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What is Happening?The world's climate has not been constant. We know that nature has caused dramatic past changes, but there is increasing evidence that human activities are altering our climate at an unprecedented rate. When assessing climate change, natural variability must also be considered. Conditions can vary from one year to the next, and cyclic phenomena like El Nino and the Pacific Decadal Oscillation exert important influences over the climate in the region. Nevertheless, analysis of temperature data from 48 climate stations across the region shows a warming trend (see map below) has been occurring throughout BC and Yukon since 1950.
Some areas of the region have been warming more than others, in particular the northeast interior region of BC and most of the Yukon. These regions are showing average temperatures increasing up to 2.5 degree C since 1950. This trend in increasing average temperatures is statistically significant for 94% of the 48 climate stations analyzed. Similarly maximum and minimum temperatures are increasing (to view click on the maximum and minimum temperature area in the above map) and the trends are statistically significant for 77% of the climate stations. In addition, the warming trend is most evident for daily minimum temperatures rather than in the warmest part of the day (maximum temperatures). In other words, temperatures at night have been getting less cold. There are also seasonal differences in the warming trends and the most significant increases are primarily observed in the spring season (for more information see data) for both day and night time temperatures. This is likely due to increases in cloud cover and the ground being snow-free earlier than historically.
Why is it Happening?
In addition to the natural global factors noted above, there are also changes within the climate system itself, such as El Nino, that can cause large regional changes in climate. But these changes alone seem insufficient to explain the steadily accelerated warming occurring across British Columbia and Yukon since the mid 1950’s. In fact, throughout North America and the globe, mean surface temperatures have generally been rising for the last 100 years. The global average surface temperature has increased between 0.6 and 0.7oC since the 20th century and it continues to set records. All of the 10 warmest years globally have occurred since 1990 and the five warmest years since 1861 now include, in decreasing order: 1998, 2002, 2003, 2001 and 1995 (WMO, 2004). For Canada, 2003 was the sixth warmest year since 1948 and the five warmest years in decreasing order were 1998, 1981, 2001, 1999 and 1987 (see Environment Canada's 2003 Climate Trends and Variations Bulletin).
Most scientists agree that the build up of energy - trapping gases from human activities is contributing to the global warming observed over the last 100 years. Since pre-industrial times (1700s), global atmospheric concentrations of greenhouse gases have grown significantly. Carbon dioxide concentrations have increased by 30%, methane by 145% and nitrous oxide by 15%. Based on Antarctic ice core data, current levels of these gases appear to be unprecedented in at least the last 400,000 years (Intergovernmental Panel on Climate Change [IPCC], Third Assessment Report, 2001). There is now abundant evidence to indicate that the above trends are caused by human activities of a rapidly burgeoning global population. In particular,widespread burning of fossil fuels, deforestation and agriculture are enhancing the greenhouse effect. In its Third Assessment Report published in 2001, the IPCC concluded that "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities".
Canadian emissions of total greenhouse gases are estimated to have risen 20.1% since 1990 to a level of 731 Mt (million metric tonnes) in 2002 (Environment Canada, 2004). Between 2001 and 2002, emissions increased by 2.1% in contrast to the previous year's 1.2% emissions decrease. In BC, the trend in greenhouse gas emissions has been increasing as it has for Canada overall. Although BC contributes only about 9.3% to Canada’s total greenhouse emissions, it mirrors the national trend increasing by 28% between 1990 and 2002 (Environment Canada, 2004). Similarly between 2001 and 2002 its emissions followed the national trend, increasing by 2.1%. The Yukon, however, with much smaller GHG emissions shows a highly variable trend but with successive declines occurring since 1998. As it is for the rest of the world, carbon dioxide is the dominant greenhouse gas emitted in Canada. In 2002, carbon dioxide made up about 78.8% of GHG emissions nationally and 80% in BC and 76% in the Yukon. Canada contributes only about 2% of the total global greenhouse gas emissions but because of its resource-based economy, climate, geographic size and energy-use patterns, it is one of the highest per capita emitters [23.3t CO2 eq per capita in 2002 (Environment Canada, 2004)]. The sectors in 2002 responsible for the largest contributions to total greenhouse gas emissions in Canada are from the electricity and petroleum industries (35%) and from transportation (26%). In BC and Yukon the largest contribution to total emissions came from the transportation sector, 38.3% for BC and 50.8% for Yukon. With traditional internal combustion engines most cars produce three to four times their weight in carbon dioxide emissions each year. The contribution of greenhouse gases from increasingly popular but less fuel-efficient Sport Utility Vehicles, vans and light trucks increased by 88% between 1990 and 2002 (Environment Canada, 2004). Why is it Significant?Studies by scientists (Taylor and Taylor, 1997) indicate that the warming trends caused by climate change could have a dramatic effect in British Columbia and Yukon. Northern Yukon is predicted to experience a shorter but more intense snow season