Читать книгу Carbon Counter - Mark Lynas - Страница 6

Fossil fuels are often termed ‘buried sunshine’, because, in essence, they represent energy captured from the sun by photosynthesis in ancient plants. By using fossil fuels, humans are getting an effective

Tip: If you think about it, all the energy humans have ever used has come from the sun. Cavemen burned wood in fires for heat and cooking, but the trees it came from used the sun’s energy.

CO2 AND ESTIMATED GLOBAL AIR TEMPERATURE

Ice cores drilled by glaciologists from Antarctica provide a good record of temperature and greenhouse gas fluctuations over the ages. Two things are striking: first, how closely correlated temperature and CO₂ are; and second, how much higher levels are now than during the whole period of record.

energy subsidy from the past. Before the discovery of coal, oil and gas, humans – like other animals and plants – had to live only from the energy provided directly by the sun.

Coal: Coal is the fossilized remains of ancient forests. Many of these forests built up thick layers of peat underneath them, much as do forests today in hot tropical areas like Indonesia. Over millions of years, this peat became compressed by layers of sediment above it, and turned gradually to carbon-rich coal. A prime coal-forming era was the Carboniferous period (300–360 million years ago), which was named after the extensive coal beds found in Western Europe. Most of the electricity produced worldwide comes from coal.

Oil: Unlike coal, oil begins its formation in the sea. The dead remains of plankton accumulate in bottom sediments, where they are eventually buried at great depths and heated up by geothermal processes. This then ‘cooks’ the dead algae, releasing hydrocarbons, which companies such as Esso and BP later hope to drill out from reservoirs of oil trapped between impermeable rocks. If the oil is cooked at too high a temperature, it instead forms gas (see page 15). Saudi Arabia and Iraq have the largest proven oil reserves on the planet. Their oil was mostly formed during the Jurassic era, 200–145 million years ago. An incredible 80 million barrels of oil are consumed by humanity each day – that’s nearly a thousand barrels per second.