Click Here for the HTML Version of This Page
David Phillips, senior climatologist, Environment Canada
Human induced global warming will not produce a uniform temperature rise everywhere - instead, it will force a fundamental change in the way the world's weather works.
One of the expected features of climate change is an increase in extreme weather events. Both computer models and recent observations agree that they are already on the rise, and promise to get worse.
Generating Weather
The earth's weather machine is like an engine, driven by heat, which moves energy around the planet. In general, hot air and water masses from the tropics migrate toward the poles, bringing warmth to higher latitudes and generating weather as they move. Cold air and ocean currents flow back toward the equator, completing the cycle.
Global warming is feeding more energy into the weather machine. Energetic air masses move more quickly and mix more violently, generating larger storms and stronger winds. Altered circulation patterns would shift major storm tracks, exposing previously sheltered regions to storm damage.
When It Rains It Pours
A larger energy input also cranks up the hydrological cycle - the natural process of evaporation and precipitation - generally meaning that dry places will become dryer, and wet places will become wetter.
In short, weather will shift from its historically moderate patterns towards what we have previously known as extremes.
In Canada, this will probably include the southern parts of Alberta, Saskatchewan, Manitoba and Ontario becoming more prone to drought and dust-bowl type conditions, while the west coast will receive even more precipitation, often in sudden downpours.
Still, simply knowing that weather patterns are changing does not mean that we can predict the new patterns in detail. There are many complex elements at work in generating weather, the most publicized of which is El Niño.
For more information, download Weather Extremes in a Changing Climate (Acrobat Reader required.)