Climate Change

Climate Change and its Impacts: British Columbia

Overview

Past Climate Change and Impacts in British Columbia

British Columbia’s climate has changed over the last 50-100 years.  Historic data suggest that many parts of British Columbia are already starting to experience some of the impacts of climate change.  During the 20th century:

• average annual temperature warmed by 0.6 degrees C at the coast, 1.1 degrees C in the interior, and 1.7 degrees C in the north (between 1895 and 1995)
• minimum temperatures increased by 0.9 degrees C at the coast, 1.3 to 1.7 degrees C in the interior, and 2.1 degrees C in northern B.C. (between 1895 and 1995)
• growing degree days (GDD), a measure of the heat energy available for plant and insect growth, increased by 5 to 13 percent (between 1895 and 1995)
• precipitation increased in southern B.C. by 2 to 4 percent per decade (between 1929 and 1998)
• sea surface temperature (SST) increased by 0.9 to 1.8 degrees C (between 1914 and 2001)
• snow depth and snow water content decreased in some parts of British Columbia (between 1935 and 2000)
• lakes and rivers throughout B.C. became free of ice earlier in the spring (between 1945 and 1993)

BC trends based on records of 50 to 60 years or longer are more strongly associated with climate change.

Although warmer temperatures may be appealing, seemingly small changes in climate can have significant ecological, social, and economic consequences. For example, slightly warmers have contributed to the devastating mountain pine beetle infestation in the B.C. interior.  There are growing concerns about summer water shortages in the agriculturally-significant Okanagan region. Glacial melting and lower flows in the Columbia-Kootenays may impact future electricity generation and other water uses.

Future Climate Change and Impacts in British Columbia

The rate of global warming projected for the 21st century is much faster than observed changes during the 20th century, and likely faster than at any time during the past 10,000 years.  The actual rate of warming will depend on how fast greenhouse gases continue to accumulate in the atmosphere, and how the climate system responds.  Although climate change appears to be gradual at the global scale, atmospheric warming may in future trigger abrupt changes in regional climate. For this reason, past trends do not necessarily predict how biophysical systems will respond in future.
The best available science suggests that the impacts for B.C. in the 21st century will include:

• a 2-5 0C increase in average annual temperature;
• increased river flood risks in the spring and coastal flooding associated with storm surges;
• glacial retreat in the south; reduced winter snow pack and earlier snowmelt; contributing to reduced summer water supply; and
• increased stress on species at risk; shifts in the geographical range of vegetation, including economically important forest species;
• increased river temperatures and stress on salmon; and
• reduced summer soil moisture and increase in forest fire risk.

Water Resources: Rising air temperatures will reduce the amount of precipitation that falls as snow in the winter and in the mountain regions, resulting in lower river levels during the dry summer period. Higher temperatures in the summer will increase the need for water — for people, aquatic life, and irrigation in agriculture. What’s more, the increased heat will heighten the evaporation of water, leading to water loss. This will make it even harder to ensure adequate water supplies.

Floods and Landslides: B.C. is expected to receive increased annual precipitation and more frequent extreme precipitation events. The outcome will be more floods and landslides, which will endanger sensitive ecosystems, people’s lives and property. Existing flood-protection structures might not be adequate in the future.

Fisheries: Warmer stream temperatures and lower water levels will make it difficult for salmon to successfully migrate and spawn. During recent warm periods, 50% of Fraser River salmon have died during migration. Further warming will increase deaths and may eventually threaten the survival of less tolerant species.

Terrestrial Ecosystems:  Hotter, drier summers increase evaporation, drying the soil and ground-fuel materials. These conditions would pave the way for more forest fires. Besides destroying forests, fires can be financially costly. As an example, in 2003, wildfires destroyed hundreds of homes in the Kamloops and Kelowna area. The total cost of fire fighting, rehabilitation and insurance claims approached $500 million. Ecosystems will change as species adjust to new climate conditions.  In areas that become too dry for trees, grasslands will flourish. Tree diseases and insect infestations (such as the mountain pine beetle) may increase as warmer winters allow pests to survive. These changes could have a considerable impact on our ecosystems and the forest industry.

It’s estimated that over the next 100 years, global sea level could rise by between 9 to 88 centimetres. A further rise in sea level could cause flooding and erosion in B.C. coastal areas. Very high water levels will occur if extreme weather and associated storm surges become more frequent or severe as a result of climate change. As sea level rises, habitat in the coastal wetlands will be lost.

Other Resources

General Information about Climate Change and Impacts in British Columbia

Historic climate change in British Columbia (PCIC)

Includes data and maps of historical temperature trends, historical precipitation trends, snow trends, baseline temperature and precipitation, ENSO/PDO temperature, precipitation and snow trends, and various projections.

Future Climate Change in British Columbia (PCIC)

This interactive site provides high resolution illustrative climate scenarios that were created based on downscaling of low-resolution Global Climate Model (GCM) results using high resolution historical temperature & precipitation observations.

From Impacts to Adaptation: Canada in a Changing Climate (NRCan 2007 – B.C. Chapter)

This chapter provides an overview of recent research findings related to climate change impacts and adaptation issues in British Columbia.

Environmental Trends 2007– Climate Change: What is Happening?

This is the fourth in a series of Environmental Trends reports from the British Columbia Ministry of Environment.

Indicators of Climate Change for British Columbia 2002

Indicators of Climate Change for British Columbia 2002 documents how temperature, precipitation, and other aspects of climate changed during the 20th century, as well as related changes in physical and biological systems.  The trends suggest that many areas of B.C. are starting to experience climate change and its impacts.

Full Report (PDF/1MB/50 pages)

Regional Information about Climate Change and Impacts in British Columbia

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Sectoral Information about Climate Change and Impacts in British Columbia

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