Canadian Extreme Water Level Adaptation Tool (CAN-EWLAT) Glossary

Allowance

Allowances are the recommended vertical distance that coastal infrastructure need to be raised to prevent the risk of flooding from sea level rise. These estimates are based on a combination of 2 factors:

1. The projections of future relative sea level change along with the uncertainties in those projections.
2. Historical water level records, including both tides and storm surge (referred to as storm tides) at tide gauge sites. At small craft harbour sites with no tide gauge data available, storm-surge models are used to simulate historical storm tides. CAN-EWLAT does not incorporate predicted changes in storm tides over the coming century because the current state of knowledge of future projections of storminess is limited.

Any infrastructure raised by this allowance would account for the possibility of flooding in the future due to sea level rise. It is important to note that the allowances only relate to flooding and not erosion of soft shorelines nor impacts associated with this erosion.

AR5

This stands for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

AR6

This stands for the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.

CurWaveSummer

Maximum wave height during the summer in the current climate

CurWaveWinter

Maximum wave height during the winter in the current climate

Fetch

The distance along open water over which the wind blows

GIA

Glacial Isostatic Adjustment is caused by the rebound of the Earth from the several kilometer thick ice sheets that covered much of North America and Europe around 20,000 years ago. Mantle material is still moving from under the oceans into previously glaciated regions on land.

GPS

In the CAN-EWLAT application, Global Positioning System (GPS) is used to measure the vertical movement (up and down in millimetres per year) of the Earth's crust over time.

IPCC

The Intergovernmental Panel on Climate Change.

MRSL projections

Relative sea level (RSL) is defined as sea level measured with respect to land. Mean RSL is defined as RSL at a given location averaged over a period of 1 year. A projection is a potential future evolution of a quantity or set of quantities, often computed with the aid of a model. Unlike predictions, projections are conditional on assumptions concerning future socioeconomic and technological developments that may or may not be realized.

ProjectedWaveSum

Maximum wave height during the summer in the projected future climate

ProjectedWaveWin

Maximum wave height during the winter in the projected future climate

RCPs

Representative Concentration Pathways (RCPs) are concentration pathways used in the IPCC AR5. They are prescribed pathways for greenhouse gas and aerosol concentrations, together with land use change, that are consistent with a set of broad climate outcomes used by the climate modelling community. The pathways are characterized by the radiative forcing produced by the end of the 21st century.

Radiative forcing is the extra heat the lower atmosphere will hold as a result of additional greenhouse gases, measured in Watts per square metre (W/m²).

Four RCPs scenarios have been designed for the AR5 and in CAN-EWLAT we are using 3 of these:

1. RCP 2.6 (low)
2. RCP 4.5 (intermediate)
3. RCP 8.5 (high)

For more details, please refer to the AR5 report.

Small craft harbour

Fisheries and Oceans Canada owns, operates and maintains a national system of harbours found in local communities across Canada to provide commercial fish harvesters and other users with safe and accessible facilities. To learn more, visit Small craft harbours.

SSPs

Shared Socioeconomic Pathways (SSPs) are scenarios of projected socioeconomic global changes up to 2100. They are used to derive greenhouse gas emissions scenarios with different climate policies, and serve as the basis for IPCC AR6. In the SSP labels, the first number refers to the assumed shared socio-economic pathway, and the second refers to the approximate global effective radiative forcing in 2100.

Storm surge

The positive or negative difference in sea level from the predicted tide, due primarily to changes in air pressure and winds.

Storm tide

The combined effect of storm surge and tides.

Tide

The rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.

Tide gauge

Tide gauges are installed by the Canadian Hydrographic Service to collect water levels against a vertical reference.

Wave climate

Wave climate is defines as the monthly average wave height for a specified time period.