Over the millennia earth has been subject to variable climate change
indépendant of the actions of mankind.There have been at least 5 distinct ice
ages in the past 650,000 years.These changes are due to a number of factors
including the tilt of earth orbit,warming and cooling of the oceans,volcanic
activity and variability of energy output by the sun.It is possible to chart
these changes through the examination of ice cores from the Greenland and
Antarctic ice caps.In support of those who believe the changes we are seeing
are due to natural causes we are at a point in the epoch where we are emerging
from the most recent ice age and there is a natural warming trend.
Having said that these natural trends are measured in tens of thousands of
years.Our current
accelerated warming trend has occurred in the last 250 years ,a mere thane
blink of an eye in time.It coïncides with the industrial revolution and the
burning of fossil fuels and explosive population growth.
Earths temperature has increased 5 degrees since the latest ice age more than
10,000 years ago which averages out to .05 degrees every 100 years.Over the
last 100 years the mean temperature of earth has increased 1.4 degrees.The
world is heating up exponentially faster than ever before.That is an undeniable
fact.Of course the warming is not a constant throughout the globe.Some areas
may be cooler than in the previous years.It is the planet as a whole that is
warming at a far greater rate than ever seen in the determinable record.
The reason is the increase in the so called greenhouse gases.The chief of these
is carbon dioxide but also include other gases such as methane and nitrous
oxide.They are called greenhouse gases because of particular qualities.They
transmit light but absorb and radiate infra red light.The world would be
uninhabitable if we did not have greenhouse gases because of their role in
warming the planet.
By the examination of air bubbles cast in ice cores scientists have determined
over the course of discernable history thé concentration of carbon dioxide in
the atmosphere has varied from 180 to 300 parts per million .Modern levels are
at more than 400 parts per million and increasing rapidly.There is no question
for the most part these emissions come from the burning of fossil
fuels.Scientist are able to differentiate fossil fuel carbon dioxide from
naturally occurring carbon dioxide.Other greenhouse gases such as methane and
nitrous oxide which have an even greater warming effect are also
increasing.Methane comes from rotting garbage and belching cows and nitrous
oxide from the use of nitrogen fertilizers.
The evidence is overwhelming and is found in the rapidity of these events far
exceeding any natural discernable natural occurrences.There are charts and
scientific literature than explains it far better than I can but here are the
bare bones of the argument.As I have said this is an accepted conclusion from
the vast majority of climate scientists.There may be the odd outlier but I have
never seen one with any credibility.The earth has been able to adapt to changes
over the millennia but can it adapt to dramatic change over centuries? We
humans are ingenious creatures and perhaps we will adapt ….or perhaps not.Bryan
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