Enjoying the mild weather? Of course you are. March came in like a lamb and exited the same way, a suitable way to cap what was a very easy winter. April, with a few exceptions, has provided more of the same.
We’ve had some unseasonably warm days. Nothing to complain about, but somewhat troubling for those keeping an eye on the climate change file. We’re not to confuse today’s weather with the big picture of climate, but every anomaly adds to the evidence.
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.
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.
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.
Extreme weather events would have consequences for the 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.
Something to keep in mind as we enjoy the nice days while they’re here.