Diese Präsentation wurde erfolgreich gemeldet.
Wir verwenden Ihre LinkedIn Profilangaben und Informationen zu Ihren Aktivitäten, um Anzeigen zu personalisieren und Ihnen relevantere Inhalte anzuzeigen. Sie können Ihre Anzeigeneinstellungen jederzeit ändern.

CRCTI CoP/CCRF Webinar: Changes in the Oceans Surrounding Canada (June 26, 2019)

On June 26, 2019, the Climate Risks for Coastal Transportation Infrastructure Community of Practice (CRCTI CoP) and the Canadian Coastal Resilience Forum (CCRF) conducted a webinar titled “Canada’s Changing Climate Report: Changes in the Oceans Surrounding Canada” presented by Blair Greenan, Fisheries and Oceans Canada and Thomas James, Natural Resources Canada

This webinar summarized the observed and projected changes for the oceans surrounding Canada that are being driven by anthropogenic climate change. The results were drawn from the recent “Canada’s Changing Climate Report”. The presentation focused on changes in sea level and coastal flooding impacting coastal communities and infrastructure. The presentation also included some results from the 2016 report on “Canada’s Marine Coasts in a Changing Climate”, a contribution to the ongoing series of reports for the National Assessment Canada in a Changing Climate.

Blair Greenan is a research scientist at Fisheries and Oceans Canada (DFO) and is based at the Bedford Institute of Oceanography in Halifax. He manages a diverse group of researchers that focus on ocean stressors ranging from marine oil spills to climate change effects such as ocean acidification. He is the Scientific Director for the Argo Canada program which contributes to the International Argo program in advancing global real-time observations of the ocean with autonomous instruments. Recently, Blair’s research has focused on developing climate change adaptation tools to provide science advice to DFO on issues related to coastal infrastructure and fisheries management. Blair received his Ph.D. from the Department of Physics at the University of Toronto.

Thomas James is a research scientist with the Geological Survey of Canada, Department of Natural Resources Canada. His undergraduate studies were at Queen’s University and he carried out his Ph.D. research at Princeton University, finishing in 1991. Tom’s research interests are in geodynamics, and specifically in understanding the interactions between the solid Earth, ice sheets and glaciers, and the oceans. He has carried out field work in British Columbia, Nunavut, and Antarctica to measure land motion and sea-level change. Recently, Tom generated sea-level projections across Canada for a volume called “Canada’s Marine Coasts in a Changing Climate”, based on the most recent assessment report of the Intergovernmental Panel on Climate Change.

  • Loggen Sie sich ein, um Kommentare anzuzeigen.

CRCTI CoP/CCRF Webinar: Changes in the Oceans Surrounding Canada (June 26, 2019)

