Wednesday, January 8, 2014

2013 temperatures for Australia were off the charts claims Climate Council

The Climate Council has released it's latest report written by Professor Will Steffen: Off the Charts: 2013 was Australia's hottest year.

It draws heavily on the detail in the Bureau of Meteorology Annual Climate Statement for 2013 which I reported on, but also puts the information in context with the global trend and other scientific papers and reviews such as the IPCC Fifth Assessment Report, IPCC Working Group 1: the Physcical Science released in late September 2013.

If follows the Climate Council's first major report published at the end of 2013 on by Professor Lesley Hughes: Be Prepared: Climate Change and the Australian Bushfire Threat.

In this latest report the heat records set over the year are explained in detail, with the major ones featured on an infographic (see below). For land temperatures, "the area-averaged mean temperature for the continent for 2013 was 1.20°C above the 1961-1990 average. The mean maximum temperature during the year was 1.45°C above average, while the annual mean for minimum temperatures was 0.94°C above average."

The report also highlights that sea surface temperatures are also tracking "about 0.51°C above the long-term average. Over the past century, SSTs for the seas surrounding Australia have risen by about 1°C, similar to the increase recorded over land." Read more on sea surface temperatures trend around Australia.

Higher temperatures and heatwaves also pose health risks for the human population with heat stress and heat related mortality. Ecosystems and animals are also affected like the mass death of flying foxes in the recent Queensland heatwave.

Much of our weather is influenced by the El Niño Southern oscillation (ENSO). The record temperatures set in 2013 were even more astounding given that ENSO conditions have been in a neutral phase. El Niño years are usually when we have our hottest years.Recent research is showing that El Niño Southern Oscillation activity and intensity increasing with Global Warming. El Niño is likely to become more intense with climate change, and produce drier conditions for Australia and the Western Pacific, with increases in rainfall in the central and eastern equatorial Pacific in the mid to late twenty first century.

The report makes clear the extreme heat is a direct response to increasing greenhouse gas emissions, and that "this requires urgent, persistent and deep reductions in greenhouse
gas emissions over the coming decades, here in Australia and around the world."

"It is very likely that human-driven climate change has contributed to warmer and/or more frequent hot days and nights over most land areas around the world since 1950, and has likely contributed to increases in the frequency and/or duration of heatwaves in many regions, including Australia (IPCC 2012; 2013).

For Australia, the annual number of record hot days has doubled since 1950 (CSIRO and BoM 2012). In fact, in the last decade, the frequency of record hot days has been more than three times greater than the frequency of record cold days (Trewin and Smalley 2012)."

According to Kevin Trenbeth all weather now occurring has a climate change component due to increased atmospheric heat and moisture carrying capacity. We are energising the hydrological cycle as shown by observational data.

Read the Climate Council report by Professor Will Steffen: Off the Charts: 2013 was Australia's hottest year. It is easy to read and understand.