Methane only lasts in the atmosphere for about 10 years, but during that time it is 20 times more potent as a greenhouse gas than CO2.
What will be required
We know most of the technologies that will be required.
Wind energy technology is well developed and not expensive. Industrialized countries such as Germany, Spain, Denmark and the USA are investing heavily in it. Among developing countries, it is chiefly India and China that have adopted it on any scale. But many others could take similar steps if supported by investment from rich countries. They need training, technical skills, and help in compiling wind atlases and integrating wind power with more conventional electricity generators in a grid.
Solar power is fast emerging too. Until recently this has mostly meant photovoltaics (PV), in which sunlight is converted directly to electricity. Buildings can be built with PV cladding to power and air-condition themselves from the sun.
But there is also growing interest in concentrated solar power, which uses mirrors and lenses to focus solar energy to heat water that then runs conventional power turbines. The first such power stations to be operational at industrial scale are in Spain and the USA. In theory, large areas of desert from Nevada to Algeria to India could be covered in mirrors catching the sun’s energy. Making concentrated solar power work is of global interest as a potential large source of clean energy.
Future vehicles are likely to be driven by either electricity or hydrogen (which, however, requires large amounts of electricity for manufacture). Electric cars, just by means of physical laws, are inherently much more efficient than those fuelled by liquid hydrocarbons such as oil. Electric cars are the political “flavour of the year” in 2009. But how climate friendly they are depends crucially on how the electricity is generated. If we end up burning more coal the gain is small.
The future is a super-efficient transport system run on electricity produced from renewable sources. Electrification of public transport also makes mass transit much more environmentally friendly. Trams, electric buses and trains must replace urban and regional diesel-powered systems. Electric high-speed trains between city centres such as those in parts of Europe do already substantially reduce the need for aviation. In addition, freight must go back on rails.
Other natural sources of energy that can be harvested include tidal and wave power, and geothermal energy (hot rocks).
Biofuels have been heavily criticized for taking the land and water needed for growing food. Some also have a large carbon footprint during production. But future biofuels, particularly those using waste products from farming and those from agroforestry and woods, may be a better bet. Biofuels may also have a long-term future for aviation.
Solid biomass generally, in particular from new and sustainably managed forests, is a crucial renewable means of replacing coal in power generation and providing reliable fuelwood for many poor communities in developing countries.
Carbon capture and storage is a set of technologies that would capture CO2 emissions from large installations that burn fossil fuels, and store it permanently deep underground in old oil and gas fields or in some types of aquifer.
The technology still has some way to go to become commercially available on the scale needed – and does itself produce some emissions. But it could one day reduce emissions from burning coal by 90% and more – in other words well below those of burning natural gas.
Carbon capture and storage could also be used with biomass fuels, making electricity production “carbon negative”.
In addition, it could be applied on a large scale to other carbon-emitting and energy-intensive processes such as cement and steel production.
The potential of nuclear power as a source of large-scale electricity is often overrated.
WWF believes that the risks of nuclear proliferation, waste disposal, accidents and future shortages of uranium fuel make it an unsafe, unwise and unsustainable option.
Methods for capturing and using methane emissions from agriculture, landfills and gas pipelines are quick, cheap and have a fast climatic payback. Methane only lasts in the atmosphere for about 10 years, but during that time it is 20 times more potent as a greenhouse gas than CO2.