  1. 1. A collaborative effort: Environment and Climate Change Canada Fisheries and Oceans Canada Natural Resources Canada University experts Wearable technology, developed with funding from the NSERC Discovery Grants program Source: Western University Chapter 7: Changes in Oceans Surrounding Canada
  2. 2. Chapter 7 Authors 2 • Blair J. W. Greenan (Fisheries and Oceans Canada) • Thomas S. James (Natural Resources Canada) • John W. Loder (Fisheries and Oceans Canada) • Pierre Pepin (Fisheries and Oceans Canada) • Kumiko Azetsu-Scott (Fisheries and Oceans Canada) • Debby Ianson (Fisheries and Oceans Canada) • Roberta C. Hamme (University of Victoria) • Denis Gilbert (Fisheries and Oceans Canada) • Jean-Éric Tremblay (Université Laval) • Xiaolan L. Wang (Environment and Climate Change Canada) • Will Perrie (Fisheries and Oceans Canada) • Acknowledgments (DFO): Jim Christian, Eugene Colbourne, Peter Galbraith, Phil Greyson, Guoqi Han, Dave Hebert, Roger Pettipas, Marie Robert, Tetjana Ross, Nadja Steiner, Igor Yashayaev and Li Zhai
  3. 3. Canada’s National Assessment on Climate Change Canada in a Changing Climate: Advancing our Knowledge for Action Interactive Website (ChangingClimate.ca/CCCR2019) Health Assessment Canada’s Changing Climate Report Canada in a Changing Climate - Regional Perspectives Enhanced SynthesisCanada in a Changing Climate- National Issues Phase 1: 2016-2018 Phase 2: 2017-2021 Phase 3: 2020-2021 Indigenous Resilience Laying a climate science foundation for the forthcoming reports of the national assessment. 3
  4. 4. Canada’s Changing Climate Report – scope and structure Chapter 4 Changes in Temperature and Precipitation Chapter 5 Changes in Snow, Ice and Permafrost Chapter 6 Changes in Freshwater Availability Chapter 7 Changes in Oceans Surrounding Canada Chapter 8 Changes in Canada’s Regions in a National and Global Context Chapter 3 Modelling Future Climate Change Chapter 2 Observed Global Climate Change Chapter 1 About this Report 10 HEADLINE STATEMENTS FOR THE WHOLE REPORT KEY MESSAGES FOR EACH MAJOR CHAPTER Assessed confidence in findings and likelihood of results 4
  5. 5. • Canada has warmed by 1.7⁰C between 1948 and 2016, about two times global warming. • Northern Canada has warmed by 2.3 ⁰C, about three times global warming. • The observed warming is primarily due to human activities and is effectively irreversible. Mean annual temperature increase 1948-2016 5
  6. 6. - more extreme heat/less extreme cold - less snow and ice cover - thinning glaciers - warmer and more acidic oceans - increased precipitation - earlier spring peak streamflow - thawing permafrost - rising sea level 6 • Because some further warming is unavoidable, these observed trends will continue. • Across Canada, we are experiencing:
  7. 7. • Scenarios with large and rapid warming illustrate the profound effects on Canadian climate of continued growth in greenhouse gas emissions. • Scenarios with limited warming require Canada and the rest of the world to reduce carbon emissions to near zero early in the second half of the century. High global emissions large warming Low global emissions limited warming The rate and magnitude of climate change under high versus low emission scenarios project two very different futures for Canada. 7
  8. 8. Oceans Surrounding Canada 8
  9. 9. 9 • Ocean warming and loss of oxygen will intensify with further emissions of all greenhouse gases. • Ocean acidification will increase in response to additional carbon dioxide emissions. • These changes threaten the health of marine ecosystems.
  10. 10. Ocean Temperature Trends 10 Pacific Ocean Atlantic Ocean
  11. 11. Ocean Temperature Projections 11
  12. 12. Ocean Salinity and Density Stratification 12 • Reference period for anomaly: 1981-2010
  13. 13. Ocean Salinity and Density Stratification 13
  14. 14. Marine Winds, Storms and Waves • Surface wave heights and the duration of the wave season in the Canadian Arctic have increased since 1970 and are projected to continue to increase over this century as sea ice declines (high confidence). • Off Canada’s east coast, areas that currently have seasonal sea ice are also anticipated to experience increased wave activity in the future, as seasonal ice duration decreases (medium confidence). • A slight northward shift of storm tracks, with decreased wind speed and lower wave heights off Atlantic Canada, has been observed and is projected to continue in future (low confidence). • Off the Pacific coast of Canada, wave heights have been observed to increase in winter and decrease in summer, and these trends are projected to continue in future (low confidence). 14
  15. 15. Ocean Acidification 15
  16. 16. Ocean Deoxygenation 16
  17. 17. Ocean Deoxygenation 17
  18. 18. 18 • Local sea level is projected to rise and increase flooding, along most of the Atlantic and Pacific coasts of Canada and the Beaufort coast in the Arctic. • The loss of sea ice in Arctic and Atlantic Canada further increases the risk of damage to coastal infrastructure and ecosystem due to larger storm surges and waves. Local sea level changes are from global sea level rise and land uplift and sinking. The vertical land motion is a response to the retreat of the last great ice sheet.
  19. 19. Canada’s Marine Coasts in a Changing Climate § Led by the Climate Change Impacts and Adaptation Division to produce a National Coastal Assessment: Lemmen, D.S., Warren, F.J., James, T.S. and Mercer Clarke, C.S.L. editors (2016): Canada’s Marine Coasts in a Changing Climate; Government of Canada, Ottawa, ON, 274p. https://www.nrcan.gc.ca/environment/resources/ publications/impacts- adaptation/reports/assessments/2016/18388
  20. 20. 20 Examples of Coastal Flooding and Damage LEFT – Storm surge on the Sunshine Coast Highway (Highway 101) at Davis Bay, British Columbia, located on the mainland coast nor th of Vancouver, British Columbia, on F ebruary 6, 2006. Photo courtesy of B. Oakford. RIGHT — Example of coastal erosion and roadway damage at Conrads Road on Queensland Beach, Nova Scotia, following the January 4, 2018, blizzard. Photo credit: Colleen Jones, CBC, January 5, 2018.
