NEW evidence confirms that global warming is now a reality and .should be taken seriously. The report by lite UN's Intergovernmental Panel on Climate Change (1PCC) concludes that man’s actions have contributed substantially to the observed warming over the last 50 years.

Glaciers provide a way to find out if climate is changing. "Since they are typically formed as a response to cold climate, glaciers always reflect any change in climate," says Gergan. a glaciologist from the Wadia Institute of Himalayan Geology.

After making numerous trips to the Dokriani Bamak glacier, a 5 km long python of ice and mud that snakes through the upper reaches of Gahrwal, Himalayas, Joseph Gergan is convinced that global warming has set in.

Around the globe, human activity is heating up the planet and weather patterns have become more erratic. This summer may be hottest ever in parts of India and Bangladesh.

The seas around India and Bangladesh have shown a rise of about 2.5 mm per year over the last few decades. Seas rising by millimeters and lands wanning by fractions of degrees might not sound like much but, in the giant thermometer that is the earth, it is enough to change life forever.

These facts dovetail ominously well

with the theory that carbon dioxide released by bunting fossil fuels is trapping excess energy from the sun. Carbon dioxide is produced when fossil fuels are used or when forests are cut or burned. Ice cap melting and agriculture release methane and nitrous oxide.

Industrial processes release chemicals known as halocarbons and other long-lived gases, some of which trap heat in the atmosphere. A study carried out by James Hansen of Nasa Space Agency differentiated "natural forcing" from man-made actions and worked out die impact of each on temperature.

The only way to slow it down is to restructure the way we produce energy. Measures like insulation, carpooling and energy efficient bulbs are useful in curbing burning of carbon-rich fossils but, as the world’s population increases and living standards rise, diey will not be enough.

At a research centre in Germany engineers at Daimler Chrysler have created a high performance car, which emits only water vapour. In Japan, scientists are perfecting paper-thin solar cells that could turn every house into its own electricity supplier. Cars like NECAR4 could help make that happen. This experimental vehicle, being joindy developed by Ford, Daimler Chrysler and Canada's Ballard Power systems, get its energy from hydrogen. Hydrogen, unlike fossil fuels, contains no carbon atoms and thus generates zero

carbon dioxide.

Fuel cells invented in the early period of die Industrial Revolution were adopted by Nasa for generating clean power in space vehicles in the 1960s. Only in the past decade have they been made small enough to fit in inside a car.

In an ideal situation, hydrogen may be produced with renewable electricity from

the sun or wind. But the electricity required to split water into hydrogen and oxygen is prohibitively expensive. So, the first large-scale plants will probably wrest hydrogen from old-fashioned fossil fuels.

That's good news for China, whose rapid industrialisation and huge domestic coal reserves threaten to pump cataclysmic amounts of carbon dioxide into the air

over the next century. While scaling fuel cells down to fit inside cars and trucks is challenging, scaling them up or linking them together to run power plants should be no problem at all.

There is still some unwanted effect in pulling hydrogen from fossil fuels because it leaves carbon dioxide behind. If the carbon dioxide is vented into the atmosphere, global warming will be as big a problem as ever, therefore, engineers are thinking of pumping it into the ground.

In Norway, Norsk Hydro is building a power plant that will be fueled with hydrogen drawn from natural gas. The carbon dioxide that is left over will be re-injected into an oil field on the continental shelf. Not only will this take the carbon dioxide out of circulation but will also pressurise the field and make the remaining oil easier to pump out. In Europe and the US, pumping carbon dioxide into underground aquifers has proved an effective way of keeping it out of the atmosphere.

Fossil fuels will remain an important source of energy for the foreseeable future, but they will eventually run out and the world will have to switch to what environmental visionaries have been dreaming about since the first Earth Day; endlessly renewable power from wind and sun.

Wind has the edge. It is fast catching up with oil and gas in cost efficiency with the help of experiments such as the one at Ames Research Centre. Colorado engineers expect to build a new generation of super-efficient wind turbines with blades well over 200 ft (60m) across. Efficiency does not help when the wind is not blowing; as such it would be necessary to store energy generated during gales for use when the air is still.

The best way to do that, says Robert Williams of Princeton University's Centre for Energy and Environmental Studies,

would be to use the excess to compress air and force it to subterranean aquifers, caves or salt domes. Then, when the wind dies the compressed air can be pulled out to help drive the turbines. This could help countries rich in wind resources to take advantage of a free, unlimited and nearly pollution-less source of electricity.

On the solar front, the environmentalist's dream can be realised if manufacturers can find a way to produce silicon - based photovoltaic cells more efficiently and reduce the cost.

Because a given solar cell is sensitive to just a few colours of the many that make up sunlight, researchers are working on multi-layered cells that will trap most of tire colours of the rainbow.

Since the sun doesn't shine with equal power everywhere, even a building covered with solar cells will need another source of electricity. One possibility is a system that uses both solar cells and a two-way fuel cell. During daylight, when the solar cells are operating, excess electricity could be run through a fuel cell to produce hydrogen from water. At night, the fuel cell could use hydrogen to produce electricity again.

Ideally, every factory, building, home and vehicle would have its own clear, renewable power source, eliminating oil wells, coal mines, power plants and power lines -- and all the environmental disruption they cause. For now, the world has a more urgent mission: to stop the planet from overheating, and to do it in a hurry. Thanks to fuel-cell cars and more advanced wind turbines and solar cells that are close to fruition, the global warming challenge seems a little less daunting than it did a fewyears ago.

Md. Asadullah Khan is a former teacher of physics and Controller of Examinations, BUET. E-mail: aukhanbd@gmail.com.