The international panel on climate change (IPCC) is the leading international body for the assessment of climate change. In their latest report (AR5) published in 2013/14, the IPCC states:
“Human activities are continuing to affect the Earth’s energy budget by changing the emissions and resulting atmospheric concentrations of radiatively important gases and aerosols and by changing land surface properties.” “Unequivocal evidence from in situ observations and ice core records shows that the atmospheric concentrations of important greenhouse gases such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) have increased over the last few centuries (AR5, 1.2.2; 1.2.3).”
As a result, mean air and ocean temperatures have increased over the last 100 years and are projected to continue warming (IPCC, 2013). Satellite imagery and field measurements show a trend of significant decline in arctic sea and land ice, which along with heat-induced water expansion, is causing sea levels to rise worldwide (IPCC, 2013). The oceans continual uptake of carbon dioxide is changing ocean chemistry, rendering waters progressively acidic. Furthermore, changing climatic conditions are likely to increase the frequency and intensity of extreme weather events as well as cause changes in local weather patterns (IPCC, 2013).
For more information, see the Climate Change 2014: Synthesis Report
Climate Change Projections for Atlantic Canada
Rising air and water temperatures
Surface temperatures are expected to rise over the 21st century under all emissions scenarios (IPCC, 2013). The average temperature increase for the region will be up to 5°C in the winter and 3.8°C in the summer by 2080 (Ouranos, 2010). The interior areas of the larger maritime provinces, including areas in Quebec around the Gulf of St-Lawrence, will see more change than coastal areas (Savard et al., 2016). Under the intermediate emissions scenario, northern Atlantic sea surface temperatures are projected to warm 1-3°C by year 2100 (IPCC, 2013). High spatial and temporal variability arise in models due to complex ocean circulation patterns and ice-ocean variability along the northern portion of the Atlantic provinces.
Precipitation and storm events
Precipitation patterns are expected to rise in the maritime provinces over the course of the decade, which is consistent with the trend established since 1948 (NRcan, 2015). Precipitation levels are however projected to vary seasonally, with the lowest increase taking place during the summer and the highest in the winter months (NRcan, 2015). Summer rainfall patterns may therefore not be high enough to offset evapotranspiration caused by rising air temperatures. The Northwest Atlantic, the Gulf of St-Lawrence and the Labrador Sea are some of the stormiest waters in North America (Savard et al., 2016). While trends in storm intensity and wind velocity are difficult to conclude, projections do indicate an increase in storm frequency in the Atlantic region due to northward shifts in storm tracks.
For more information, see Chapter 4, Section 2 of Canada’s Marine Coast in a Changing Climate
Climate scenario maps of annual minimum, median and maximum temperature changes (ºC) for the 2020s, 2050s, 2080s. Capital letters in parentheses after the seasons represent the relevant months (Figure 5a from From Impacts to Adaptation: Canada in a Changing Climate)
Evidence suggests that North Atlantic waters are freshening, potentially due to the increased inflow of melted fresh water in marine systems (Savard et al., 2016). Additionally, warming sea surface temperatures are expected to strengthen stratification, increasing hypoxia in deep waters which are home to important groundfish and crustacean species (Savard et al., 2016). Runoff from coastal land driven by increased precipitation may intensify nutrient loading in marine systems, driving higher levels of hypoxia (Savard et al., 2016). Marine ecosystems adjacent to the coasts are also subject to worsening water quality during heavy downpours due to flooded sewer systems, water treatment plants, as well as land-based pollutants and garbage seeping into waterways (Savard et al., 2016). With increased risk of flooding, there is also a greater risk of drinking water contamination. With changes in temperature and rainfall patterns, the amount surface water in watersheds may be affected as well.
