The Earth has just experienced its warmest March, April, and May on record, according to the US National Climatic Data Center (NCDC), and 2010 is well on track to becoming the warmest year on record.
March 2010 was not only the warmest March globally, but also the third warmest month of all time. I don’t mean it was the third warmest month in terms of absolute temperature — Julys are always several degrees warmer than Januarys — but after the seasonal cycle is filtered out. To be precise, the global temperature was 0.77°C above the 20th century average of 12.7°C for March, the third highest monthly temperature anomaly after February 1998 and January 2007. (In climatology, anomalies are generally more useful than absolute temperatures.)
The global temperature for this April was not far behind, at 0.73°C above the April average of 13.7°C. Similarly, it’s both the warmest April on record and the sixth warmest month of all time. In Australia, May 2009 – April 2010 was the warmest 12-month period on record in the states of Victoria and Tasmania, and the third warmest for the continent overall.
Although this year’s El Niño has now come to an end, May 2010 was still the warmest May (and 13th warmest month), at 0.69°C above the average 14.8°C. Unusually warm temperatures were seen in eastern Europe, Siberia, eastern North America, and large parts of Africa; meanwhile, the Southern Ocean cooled.
Though not record-breakers, January and February were also relatively warm months globally. Despite cold spells in northern land areas (which unfortunately happens to be where the weather most affects public opinion), the Southern Hemisphere had its warmest February on record.
The year-to-date (January-May) has been the warmest such period on record, at 0.68°C above average. So will 2010 break the record for the warmest January-December period? It’s still too early to tell, as we’re not even halfway through the year yet. It’s worth remembering that the opening months of 2007 also saw record-breaking warmth during an El Niño, but later in the year the Earth’s surface cooled rapidly after the Pacific shifted to a La Niña phase.
The last 12 months (June-May) were the sixth warmest 12-month period on record with a mean temperature anomaly of 0.62°C. The current record is 0.64°C, held by August 1998. However, the 12-month mean should continue to climb in the coming months…
In summary, this year is breaking all the temperature records, and it might just break the biggest one of all: that of the Earth’s warmest year on record.
I’m archiving past updates on 2010 global temperatures on this page.