Gobar Times
Cover Story

Carbon Capers

    The Building Block of Life    

It is that time of the year again. School students of all shapes, sizes, and age groups are gearing up to bury their noses in piles of books. Meet one of them. Naina. She studies in Class IX. Her examinations begin next week. "I wish studying could be a bit more fun," she groans. No time to brood, though, she reminds herself. She still has to wade through an array of subjects. "Ah well, might as well begin with the toughest of them all… chemistry," she decides.

Atomic Number: 6
Atomic Weight: 12.0107
Melting Point: 3823 K (3550°C or 6422°F)
Boiling Point: 4098 K (3825°C or 6917°F)
Density: 2.2670 grams per cubic cm

              

CARBON (C)
The fourth most abundant element in the Universe, after hydrogen (H), helium (He), and oxygen (O), is the building block of life. It's the element that anchors all organic substances, from fossil fuels to DNA

Phase at  
Room Temperature:    Solid
Element Classification: Non-metal
Period Number: 2

The name of Carbon comes from Latin carbo, whence comes French charbon, meaning charcoal. In German and Dutch, the names for carbon are Kohlenstoff and koolstof respectively, both literally meaning coal-stuff.

The chapter she is about to revise is on 'Carbon'. "Carbon is a remarkable element in many ways', began the paragraph, "It is essential to all known living systems, and without it, life cannot exist". It is what all human beings, as well as all plants and animals on Earth are made of. 50 per cent of an individual's dry weight actually consists of carbon! "So obviously I am made of carbon too," thought Naina, as she ran her hand over her face. It is the basis of all life forms, and combined with other elements, it sustains us! Now this is getting a little more interesting…Naina sat up on her chair and dug deeper into her book.

"This means, carbon makes us by our chemical codes, creates life through oxygen produced by plants that survive on carbon, protects and sustains us," concluded Naina. "It's everywhere in our lives"

 

     Carbon-ements      

Carbon's electron structure gives it a plus- 4 charge, which means that it can readily form bonds with itself, leading to a great diversity in the chemical compounds that can be formed around it. Hence, the diversity and complexity of life.

With Oxygen, it forms carbon dioxide. Carbon dioxide is mandatory for plant growth. Plants use it in Photosynthesis and produce the oxygen we breathe in. (See Carbon cycle).

With Hydrogen, it forms various flammable compounds called hydrocarbons (like fossil fuels), and other important living plant components like carotenoids and terpenes.

All Three together, they produce many groups of important biological compounds including sugars, celluloses, lignans, chitins, alcohols, fats, and aromatic esters.

With Nttrogen it becomes alkaloids, and addition of sulphur creates antibiotics, amino acids and proteins. The carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. And finally, when PHOSPHORUS is added to these other elements, carbon forms chemical codes of life - DNA and RNA.

   Carbon-teristics     

But what make Carbon truly an element to watch out for are its extraordinary properties.

  • It forms the hardest naturally occurring substance: diamond. And also one of the softest substances known: Graphite. Completely paradoxical properties!
     
  • It is also a component of great rock masses as carbonates of calcium (limestone), magnesium, and iron.
     
  • It easily bonds with other small atoms, including other carbon atoms.
     
  • Its small size makes it capable of forming multiple bonds.
     
  • It forms nearly ten million different compounds! These compounds are the large majority of all chemical compounds. And form the basis of all life on Earth.
     
  • It has the highest melting or sublimation point of all elements. At atmospheric pressure it has no actual melting point. It remains solid at higher temperatures than even tungsten or rhenium (metals with highest melting points).
     
  • Most forms of carbon are comparatively un-reactive under normal conditions. At standard temperature and pressure, it resists all but the strongest oxidizers (such as fluorine and nitric acid). It does not react with sulphuric acid, chlorine or any alkalis.
 

