Anthropocene: why this naming has risen in the earth’s history-GS-3

  • Back 11,000 years ago, the carbon dioxide (or CO2) level in the atmosphere surrounding the globe was about 220 parts per million (ppm); even 8,000 years ago, it was about 260 ppm. But starting the nineteenth century, when the industrial revolution started in the West, coal from the earth and beneath it was used extensively as the fuel for transport and industry.
  • The other major fossil fuels, oil (petroleum) and natural gas were discovered and put to use on a large scale. Burning carbon-rich fossil fuel liberates CO2. And CO2 is an example of what is referred to as a Greenhouse gas, which lets sunlight in, but traps the heat radiation that the earth and its oceans emit in return.
  • Non-stop burning of fossil fuels for industry, transport and other uses over these years has accumulated a large amount of CO2, which does not escape the earth (thanks to the gravitational pull of the earth; lighter gases such as hydrogen or helium gases escape, which is why they are not earthbound).
  • As a result, the average surface temperature over these two centuries has gone up by 1.5 degrees Centigrade. This has also started melting glaciers and raised the sea level by 3.2 mm every year.
  • Added to the warming of the oceans and landmass caused by the Greenhouse gases (CO2, NO, Ozone, methane…), are the plastics and their debris, strewn all across the world and its oceans. Plastic pollution is an even more recent phenomenon.
  • Cyanobacteria reproduce very fast (doubling every 30 minutes), thus leading to vast amounts of oxygen in the atmosphere. Some of this was ‘fixed’ by iron and organic matter of earth, but the rest soon led the ‘poisonous’ gas, oxygen, attain levels of about 20 per cent in the air. This burnt off many living forms and it took a long time before oxygen- using life forms (aerobics) started flourishing about 500 million years later.
  • As usual, vested interests still refuse to believe that climate change has occurred, and that the use of fossil fuels is not responsible for this dangerous ‘greenhouse gas catastrophe’.

Anthropocene 2: Damage control measures

  • Here we highlight some of the remedial measures being taken, wherein fossil fuels can hopefully, and soon, be replaced by renewable and thus sustainable methods for energy production.
  • The main source of energy for all industrial and manufacturing processes during the last 250 years has been coal. Besides solid coal, we also use liquid petroleum and natural gas as fuel for generating energy. The total amount of crude oil on earth today is about 1.7 trillion barrels, which, too, will be finished off in 53 years
  • Burning these carbonaceous fuels has rapidly damaged the earth by increasing the levels of the resulting carbon dioxide (CO2) surrounding our earth. Carbon dioxide would not escape, being locked in by the gravity of the earth.
  • This greenhouse effect has rapidly warmed the earth and its atmosphere, slowly melting icebergs, raising sea levels and endangering island populations. This has led to what geologists have now declared as the start of a new epoch in earth’s history, a man-made one termed Anthropocene, thus ending Holocene.

Scientists are thinking about several possibilities and, in fact, putting them into action-

  1. Reduce (and totally forego) fossil fuels, and use what are termed renewable energy sources, also called sustainable energy sources. These are clean, produce no greenhouse gases, consume no water and do not need large amounts of land.
    1. The amount of ozone in the atmosphere and stratosphere above the earth was getting depleted, thanks to the use of some gases (such as Freon) used as refrigerants. Ozone, which forms a layer above the earth, effectively absorbs ultraviolet radiation, which can harm life forms on earth through oxidation.
    2. But refrigerant gases, upon decomposition, react with and deplete the levels of ozone, now replaced these gases by much safer ones, and the ozone layer is slowly turning back to normal levels.
    3. Use solar panels made up of materials that convert light into electricity (photo-voltaic cells, made of layers of silicon, gallium arsenide, cadmium telluride or other materials).
    4. India is ranked number 1 in the world in utilising solar panels to generate electricity. Today, we are generating over 8,000 MW of power across the country, with Rajasthan, Tamil Nadu and Gujarat in the lead.
  2. Using wind energy through the use of wind turbines to generate electricity. Here, China leads the pack, producing about 150,000 MW of power; India is second with 25,000 MW
  3. Use of ocean tides, and the exploitation of the difference in temperature between the surface of the ocean and in deeper layers. Using the tides, we can generate mechanical energy and the temperature difference for thermal energy production.

Still growing way is the use of microbial fuel cells, wherein waste water is used by bacteria to generate electricity. This field is in its infancy and needs to be developed further.

Source: The Hindu

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