The indications of climate change are all around us today
but now researchers have revealed for the first time when and where the first
clear signs of global warming appeared in the temperature record and where
those signals are likely to be clearly seen in extreme rainfall events in the
The new research published in Environmental Research Letters
gives an insight into the global impacts that have already
been felt, even at this very early stage, and where those impacts are likely to
intensify in the coming years.
"We examined average and extreme temperatures because
they were always projected to be the measure that is most sensitive to global
warming," said lead author from the ARC Centre of Excellence for Climate
System Science, Dr. Andrew King.
"Remarkably our research shows that you could already
see clear signs of global warming in the tropics by the 1960s but in parts of
Australia, South East Asia and Africa it was visible as early as the
The reason the first changes in average temperature and
temperature extremes appeared in the tropics was because those regions
generally experienced a much narrower range of temperatures. This meant smaller
shifts in the temperature record due to global warming were more easily seen.
The first signal to appear in the tropics was the change in
average temperatures. Later extreme temperature events showed a global warming
Closer to the poles the emergence of climate change in the
temperature record appeared later but by the period 1980-2000 the temperature
record in most regions of the world were showing clear global warming signals.
One of the few exceptions to this clear global warming
signal was found in large parts of the continental United States, particularly
on the Eastern coast and up through the central states. These regions have yet
to manifest obvious warming signals according to the models but it is expected
they will appear in the next decade.
While temperature records generally showed pronounced
indications of global warming, heavy rainfall events have yet to make their
mark. The models showed a general increase in extreme rainfall but the global
warming signal was not strong enough yet to rise above the expected natural
"We expect the first heavy precipitation events with a
clear global warming signal will appear during winters in Russia, Canada and
northern Europe over the next 10-30 years," said co-author Dr. Ed Hawkins
from the National Centre for Atmospheric Science at the University of Reading,
"This is likely to bring pronounced precipitation
events on top of the already existing trend towards increasingly wet winters in