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Global indicators of climate
change
CLIMATE CHANGE IS ALREADY HAPPENING
Our climate is changing and will continue to change in the future.
In 1996 the Inter-Governmental Panel on Climate Change (IPCC) -
representing the international scientific consensus in the climate
debate - concluded that "the balance of evidence suggests a discernible
human influence on the climate". The extreme events which have
characterised recent trends have all too often been a source of
misery for many.
UNUSUAL TIMES
During the closing decades of the 20th century record breaking
temperatures and a run of extreme weather events rang the alarm
bells. Temperatures have risen about 0.6 °C since 1860 when records
began. Six of the warmest years globally occurred during the 1990s
with 1998 being the warmest year on record. 1999 was 'only' the
fifth warmest year but is remarkable as it occurred despite the
cooling influence of La Niņa conditions in the Pacific.
The 1990s were not only the warmest decade of the century but also
that of the millennium according to analyses of proxy indicators
of climate (such as tree growth rings and geological records). 1998
is believed to have been the warmest year of the millennium and
601, the coldest year. The recent warming trend has been paralleled
by a number of other disturbing environmental trends.
The global warming trend over the last 100 years is, according to
the IPCC, "unlikely to be entirely natural in origin". Emissions
of so-called greenhouse gases are thought to be a key contributing
factor to recent climate changes. The most important of these gases
is carbon dioxide which is released when fossil fuels - coal, oil,
gas - are burnt.
The significance of fossil fuel driven climate change has been subject
to a disinformation campaign by the producers and users of the fuels.
Many industrialists and their associations struggled hard to secure
good returns on their investments by trying to convince scientists,
the public and policy makers that there is not a problem. All this
has been to little avail in the face of mounting evidence of actual
climate change. According to chief British and US Meteorologists,
the evidence "confirms that our climate is changing rapidly".
SOME DISTURBING TRENDS
Melt down: Glaciers are melting and the Arctic Sea ice has
thinned dramatically since the 1960s and 70s; nearly 40 percent
in less than 30 years. A recent NASA aerial survey indicates severe
thinning of the Greenland ice sheet.
More El Niņo events: The behaviour of the El Niņo/Southern Oscillation
has undergone a distinct change since 1976, with more El Niņos and
few La Niņas. Moreover, the 1982-1983 and 1997-1998 events were
the strongest for over 100 years, while the longest was 1990-1995.
Such behaviour is, as the IPCC remarks, "unusual in the
context of the last 120 years".
Fire, frost and disease outbreaks: In Canada, forest fires,
insects and diseases affected twice as much forest area in the 1980s
and 90s as in previous decades. In Calgary, the average frequency
of large hailstorms increased from one every four years in the 1980s
to two every year in the 1990s.
Changes in the natural world: Earlier migration and egg-laying
dates have been recorded for several bird species along with earlier
budburst and flowering of plants.
Global indicators of climate change
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