Predictions and Scenarios
Global models are increasingly used to predict the impacts of climate change (e.g. surface temperatures, winds, rainfall, changes in river flow). They are proving successful in explaining general trends such as the rapid warming of the Arctic region. However, since global models are unable to look at regional impacts in any detail regional models still need to be developed.
These models will be used to create predictions and scenarios that describe future ocean conditions. With this view of the future, policy and decision makers will be able to anticipate the changing geographic range and movement of commercial fish species and species at risk as well as track invasive species, as just a few examples. Coastal communities will be able to use this information to determine if protective seawalls and dykes should be strengthened or raised. New harbours can be designed to adapt to rising or lowering water levels and storm events.
Ocean science models are created by measuring and integrating many different types of data, such as salinity, temperature, ocean colour (which indicates blooms of tiny aquatic organisms), atmospheric pressure, dissolved oxygen content of water, and surface winds.
DFO scientists working on Climate Models can be found here.
Regional climate models are being developed on all three coasts.
Arctic climate model
Arctic climate model
The Arctic is a unique and sensitive region undergoing intense rates of change. DFO scientists are using models to gain a better understanding of the changes occurring in the Arctic aquatic ecosystems. This will enable scientists to make predictions about the impacts of climate change on a variety of Northern issues including the migration of Southern aquatic species northward and impacts on Northern species; the effect of thawing permafrost on coastal infrastructure, and storms on coastlines; increased use of the Northwest Passage for transportation; and development of resources (i.e., oil and gas in the Beaufort).
Atlantic climate model
Atlantic Climate Model
Climate change is expected to affect different parts of the world's ocean differently, as a result of regional atmospheric, ice and ocean features and other dynamics. The climate response of the North West Atlantic on the eastern coast of Canada is expected to be particularly complex in view of the competing influences of Arctic outflows, continental run-off, sea ice; the Labrador Current and Gulf Stream, and continental and subtropical air masses.
While Global Climate Models (GCMs) have become very useful tools for predicting the impacts of climate change over large geographic areas, they are unable to look at regional impacts in any detail. As a result, DFO researchers are developing regional models to address this knowledge gap.
The models are being used to describe, understand and simulate the ocean's response to recent and potential future climate variability and change. They are providing a basis for assessment of the impacts of climate change on the ocean's physical environment, ecosystem, fisheries and other important aspects in the region. They are supported by a high-resolution ice-ocean-plankton model for the region spanning the Gulf of St. Lawrence to the Gulf of Maine. Recent analysis of regional models indicate that the expected reduction in the mid-latitude occurrence of extreme winter storms by the mid 21st century may be greater and more widespread than Global Climate Models have previously predicted.
Due to improved methods for computing continental run-off into the ocean from precipitation, models will be able to provide an improved representation of future freshwater discharge into the coastal ocean. The discharge can have a major influence on estuaries, some bays, and the Gulf of the St. Lawrence by changing the salinity of the waters and the associated ecosystems. Such changes could potentially lead to the disappearance of marine species from localized areas.
Pacific climate model
Pacific Climate Model
As global scale climate models are too generalized for regional purposes, a regional model for the British Columbia continental shelf is being developed to provide credible long-term forecasts of oceanographic features such as:
- upwelling off the western Vancouver Island shelf;
- the magnitude and frequency of future Haida Eddies;
- deep water renewal in the Strait of Georgia; and
- future temperatures and discharges in coastal rivers.
All of these features are relevant to biological productivity along the shelf yet they cannot be accurately predicted using global-scale climate models since they are localized occurrences.
The shelf model used in these British Columbian climate studies was developed by the Centre for Ocean Model Development for Applications (COMDA). The model is based on the Regional Ocean Modelling System (ROMS), has a 3 km resolution, and incorporates atmospheric, freshwater, and oceanic variables.
Changes in precipitation due to climate change are expected to affect the amount and timing of fresh water input into North East Pacific coastal waters. Using discharge time series from coastal rivers with at least 25 year records dating back from 2005, analyses were carried out to determine if the peak discharge was happening earlier and/or if the cumulative flow was becoming larger. Changes to flows and temperatures in the Fraser River may impact the survival of sockeye salmon. Spatial/temporal relationships between precipitation and discharge are being examined so that ungauged coastal rivers can also be included in projections of total runoff onto the BC shelf.
DFO collaborates with several partners on Ocean climate models.