Warming Trend Continues in 2014
World Meteorological Organization (Geneva)
Press Release, 2 February 2015
14 of 15 Hottest Years Have Been in 21st Century
Geneva, 2 February 2015 (WMO) The World Meteorological Organization (WMO)
has ranked 2014 as the hottest year on record, as part of a continuing trend. After
consolidating leading international datasets, WMO noted that the difference in
temperature between the warmest years is only a few hundredths of a degree – less
than the margin of uncertainty.
Average global air temperatures over land and sea surface in 2014 were 0.57 °C
(1.03°F) above the long-term average of 14.00°C (57.2 °F) for the 1961-1990
reference period. By comparison, temperatures were 0.55 °C (1.00°F) above average
in 2010 and 0.54°C (0.98°F) above average in 2005, according to WMO
calculations. The estimated margin of uncertainty was 0.10°C (0.18°F).
“The overall warming trend is more important than the ranking of an individual year,”
said WMO Secretary-General Michel Jarraud. “Analysis of the datasets indicates that
2014 was nominally the warmest on record, although there is very little difference
between the three hottest years,” said Mr Jarraud.
“Fourteen of the fifteen hottest years have all been this century. We expect global
warming to continue, given that rising levels of greenhouse gases in the atmosphere
and the increasing heat content of the oceans are committing us to a warmer future,”
he said.
Around 93% of the excess energy trapped in the atmosphere by greenhouse gases
from fossil fuels and other human activities ends up in the oceans. Therefore, the
heat content of the oceans is key to understanding the climate system. Global seasurface temperatures reached record levels in 2014.[1]
It is notable that the high 2014 temperatures occurred in the absence of a fully
developed El Niño. El Niño occurs when warmer than average sea-surface
temperatures in the eastern tropical Pacific combine, in a self-reinforcing loop, with
atmospheric pressure systems. This has an overall warming impact on the climate.
High temperatures in 1998 – the hottest year before the 21st century – occurred
during a strong El-Niño year.
“In 2014, record-breaking heat combined with torrential rainfall and floods in many
countries and drought in some others – consistent with the expectation of a changing
climate,” said Mr Jarraud.
Strong weather and climate services are now more necessary than ever before to
increase resilience to disasters and help countries and communities adapt to a fast
changing and, in many places, less hospitable climate, said Mr Jarraud.
WMO released the global temperature analysis in advance of climate change
negotiations to be held in Geneva from 8 to 13 February. These talks will help to
pave the way for an agreement on action to be adopted by the Parties to the UN
Framework Convention on Climate Change next December in Paris.
The WMO analysis is based, amongst others, on three complementary datasets
maintained by the Hadley Centre of the UK’s Met Office and the Climatic Research
Unit, University of East Anglia, United Kingdom (combined); the U.S. National
Oceanic and Atmospheric Administration (NOAA) National Climatic Data Centre; and
the Goddard Institute of Space Studies (GISS) operated by the National Aeronautics
and Space Administration (NASA).
Global average temperatures are also estimated using reanalysis systems, which use
the most advanced weather forecasting systems to combine many sources of data to
provide a complementary analysis approaches. WMO in particular uses data from the
reanalysis produced by the European Centre for Medium-Range Weather Forecasts,
which also ranks 2014 as among the four warmest.
The final report on the Status of the Climate in 2014, with full details of regional trends and
extreme events, will be available in March 2015.
Weather, Climate and Water
For more information: Please contact Clare Nullis at +41 22 7308478 or 41 79 709 1397 or
cnullis{at)wmo.int.
The full datasets are available on request