El Niņo events (which intensify warming)
and cooling La Niņas are major drivers of natural climate variability.
Neither occurred during 2013, which was warmer than 2011 or 2012, when
La Niņa exerted its cooling influence. 2013 was among the four warmest
neutral years recorded, when neither El Niņo nor La Niņa affected
“The global temperature for the year 2013
is consistent with the long-term warming trend”, said WMO
Secretary-General Michel Jarraud adding that “The rate of warming is not
uniform but the underlying trend is undeniable. Given the record amounts
of greenhouse gases in our atmosphere, global temperatures will continue
to rise for generations to come."
No warming standstill
“Our action – or inaction – to curb
emissions of carbon dioxide and other heat-trapping gases will shape the
state of our planet for our children, grandchildren and
great-grandchildren”, Mr Jarraud said.
Asked by Climate News Network how WMO
regarded claims by some critics that there has been a "global warming
standstill since 1997", Mr Jarraud said, "Which standstill? The coldest
year since 2001 is warmer than any year before 1998.
"Each decade is warmer than the previous
one. There is global variability from year to year. You have to look at
the longer period. If you do that, then the message is beyond any
doubt...Despite the fact that there was no El Niņo in 2013, it was still
the sixth warmest year. This is significant."
The WMO says surface temperature is just
part of a much wider picture of climate change. "More than 90% of the
excess heat being caused by human activities is being absorbed by the
ocean", it says.
It has released the temperature data in
advance of its full Statement on the Status of the Climate in 2013, to
be published in March. This will give more details of regional
temperatures and other indicators.
In contrast with 2012, when the US in
particular experienced record high annual temperatures, the warmth in
2013 was most extreme in Australia, which had its hottest year on
WMO's global temperature analysis is based
mainly on three independent and complementary datasets. One is
maintained by two UK centres, the Met Office Hadley Centre and the
Climatic Research Unit at the University of East Anglia. The other two
are based in the US: NOAA's National Climatic Data Center, and the
Goddard Institute for Space Studies (GISS), operated by NASA.
Each dataset uses slightly different
methods of calculation and so each gave 2013 a different temperature
ranking, but they were consistent on the year-by-year changes and the
longer warming trends globally.
WMO also uses reanalysis-based data from
the European Centre for Medium-Range Weather Forecasts (ECMWF), which
showed annual global land and ocean temperature to be the fourth highest
Source: Climate News Network