Sea level rise is a complex phenomenon with a number of uncertainties. Many municipalities are beginning to consider the impacts on their area. Below are some questions that often arise during discussions about sea level rise.
A: For more than a century, sea levels have been recorded around the world using tide gauges, and more recently satellite measurements. This data allows us to track global and local trends in sea level. There is large variation between local sea level trends due to regional differences in geological (e.g. post glacial rebound, plate tectonics), and oceanic processes. However, the results of numerous studies from credible, peer-reviewed journals and publicly-funded organizations (such as IPCC, NASA, NOAA) indicate global average sea level is rising. Furthermore, studies have found that the rate of global sea level rise has increased. Therefore, the scientific consensus indicates overall sea level is rising although this will not be experienced equally around the world.
A: The atmosphere’s warming temperatures cause our ocean’s waters to warm and expand and cause glaciers and ice sheets on land to melt, causing sea level rise. During the 20th century global sea levels rose 17 cm at an average rate of 1.7 mm a year. However, since 1993 this has increased, with sea levels estimated to be rising at over 3 mm a year; and this is projected to continue speeding up. The Province of British Columbia is currently advising that communities plan to adapt to one metre of sea level rise by the year 2100.
With climate change, more extreme weather events are expected. These two factors coupled could result in more severe storms, higher waves, and flooding.
A: Sea level rise is not felt uniformly around the world, or even within British Columbia. One reason for this is glacial isostatic adjustment: land masses, once depressed by huge ice sheets during glaciation, are in the process of rising again. This is why 2013 data from Fisheries and Oceans Canada indicates that Prince Rupert has seen 9.8 cm/century of sea level rise, while Victoria has seen 3.1 cm/century. Different locations are therefore responding to post-glaciation and rising at different rates. However, isostatic adjustment does not mean BC communities are immune to sea level rise, instead they’re just affected differently over time.
A: Local sea levels are determined by a variety of factors such as, the volume of water in the ocean, plate tectonics, post glacial rebound (where earth previously weighed down by glaciers rises up after the ice melts), and ocean dynamics. When observing local trends in sea level all of these influences must be accounted for. Campbell River experiences annual uplift (vertical land movement) of approximately 4mm as a result of post glacial rebound and plate tectonics. Currently, the rate of global sea level rise is less than the rate of local uplift, resulting in the observed decrease in local sea level. This is helpful, however, the rate of global sea level rise is accelerating. Therefore, in time the rate of sea level rise may be expected to surpass local uplift in Campbell River, leading to a net increase in local sea level. Local uplift has been accounted for in all of the sea level rise risk assessments carried out by the City’s consulting team.
A: Melting sea ice is not a factor contributing to rising sea levels. However, melting glaciers and ice sheets on land are adding significantly more water to the oceans. These ice sheets are normally confined on land and exist yearlong, but with warming temperatures they are quickly melting and the water runs into the ocean. This, coupled with water undergoing thermal expansion as average global atmospheric temperatures increase, are the principal causes of sea level rise.
A: With sea level rise, high tide will reach farther inland. Twice a month, during the new moon and the full moon, higher-than-normal tides occur as a result of the sun and moon’s gravitational forces. Although the tidal patterns won’t change, the “base level” of the ocean will be higher. In future, tidal flooding occurring on storm-free days will become more frequent, and more damaging tidal flooding from storm waves and King Tides (the year’s highest) will occur. Floods are expected to become more frequent and last longer as the high tidemark rises with sea level.
A: By planning for future sea level rise now, the City will be able to develop an adaptation strategy that will not require immediate, large scale updates to existing infrastructure. Ideally, adaptations will be incorporated as buildings and infrastructure undergo normal reconstruction at the end of their serviceable life. Planning now will also help guide new development, by accounting for future sea level rise in building design and avoiding further development in vulnerable areas. Campbell River already experiences coastal erosion and flooding during severe storms. Sea level rise planning helps address not only future hazards, but those we experience today.
A: There is no single solution to prepare for sea level rise. Approaches include:
A combination of these approaches will likely be used in Campbell River.
More specific solutions will be developed and shared for community feedback as we acquire more precise data.
A: An assessment of Campbell River’s foreshore will determine the possible future extent of marine flooding. The City will produce detailed maps based on this assessment and make them available for community use.
A: The City of Campbell River is planning for sea levels projected for the year 2100. Planning today, can help avoid and minimize potential hazards in the future, and help improve coastal resiliency against winter storms and coastal flooding already experienced in Campbell River.
A: Plans for these two projects will consider the future impact of sea level rise. For more information, check out City webpages dedicated to the Hwy 19A and Big Rock Boat Ramp upgrades.
A: In many cases beach rehabilitation can help and this is an option the City will explore where possible. The City has implemented an agreement with the Department of Fisheries and Oceans to use the softest possible shore protection measures that will provide protection. Less rigid materials and beach enhancements are used, and the natural boundary of existing shores are protected, to preserve intertidal areas and protect wildlife habitat.
Soft shore rehabilitation at Dick Murphy Park:
Hard shore rehabilitation at Ostler Park:
A: In response to sea level rise there is no one solution. A mixture “hard” and “soft” solutions will be used (in conjunction with regulatory tools and land-use changes) where needed based on technical studies and public input.
A: The City recognizes the value of Campbell River’s beaches, and sea level rise does not mean beaches will become unusable. If fact, soft shore approaches to combat marine flooding frequently improve access and the health of the marine environment. An agreement between the Department of Fisheries and Oceans and the City has been signed to implement soft shore restoration approaches wherever possible to protect recreation and habitat opportunities unique to the community. Some beach and wetland areas could be squeezed or shortened by sea level rise, reducing habitat and recreation, in cases where hard shores are appropriate solutions.
A: In 2015 plans to restore the foreshore at Ostler Park were approved by Council. However, the potential impact of sea level rise has significant implications for the long-term design. The foreshore assessment will include Ostler Park and as the City gets more information about the effects of sea level rise on Campbell River, the Ostler Park plans can be revisited.
A: If you think your home is at risk of flooding, there are a number of steps you can take to prepare. Refer to the following documents for more information.
For information on mitigating the effects of coastal flooding on future developments, see FEMA’s Home Builder’s Guide to Coastal Construction.
For information on adapting your home and property to mitigate the effects of coastal flooding, see FEMA’s Homeowner’s Guide to Retrofitting.
301 St. Ann's Road, Campbell River, BC,
V9W 4C7 | Tel. 250-286-5700 |