Storm clouds gathering on the horizon

With climate change comes more extreme weather, say the experts. The windstorm that tore through a good chunk of Ontario last weekend certainly fits the bill.

That’s not to say the wind and intense rain we saw is definitive proof – it’s just one more example. We’re not to confuse today’s weather with the big picture of climate.

Still, as climatologist Dave Phillips notes in this week’s issue, what we saw could be a harbinger of things to come, with unsettled weather making for an interesting spring and summer.

If climate models are on target, we can expect more extreme weather days ahead, even putting aside the human contribution to global warming/climate change.

For Ontario, results from some of the latest simulations of climate, with an atmosphere containing twice the current amount of greenhouse gases, suggest an average annual warming of some 2° to 5°C by the latter part of the 21st century. Even if greenhouse gas amounts stabilize at that point, temperatures would continue to increase thereafter, with overall warming of 3° to 8°C possible. Increases will probably be greater in the winter than in the summer, according to Environment Canada.

These changes would significantly decrease the duration of the annual snow season and lengthen the growing season. They could increase the frequency and severity of extreme heat events in summer.

If the models hold, we can expect more than just rising temperatures. Greater impacts could include changes in precipitation patterns, in soil moisture, and possibly in the frequency and intensity of severe weather events.
Changes in weather patterns may affect the frequency and intensity of pollution episodes.

Increased heat stress, and possible increases in the number or severity of episodes of poor air quality and extreme weather events could all have a negative effect on human health. A warmer climate may facilitate migration of disease-carrying organisms from other regions.

Average water levels of the Great Lakes could decline to record low levels during the latter part of the 21st century. Water supply from both surface and groundwater sources is expected to decrease in southern Ontario. In landlocked Waterloo Region – where a pipeline to the Great Lakes has long been discussed – action may have to come sooner.

More extreme weather events would have consequences for the property insurance industry and possibly for disaster-relief agencies. Changes in human health could affect the health and life insurance and pension industries.

Changes in the hydrologic cycle may result in more variability in water supply for hydroelectric power production.

Additional damage to forest ecosystems by pests and diseases, and increased frequency and intensity of fires may occur.  Species currently threatened with extinction face the greatest risk of extinction in a changing climate.

Ontario falls prey to a number of natural hazards: drought, heat waves, floods, rain, snow and ice storms, tornadoes, and even hurricanes, although they’re rare. Small changes in average climate conditions are expected to generate significant changes in extreme events.

Experts anticipate fewer extremely cold days and more extremely hot days and  more severe thunderstorms, which can cause injury and property damage.

If those predictions come to pass, and it seems increasingly likely that will be the case, we can expect a rougher ride ahead.