GLOBAL temperatures are on the increase, with a new study showing a rise of about half a degree celsius over the past 160 years.
An Australian National University (ANU) report on global temperature found a trend towards a rise in worldwide temperatures since 1850, with a steeper increase since the mid 1970s.
Professor Trevor Breusch, of the Crawford School of Economics and Government at ANU, studied three series of recorded global temperature data to look for clear evidence of a trend in global temperatures.
His original study was prepared for the Garnaut Review in 2008 – an independent study commissioned by the government on the impact of climate change on the Australian economy – and has since been updated with the latest data.
“There is sufficient evidence in the long run of temperature records to support the existence of a warming trend,” Prof Breusch said today. “From the 1850s to today it’s somewhere over half a degree (celsius) a century.
“The additional three years for which temperature data are now available were among the warmest on record.”
Prof Breusch said around the mid 1970s there had been an increase in the warming trend.
“There is no evidence of a weakening or reversing trend in more recent years, as suggested by some commentators,” he said.
Prof Breusch’s study did not explore the cause of the trend in temperature rises. (AAP)
Some of the statements about trends are worrisome - although there appears to have been a step change with the new millennium there doesn’t really seem to be a recent trend with current lower tropospheric temperatures having returned to the 30-year average:
We can show a surface temperature amalgam with a rising trend but can’t support the cited “increase in the warming trend” because it is the same as the trend earlier in the 20th century.
As far as the mid-troposphere is concerned, where the really big warming should theoretically take place under enhanced greenhouse – that’s basically nothing with some ENSO blips: