Carbon - Life wouldn't be the same without it
Carbon is at the root of the sustainability issue. It's partly because burning fossil carbon like coal and oil is disturbing the balance of our climate and partly because, in the grand scheme of things, there's not much of it, and it took a couple of billion years to make.
We've used getting on for half of the world's supply over the last 200 years, that's about 5 million times faster than it was made! Oil, Coal, Carbon Cycles, Greenhouse Gasses, Fossil fuels... They are at the heart of the economy and of a slow moving tsunami that could cause devastation on an unprecedented scale.
Carbon is not an environmental threat. Anything but,, it's a fundamental building block of life, and in a sense, that is the root of the problem. All organic life is carbon based. Coal and oil, hydrocarbons, are the remnants of plants and animals that were frozen in the depths of time. Burning them releases carbon dioxide (CO2), a key greenhouse gas.
CO2 forms only 0.039% of the earth's atmosphere – most of the carbon available to the global eco-system is locked away in the short term, either in solution in the sea or in biomass, (plants, frozen tundra and soil). Since the beginning of the industrial revolution burning hydrocarbons has increased the concentration of CO2 in the atmosphere by 1/3 .
Carbon dioxide is constantly recycled in one of the great, planet wide, processes that make our world the place it is. The carbon cycle is a process that recycles free carbon through the atmosphere, oceans, and vegetation on a colossal scale. By far the largest reservoir of “free” carbon (carbon that is not permanently locked into carbonate rock or fossil fuels) is dissolved the worlds oceans or trapped in sediments on the sea floor - there's roughly six times more carbon in the sea than in the world's soil, vegetation and atmosphere combined!
Gigitons of free carbon
- Oceanic 39,000
- soil 1,500
- vegetation 610
- atmosphere 750
Movements of carbon in the cycle far outweigh production of carbon dioxide from burning fossil fuels. Man-made carbon emissions are 5.5 billion tons a year, compared to the 200 billion tons produced by soil, vegetation and the sea. The difference is that the biological carbon is reabsorbed in roughly the same proportions as it is released. Fossil fuels release carbon that was “locked” away millions of years ago, and it doesn't balance its carbon budget", which is why atmospheric concentrations, having remained stable for at least the previous 10,000 years, (and almost certainly far longer) have risen so dramatically over the last two centuries.
Fossil Fuels - Fossil Sunshine
Fossil Fuels are the world's primary energy source, providing about 86% of our total energy supply. All fossil fuels are hydrocarbons, and the two words are often used interchangeably in discussions about issues like global warming. The word "hydrocarbons" gives a clue why they are both a fantastic source of energy and a massive problem for the global environment.
Almost all life on earth depends on the ability of plants to create very large complex molecules from simple inorganic compounds. They use photosynthesis (making things from light) to combine simple compounds like carbon (extracted by plants from atmospheric carbon dioxide) hydrogen and energy from the sun to create organic compounds like sugars and starches, that eventually go to make up the leaves, branches, flowers and fruit of plants. It takes a lot of energy to make these complex chemicals. Creating them effectively stores huge quantities of solar energy. Under normal conditions plants grow, die and decay as bacteria oxidise the complex structures of the plant to extract energy (by breaking down the complex molecules) and recycle carbon into the carbon cycle.
Fossil fuels were created when dead plant and animal matter was preserved in anaerobic (oxygen free) conditions. Just like peat banks today, the lack of oxygen stopped the complex molecules from breaking down in the normal way and eventually pressure and heat from geological forces created coal, oil and gas. The reason why fossil fuels are such a great source of power and such a problem is that when we burn them (a very rapid form of oxidation) to release that ancient solar energy we also release the locked away carbon. (the section on global warming explains how carbon can cause big problems for the planet).