For more information, see Chapter 4, Section 3 of Canada’s Marine Coast in a Changing Climate
Relative sea level rise projections are based on the rate of meltwater generated from the Greenland and Antarctic ice sheets, polar ice caps and mountain glaciers, the thermal expansion of sea surface waters, regional and local ocean dynamics as well as the rate of isostatic adjustment (the rise and fall of land as the delayed response of surface unloading that occurred during the last ice age) (IPCC, 2013). Sea levels in Atlantic Canada are expected to be most severe in New Brunswick (NB), Prince Edward Island (PE) and Nova Scotia (NS) with a mean increase of 80-100cm by year 2100. Sea levels in Newfoundland and Labrador (NF/L) are projected to increase by 60-80cm by year 2100, and by 20-60cm in the Gulf of St-Lawrence region. The potential collapse of the Western Arctic ice sheet could additional contribute an extra 65cm in global sea level rise (IPCC, 2013). Storm surge, which arises from changes in wind and atmospheric pressure, raises the water level above the regular tidal range (IPCC, 2013). High tides combined with strong storm surge can raise rea levels by several meters (Savard et al., 2016). Due to rising sea levels and the increasing frequency of storm events, climate change is expected to exacerbate storm surge events in the Atlantic region. The observed and projected melting of winter sea ice in the Northern region of Atlantic Canada will result in shorter ice season as well as a decrease in percent ice coverage and thickness (Senneville et al., 2014). Winter sea ice buffers wave formation; the melting of sea ice will therefore increase the amount of energy in ice-free seas. Cumulatively, sea level rise, storm surge and melting sea ice will increase the risk of costal-land flooding, erosion, saltwater intrusion, coastal squeeze and sediment transport, creating grave implications for coastal communities, infrastructure and ecosystems.
For more information, see Chapter 4, Section 3 of Canada’s Marine Coast in a Changing Climate
The Atlantic region is subject to summer heat and drought events, early and late season frost, winter rain and thaw event, inland flooding as well as high wind activity (Lemmen et al., 2008). There is evidence that these events may become more frequent and more extreme. While there in moderate to high evidence that both forests and agriculture will be affected on land, there remains significant knowledge gaps concerning the geophysical implications of climate change on in-land systems such as the change in forest fire frequency and magnitude (Vasseur., 2016).
For more information see Chapter 4, section 3.1 of Natural Resources Canada’s Impacts and Adaptation Report
Water resources will come under pressure as conditions shift and needs change. Seasonal and yearly variations in precipitation will combine with higher evapotranspiration to induce drier summer conditions, especially in Maritime Canada. Limited water resources could affect municipal water supplies and challenge a range of sectors, including agriculture, fisheries, tourism and energy. Furthermore, increased precipitation and storm events could drive contaminants and pollutants out of agricultural lands, sewers and industrialized areas into freshwater bodies, generating negative implications for habitat and drinking water supplies. Alterations to the hydrological cycle in Atlantic Canada will undoubtedly have far reaching effects on the quantity and quality of freshwater imperative to ecosystem and human health.
For more information see Chapter 4, Section 3.4 of Natural Resources Canada’s Impacts and Adaptation Report
Warming temperatures and changing weather patterns will alter species composition, distribution and abundance in terrestrial, aquatic and marine ecosystems. As warmer temperatures settle in the southern latitudes, species will migrate north seeking cooler conditions, likely causing a shift in ecoregions (Lemmen et al., 2008). With changing conditions and shifting seasons, species level metabolic, reproductive and behavioural processes will change and thus alter ecosystem dynamics (Lemmen et al., 2008). On land, the phenological onset of spring has been earlier in anterior regions of maritime Canada, and frequent episodes of winter thaw and late spring freezing events have impacted certain crop and tree species (Bourque et al., 2005; Vasseur et al., 2001). The reproductive success of Atlantic migratory birds has declined with increasing spring temperatures (Gaston et al., 2002), while the geographical range of mammals such as moose are expected to shift north (Snaith and Beazley, 2004). Similarly, there is evidence of East Coast fish species moving the higher latitudes or greater depths to search for favourable temperatures (Cheung et al., 2011). Because forestry, agriculture, fisheries, aquaculture and tourism are important industries that rely on ecosystem health for economic sustainability, climate change is expected to have big implications for businesses in the Atlantic.