  21. 21. 21 Long-Term Trends of Relative Sea-Level Change
  22. 22. 22 • A major determinant of sea-level change in Canada is vertical land motion. • Oceanographic factors also affect the absolute elevation of the sea surface. • Land subsidence (sinking) increases relative (local) sea-level, while land uplift does the opposite. • Across much of Canada, land uplift or subsidence is mainly due to the delayed effects of the last continental glaciation (ice age), called glacial isostatic adjustment (GIA). Crustal Uplift and Subsidence
  23. 23. 23 Projected Global Sea-Level Rise During the 21st Century • Global (absolute) mean sea level is projected, in IPCC AR5, to rise by 28 to 98 cm by 2100, relative to 1986–2005 • But global mean sea-level rise could exceed 1 m by 2100 if additional contributions of water come from the marine-based sectors of the Antarctic Ice Sheet
  24. 24. 24 • A major determinant of sea-level change in Canada is vertical land motion. •Land subsidence (sinking) increases relative (local) sea-level, while land uplift does the opposite. Crustal Uplift and Subsidence
  25. 25. 25 • End-of-century projected relative (local) sea-level change under a high emission scenario, relative to 1986-2005 reference period • Global mean sea level is projected to rise, but along Canada’s coastlines, sea level will rise in some places, fall elsewhere. • Much of Hudson Bay and the Canadian Arctic Archipelago are projected to experience continuing sea-level fall, while the rest of Canada is projected to experience sea-level rise. Relative Sea-Level Change in Canada
  26. 26. 26 • Projected relative (local) sea-level change through the century, relative to 1986-2005 reference period, for four different locations with different amounts of vertical land motion. • Relative sea level will rise in some places, fall elsewhere. • Green triangle shows the projection for the enhanced scenario with additional sea-level rise from Antarctica • Sea-level projections are similar through to about 2050 or 2060. Relative Sea-Level Change in Canada
  27. 27. What do we Know for Sure? Impacts of changes in sea level will increase throughout this century and beyond KEY FINDINGS § Global sea level will continue to rise past 2100. § With a high emission scenario, sea level rise could reach many metres in a few hundred years. § Low emission scenario would limit the rise to 1 metre. James et al., 2014; after Church et al., 2013
  28. 28. What are other countries doing? Most follow IPCC AR5 A few countries have a high- end scenario (Canada, NZ, Singapore) US approach differs strongly from other countries.
  29. 29. What is the largest value? Garner et al., 2018 Shows all publications, including those superseded or given low confidence. 2.6 m at 2100 is the largest amount cited.
  30. 30. 30 Extreme Water Levels • Hourly water levels recorded at Halifax Harbour for 1920 to 2018, with 5% extremes shown in dark blue and the 90% mid-range in light blue. • Mean sea level (thick blue line) exhibits short-term variability superposed on a long-term increase throughout the record duration. • The table shows that the frequency of high-water level events has increased with the rise in sea level over the decades. Decade 1920-1929 1930- 1939 1940-1949 1950- 1959 1960- 1969 1970- 1979 1980- 1989 1990- 1999 2000- 2009 2010- 2017 sum Number of events (>2.3m) 1 3 4 5 10 15 11 12 24 46 131 Number of events (>2.2m) 3 8 16 15 32 33 31 31 46 76 291 Number of events (>2.1m) 14 16 32 39 64 72 73 70 86 130 596 Number of events (>2.0m) 39 44 78 80 121 126 134 149 154 186 1111
  31. 31. Halifax Tide Gauge Record Key Findings With 40 cm of sea level rise at Halifax, a one-in-50 year extreme water-level event would occur about every 2 years. Atkinson et al., 2016, after Forbes et al., 2009
  32. 32. Summary (Sea level) 32 • Sea-level projections are robust through about 2050 or 2060 and they don’t strongly depend on scenario. • Intermediate and high-emission scenarios lead to metres of sea-level rise over centuries. • Sea-level projections at intermediate times are uncertain and there is a low- probability, high-impact potential for large amounts of sea-level rise (> 1m at 2100), but the largest projections for 2100 are around 2.5 m and recent scientific results point to smaller values.
  33. 33. Summary (CCCR) 33 • There is strong evidence of human-induced changes during the past century in key ocean-climate properties — such as temperature, sea ice, sea level, acidity, and dissolved oxygen — off Canada. • Warmer ocean temperature has contributed to declining sea ice and increasing sea level. However, there is an area south of Greenland where there has been little ocean warming, so regional trends do differ. • In general, warming and freshening at the ocean surface is projected during this century, which will continue to increase stratification and reduced sea ice. • Ocean acidification and decreasing subsurface oxygen levels will continue, with increasingly adverse implications for marine ecosystems. • Where relative sea level is projected to rise (most of the Atlantic and Pacific coasts and the Beaufort coast in the Arctic), the frequency and magnitude of extreme high water-level events will increase, leading to increased flooding. • Declining sea-ice cover is projected to lead to increased wave action and larger storm surges, causing larger and more frequent extreme high water-level events along Canada’s Arctic and Atlantic coasts. • The impacts of climate change (warming waters, ocean acidification, sea-level rise) depend on the pathway of carbon emissions. Strong mitigation of carbon emissions will minimize future effects of climate change.
  34. 34. http://www.changingclimate.ca/CCCR2019 https://www.nrcan.gc.ca/environment/impacts-adaptation/21177 Blair Greenan: Blair.Greenan@dfo-mpo.gc.ca Thomas James: Thomas.James@Canada.ca Thank you! Questions?