Ziggy Switkowski | The Australian
THE year is 2050. Greenhouse gas concentration has reached 500 parts per million and is growing steadily, although annual global emissions have fallen to below year 2000 levels. The average temperature is 1C higher than 50 years earlier but with considerable variation across the globe.
Predictions by early computer models appear to be confirmed by noticeable climate changes. Weather is clearly more volatile, hurricanes more frequent and extreme, dry zones have become drier still and bushfires more intense. Availability of fresh water is a serious worldwide problem.
Melbourne’s temperatures are more like Adelaide once had, and Sydney is morphing into Brisbane, which for the first time finds itself within the cyclone footprint. Satellite measurements confirm that average sea levels have risen 20cm in a half century. This seems consistent with the observed higher ocean temperatures, melting icebergs and receding glaciers.
Damage from storm surges is regularly reported and can be seen in estuaries, bays and unprotected coastlines. Weather-related insurance claims have multiplied by a factor of 40 through five decades to $20 billion annually in Australia.
The previous decades have seen tragic consequences for marginal communities internationally: soil degradation and loss of agriculture and food production in Africa, destruction of coastal habitats in southern Asia, the disappearance of some South Pacific islands. But Siberian Russia, Canada and Scandinavia have prospered in the warmer climate. Harvest yields have improved dramatically in key food bowls such as the American midwest. The global population has stabilised just short of 10 billion people.
Many communities have deployed flood control systems, upgraded their emergency response capabilities, invested in desalination plants and imposed tough energy and water-efficient building codes on new construction. Latest model cars don’t use petrol; new power stations do not release much greenhouse gas emissions, but fossil fuels remain important for stationary energy and transport.
Not everyone believes that returning to the climate of the previous century represents progress.
Such a scenario is realistic, likely, and consistent with mid-point views in the reports by the Intergovernmental Panel on Climate Change, Nicholas Stern and Ross Garnaut. But the probability of unconstrained global warming at the end of the century is still 50 per cent.
With this history and in these circumstances, what will mid-century societies do? In analysing this, what are the implications for today?
By 2050, new developments may offer the promise of stabilising and reversing global warming. Schemes will emerge to seed the atmosphere with aerosols, microfoils and other particulate matter that scatter incoming sunlight and reduce temperatures at sea level. Nanoparticle and biological additives may be designed to increase the reflective properties of the oceans and compensate for loss of albedo associated with the reduction of ice cap coverage. Giant mirrors, land-based and in orbit, could track the sun to augment this reflection. More futuristically, techniques may be discovered to alter the temperature and chemical gradients of our seas and shape the great ocean currents to achieve a more benign global climate outcome.
But how do we approach the deployment of these technologies? Unless there was unambiguous evidence of imminent global catastrophe (unlikely), complete confidence in climate forecasting (debatable) and in environmental technologies (perhaps), a consensus to interfere with the global climate of the day, producing uncertain and uneven consequences among countries, could not be reached. And unilateral intervention by any single country or coalition with sufficient resources to do so could be viewed as a risky, even hostile, act by some.
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