PESTS AND INVASIVE SPECIES
Pest, insect and invasive species proliferation is expected to worsen with increased precipitation and warming temperatures. In agriculture, the complex nature of the dynamics existing between crops, pests and their predators, render predicting the impacts of climate change on pest outbreaks difficult to assess. Insects carrying harmful pathogens, such as blacklegged ticks carrying lyme disease, are expected to progressively expand their geographical range throughout the Atlantic provinces (McPherson et al., 2017). Invasive species will likely thrive in a changing climate, due to their ability to reproduce and disperse quickly compared to native species (Dukes & Mooney, 1999). Invasive species have the potential to outcompete important native and endemic species in Atlantic Canada.
When seawater absorbs carbon dioxide from the atmosphere, the chemistry of the ocean is altered such that there is an increase in hydrogen ions and a decline in free carbonate ions, rendering the water more acidic (NOAA, 06/25/18). In these conditions, biological fitness in many marine species is reduced. Impacts are vast, including the dissolution of calcium carbonate shells and exoskeletons, reduced capacity for development and reproduction as well as changes in algal, benthic and pelagic species composition (Fabry et al., 2008). Ocean acidification is expected to have negative socio-economic impacts in the Atlantic, especially in areas where aquaculture and fishing are important industries (Savard et al., 2016).
Climate change has the potential to affect human health in numerous and diverse ways. Extreme weather events such as flooding can cause serious injury or death, contaminate waterways with sewage and pollutants, and increase the likelihood of waterborne disease and parasites. Mental health issues arising from to loss of economically, socially and culturally important ecosystems, industries and geographical spaces are expected to take place. Both short and long-term risks have the potential to impact human health and wellbeing.
For more information regarding the biological implications of climate change, please see Natural Resources Canada’s Impacts-Adaptation Report and Chapter 4 of Canada’s Marine Coast in a Changing Climate
The east coast’s economy will likely both benefit and suffer from the impacts of climate change. A major cross-sectoral concern is damage to infrastructure such as power lines, roads, bridges, residential homes and public facilities. Research identifies fisheries, aquaculture, agriculture, tourism and the offshore oil and gas as particularly vulnerable industries, given their strong reliance on the external environment for viability. Due to the biological implications of climate change, there may however be opportunities for new industries or resources to flourish, such as longer growing seasons or the development of new fisheries.
For more information regarding the ecosystem and sectoral implications of climate change, see:
Chapter 4 from Natural Resources Canada’s Impacts and Adaptation Report
The 2014 update to this assessment report.
Atlantic Canada’s vulnerability to climate change highlights the need for adaptive measures focused on limiting exposure to risk through effective planning (Lemmen et al., 2008). The IPCC defines adaptation as the “the process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects” (IPCC, 2014). Communities, indigenous groups, organizations, and government at all levels are making progress in implementing adaptation measures across Atlantic Canada. See Natural Resources Canada’s upcoming federal assessment on climate change:
The Atlantic Climate Adaptation Solutions (ACASA) Project is a partnership among the provincial governments of all Atlantic Provinces and regional stakeholders including nonprofits, tribal governments, and industry. ACASA applied for and received a grant from Natural Resources Canada as part of the Regional Adaptation Collaborative (RAC) Program to build a collaborative effort to address regional climate change impacts. The link below provides access to ACASA's projects, publications, and other research outputs that help Atlantic Canadians better prepare for, and adapt to, climate change:
Over 50 countries have signed the Paris Agreement in a global effort to keep global temperature rise below 2 degrees Celsius above pre-industrial levels within this century, and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius. Canada has committed to this agreement and thus has been implementing various climate mitigation strategies at all scales. The IPCC defines mitigation as “a human intervention to reduce the sources or enhance the sinks of greenhouse gases [...] (IPCC, 2014)”. The following links provide information about provincial and federal climate action plans:
For more information on what the Canadian government is doing to reduce our contribution to climate change, see Natural Resources Canada’s page on climate change.