Naina, by now, is fascinated by this super C_Factor. It seems to hold the key to ALL of this world's secrets. It has transformed the mundane Chemistry text book into a breathtaking Harry Potter adventure story! But, she cannot afford to be glued to just one subject because of this fascinating element. She must move on to other subjects now. A lot needs to be covered in Economics, for instance…

    Fuelling economy    

Naina turned to the chapter on the Industrial Revolution. "The Industrial Revolution took root in Europe in the 19th century, and changed the world of trade and economy forever," said the book. But, Naina's eyes were fixed on a few lines below. "With it began the search for alternative sources of fuel to meet the energy needs of the mushrooming industries. Fossil fuels could meet this requirement. And today, the world economy and global geopolitical system bank on them. Everything that is used as fuel today—from natural gas through petrol and alcohol to oil to wax and plastic—is composed of hydrocarbon chains of various lengths," she read. The C Factor seems to be the core element here too!

"So, carbon fuels our industries, acts as an “aid” to various processes, and may even be a raw material. And oh! carbon is a by-product as well" exclaimed Naina, "It runs everything”

 

   Carbon-era    

Fossil fuels are derived from-yes, fossils made up of decomposed plant and animal matter. It took millions of years to form these layers into a hard, black rocklike substance called coal, a thick liquid called crude oil or petroleum, and natural gas - the three major forms of fossil fuels. These fossils were formed about 360 to 286 million years ago during the time of the dinosaurs (Paleozoic Era) in the Carboniferous Period. The period gets its name from carbon, as all fossil fuels are made of carbon. So, back to square one: Carbon. Carbon, mainly as fossil fuels, forms the backbone of all industries. The reason behind its rampant use is simple. Carbon either serves as energy source, or as input (as aid in production processes).

Energy source

Burning coal, natural gas, and petroleum releases energy stored in the fuel, derived from the sun, as heat. Industrial processes that require extremely high temperatures burn a great deal of very pure coal known as Coke, and use the energy released to directly heat a system. Combustion of fossil fuels can also be used to generate electricity. The fuel is burned to heat water, and the steam from the boiling water spins turbines that power a generator. Electricity is ready to be used! They are used in transportation — cars, planes, trucks, motorcycles, trains, and buses. Oil goes through a refinery where it is made into different products. Some of them are used as: aviation fuel, gasoline and diesel fuel. Carbon is used as a neutron moderator in nuclear reactors. Clean natural gas is often used (burnt) to heat homes.

 

What’s in a barrel of oil

Source: American Petroleum Institute (www.api.org). Figures are based on 1995 average yields for U.S. refineries. One barrel contains 42 gallons of crude oil. The total volume of products made is 44.2 GALLONS — 2.2 gallons greater than the original 42 gallons of crude oil. This is called "processing gain," where other chemicals are added to the refining process to create the products.

Around 1900 gigatonnes of carbon are present in the biosphere

Around 1900 gigatonnes of carbon are present in the biosphere
 

   Carbon-vironment      

The world of 'carbon economy' had just begun to unfold before Naina. And it was fascinating, with its many layers and nuances. But Naina would have to move on again. The examinations were looming large in the horizon, and there is still so much to cover. So her mind still in a whirl over the 'C' factor — that seemed to have pervaded every sphere of life on this planet- Naina opened the pages of her textbook on Environmental Sciences. Uh, huh, she knew what to focus on in this subject! For weeks the newspapers and the television channels have been agog with the latest report published by the Intergovernmental Panel on Climate Change (IPCC). Oh yes, Global Warming was bound to be the examiner's favourite chapter this time. Naina rubbed her eyes in disbelief, as she turned the pages. The 'C' factor has left its mark here too! Only this time it appears in a different avatar-as a menace, rather than a life giver. This is how it happens…

   Black carbon    

In the atmosphere, carbon usually pairs up with two oxygen atoms and takes the form of carbon dioxide (CO2). The heat trapping properties of CO2 helps keep the Earth from freezing, by creating the Greenhouse Effect. In this, Carbon, with a host of gases like methane, sulphate, chloride and nitrates, heat up the planet like a garden greenhouse. So, how can humans affect this balance? We can rapidly raise the level of carbon in the atmosphere, and hence, the greenhouse effect.

