According to the National Oceanic and Atmospheric Administration (NOAA), July 2009 was the hottest month on record for the average global ocean surface temperature. The previous record was broken in 1998. When combined with global land surface temperatures, July 2009 was the fifth warmest month since data collection began in 1880.
The New York Times describes NOAA’s briefing:
The agency said the average sea surface temperature was 1.06 degrees higher than the 20th-century average of 61.5 degrees. Though July was unusually cool in some areas, like the eastern United States, analysts at the NOAA Climate Data Center said the combined global land and ocean surface temperature was 1.03 degrees higher than the 20th-century average of 60.4 degrees, the fifth warmest since worldwide record keeping began in 1880.
Specifically, NOAA reports the “Notable Developments and Events” responsible for the increased warming:
- El NiÃ±o persisted across the equatorial Pacific Ocean during July 2009. Related sea-surface temperature (SST) anomalies increased for the sixth consecutive month.
- Arctic sea ice covered an average of 3.4 million square miles during July. This is 12.7 percent below the 1979-2000 average extent and the third lowest July sea ice extent on record, behind 2007 and 2006. Antarctic sea ice extent in July was 1.5 percent above the 1979-2000 average. July Arctic sea ice extent has decreased by 6.1 percent per decade since 1979, while July Antarctic sea ice extent has increased by 0.8 percent per decade over the same period.
- Cooler-than-average conditions prevailed across southern South America, central Canada, the eastern United States, and parts of western and eastern Asia. The most notably cool conditions occurred across the eastern U.S., central Canada, and southern South America where region-wide temperatures were nearly 4-7 degrees F (2-4 degrees C) below average.
- Large portions of many continents had substantially warmer-than-average temperatures during July 2009. The greatest departures from the long-term average were evident in Europe, northern Africa, and much of western North America. Broadly, across these regions, temperatures were about 4-7 degrees F (2-4 degrees C) above average.
Some scientists suspect a link between global warming and El NiÃ±o. Kevin Trenberth, a National Center for Atmospheric Research climatologist, believes that during periods of global warming, the “ocean currents and weather systems might not be able to bleed off all the heat pumped into the tropical seas.” Under such a scenario, El NiÃ±o acts as a “pressure release valve” for this excess heat.
All of the “Notable Developments and Events” could all be attributed to climate change.