The heat is on!

The heat is on!

15.01.2013 - Posted by David Barratt

Preliminary data released by the World Meteorological Organization estimated the global mean temperature for 2012 (January–September) to be 0.43 ±0.11 °C above the 1961–1990 annual average of 14.0 °C. Based on these preliminary figures, 2012 ranks as the ninth-highest on record. In no year since 1985 has the global mean temperature been below average, and the years between 1997 and the present have been the 14 warmest on record. The 10-year global average for 2003–2012 was 0.45 °C above average, making it the third-warmest 10-year period since 1880.

South east Australian landscape (from the 2008 BoM calendar, photo: Ralph Whitten)

According to NASA's Goddard Institute for Space Studies in Manhattan, the Earth has warmed about 1.44 degrees Fahrenheit during the last 40 years. But the poles are warming even faster; the Arctic has warmed by more than 3.5 degrees Fahrenheit during the same time period due to changes in clouds, water vapour, surface albedo, atmospheric temperature and energy transport.

While obviously a lot of uncertainty remains, two significant consequences of global warming for southern Australian landscapes are more extreme flood events, particularly in summer, and longer and more extreme dry periods. All communities, and rural communities in particular will need  strategies and actions that better mitigate flood events and increase dry season base flow.

POAMA Equatorial Pacific Ocean Sea Surface Temperature forecast from the Australian Bureau of Meteorology

As for the coming year, for Australia at least, sea surface temperatures in the Equatorial Pacific are currently predicted to remain ‘neutral’ for much of the year (less than a ±0.8°C anomaly), so rainfall is unlikely to be particularly remarkable one way or the other. Having said that, on the temperature side, in the absence of the sudden appearance of an unexpected La Nina, I’m happy to bet it’ll be another warm year…