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Environment Canada defines climate change as “…a long-term shift in average weather conditions over time, including temperature, precipitation, winds, and other indicators. The impacts of climate change are far-reaching, affecting our infrastructure, weather patterns, wildlife and landscapes.” The issue of climate change is a very complicated one and it is very difficult to predict the future intensity or consequences of climate change due to the fact that it involves the complex interactions of a variety of positive and negative feedback cycles. The greenhouse effect is usually considered the main agent of climate change and global warming. Environment Canada describes this problem in the following passage:

“The earth's atmosphere acts somewhat like the glass of a greenhouse. About 31% of the incoming radiation from the sun is reflected directly back to space by the earth's atmosphere and surface (particularly by snow and ice), and another 20% is absorbed by the atmosphere. The rest of the incoming radiation is absorbed by the earth's oceans and land, where it is converted into heat, warming the surface of the earth and the air above it. Particular gases in the atmosphere act like the glass of a greenhouse, preventing the heat from escaping.These greenhouse gases (GHGs) absorb heat and radiate some of it back to the earth's surface, causing surface temperatures to be higher than they would otherwise be. The most important naturally occurring GHG is water vapour and it is the largest contributor to the natural greenhouse effect. However, other gases, although they occur in much smaller quantities, also play a substantial and growing role in the greenhouse effect. These include carbon dioxide, methane, and nitrous oxide.”

It is important to note that the greenhouse effect occurs naturally on Earth, and that some degree of a greenhouse effect is necessary to produce the temperate climates ideal for sustaining life that we experience now. However, human actions (known as anthropogenic processes) since the industrial revolution have contributed a large amount of greenhouse gases to the atmosphere which now threatens to change Earth’s climate at a much quicker rate than would otherwise occur. These anthropogenic greenhouse gases include carbon dioxide, CFCs, methane, nitrous oxides, and ozone. According the TIG climate change guide to action : “The world is warming incredibly fast. Global temperatures have risen by 0.76˚C since 1850, with the rate of warming for the past 50 years double that for the past century. Eleven of the past twelve years rank among the twelve warmest years since records began in 1850.

There are three main dangers that climate change presents, which are; changes in climate patterns, changes in sea levels, and changes in the biosphere. A change in climate patterns refers to changes in average temperature, changes in the hydrologic cycle, and changes in the frequency and intensity of storms or other extreme weather events. This means changes in the frequency and intensity of floods, droughts, water levels, and other extreme weather events. This can lead to extremely serious problems that will affect the global population, if changes in the hydrologic cycle interfere with levels of food production. Today, 80 million people are malnourished; and as population increases, so will demand for food.”

Changes in sea level are also a great cause for concern, as this will cause the flooding of many coastal regions and islands where a large proportion of the world’s population lives. Also, it is these areas of the world that are experiencing the highest rate of population growth. Finally, changes in the biosphere are also a great cause for concern. As climates quickly change, many species which take longer periods of time to adapt to new conditions, such as many species of trees, will be unable to either adapt or migrate quick enough to survive in the new climate and will eventually face extinction. This will cause an even greater loss in biodiversity. Also, many pests or disease carrying species, such as mosquitoes carrying malaria or dengue, will have far greater areas of which will now support them.

The good news is that if we act now, we can still make a difference is limiting the various impacts that climate change will have upon the Earth. For more information, a wealth of information can be found in the TIG climate change guide to action that not only explains the issue of climate change, but also provides a framework for how you can start making a difference.