Dear Pandit ji, Thank you for giving us such interesting and knowledgeable information about our surroundings. Every month on 20th, I wait for the postman to receive Gobar Times… only Gobar Times. Akshat Pathak Via e-mail Dear Pandit ji, I’m Tista, age 12. Gobar Times provides us with a lot of information about environmental issues around the world. I enjoy Gobar Times a lot and come across some very interesting facts. It also enhances our scientific knowledge and makes us look at various issues differently. Tista Via e-mail

I am a regular reader of Gobar Times. It has been seen that now obesity has become a global problem. I would appreciate it a lot if you could supply me with some information of food and eating habits of the young. I require this information for a school project called The Project Citizen.

Tista
Sardar Patel Vidyalaya, New delhi

Dear Tista ji,
You are absolutely right; obesity has become a global problem thanks to our fascination with packaged, processed and junk foods. Worldwide, around 17.6 million children younger than five are estimated to be overweight.

Obesity is the most prevalent disease among children and young adults in the US.

In the UK, obesity has risen by 400 per cent in the past 25 years.

In Australia, over the past 20 years, there has been a 2.5-fold rise in number of obese people identified in its major cities. And the country also has one of the highest rates of type-2 diabetes in children in the developed world.

The World Health Organisation (WHO) declares that each additional can of soft drink that a child consumes increases her risk of becoming obese by 60 per cent!

In India, an average family today spends less on cereals and more on packaged refreshments (chips, cookies and salties), and processed food. The average per capita fat consumption has risen sharply, both in rural and urban India. School surveys in various cities show that 30 per cent of adolescents from the middle class are overweight.

The effect – “An increase in calorie intake, which disturbs our metabolic activity. This, along with a sedentary life style, lead to an increase in chances of obesity, which has become a rule, rather than an exception in the upcoming generation,” says Navjeet Talukdar, heart specialist at the Batra Hospital and Research Centre, Delhi. Type-2 diabetes and heart diseases, which come as ‘free gifts’ with obesity, are also on the rise.

For more information check out our July 31, 2006 issue on ‘The must-buy generation’.

Dear Pandit ji,
Can you please tell me the meaning of Bio-fuels, Biogas, greenhouse effect, and global-warming?

Rajvi
Via e-mail

Dear Rajvi ji,
These are very complex topics. In short, they are...

1. BIO-FUELS: Fuels produced from plants, crops and animal feedstock (biomass). They are made of renewable, locally available resources, and have various advantages. Such as:

They release less toxic and thus, ensure better air quality.

They cut down wastes, as even the leftover plant masses can be recycled as fodder or as fertilisers.

Some of these oil-yielding plants can be cultivated on wastelands that cannot be used for agriculture, as they can grow on poor soils and need very little water or manure.

The production process – growing the crops and processing them – creates fresh employment.

They make nations less dependant on others for supply of fuels.

Here are a couple of these plants that are being tried out in our own country:

Jatropha: The seeds of this plant (Jatropha curcas; ratanjyot in Hindi) and Pongamia (Pongamia pinnata; karanj in Hindi) yield oil that, after processing, makes biodiesel. It is a hardy plant that can to grow in abundance in dry, arid zones. Oil is extracted and put through a process called transesterification (to convert it to fatty acid esters by incubation with alcohol and alkali), making it a suitable blend for petroleum-derived diesel. The jatropha blend reduces greenhouse gas emission by half. Scientists claim that as the conversion process improves with time, emission level will be zero!

Ethanol: Ethanol is made by fermenting molasses or gurh (a product of sugarcane). Ethanol (CH3CH2OH) is an alcohol with a very low freezing point. Zymase, an enzyme from yeast, changes the simple sugars into ethanol and carbon dioxide. Starches from potatoes, corn, wheat, and other plants can also be used in the production of ethanol by fermentation, after breaking them down into simple sugars. Besides providing a source of less-polluting fuel, it also helps sugar-cane farmers to get better returns from the fields.

But developing countries, like India, need to be careful. Because every patch of soil is used either for growing crops, or fodder. Even the so-called ‘wastelands’ provide livelihood for innumerous communities. So growing these oil-yielding plant varieties here may spell doom for our farmers and shepherds who literally live off these seemingly useless tracts.

2. BIOGAS: A gaseous biofuel produced by fermentation or anaerobic digestion of organic matter like plant waste, sewage sludge, biodegradable waste or feedstock. It is comprised primarily of methane and carbon dioxide. It can be used as a vehicle fuel or for generating electricity. It can also be burned directly for cooking, heating, lighting, and so on. Gobar gas is a biogas generated out of cow dung.

3. GREENHOUSE EFFECT: Earth receives energy from the Sun in the form of radiation. It reflects about 30 per cent of the incoming solar radiation, and absorbs the remaining 70 per cent to warm the land, atmosphere and oceans. This helps life forms to exist and flourish on earth. But gases, like carbon dioxide, methane and chlorofluorocarbons, absorb the infrared radiation going out from the earth, thereby increasing temperatures across the world. This is known as the greenhouse effect (the name comes from garden greenhouses that trap heat, helping some plants to grow).

4. GLOBAL WARMING: Global warming is the increase in the average temperature of Earth’s near-surface air and oceans, as a consequence of the greenhouse effect. This may trigger events that could lead to global changes in the climate. It is estimated that the average global surface temperature – now about 15 degres centigrade – could increase by 2 to 3 degree celsius, and could be even more in the polar regions. The consequences would be dire – ranging from sea level rise, glacier retreat, increased intensity of weather phenomena like cyclones, changes in the amount and pattern of precipitation, changes in agricultural yields, increases in the ranges of disease vectors to species extinctions.