with faster snow melt and longer and warmer summers. The climate change impacts on Yukon ungulates such as the Porcupine Caribou are expected to be significant as snow depth affects their ability to forage. There could be significant negative effects on water resources of the dry BC Interior, which rely heavily on snow melt, particularly in the mid to late summer low flow period. Migrating salmon would also be affected if water temperatures become too warm. According to the Pacific Fisheries Resource Conservation Council (2000) climate change may be having the biggest single impact on the deterioration of salmon production, and it poses the most apparent long-term risk to the future of Pacific salmon. Some ski areas in the Rockies and southern BC may have shortened ski seasons. Less snow may also upset sensitive ecosystems and threaten species at the most southern edge of their geographic range. Global warming may add to stratospheric ozone depletion (commonly referred to as the ozone hole). Higher carbon dioxide levels can lower Arctic stratosphere temperatures aiding ozone-destroying chemical reactions. This could delay the recovery of the thinned Stratospheric Ozone Layer and allow more harmful ultraviolet radiation to reach the earth’s surface (see Stratospheric Ozone Thickness Indicator). The warming trend being documented in the region already appears to be having an effect. Earlier breeding of certain seabirds has already been observed (DFO, 2001) as they adjust to the advanced timing of peak prey food availability due to increasing ocean temperatures. As a result, prey availability is mismatched with timing of breeding and chick growth is retarded and survival is reduced (Bertram et al., 2001). The growing abundance of Lesser Snow Geese may be linked to recent warmer summers on their arctic nesting grounds. Also within BC, the evergreen broadleaf arbutus trees found only in micro-climates along the southwest coast are showing signs of die-back believed to be caused by changing weather patterns.
Along with the trend in increasing minimum temperatures throughout the region, the numbers of frost free days since 1950 have also been increasing across the region. This fits in with data from other regions like the Canadian Prairies where there are now 19 more frost free days a year than 75 years ago. This lengthening of the freeze-free season can improve agricultural growing conditions, but may also increase problems with plant pests and disease. For example, mild winters in North-Central BC have contributed to the province’s worst forest infestation of mountain pine beetle. Normally controlled by freezing temperatures, the beetle population has been able to increase because of the warmer winters. Detecting changes in precipitation trends is difficult because precipitation varies widely across even small geographic areas. The trend in annual precipitation since 1950 is depicted in the map below and it is expressed as a percent change from the 1961 to 1990 average. Although most of the changes are not statistically significant, an increasing precipitation trend has been measured for some areas of the region while others particularly the region along the Rocky Mountains has been showing a decreasing trend in precipitation.
These trends vary considerably between seasons (click on seasonal trends area of the map above). In general, since 1950, the seasonal precipitation trends have been for drier winters for much of the interior and southern BC, wetter springs for the Yukon and for the southern and coastal BC, and wetter summers for southern and coastal BC but drier for the northern Yukon. Regional hydrologists have also observed changes in the temporal pattern of stream flows as a result of warmer temperatures. Stream flows in south central BC peak earlier but have lower summer-early fall flows and higher early winter flows (Leith and Whitfield, 1998). Similar changes have also been observed in the timing of stream flows of coastal rivers (Whitfield and Taylor, 1998) where spring and summer river flows have decreased. These reduced coastal river flows are believed to result from an earlier starting and longer lasting growing season which leads to a lowering of the water table. Such low flow periods will begin even earlier in the year and will last even later into the fall as higher air temperatures increase evaporation from soils and surface waters. Declining stream flows in summer would result in warmer river and lake temperatures and increased fish mortality. Reduced water supplies and increased forest fire hazards would become common in the late summer. Changes already documented in the Northern Hemisphere during the 20th century include reductions in both snow cover and the duration of lake and river ice cover, a decline in Arctic sea-ice thickness and extent, and a retreat of mountain glaciers. A 2004 multinational four year assessment of the circumpolar climate and levels of ultraviolet radiation of the Arctic reaffirms these observations as well as presenting mounting evidence that the Canadian Arctic is already experiencing some of the most serious and wide-ranging impacts of climate change seen anywhere (Arctic Climate Impact Assessment, 2004). Associated with temperature increases has been an observed increase in global sea levels, at an average rate of one to two mm per year over the past 100 years (IPCC, 2001). Sea levels at most BC ports are rising by about 1 mm per year and a slight increase in sea level has already been noted in Richmond, BC (BCWLAP, 2002). Some researchers have reported that the frequency and intensity of extreme weather events has increased over the last 10 - 15 years. Certainly in Canada the number of weather-related disasters has increased since 1900 and more so in the last 50 years as can be seen in the graph below. These weather-related disasters account for 51% of all Canadian disasters (Etkin et al., 2004).
