Messages from a sizzling continent: Salinger on the Aussie heatwave

By Gareth Renowden 20/01/2013

This op-ed by climate scientist Jim Salinger first appeared in print editions of the New Zealand Herald last Tuesday.

Global warming is not a phenomenon for future generations to deal with: it has arrived. And more frequent heat waves and climate extremes are part of this phenomenon. As I watch from my summer roost in northern New South Wales, the somewhat unprecedented heat is searing the Australian continent making it tinder dry with fires springing up everywhere. These raise some pertinent lessons on climate and risk management for New Zealand.

Firstly let’s look at some figures and ask the question of what are the climate mechanisms behind the heat waves.

Incessant heat has struck the interior with daytime highs soaring to the high forties. As I pen this on Saturday 12 January the mercury rose to 49.6ºC at Moomba, just shy of the all-time Australia record of 50.7ºC recorded at Oodnadatta in 1972. The national average maximum temperature (the average daytime maximum temperature for the entire Australian continent); which in this case is gauging the areal extent of the heat, jumped back up to 39.2ºC on Friday  — making 8 days above 39ºC this year and 11 days straight above 38ºC. The temperatures since 2 January are 39.21, 39.55, 39.31, 39.71, 40.33, 40.11, 38.36, 38.65, and 39.20ºC.

There have been locations in Australia (not the same location, somewhere over an area of thousands of square kms) that posted a temperature in excess of 47.7ºC since the 2nd of Jan. A temperature in excess of 48ºC was posted on 7 of those days. As a comparison the highest global temperature recorded is 56.7 C recorded in Death Valley, California in 1932. During that event dead birds rained out of the sky at Furnace Creek.

For New Zealand, the messages from the climate system of global warming are far more subtle. This is because we are immersed in an oceanic environment. Our clearest signal is seen in night time temperatures. Over the period 1941 – 2011 the number of days with temperatures less than 0 deg C has decreased from 11 to 4 per annum at measured North Island locations, and 35 to 23 days a year in the South Island. And the lowest night temperature in any one year has increased from -2 to -1ºC in the North Island and -4.8 to -4.3ºC in the South Island over this 70 year period.

More tellingly has been the fate of the permanent ice that makes Aotearoa ‘The land of the long white cloud’. This has shrunk dramatically from over 100 cubic kilometres (km3) clothing our Southern Alps around 1900 to 45 km3 in 2008. Allowing for the 3 deg C warming projection (Dr James Renwick, New Zealand Herald, 10 January) this ice mantle would diminish to a mere 15 km3 if its former glory!

New Zealand is now lagging well behind our Pacific neighbours in taking action to diminish carbon emissions to the atmosphere. On 1 July 2012 Australia took a very bold step and introduced a A$23-a-tonne price on carbon emissions which directly affects 294 electricity generators and other companies. The federal Government is aiming to cut carbon emissions by 5 per cent by 2020, with the carbon tax shifting to an emissions trading scheme in 2015.

And on 24 November 2012 California issued the USA’s first broad-based cap-and-trade blueprint to reduce greenhouse emissions. The pioneering effort caps greenhouse gases emitted by more than 600 power plants, refineries, cement plants and other big factories at 15 percent below today’s levels by 2020. And although the Obama administration may not be able to ratify Kyoto through Congress, carbon dioxide has now been ruled a pollutant by the U.S Supreme Court. As such carbon dioxide emissions can be regulated by executive order of the president.

The current National Government has been rapidly back pedalling from the robust emissions trading scheme (ETS) introduced by the former government. It has progressively gutted the ETS to what Herald columnist Brian Farrow described as an already pretty aqueous ETS. It has also opted out of the 2nd Kyoto Protocol period committing to legally binding emissions reduction target until 2020. This earned New Zealand several “Fossil of the Day” awards at the international climate talks in Doha, Qatar, December 2012.

The climate system is now speaking louder. Global warming is now becoming very serious and is already impacting on life and property. It is here, now and not a phenomenon for future generations to deal with. New Zealand must step up to the plate and embark on a course of emissions reductions targets as soon as possible, to claw back rapidly rising greenhouse gas levels in the atmosphere. If we do not act now the severity of such heat waves, other climate extremes and sea level rise impacts and the subsequent damage to life and property will increase. There is no time like the present to invest in our future wellbeing.