 

Raw material

The petrochemical industry uses crude oil to produce gasoline and kerosene through a distillation process in refineries. Crude oil forms the raw material for many synthetic substances, such as plastics. Apart from being used for decorative purposes, diamonds are used in the boring industry. Diamond is also used as drill bits and other applications making use of its hardness. Even the 'lead' of pencils is carbon; Graphite mixed with clays. Graphite is also used as a lubricant and a pigment. Graphite carbon in a powdered, caked form is used as charcoal for grilling, artwork and other uses.

C Factor in factories

Carbon (usually as coke) is used to reduce iron ore into iron. And added to iron to make steel. Carbon fibre is mainly used for composite materials, and hightemperature gas filtration. Carbon black is used as a filler in rubber and plastic compounds. Carbon is even used in medicines! Activated charcoal is used to absorb toxins, poisons, or gases from the digestive system. Carbon, due to its non-reactivity with many substances that corrode most materials, is often used as an electrode. The chemical and structural properties of fullerenes, in the form of carbon nanotubes, has promising potential uses in Nanotechnology.

 

Carbon as energy
As the trees and plants died, they sank to the bottom of the swamps of oceans. They formed layers of a spongy material called Peat. Sand, clay and other minerals covered it, and turned into a type of rock called sedimentary. More and more rock piled on top, and it began to press down on the peat. It was squeezed until water came out of it. Over millions of years, this turned into coal, oil, and natural gas.

Natural Gas
Around 6,000 to 2,000 years BCE, the first discoveries of natural gas seeps were made in Iran. They, first ignited by lightning, provided the fuel for the "eternal fires" of the fire-worshiping religion of the ancient Persians.

Coal
The earliest known use of coal was in China. It is made up of carbon, hydrogen, oxygen, nitrogen and varying amounts of sulphur.

Oil or Petroleum
Oil has been used for more than 5,000-6,000 years. Some scientists say that tiny Diatoms, pinhead-sized sea creatures that convert sunlight directly into stored energy, are the source of oil.

There are nearly ten million known carbon compounds

    Breaking the balance     

Since the Industrial Revolution, the world has been pumping in monstrously high quantities of carbon dioxide into the air. The main culprits are the fossil fuels (remember Naina's lessons on Economics?) like coal, oil and gas-the fumes of which contain CO2 gas. The current global average atmospheric concentration of CO2 is 380 parts per million-36 per cent more than the 280 ppm present in the pre-Industrial Revolution era. Now, the world's top climatologists predict that unless something drastic is done to cut down fossil fuel emissions, the global average temperatures would rise to 3 to 6 degrees Celcius by 2100. And as the Earth's surface temperature increases, glaciers will melt as a result of the rising heat, and cause oceans to slowly creep up and swallow low-lying islands.

Nature had, of course, provided an in-built solution to this problem. The Earth's ecological sinks - its forests, oceans, soil, and vegetation-have the capacity to absorb the harmful gases. Global warming is caused only when GHG emissions exceed the cleansing capacity of these sinks. Obviously the world has now crossed this limit. Many times over. Naina chewed her nail in consternation as she read. "Shall we feel the heat?", she wondered. Unfortunately yes, in more ways than one, as she found out..

  • The most critical link between glaciers and climate is maintaining the earth's water balance. In fact, glacier melt has contributed as much as 30 per cent of sea level change in the 20th century.

  ‘But we really have no idea what we are doing   

On Earth, carbon is continually on the move — cycling through living things, the land, ocean, atmosphere. What happens when humans start driving the carbon cycle? We have seen that we can make a serious impact — rapidly raising the level of carbon in the atmosphere. But, we really have no idea what we are doing.

At the moment we don't even know what happens to all the carbon we release from burning fossil fuels. Obviously, a lot of it goes into the atmosphere but, every year we loose track of between 15 and 30 per cent (NASA). Scientists speculate that it is taken up by land vegetation, but no one really knows. This sort of uncertainty makes it doubly difficult to predict the outcome of tampering with something as complex as the carbon cycle.

