The Intergovernmental Panel on Climate Change (IPCC) has recently launched a report on renewable energy. Compared to 13% at present, the study claims that 77% of the world's energy supply could be met by renewable energy by 2050 if backed by the right enabling public policies. This scenario also represents a cut of around one third in greenhouse gas emissions from business as usual. The ribbon looks great; let us unbundle the package.

Not all the cuts in emissions in the scenario should be attributed to a shift to renewable energy. The study envisages a decrease of 17% from the current energy consumption levels, by curtailing demand. Will the cut be borne by peasant women in Africa and rural Asia or by socialites in NYC and London?

The six renewable energy technologies reviewed by the study are bio-energy, solar, geothermal, hydropower, and ocean and wind energy. Currently, bio-energy accounts for 77% of all renewable energy. Much of it is derived from disappearing forests and woodlands, and from crop residues, and is used by peasant women for cooking. The IPCC projects that bio-energy production would double at a minimum and perhaps grow as much as six times by 2050. But already a modest diversion of US corn lands to the production of bio-diesel is implicated in the recent world food price spike. The much-touted Brazilian ethanol is derived from vast sugarcane fields that are in fact green deserts, stripped down of other plant and animal life, except rats and snakes. And besides, how many countries have the water resources to grow sugarcane on the Brazilian scale?

The study projects that wind energy could grow from 2% of world electricity supply to 20% by 2050. But it implies going offshore with wind farms. That is going to cost more.

The study assesses that solar energy could grow to achieve a 10% share in electricity production. But what about the need to properly dispose of the toxic wastes generated in the production of photovoltaic cells and films? Are large areas of land available near cities for concentrating solar power plants?

And the study is not sanguine about the prospects of hydro-power. Its share could decline from the current 16% of renewable energy to between 10-14%, perhaps owing to the palpable political costs of stream diversions. It assesses that geothermal is abundant but location-specific, and it could perhaps meet 3-5% of global electricity and heat demands. Ocean energy will remain nascent during the next decade.

The study offers an illusion that the huge foot-print of the well-off billion among the 6.5 billion inhabitants of the planet can be somehow maintained in an impending post-oil and gas future.

The writer of this post, Syed Ayub Qutub is Executive Director of the Pakistan Institute for Environment & Development Action Research (PIEDAR), a prestigious think tank focusing on urban, environmental and developmental issues.