Monday, May 3

Worst-Case Scenario: Fighting the Gulf Oil Spill

As an environmental disaster, the oil spill in the Gulf of Mexico just keeps getting worse. Late on Thursday, April 29, BP — the energy company that operates the sunken Deepwater Horizon rig and is financially responsible for the spill — revealed that oil was leaking from the burst well at a rate of 5,000 bbl. a day, five times faster than previously estimated. That means about 210,000 gal. of oil are now spilling into the Gulf each day, forming a metastasizing oil slick that is 5,000 sq. mi. (13,000 sq km) large and growing by the hour.

Worse, shifting winds and currents are pushing the oil toward the Gulf Coast, where the Coast Guard and other government agencies are already preparing to minimize the environmental impact when the crude washes ashore. "We are being very aggressive, and we are prepared for the worst case," said Rear Admiral Sally Brice O'Hara of the Coast Guard in a press briefing on Thursday.

http://www.time.com/time/health/article/0,8599,1986102,00.html

Tuesday, April 27

UK Temperature

The UK should expect a 4°C rise in temperature by 2080 according to the most likely results of the experiment.

Heatwaves are on the rise and, by 2080, summer temperatures of 40°C will be common. Winters will also be warmer.

UK rainfall

Summer rainfall is set to decrease and the UK can expect more frequent droughts

Winters will bring less snow and more rain, especially in the north and west. Storms will be more frequent and more severe.

Global changes

Different regions around the world can expect varying levels of warming. New Zealand faces a smaller temperature rise than the UK's 4°C change, while Alaska should prepare for a greater increase

Wednesday, April 7

दुइ आँखा चिम्ले मनमा आयो तपाईंको सम्झना, कल्पना गरे केही दिन खोजे भेटाये शुभ-कामना, झर्ना झै चोखो बगिनै रहोस् मन्का ति भावना। फुल झै हर्पल् फुलिनै रहोस्,प्रगति र चहना।। नाम र किर्ति फैलिनै रहोस्,सिद्ध होस् कामना। नव बर्ष २०६७ सुखमय बनोस्, यही छ मेरो शुभ-कामना।।।

Tuesday, January 12

solar hot water system

Solar hot water systems use the sun's energy to heat water in liquid-based solar collectors; they are almost always used along with conventional water heaters. Solar collectors for these systems are typically 3–6 m2 in area and the systems are sold as a standard package like appliances. A typical solar hot water system can provide about 50% of the water heating energy needs in a home.


How they work

Solar water heating systems include storage tanks and solar collectors. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don't.

Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.

Three types of solar collectors are used for residential applications:
  • Flat-plate collectors

    Glazed flat-plate collectors are insulated, weatherproofed boxes that contain a dark absorber plate under one or more glass or plastic (polymer) covers. Unglazed flat-plate collectors – typically used for solar pool heating – have a dark absorber plate, made of metal or polymer, without a cover or enclosure.


  • Batch collectors

    Also known as integral collector-storage (ICS) system, these feature one or more black tanks or tubes in an insulated, glazed box. Cold water first passes through the solar collector, which preheats the water. The water then continues on to the conventional backup water heater, providing a reliable source of hot water. They should be installed only in mild-freeze climates because the outdoor pipes could freeze in severe, cold weather.


  • Evacuated-tube solar collectors

    These feature parallel rows of transparent glass tubes. Each tube contains a glass outer tube and metal absorber tube attached to a fin. The fin's coating absorbs solar energy but inhibits radiative heat loss. These collectors are used more frequently for commercial applications.

Tuesday, January 5

Poverty and environmental degradation Formidable challenges

The twin process of poverty and environmental degradation are among the most formidable challenges facing humanity today. The Food and Agriculture Organization has reported that the 10 percent of world population face starvation, 70 per cent of the population live in inadequate sanitary conditions and 1.5 billion people still lack clean drinking water.

This vast majority of people live in the Third World and depend on agriculture for their livelihood. Moreover, the single most important input for agriculture is land and it is here that the situation is most critical. Nearly a thousand million people are either landless or have so little land that cannot produce enough food to feed their households. Thus, limited access to land is undoubtedly a major cause of poverty in the Third World.

Lack of resources is the first element of the local poverty trap. This is especially true in Nepal where the per capita land availability indicates a very tight situation as it has declined from 0.17 hectare in 1985 to 0.09 hectare by 2005. It is estimated that, given the present yields, an additional around 1million hectares of land should be brought under cultivation if the deficit in calorie intake is to be met by increasing the production of food grains. Similarly, grazing pressure is higher than the carrying capacity of the land as the shortage of fodder of the whole country has become as high as 33 per cent. The average hill family maintains four cattle and two buffaloes and requires about 3.5 hectares of uncultivated forest to sustain each hectare of land under cultivation. Fodder shortage translates directly into a lack of manure, declining soil fertility and declining crop yield. As a result Nepal’s agriculture is suffering from low and declining farm productivity.

Inequality in land ownership also has a dramatic effect in environmental degradation. It confines the poor to marginal areas, and intensifies population pressure there. Moreover, the geographical concentration of poverty on inhospitable land is driven partially as people move in, but more so by the heightened population growth rates that poverty itself brings. Land degradation is, thus, now becoming a global problem. But it is becoming more acute in Nepal where due to rapid population growth, peasants in the highland valleys are forced to expand their plots on to steep, forested hillsides where land is less productive and tenure least secure.

The heavy monsoon rainfall often triggers mass wasting and landslide. In this extremely vulnerable region, increased terrace farming often at the peak of the hill, overgrazing and over cutting of the forest have resulted in the problem of degradation and desertification. As a result, Nepal is losing 240 million cubic meters of soil which is well above the maximum limit of acceptable soil level loss. The sediment load in the Nepalese rivers is alarming as river-beds in the Terai are rising 15 cm to 30 cm annually with excessive sedimentation. It is said that in around 200 years the Kosi river has shifted 115 kilometers westwards destroying land which had provided subsistence to 6.5 million people. Similarly, it is estimated that about 10,000 sq. km. in Dolpa and Mustang districts are devoid of vegetation indicating the desertification process.

In all this, the energy sources need focus as it has ramifications on the environment and thereby the status of poverty. The energy consumption rates to a considerable degree characterize the scale and efficiency of any society’s productive forces. While the energy commodities of the affluent are commercial, poor people largely depend on traditional energy.

Traditional forms of energy supply about 90 percent of energy consumption in Nepal; in which the share of fuel wood consumption is about 80 per cent. Because of this the national deficit in fuel is severe in Nepal and forests are declining at a very fast rate. The increasing cost of fodder and fuel-wood provisions are borne by family labor. As forests and pastures became degraded, fodder and fuel-wood must be fetched from increasing distance from less productive sources, using time that could otherwise be spent in income earning activity. Because of this, the working days in the field has shortened, family incomes have fallen, and diets have deteriorated. As a further result of forest depletion, dung is increasingly burnt in poor families as fuel instead of being returned as fertilizer to the soil. It is estimated that 8 million tons of dung are burnt each year.

Poverty should be placed on the environmental agenda as co-operator rather than competitor of those seeking economic and social development. It is also important to be aware of the costs of farmers on environmental measures and to be prepared to compensate them if necessary. In the meanwhile, it is legitimate to consider sustained production and welfare-oriented programs of support to the poor to protect the environment.