In Canada, floods are the main cause of the increase in the number of these weather-related disasters and droughts are the most expensive in a cumulative sense (Dore, 2003). These weather-related disasters can exact a severe toll in human life and economic losses. The Meteorological Service of Canada estimated that between 1987 and 1998, 70-100 lives were lost and 58,000 people were displaced by extreme weather events (Environment Canada, 2001a). Ever since the Edmonton, Alberta tornado in 1987, there has been an increase in both the frequency and severity of multi-million-dollar weather related disasters. These are summarized as follows (as per Environment Canada, 2003b and 2001a and Beyond the Breaking Point, 2004):
Although information such as the above about extreme weather events continues to be compiled, scientists agree that there is not yet enough scientific evidence to show they are directly linked to a changing climate. However, they do believe that such events will occur more frequently as global temperatures and the hydrological cycle intensifies (Etkin et al., 2004). In 2002, the United Nations Environment Programme Finance Initiatives Climate Change Working Group reported that climate change poses a major risk to the global economy. Worldwide economic losses due to natural disasters appear to be doubling ever 10 years and, based on current trends, annual losses will reach almost $150 billion in the next decade (UNEP, 2002). What is Being Done?Although we recognize the need to take action within our region and throughout the country, climate change is a global problem that needs a global solution. At the third conference of the Parties (CoP3) of the U.N. Framework Convention for Climate Change held in Kyoto, Japan in 1997, Canada signed the Kyoto Protocol which set targets for industrialized countries which ranged from -8 per cent to +10 per cent of the countries' individual 1990 emissions levels "with a view to reducing their overall emissions of such gases by at least 5 per cent below existing 1990 levels in the commitment period 2008 to 2012" (see www.unfccc.org ). In order to come into effect, the Kyoto Protocol requires that a minimum of 55 countries ratify the Protocol and that they account for at least 55% of the 1990 emissions from industrialized countries. With Russia’s ratification of the Protocol on November 18, 2004, at total of 128 countries have now ratified representing 61.6% of 1990 industrialized emissions. The Protocol became legally binding on its 128 Parties on 16 February 2005. Canada will host the Eleventh Conference of the Parties (CoP 11) to the United Nations Framework Convention on Climate Change in Montreal from November 28 to December 9, 2005. The meeting, the first of the Parties (MoP1) to the Kyoto Protocol, will mark the beginning of discussion among countries to determine the longer term global approach on climate change after 2012. Only four industrialized countries have not ratified the Kyoto Protocol: they are Australia, Liechtenstein, Monaco and the United States. Australia and the United States have stated that they do not plan to do so; together they account for over one third of the greenhouse gases emitted by the industrialized world. Developing countries, including Brazil, China, India and Indonesia, are also Parties to the Protocol but do not have emission reduction targets. Canada is committed to the Protocol, which it ratified on December 17, 2002. In the Speech from the Throne, on October 5, 2004, the Government of Canada stated, “The Government reiterates that it will respect its commitment to the Kyoto Accord on climate change in a way that produces long-term and enduring results while maintaining a strong and growing economy. It will do so by refining and implementing an equitable national plan, in partnership with provincial and territorial governments and other stakeholders.” On April 13, 2005, the Government released its revised climate change plan, Moving Forward on Climate Change: A Plan for Honouring our Kyoto Commitment. This is the first phase of Project Green, the government's national project to create a healthier environment and a stronger economy and ultimately to build a more sustainable future. In 2000, Canada’s Action Plan on Climate Change was unveiled. This $500 million Plan focuses on key sectors and includes initiatives in transportation, energy, industry, buildings, forestry and agriculture, international projects and science and technology. In its February 2000 budget, the government committed $100 million for climate change initiatives in developing countries and $15 million to join the World Bank’s prototype carbon fund. The 2000 budget provided funds for a variety of activities related to climate