  • Alaska's melting glaciers, sea ice, and a type of frozen soil called permafrost are adding an extra 0.3 millimeter a year to the depth of oceans. Between the 1950s and 1990s, Alaskan glaciers contributed only half that much water. If drastic steps are not taken, the world can expect sea level to rise by 18-59 cm by 2100. This will spell doom for small island states and low-lying deltas like Bangladesh and Egypt. ?
  • There will be dramatic changes in weather patterns. Rainfall will increase sharply in higher altitudes and decrease in lower levels.
  • Storms and hurricanes will become more frequent. So will heat waves and droughts. Threats of natural hazards, ranging from cloudbursts, avalanches, landslides, to glacial lake outburst floods (GLOFs), mudflows and earthquakes will intensify.

   The Carbon Culprits      

The IPCC report declares that the chances of human activities causing climate change is as high as 90 per cent…"In other words, it is all upto us," thought Naina, "Are we prepared to deal with this crisis? Have we, the global community, taken some steps already?" Nearly fifteen years ago, at the Earth Summit in Rio de Janeiro, the world's governments had signed a pledge to prevent 'dangerous climate change'. But, the planet continues to sizzle. Why? Because the use of fossil fuels is, unfortunately, closely linked with economic growth and lifestyle. As a nation grows more prosperous, its consumption of fuel—for transport, power generation and various other so-called 'necessities' of life—zooms up, too. So, in today's world, any limit on carbon emissions amounts to a limit on economic growth.

No wonder the ongoing International negotiations under the UN Framework Convention on Climate Change— have turned into a tug of war between the developed (read rich) and the developing nations (ranging from middle-class to poor). While the rich are unwilling to tone down their lifestyle, countries in the opposite camp refuse to take on emission cut at their current stage of development. Developing countries like India, are demanding their space to 'grow'.

Asking them to reduce carbon emissions now, amounts to asking them to freeze their standards of living as they stand today. This, in fact, amounts to freezing global inequality. Because, in that case, some countries will always be more developed than the rest. Why should they accept that?, especially since the Unites States—the largest emitter of them all—still refuses to make a firm commitment to cut its use of carbon-based fuels.

     Swapping carbon      

"So how can we calculate each country's share of responsibility?", Naina cried out in frustration. Well, governments around the globe have been considering various options. In future, both companies and countries would need a licence to emit carbon dioxide. And to stop dangerous climate change there will only be a fixed number of licences worldwide. So now, the countries are fighting over who should get how many. Again the crux of the problem is that Europe and the United States have already used up most of the available 'space' for safe emissions. Big developing nations like China and India may rank high in the emissions league, but measured per head of their populations their emissions remain low. China is below 1 tonne a year for every citizen and India below 0.5 tonnes, while the US and Australia emit around 5 tonnes and Europeans under 3 tonnes.

When it comes to CO2 we all over-indulge. We all need to work towards a low-carbon lifestyle

Some governments are trying out the system of 'carbon trading'. It allows low level polluters to trade their permits with high level polluters. For example, in January 2005, European governments issued major industrial polluters like steel firms, power generators and chemicals companies with carbon dioxide emissions permits. The companies that innovate ways and means of cutting their emissions would have spare permits that they can sell to the less responsible ones who have not.

Yet another carbon trading system is between countries—the developed and the developing ones. Here, instead of the low emitters selling their share of unused permits to the high emitters, the emissionindebted developed countries are paying their counterparts in the developing world to invest in clean technologies. Unfortunately, here too, the global community has failed to deliver. Instead of focussing on technologies and energy-saving devices that could stem the rising temperatures and rising tides, countries are quibbling with each other to strike the cheapest deal… So, a few companies may have struck gold already, but no real solution has been found. And the stalemate among the nations continues.

     Zero Carbon     

"But we cannot simply sit back and oppose others. We are also responsible for turning the life-infusing C factor into a deadly menace. It is time we actually did something" decided Naina. Yes Naina, its time we have an agenda of our own-that suits our own economics and our own resources. The first step, of course, would be to take a pledge to manage energy more efficiently, more prudently. This will be our best defence against any possible impact of global warming. We can begin by taking a close look at the various sectors of our economy and consider which of these can best take advantage of clean technologiespublic transport? Power plants? Industries? But before we do that, let us first concentrate on what can be done at home. Yes, you and the rest of us are major carbon emitters too! Can you think of ways to clean up our act?

 

Slider Heading: 
The Building Block of Life