It took a couple of billion years to accumulate this reservoir of ancient energy - its only taken us a couple of hundred years to burn our way through around half of these reserves. Once they are used we will never get them back. We really need to recognise that massive boost fossil fuels have given us is a "once in a planet-time" advantage. Our exploitation of fossil fuels is an opportunity we will never have again. One of the reason our economy is struggling today is because of the high cost of fuel - and in a world with ever increasing demand - supply is more or less at capacity - developing sustainable renewable fuel isn't just an environmental imperative - it's an economic one as well.
Coal - The Base of Industrialisation
Coal was at the heart of the industrial revolution. It fuelled the boilers that drove the pumps and lathes, powered the steam locomotives, fed the coking ovens to bring gas to towns and to feed the furnaces that smelted the iron.
The Carboniferous period, which lasted about 60 million years takes it's name from the coal measures. It was a relatively temperate stage of the earth's history and conditions were good for both plant growth and for the formation of acidic, low oxygen peat bogs, ideal for conserving organic material. The evolution of bark bearing trees (containing large amounts of lignin, the fibrous component of bark, and a compound resistant to rot and insect attack) led the formation of extensive peat deposits which eventually became overlain and compressed by sediments to form coal.
Coal (and oil) are really “fossil solar power”. All the energy that lies behind the astonishing biological processes that allow plants to break the bonds that bind carbon to oxygen and build complex organic compounds comes from the sun. The plants that formed the coal measures locked away vast quantities of energy in the form of carbon deep underground. The price we pay for burning the carbon to release this ancient energy is the recreation of the ancient CO2.
Today, coal is the worlds biggest single source of electricity, is essential for the production of iron and steel and a vital feedstock for the chemical industry. 45% of power in the USA and almost 70% of China's electricity comes from coal fired thermal power stations. Production in China has trebled in the last decade and over 2/3 of China's greenhouse gas (GHG)emissions come from coal . It's a particularly harmful polluter because it produces higher levels of other Greeenhouse Gasses (GHG's) than oil and gas and far more sulphur, soot and ash.
Carbon dioxide aside, the effects of these emissions range from severe local air pollution to acid rain. Soot is believed to be a key reason for increased melt rates of glaciers and the polar ice caps – the dark fine carbon particles absorb far more solar energy than reflective snow and ice.
Oil - Keeping the World Running and Running Out
Oil's originals are similar to coal. Both depended on a temperate climate and oxygen low water, and both were covered in sediments and subject to geological pressures over time. The difference is that the biological origin of oil were microscopic algae and planktons rather than woody plants. Oil is also “fossil sunlight” and a net contributor to greenhouse gasses (GHG's)
It's is the lifeblood of the modern world. Without it, industrial civilisation would collapse. Almost every aspect of our lives, from the clothes we wear to the food we eat, is touched in some way by oil, especially transport.
More than half the UK's annual oil consumption is used by road transport and three quarters of the total goes to private transport. If air and rail are added to the equation, transport alone accounts for over 75% of UK oil use.
About 90% of all vehicles depend on oil for fuel - in the USA transport represents 40% of the countries total energy consumption. Oil is also a valuable feedstock for the chemical and plastic industry – regarded by some as “too valuable to burn”. About 80% of the world's readily accessible oil is in the Middle East and Russia is the worlds second largest producer. Concerns about security of oil supply in the Middle East is one of the reasons why the oil markets have become so volatile.
Associated natural gas has become an important component in thermal power generation. Almost 40% of British electricity comes from gas turbines – which are far more thermally efficient that coal powered plants, up to 60% as opposed to 30-35% for coal. Natural gas is also the main fuel used in fertiliser production – production of one ton of artificial nitrate fertiliser uses the equivalent of 1.5 tons of oil.
Oil used for transport accounts for around a third of the worlds fossil carbon emissions – It is important to explore strategies to reduce the link between mobility and oil for this reason alone but there are possibly even more pressing reasons for reducing oil dependency - Peak Oil - the point when the production of oil matches demand is probably here - rising demand and steady supply can only mean ever rising prices.