Why Winters in North America are crazy despite Global Warming

pexels-photo-1004665.jpegWith thousands of tons of carbon dioxide and other greenhouse gases being pumped into our environment every day, global temperature is increasing faster (between 20C to 50C per century) than predicted by scientists. Yet we are faced with bone-chilling winters in the North America, pointing to an upside down situation. There have been extremely cold (– 630 C in Yukon ) and long-stretched winters in Canada during 2014 (in Winnipeg, in particular) and 2017 (especially in BC and New Brunswick with heavy (155 cm against a maximum of 100 cm in the past) and high frequency snowfall (50 cm in 15 seconds) in Ottawa in 2016. Accumulation of solid ice on ground makes roads dangerously slippery and is the major cause of accidents for several months.

In addition to dislocation of road and train transportation; aviation, industries and agriculture sectors get thrown out of gear and all types of flora and fauna are very adversely affected. Living mostly indoors leads to diseases like influenza and depression.  This happened in many parts of Canada in the past and during 2018 also. In most such cases, the usual winter from December (winter solstice, the shortest day) to February (vernal equinox, day and night of equal length)  extends to a wider span covering November to April period, with temperatures in the teeth-chattering range of – 450 C to – 550 C. Add to this the windchill which makes the winter bitterly cold and intolerable. Wind-chill results from the combined effect of cold winds and low temperatures. It indicates the rate of heat loss from the exposed parts of the body.

Such abnormal, often bewildering, phenomena are sometimes observed during winters generally in the northern hemisphere. In the southern hemisphere winters occur during June, July and August when the  south pole of the earth is tilted away from the sun, while the northern hemisphere has summer during this (June to August) period due to tilt of the north pole of the earth towards the sun. The distance of the earth from the sun varies with the tilt of the earth‘s axis of rotation, which is responsible for the seasonal variations observed in temperatures. Winters in the southern hemisphere are milder as there is less of land and more of water, giving rise to a moderate maritime climate.

Scientists believe that such prolonged and severe winters cannot be treated as isolated and freakish weather (like the unpredictable mood of a crazy person) but constitute a definite climatic transition (similar to the change in one’s personality due to environmental influences). In the absence of global warming, the frigid Arctic air flows from west to east and remains confined mostly to the north-polar region. The strong polar vortex keeps this super-cooled air hemmed-in.  Also, it may percolate slightly up north or down south. Today, thanks to the increasing global warming, hundreds of thousands of tons of heated glaciers, extending over several square miles and as high as the Empire State Building (nearly 1250 feet), are disappearing before our eyes. Almost half of the Arctic sea ice has been lost in the last 30 years. Huge icebergs are eroding in the warming waters of the North Atlantic. These shrinking temperature differences provide the channels for the unusual meandering of the cold jet-streams from the polar region to lower latitudes. Also, waters from over-heated oceans, lakes and rivers are now evaporating at a scale much larger than ever before. These enormous vapors in the Arctic regions condense into much greater amounts of clouds, rain and snow that move swiftly down toward the south and bring intense and long winters in Canada (which extends over large latitudes) and the north of America.

The rise in surface temperature, particularly near the equatorial latitudes, in the Pacific oceans due to short-lived and irregular phenomena, called ElNino, make the air on the west coasts of Canada and Northern America warmer while the cold polar air sweeping towards the east makes their eastern coasts cooler. This imbalance in east-west temperatures and the reducing north-south temperature difference (due to global warming) add up to produce intense bursts of cold air moving in the south-east direction and the consequent heavy snowfall over these regions (in the northern hemisphere). However, low surface water temperatures due to LaNina, in the central Pacific region complicate this unstable scenario further as winters become warmer than normal in the Southeast and cooler than normal in the Northwest.



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