What is Climate Change?
Climate Trends
An analysis of temperature records shows that the Earth has warmed
an average of 0.6°C over the past 100 years. There appears to
have been a warming until the early 1940's then a moderate cooling
until the mid 1970's, followed by a renewed and pronounced warming
continuing through the present. The 1990's was the warmest decade
on record. (In fact, ice core and other proxy data indicates that
the 1980's and 1990's were the warmest decades of the past millennium).
Night-time temperatures over land have generally increased more
than daytime temperatures. Regional changes are also evident. For
example, recent warming has been greatest over the mid-latitude
continents in winter and spring, with a few areas of cooling such
as the North Atlantic Ocean. Precipitation has increased over land
in high latitudes of the Northern Hemisphere, especially during
the cold season.
![Global Temperature Change](/web/20060212015613im_/https://www.ec.gc.ca/climate/images/pics/pic16.gif)
This is consistent with predictions of climate change due to an enhanced greenhouse effect and increased aerosols. Yet, it could also be within acceptable limits for natural temperature variation.
Canada has warmed by 1.0°C over the last century. However this warming
has not been consistent throughout the entire time span. The 1980's
and 1990's were undisputedly the warmest decades on record in Canada.
The warming that has been observed in Canada over the past century
is real and significant though its intensity has varied from decade
to decade, from region to region, and from season to season.
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