Bourque, C. P. A., Cox, R. M., Allen, D. J., Arp, P. A., & Meng, F. R. (2005). Spatial extent of winter thaw events in eastern North America: historical weather records in relation to yellow birch decline. Global Change Biology, 11(9), 1477-1492.
Cheung, W. W., Zeller, D., & Pauly, D. (2011). Projected species shifts due to climate change in the Canadian Marine Ecoregions. A report prepared for Environment Canada, 47.
Dukes, J. S., & Mooney, H. A. (1999). Does global change increase the success of biological invaders?. Trends in Ecology & Evolution, 14(4), 135-139.
Fabry, V. J., Seibel, B. A., Feely, R. A., and Orr, J. C. 2008. Impacts of ocean acidification on marine fauna and ecosystem processes. – ICES Journal of Marine Science, 65: 414–432.
Finnis, J. (2014). Projected Impacts of Climate Change for the Province of Newfoundland & Labrador. Office of Climate Change and Energy Efficiency.
IPCC. (2013). Summary for policymakers; in Climate Change 2013: The Physical Science Basis (Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change), (ed.) T.F. Stocker, D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley; Cambridge University Press, Cambridge, United Kingdom and New York, New York, 27 p., http://www.ipcc.ch/pdf/ assessment-report/ar5/wg1/WGIAR5_SPM_brochure_en.pdf>.
IPCC. (2014). Annex II: Glossary [Mach, K.J., S. Planton and C. von Stechow (eds.)]. In: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, pp. 117-130.
Gaston, A. J., Hipfner, J. M., & Campbell, D. (2002). Heat and mosquitoes cause breeding failures and adult mortality in an Arctic‐nesting seabird. Ibis, 144(2), 185-191.
Lemmen, D.S., Warren, F.J., Lacroix, J., and Bush, E., editors (2008): From Impacts to Adaptation: Canada in a Changing Climate 2007; Government of Canada, Ottawa, ON, 448 p.
McPherson, M., García-García, A., Cuesta-Valero, F. J., Beltrami, H., Hansen-Ketchum, P., MacDougall, D., & Ogden, N. H. (2017). Expansion of the Lyme disease vector Ixodes scapularis in Canada inferred from CMIP5 climate projections. Environmental health perspectives, 125(5).
Ouranos (2010): Élaborer un plan d’adaptation aux changements climatiques – Guide destiné au milieu municipal québécois; Ouranos, Montréal, Québec, 45 p.
Savard, J.-P., van Proosdij, D. and O’Carroll, S. (2016): Perspectives on Canada’s East Coast region; in Canada’s Marine Coasts in a Changing Climate, (ed.) D.S. Lemmen, F.J. Warren, T.S. James and C.S.L. Mercer Clarke; Government of Canada, Ottawa, ON, p. 99-152.
Senneville, S., St-Onge, S., Dumont, D., Bihan-Poudec, M.-C., Belemaalem, Z., Corriveau, M., Bernatchez, P., Bélanger, S., Tolszczuk-Leclerc, S. and Villeneuve, R. (2014): Rapport final : Modélisation des glaces dans l’estuaire et le golfe du Saint-Laurent dans la perspective des changements climatiques; report prepared by the Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski (UQAR) for the ministère des Transports du Québec., 384 p.
Snaith, T. V., & Beazley, K. F. (2004). The distribution, status and habitat associations of moose in mainland Nova Scotia. Proceedings of the Nova Scotian Institute of Science.
Vasseur, L., Guscott, R. L., & Mudie, P. J. (2001). Monitoring of spring flower phenology in Nova Scotia: comparison over the last century. Northeastern Naturalist, 8(4), 393-402.