Renewable energy

In 2010, 194 countries at the UN Cancun Climate Change Conference agreed that average temperatures should rise no more than two degrees Celsius above pre-industrialization levels. Leading climate experts from the Intergovernmental Panel on Climate Change (IPCC) consider this the absolute cut-off point. If two degrees is exceeded, they say environmental and economic consequences will follow.

They are demanding faster action.

IPCC calculations show that a maximum of 570 billion tons of CO2 should be allowed to disperse into the atmosphere in order to maintain the two-degree target. If yearly discharges of greenhouse gases remain at today's levels, the 570-billion-ton ceiling will be reached in just 17 years.

These figures don’t take into account fossil fuels. When untapped reserves of coal, oil and gas are included in the IPCC's 100-year forecast of CO2 emissions, the data predicts 5 trillion tons of CO2. That is more than nine times above the highest acceptable level. This would put us far over the two degree goal.

Redemption in renewables

One way of keeping the planet cool is to turn to renewables. Last year, the IPCC released its long awaited special report on renewable energy sources (SRREN). In it, a group of 120 international experts said that "nearly 80 percent of worldwide energy supplies could be met with renewable energies". They carried out 160 ‘energy scenarios’, including one with the German Aerospace Center (DLR).

Together with Greenpeace International and the European Renewable Energy Council, DLR experts examined exit strategies from fossil fuel – and the implications these would have for global economies. With scenarios based on 40 countries, the findings are now being used by scientists, politicians and NGOs as they design future energy models.

Harvesting more energy

The population of the world is expected to expand to more than nine billion people by 2050. Supplying all these people with climate-friendly energy will be no easy task.

Today, fossil fuels provide 80 percent of the world’s energy needs. But according to the DLR's findings, it is possible to drop dependency to 16 percent by mid-century. In one of their energy scenarios, they envision a world in which the burning of coal falls to one eighth of today's levels, and oil and gas to one quarter. In this scenario oil and gas would be used almost exclusively in the transportation sector.

At the same time, the DLR believes that 84 percent of world energy needs can be met in 2050 by renewable energies. The largest share will come from the sun, experts say, which will provide 28 percent of the world's energy. Geothermal supplies will account for a further 24 percent, and bio fuels another 15. Windmill energies will make up 10 percent, water four, and marine energy from waves and currents, two percent.

If avoiding global catastrophe isn't enough of an incentive, however, there's another reason to change energy sources. In the long run, researchers say, replacing fossil fuels with renewable energy will ultimately prove less expensive.