3 December 2014

2014 Poised To Take Title as Hottest Year On Record

Posted by Dan Satterfield

From WMO.

From WMO.

It is almost certain now that 2014 will be among the hottest years on record globally. The NASA (and NOAA), numbers are showing that it will likely be the absolute hottest, but it does depend on December temperatures. It would have to be an unusually cool December globally for a record to not be reached, and that is very unlikely based on how how warm the oceans are right now. Let’s put it this way, betting we will break the record would be safe money.

The WMO has released a very informative statement about the climate of 2014 and it is available here.

Some highlights from the statement are below:

Highlights from the WMO Statement:

Land surface temperatures

Average surface air temperatures over land for January to October 2014 were about 0.86°C above the 1961-1990 average, the fourth or fifth warmest for the same period on record.

Western North America, Europe, eastern Eurasia, much of Africa, large areas of South America and southern and western Australia were especially warm. Cooler-than-average conditions for the year-to-date were recorded across large areas of the United States and Canada and parts of central Russia.

Heatwaves occurred in South Africa, Australia and Argentina in January. Australia saw another prolonged warm spell in May. Record heat affected northern Argentina, Paraguay, Bolivia and southern Brazil in October.  Notable cold waves were reported in the U.S. during the winter, Australia in August and in Russia in October.


Ocean heat

From the WMO Report.

From the WMO Report.

Global sea-surface temperatures were the highest on record, at about 0.45°C above the 1961-1990 average.

Sea surface temperatures in the eastern tropical Pacific approached El Niño thresholds. They were also unusually high in the western tropical Pacific Ocean, across the north and north-east Pacific as well as the polar and subtropical North Atlantic, southwest Pacific, parts of the South Atlantic and in much of the Indian Ocean. Temperatures were particularly high in the Northern Hemisphere from June to October for reasons which are subject to intense scientific investigation.

Ocean heat content for January to June was estimated down to depths of 700m and 2000m and both were the highest recorded.

Around 93% of the excess energy trapped in the atmosphere by greenhouse gases from fossil fuels and other human activities ends up in the oceans. Therefore, the heat content of the oceans is key to understanding the climate system.


Sea level and sea ice

As the oceans warm, their volume increases through thermal expansion. Water from the melting of ice sheets and glaciers also contributes to sea level rise. Local variations in sea level are affected by currents, tides, storms and large-scale climate patterns like El Niño. In early 2014, global-average measured sea-level reached a record high for the time of year.

Arctic sea-ice extent reached its annual minimum extent of 5.02 million km2 on 17 September and was the sixth lowest on record, according to the National Snow and Ice Data Center.

Antarctic daily sea ice reached a maximum daily extent of 20.11 million km2 on 22 September, setting a new record for the third consecutive year. The changes in the atmospheric circulation observed in the past three decades, which resulted in changes in the prevailing winds around Antarctica, are considered by scientists as factors related to this increase. However, it is possible that this increase is due to a combination of factors that also include effects of changing ocean circulation.