Australasian Science: Australia's authority on science since 1938

Climate Action Cools

By Ian Lowe

United Nations talks in Mexico lacked the “hot air” required for meaningful government action on climate change.

The climate change talks in Cancun last December produced a timid step forward. There is still not the sense of urgency and purpose that the science demands, but at least there was some movement in the right direction.

Australian climate change Minister Greg Combet was positive about the mood at Cancun, but the government is still only talking about a 5% target for greenhouse gas emission reductions, which is not even at the bottom of the agreed range of 25–40%.

The fundamental problem remains the obsession with short-term economics in political circles. This sets up two huge road-blocks. The first is a reluctance to take any action that slows economic growth. Governments are still approving new large coal mines when it is clear that coal has a limited future.

The second is an assumption that the most effective way to rein in pollution is to use a pricing mechanism, either a carbon tax or an emissions trading scheme. As large corporations weigh up investments, such as new electrical generating capacity or energy-intensive processing operations, the price of energy influences decisions.

But energy prices have very little impact at the level of households or individual citizens. Domestic electricity users see no price signals at all as they use power, so they can’t possibly make rational judgements about the relative value of an hour of lighting or air-conditioning compared with other returns for the same amount of money. Car users do see a price signal when they fill their tank, but motoring groups calculate that fuel costs only account for 10–15% of the overall cost of driving. That makes it very unlikely that the individual motorist knows what it costs to drive their car.

If governments restrict themselves to using price they are choosing to use an approach that is very unlikely to be effective.

It is still an open question whether the extreme weather events that affected Australia in January are linked to climate change. The science was saying more than 20 years ago that warming would produce “a more vigorous hydrological cycle”, and hence heavier rain in the northern half of the continent. But the jury is still out on the question of whether climate change is contributing to either the frequency or the intensity of changes to ocean circulation patterns.

It was depressingly predictable, however, that some politicians would make the absurd claim that the floods could have been prevented by building dams. The most severe problems affected the flood plains of rivers that flow through very flat country, where there are no logical sites to build dams.

In any case, reservoirs can only moderate flood events if there is significant unused capacity when the rain falls. With the dams in south-eastern Queensland already overflowing from the December rain, they had little capacity to absorb extra water when the January deluge hit. The Queensland floods do show the need to think about the location of crucial infrastructure, like airports and sewage treatment facilities.

I suppose the next thing we will hear is that we should be diverting the floodwater from northern Australia to the drier south. It’s a dotty idea, but one current state premier publicly advocated it when in opposition and survived the political fall-out.

As last month’s issue reported (p.8), research into the response of trees to increasing carbon dioxide levels shows the complexity of natural systems and the need to consider the whole picture.

Some denialists have argued that increasing carbon dioxide levels are not a problem because accelerating photosynthesis will soak up the CO2, ushering in a new era of luxurious vegetation. The study by US and Australian scientists exposed deciduous trees to levels of carbon dioxide that are about 25% above current concentrations. For the first few years the trees did grow faster, but then the availability of soil nutrients became a problem, slowing growth rates.

A report by the International Geosphere–Biosphere Programme nearly a decade ago warned that interference in the nitrogen cycle could eventually be as big a problem as our perturbation of the carbon cycle. So, trees will not soak up as much CO2 as had been hoped, especially where soils are nutrient-poor – as they generally are in Australia.

Ian Lowe is Emeritus Professor of science, technology and society at Griffith University.