data sets for global temperature indicate a clear and consistent
increase in global temperatures, particularly since the industrial
revolution in western countries.
Large variations, resulting from events such as volcanic eruptions,
can make the short term trend in global temperature change difficult
to establish, but the long term data sets available allow the
bigger picture to be seen.
Much of the argument surrounding climate change hinges not on
whether global warming is occurring, but rather whether this warming
is a result of human activity. Natural causes, such as sun-spot
activity, have been invoked by some to explain the accelerated
rate of global warming in recent decades.
In recent years though, even those previously sceptical of human-induced
global warming have largely recognised the important role our
greenhouse gas emissions are playing in climate change.
Figures courtesy of the Intergovernmental
Panel on Climate Change (IPCC). Click figures to enlarge.
As concentrations of the main greenhouse gases have risen in
our atmosphere, global temperatures have increased at a similar
rate. See the Human Influence
page for data sets on carbon dioxide, methane and nitrous oxide.
As this site is devoted to greenhouse gases I will not here extensively
cover the subject of global warming. There are several excellent
websites, see the links page, where
the various data and arguments can be seen and assessed.
My only recommendation is that readers look at several sites
before they form a final opinion on the importance and causes
of global warming. For myself, it is one of the greatest threats
humankind is likely to face in the 21st century.