Perilous
Times and Climate Change
Global warming not slowing down
by Staff Writers
Washington DC (SPX) Dec 08, 2011
As global temperatures are constantly being measured by several
different scientific teams, each adopting different methods for
dealing with their data, it is clear that no single record is free
of complications, uncertainties and corrections.
Researchers have added further clarity to the global climate
trend, proving that global warming is showing no signs of slowing
down and that further increases are to be expected in the next few
decades.
They revealed the true global warming trend by bringing together
and analysing the five leading global temperature data sets,
covering the period from 1979 to 2010, and factoring out three of
the main factors that account for short-term fluctuations in
global temperature: El Nino, volcanic eruptions and variations in
the Sun's brightness.
After removing these known short-term fluctuations, the
researchers, statisticians and climate experts from Tempo
Analytics and the Potsdam Institute for Climate Impact Research,
showed that the global temperature has increased by 0.5C in the
past 30 years. In all of the five global data sets, 2009 and 2010
were the two hottest years. In the average over all five data
sets, 2010 is the hottest year on record.
Their study, published in IOP Publishing's journal Environmental
Research Letters, comes at a time when global warming is at the
forefront of the political agenda, with the United Nations
Framework Convention on Climate Change (UNFCCC) currently taking
place in Durban.
It is well known that temperatures have been rising since the
early 20th Century and the effects have become visible in
shrinking mountain glaciers, accelerating ice loss and sea level
rise. In recent years, however, there have been claims by some
that the global warming trend has slowed or even paused over the
last decade or so.
"Our approach shows that the idea that the global warming trend
has slowed or even paused over the last decade or so is a
groundless misconception. It shows that differences between the
five data sets reside, to a large extent, in their short-term
variability and not in the climatic trend. After the variability
is removed, all five data sets are very similar," said study
co-author Stefan Rahmstorf.
As global temperatures are constantly being measured by several
different scientific teams, each adopting different methods for
dealing with their data, it is clear that no single record is free
of complications, uncertainties and corrections.
By bringing together and analysing the five records - three
surface records and two lower-troposphere records - the
researchers were able to clarify the discrepancies between each
one and, when factoring out the naturally occurring variability,
show the excellent agreement between all five data sets.
The three surface temperature data sets analysed by the
researchers were from NASA, the National Oceanic and Atmospheric
Administration (NOAA) and the Hadley Centre/Climate Research Unit
in the UK. Data representing the lower troposphere temperatures
was based on satellite microwave sensors.
El Nino is a naturally and irregularly occurring warming of
surface ocean waters in the eastern tropical Pacific, whilst solar
variation is the change in the amount of radiation emitted by the
sun, dominated by an approximately 11-year-long cycle. Volcanic
eruptions predominantly have a cooling effect lasting a few years,
due to the very tiny erupted particles and droplets shielding
light from hitting the earth.
"The unabated warming is powerful evidence that we can expect
further temperature increase in the next few decades, emphasizing
the urgency of confronting the human influence on the climate,"
says Grant Foster, lead author of the study.