The disintegration last Sunday of a 40-kilometre ice bridge connecting the Wilkins Ice Shelf to the Antarctic Peninsula is another stark indicator of the threat posed by climate change.

The ice bridge was the last link between the 14,000 square kilometre Wilkins Shelf and the Antarctic mainland. Scientists now anticipate that the ice shelf—a vast expanse of ice—will be rapidly eroded or completely melted, especially if it drifts north into warmer ocean currents. The erosion of the Wilkins Shelf, first identified by scientists through satellite images taken in March 2008, proceeded much faster than anticipated. In 1993 the British Antarctic Survey identified the area as vulnerable, but predicted that significant deterioration would take 30 years.

Average world temperatures are 0.8 degrees Celsius higher than in the pre-industrial era, but the Antarctic Peninsula (the part of the continent that juts toward South America) has proven much more sensitive to global warming. Temperatures there have risen by 2.5°C in the past six decades alone.

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A number of climate scientists, including NASA's James Hansen, have concluded that the level of carbon dioxide in the earth's atmosphere has already surpassed the maximum tolerable limit beyond which potentially irreversible climate change may be triggered.

In this case, what is required is an immediate transition to a world economy with "net zero" carbon emissions—that is, emissions no greater than those able to be absorbed by the environment through natural processes. The technology and material resources necessary for such a transition already exist. But the marshalling of the world's productive forces and technological capacities to this end is impossible under the present social order.

By its very nature, climate change is a global problem, but it cannot be solved within the framework of the capitalist system. All rational plans for tackling this crisis immediately founder on the dictates of the profit system and the conflicting interests of the major capitalist nation states. To cut carbon emissions to the required levels requires nothing less than the complete re-organisation of the global economy—including the restructuring of energy generation and distribution, urban planning and public transport, agriculture and industrial production, waste disposal, and a host of other areas.

Such a reorganisation is only conceivable on the basis of a socialist movement of the working class. What is needed is a democratically-planned, world economy to satisfy long-term social needs and lift the living standards of ordinary people in every part of the globe.