Millennium bug melee misses true challenge

TIM Flannery's 1000-year carbon concession is a straw man that will no doubt burn brightly throughout the highly contested carbon tax debate.

Asked what impact Australia's carbon tax would have on global temperatures, Professor Flannery said that if the world cut all emissions tomorrow, it would take a millennium for global temperatures to drop because the system is already choked.

It is easy to ask, therefore, what the point is of painful and costly action today for such a small and distant return. But it is a question that misunderstands the climate change challenge.

The aim of climate change action today is not to return to a cooler world of yesterday. The urgent aim is to stop the runaway speed of carbon emissions growth - and global temperatures - as billions of people in China, India and elsewhere make their way from poverty to material wealth.

Climate scientists say that since the industrial revolution, the planet's natural systems, such as oceans and forests, have been able to absorb only half of the CO2 emissions from human activity. The other half has been left to accumulate in the atmosphere and warm the climate by stopping the earth's heat from being radiated back into space.

With the planet's absorption capacity saturated, every additional tonne of CO2 above today's levels will continue to build up in the atmosphere and cause average global temperatures to increase.

Carbon emissions must be either stopped or stored.

This can be done by switching to new technologies to limit CO2 emissions and promoting enhanced sequestration using both artificial and natural systems.

The scientific view is that if CO2 emissions are left unchecked, the world will warm by 4C by the end of the century.

Flannery's point is we must act to stop the forecast additional 4C temperature rise before we even consider returning to pre-industrial age temperatures.

He didn't want to answer the question about what impact Australia's action alone would have because the answer is obvious: next to nothing.

But the real answer is if Australia is not prepared to do anything, how can we expect anyone else to act.