The State of the Climate in 2006 report summarizes the year's weather and climate conditions, both globally and regionally. In addition, the year is placed into a long-term climatological context. Furthermore, notable events are also discussed.
Overall global temperatures were fifth or sixth warmest on record, depending on the dataset, continuing an upward trend in temperatures. Many countries and regions experienced their record warmest year (or tied for warmest), including Spain, the Netherlands, the United Kingdom, and China, as well as parts of Australia and Canada. In many regions, the warmth in 2006 is statistically indistinguishable from the record warmth in 1998. However, 1998 was influenced by the unprecedented warming associated with the record 1997/98 El Niño, whereas 2006 was marked by a 2005/06 La Niña that transitioned into a weak-to-moderate 2006/07 El Niño.
Consistent with the warming, sea ice extent in both polar regions reached record or near-record minima. In addition, Antarctic ozone concentrations reached an all-time minimum. Also, carbon dioxide measurements increased in the atmosphere by 2.3 parts per million (ppm) in 2006 to reach a global average of 381.1 ppm.
In the global oceans, sea levels were above average for ∼80% of the ocean. The global mean sea level anomaly change of +6 mm from 2005 was the highest increase since the altimeter record began in 1993. Relative sea level change was also the highest ever recorded. Significant heat flux and current anomalies were observed in the regions of the 2006 El Niño and Indian Ocean dipole mode event.
Despite the warmth around the globe, tropical cyclone counts were near average. However, Tropical Cyclone Larry made landfall in northern Australia as one of the most intense storms in decades. Following the record Atlantic hurricane season of 2005, the 2006 season was very quiet.