections. A report for the Atlantic Climate Adaption Solutions Association.

IPCC Special Report on Sea Level Rise: Oppenheimer, M., B.C. Glavovic , J. Hinkel, R. van de Wal, A.K. Magnan, A. Abd-Elgawad, R. Cai, M. Cifuentes-Jara, R.M. DeConto, T. Ghosh, J. Hay, F. Isla, B. Marzeion, B. Meyssignac, and Z. Sebesvari, 2019: Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

Unama’ki Institute of Natural Resources (2016). Impacts of Climate Change and Sea Level Rise on the Mi’kmaq Communities of the Bras d’Or Lakes.