Climate Change

Overview - What is Happening?

The climate in British Columbia has changed noticeably over the past half-century:

• The average air temperature has become higher in many areas. Air temperature on the coast has been less affected than in the interior and northeast of the province.

  Photo credit: L. Bonner

• The sea surface temperature has risen along the coast, and deep-water temperatures have increased in some inlets on the South Coast.

• Relative sea level has risen along the B.C. coast, except in those areas being pushed upward by geological processes.

The pattern of climate change reported for British Columbia is consistent with broader trends in North America and with climate models. Projections show continuing warming over the whole province. For much of the province, winters will also likely become wetter and summers will be drier.

Concentrations of carbon dioxide and other greenhouse gases in the world’s atmosphere are rising, which causes the atmosphere to trap more heat. As the air, land, and water warms, it causes changes in patterns of precipitation, evaporation, and wind, and may influence ocean currents.

Climate scientists agree that human activities, especially the burning of fossil fuels, are largely responsible for the increase in greenhouse gases in the atmosphere. More than 90% of the greenhouse gas emissions in Canada are associated with the consumption and production of energy from fossil fuels.

In B.C., the largest source of greenhouse gas emissions is the transportation sector, which includes commercial and private vehicles of all kinds. From 1990 to 2002, B.C.’s greenhouse gas emissions continued to rise by about 2% per year (see graph).

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IMPACTS OF CLIMATE CHANGE

As the climate changes it is expected to affect physical and biological systems, and have social and economic costs. For British Columbia, impacts of climate change are projected to include:

• a reduced snow pack in southern B.C. and at mid-elevations in the mountains;

• an earlier spring freshet and reduced water flow in the summer particularly on river systems that depend on snow melt as a source of water;

• retreat and disappearance of glaciers in southern B.C.;

• warmer water in some lakes and rivers and changes in ocean temperature, salinity, and density, which, in turn, may affect ocean circulation and productivity.

• lower soil moisture in some regions in the summer;

• increased frequency and severity of natural disturbances, such as fire, and pest outbreaks, such as mountain pine beetle;

• large-scale shifts in ecosystems and loss of ecosystems, such as some wetland and alpine areas;

• an increase in number of growing days each season for crops.

These changes have social and economic costs, such as:

• higher risk of damage to building and communities from extreme weather

• increasing risk of floods and erosion in low-lying areas as sea levels rise; also, intrusion of saltwater into wells and aquifers and contamination of low-lying agricultural land with salt;

• shortage of fresh water and hydroelectricity for communities, agriculture, and industries that rely on snow pack and glaciers as a water supply;

• changes to economic sectors that depend on natural resources, such as agriculture, forestry, fisheries, tourism;

• increasing geographical range of certain diseases (e.g., malaria) and the risk of heat-related illnesses, such as heat stroke.

For detailed information, including graph data, see In-Depth report [pdf].

Next: Air Temperature Trends >>