10 Things You Should Know About Climate Change

1. Climate change refers to a long-term change in average weather conditions over time. This includes changes in temperature, precipitation and winds. Climate change can be the result of natural processes or human activity.
   
2. Global warming observed over the last 50 years has been largely attributed to human influences on the climate. This human influence is largely a result of burning fossil fuels such as coal, oil and natural gas. Burning these fuels generates carbon dioxide, a greenhouse gas that is blamed for much of the warming. Land use changes, such as deforestation and conversion of land to agriculture, have also contributed carbon dioxide to the atmosphere. 
   
3. Natural processes can also cause climate change. The Earth's climate has changed throughout its history, with the planet experiencing glacial periods or "ice ages", as well as natural warming cycles. These changes can be explained by changes in the Earth's orbit, changes in the sun's intensity, and by volcanic eruptions that produced aerosol and carbon dioxide emissions.
   
4. Climate change is primarily attributed to the enhancement of the natural greenhouse gas effect caused by increased levels of gases in the atmosphere from human activity. Greenhouse gases are atmospheric gases that absorb and emit thermal radiation. So-named for their ability to trap heat in, greenhouse gases greatly affect the temperature of the Earth. Major greenhouse gases in Earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide and ozone. 
   
5. The ozone hole does not have a strong effect on global climate change, although research indicates that it has affected the circulation (winds) in the southern hemisphere. The thinning of the ozone layer is caused mainly by chlorofluorocarbon chemicals (CFCs), used in the past in refrigerator and air conditioning units. The Montreal Protocol, which has effectively banned the emission of CFCs, has put the climate on a path towards gradual recovery of the ozone hole, but these actions alone will not slow climate change.
   
6. Climate change is a warming trend, not just a warming cycle. Global temperature naturally varies up and down from year to year and decade to decade. However, over the long term, global temperatures have been warming, and most of the warming over the past half-century has been attributed to human influences on the climate system, primarily greenhouse gas emission. This has resulted in glaciers melting, sea levels rising, and changes in weather patterns and precipitation.
   
7. Climate change will have adverse effects on communities all over the world. Extreme weather is likely to increase, potentially destroying human and animal habitats. As well, rising sea levels and changes in weather and precipitation will affect communities, agriculture and food supplies. 
   
8. Individuals, organizations and the international community can make a difference in dealing with climate change. We must act. Measures such as reducing greenhouse gas emissions and gaining awareness of the issues surrounding climate change can make a significant difference. 
   
9. The 15th Conference of the Parties culminated in the Copenhagen Accord, a significant breakthrough in the global effort to address climate change. Canada will continue to work constructively in 2010 to implement the Copenhagen Accord and to complete the negotiations under the UNFCCC for a comprehensive, legally binding post-2012 agreement.
   
10. G8 leaders met in July 2009 in L'Aquila, Italy, and agreed to work together towards the goal of achieving a 50 percent reduction of global emissions by 2050. This goal is consistent with the scientific view that the global average temperature should not exceed two degrees Celcius above pre-industrial levels.