Contact: Karolin Eichler (WMO/OBS/WIS/DMA)
Features of the decade – temperature
The decade 2001-2010 was characterized by a record in global temperature increase since sufficiently comprehensive global surface temperature measurement began in 1850
For global land-surface air temperatures as well as for ocean-surface temperatures this decade was the warmest on record
This trend is confirmed at national level where 96% of the countries had their warmest decade in 2001 to 2010 and 4% in 1991 to 2000
The rate of temperature increase was particularly high in the northern hemisphere
Features of the decade – extreme events
Flooding was reported by a great majority of countries as the most frequent extreme event during the last decade followed by droughts, heat waves, heavy rainfalls and severe storms.
Consistent with the conclusions of the recent IPCC Special Report on Extremes, fewer minimum temperature records and more maximum temperature records were broken during 2001 –2010 than in earlier decades.
The decade saw two unprecedented heat waves in Western Europe in 2003 and Russia in 2010 with many associated fatalities and other severe health impacts.
The decade also saw the most costly Atlantic hurricane, Katrina, in 2005, and major flooding in Pakistan in 2010 with more than twenty million people affected. Many other extremes were also experienced elsewhere in the world.
Features of the decade – GHG and sea ice decline
Increases of the atmospheric content of greenhouse gases due to anthropogenic activities are recognized by IPCC as the key driving factors of the observed climate change.
CO2 mixing ratio continued to increase through the decade, with a rate higher than in the previous decade, reaching 389 ppm by the end of the decade. This value is the highest recorded for at least 10000 years and it is 39% higher than the mixing ratio at the beginning of the industrial era (1750).
The dramatic and continuing sea ice decline in the Arctic is one of the most prominent features of the changing state of the climate during the decade with the five lowest minimum sea ice extents at the end of the melting season all recorded in the second half of the decade with the record set in 2007.