NOAA Joins NASA in Declaring that July 2010 was Warmest on Record for Northern Hemisphere

The National Oceanic and Atmospheric Administration (NOAA) has released climate data for July 2010 confirming what NASA data separately found last week: it was the warmest July on record for the Northern Hemisphere. 

Global Surface Temperature Anomalies, July 2010

In Northern Hemisphere Temperature Shatters July Record (11 Aug 2010) we reported on NASA data showing that the average surface temperature in July 2010 in the Northern Hemisphere shattered the previous record set in 2005.  Globally, both NOAA and NASA reported that the year to date was the warmest on record (i.e. since the late 19th century). 

NOAA lists the following global highlights for July:

  • "The combined global land and ocean average surface temperature for July 2010 was the second warmest on record, behind 1998, at 16.5°C (61.6F), which is 0.66°C (1.19°F) above the 20th century average of 15.8°C (60.4°F).
  • The July worldwide land surface temperature was 1.03°C (1.85°F) above the 20th century average of 14.3°C (57.8°F)—the warmest July on record.
  • The worldwide ocean surface temperature was 0.54°C (0.97°F) above the 20th century average of 16.4°C (61.5°F) and the fifth warmest July on record. The warmth was most pronounced in the Atlantic Ocean.
  • La Niña conditions developed during July 2010, as sea surface temperatures (SST) continued to drop across the central and eastern equatorial Pacific Ocean. According to NOAA's Climate Prediction Center, La Niña is expected to strengthen and last through the Northern Hemisphere winter 2010-2011.
  • For the year-to-date, the global combined land and ocean surface temperature of 14.5°C (58.1°F) was the warmest January-July period on record. This value is 0.68°C (1.22°F) above the 20th century average. "

In the video below, climate change expert Heidi Cullen of Climate Central discusses the latest data.

Severe Weather of Summer 2010 from Climate Central on Vimeo.

July Anomaly Rank
(out of 131 years)
Warmest/Next Warmest
Year on Record
Land +1.03°C
1st warmest 1998 (+1.02°C/1.84°F)
Ocean +0.54°C
5th warmest 2009 (+0.58°C/1.04°F)
Land and Ocean +0.66°C
2nd warmest 1998 (+0.70°C/1.26°F)
Northern Hemisphere
Land +1.18°C
1st warmest 1998 (+1.04°C/1.87°F)
Ocean +0.61°C
3rd warmest 2009 (+0.64°C/1.15°F)
Land and Ocean +0.82°C
1st warmest 2005 (+0.74°C/1.33°F)
Southern Hemisphere
Land +0.63°C
6th warmest 1998 (+0.96°C/1.73°F)
Ocean +0.49°C
5th warmest 1998 (+0.60°C/1.08°F)
Land and Ocean +0.51°C
7th warmest 1998 (+0.66°C/1.19°F)

As the figure below indicates, surface temperatures for the globe and for the two hemispheres individually are increasing over the long term.  The long-term increase is being driven primarily by growing concentrations of greenhouse gases in the atmosphere. 

July Land & Ocean Surface Mean Temperature Anomalies, 1880-2010

Online Resources:

State of the Climate Global Analysis > July 2010.  From NOAA.  Last Updated Monday, 16-Aug-2010.

WWF Climate Blog:


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