change: $60 million to extend a number of energy efficiency and renewable energy programs; $100 million to establish the Sustainable Development Technology Fund; $125 million to establish the Green Municipal Enabling Fund and the Green Municipal Investment Fund; $15 million to expand the government’s purchase of green power; and $60 million to enhance Canada’s capability in climate science. $1.3 million was specified for BC Climate Change projects. In June 2001, the federal government announced a 5 year $23 million Fuel Cell Alliance program to help reduce vehicle emissions that contribute to global warming. To help the transition to clean-burning fuel cells, hydrogen refueling stations will be provided in several provinces including British Columbia. Other initiatives include a $16 million program to negotiate voluntary improvements in vehicle efficiency; a $40 million program to help municipalities showcase innovative public transit ideas; and a $30 million program to encourage new projects to make transportation more efficient.
Environment Canada plays a key role in improving global awareness of climate change and its impacts. It is a major participant in the United Nations Framework Convention for Climate Change, the Intergovernmental Panel on Climate Change and the World Climate Change Research Program. At the Canadian Centre for Climate Modelling and Analysis in Victoria, BC , Canadian scientists are studying the mechanisms of climate variability with the aid of computerized global climate models. Glaciologists from the Geological Survey of Canada and scientists at Environment Canada’s National Water Research Institute (NWRI) in Saskatoon have joined together in a National Glaciology Program to study the impact of climate change on glacier reserves. The glaciers that feed BC’s Columbia River system are a major component of that work since changes in the hydrology would lead to reductions in the system’s ability to achieve the goals of reliable power production, flood control and sustainable fisheries. Many other climate related research activities are also in progress across Canada . Climate change is a complicated phenomenon and the impacts will vary from region to region. The identification of climatic changes at regional scales is therefore important. While a future regional cooling trend is always a possibility, the preponderance of evidence is for continued warming in BC and the Yukon , but at rates that are difficult to estimate. The continued tracking of temperature and precipitation trends serves as a valuable indicator of regional-scale climate change. This indicator can help understand how the daily lives of residents of British Columbia and Yukon may be affected and how to deal with the consequences.
For more information contact: Bill.Taylor@ec.gc.ca or Wendy.Avis@ec.gc.ca for updates on what's being done. Check the following sites for additional information on this indicator: Environment Canada web sites:
Other Federal Department web sites:
The following Web sites are not under the control of Environment Canada (EC) and they are provided solely for the convenience of users. Environment Canada is not responsible for the accuracy, currency or the reliability of the content. Environment Canada does not offer any guarantee in that regard and is not responsible for the information found through these links, nor does it endorse the sites and their content. Users should be aware that information offered by non Government of Canada sites that are not subject to the Official Languages Act, and to which Environment Canada links, may be available only in the language(s) used by the sites in question. Science Sites:
General Information Sites:
For references used for this indicator click here. |
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It
is well known that the earth does warm and cool on a long time scale.
The ice ages and intervening warm periods have been examples. These changes
are caused by a number of natural factors which include solar output,
changes in the Earth’s orbit around the sun, and changes in the reflective
properties of the atmosphere and the earth's surface that return some
of the incoming sunlight back to space. Naturally occurring gases in the
atmosphere also form an insulating blanket around the earth. In what is
referred to as a “greenhouse effect”, this blanket of greenhouse gases
(GHGs) - primarily water vapour, carbon dioxide (CO2), methane (CH4)
and nitrous oxide (N2O) - traps outgoing energy of the earth that would
otherwise be radiated back into space. Without the effect of these naturally
occurring gases, the temperature on earth would be too cold to support
life as we know it.
On November 21, 2002,
the Government of Canada released the "
