There are a number of questions or unfinished sentences below. Choose the best answer from A, B, C or D.

1. Some scientists believe that global warming could

A. modify ocean currents.

B. change wind directions in the polar regions.

C. reduce the influence of currents.

D. increase wind speeds.

2. The first results have already confirmed

A. that heat is stocked at great depths.

B. that the last Ice Age ended about 10,000 years ago.

C. the complexity of ocean currents.

D. that Gulf Stream currents are situated in the surface layer of water.

3. Heat is transferred from the tropics to the poles

A. in the surface currents.

B. in the atmosphere.

C. in the deep currents.

D. along the seabed.

4. The atmosphere and the ocean

A. influence the climate independently.

B. interact and create a global climatic balance.

C. have no effect on the climate.

D. have only modified the climate since the last Ice Age.

5. Why is this research considered to be of great importance?

A. It will enable scientists of the future to prevent extreme climatic

changes.

B. It will help scientists predict climate changes.

C. It unites a large number of different countries.

D. It will help dissipate the climatologists' 'nightmare scenario'.

3. Scientific texts often look more complicated than they really are. Look at the article in this section again and note down any 'difficult' scientific words or expressions.

4. The opening sentence of the text suggests that there are other 'nightmare scenarios'. What scenarios is the writer probably referring to?

■ 3.6 D. Breezing into the Future

By Dick Thompson

A decade ago, windmills promised to be a clean, reliable source of power that could help wean America from its dependence on dirty fuels and foreign oil. The idea of harnessing an en­ergy supply that was free as the breeze generated enough megawatts of excite­ment to light up an entire new industry. Spurred by generous government tax in­centives, investors poured more than $2.5 billion into U.S. wind projects during the early 1980s.

But enthusiasm was not enough to propel the dream into reality. "Wind de­veloped a reputation for not working, and it had the stigma of a tax scam," says Robert Thresher, the wind-program man­ager at the National Renewable Energy Laboratory in Golden, Colo. Eventually the problems caused power companies to back away. And by 1985, when the tax credits expired, the remaining wind tow­ers began looking more and more like monuments to a lost cause.

Now, however, there's new energy in the wind. Engineers have used advanced technology to make wind turbines that are far more efficient and cost effective than those of yesteryear. Says J. Michael Davis, chief of renewable-energy programs at the U.S. Department of Energy: "These machines are real and reliable." Today's models are capable of meeting 10% of America's energy demand, and within 30 years, newer versions could provide for a quarter of the nation's power needs. Such figures have re-energized the manufactur­ers of wind-power equipment and attracted the interest of foreign competitors. Utili­ties are conducting wind surveys and start­ing pilot projects. And a new breed of wildcatter is scurrying to buy up wind rights—licenses to erect what may be the oil wells of tomorrow.

For years, the wind industry's goal has been to produce power at rates similar to oil's: roughly a nickel for a kilowatt. Ma­chines now operating in California can produce energy at 7cents per kW. In areas of consistent high winds, the next genera­tion, currently being deployed, will bring that cost down to 5cents by 1995, and more advanced designs are likely to shave off another penny by the year 2000. While many locales do not have enough wind to use the technology, enhancements already in the works will expand by a factor of 20 the area of land that can generate wind power profitably, according to experts at the National Renewable Energy Lab.

Wind's success says something about a dicey political issue: Should government tamper with free enterprise to nurture a new technology? The answer for renew­able energy sources is definitely yes. Had manufacturers and utilities not received state and federal assistance early on, the future of wind power would now be con­trolled by either Japan or Europe; both have consistently funded wind research. Today American technology dominates the field.

In a sense, wind power has come full circle. In the early 1900s, most of the electricity on U.S. farms was provided by windmills. Those were replaced during the 1930s when the Rural Electrification Administration wired the countryside. But the oil embargoes and environmental con­cerns of the '70s prodded politicians to encourage the investigation of alternative energy sources. States began requiring their utilities to spend between 1 % and 2% of profits on research, and the federal government added its generous tax cred­its for investments in renewables.

Unfortunately, the credits were for investment, not performance. Conse­quently, many wind-power machines seemed to be designed on an accountant's calculator to capture more deductions than breezes. Some towers were planted in fields of feeble winds. Others broke down with frustrating regularity. But a few com­panies persisted, and California in par­ticular became the nursery for advanced technology. The state's hot central valleys are linked to the cool ocean by a series of gorges and valleys along the coast that act like wind tunnels. It was in these natural labs that engineers began testing new de­signs.

The failures of the 1980s showed the researchers that they knew almost noth­ing about building machines that could withstand and harness the turbulence of wind. Early models used blades of a type originally designed for helicopters. Since wind pressure could vary considerably from one end of the blade to the other, the rotor would wobble wildly and eventually break off. Sudden gusts of wind could overpower the machine and burn out its energy-converting turbine. Some engi­neers tried solving the problems by build­ing heavier machines, but that simply made them more expensive.

After much trial and error, research­ers modified the contours of the blades; some, for instance, are thicker in the middle in order to provide more stability. Engineers put electronic sensors atop the towers that could constantly monitor wind direction and turn the machine to correct for changes. The sensors do not respond to every fluctuation, but when a computer calculates a sustained 15° shift, it signals for a turn into the wind. The leading Ameri­can manufacturer, U.S. Windpower of Livermore, Calif., has built machines with electronic components that act as a giant surge protector, keeping sudden bursts of energy produced by gusts from overpow­ering the turbine.

Researchers also found that less than ideal placement of a windmill can have a major impact: missing 10% of the wind can reduce power 30%. Moreover, the arrange­ment of turbines within a wind "farm" is important because the wake produced by one windmill affects those around it. Com­puters are being used to simulate varied terrain and calculate how to produce the most energy.

The advances are slowly changing the way utilities evaluate the technology. "We look at it as a real competitive option," says Carl Weinberg, director of research for San Francisco-based Pacific Gas and Electric. Outside California, however, wind power still carries the burden of past fail­ures. Even though a government survey found that 10 Midwestern states could more than meet all their electrical power needs from wind, no major wind projects are planned in the region.

But growing public concern over pollution from burning fossil fuels will increase the pressure for renew­able energy. Several states are starting to require utilities to fac­tor the cost of environ­mental damage into the cost of power produc­tion. In California, where the process of calculating environ­mental cost is just be­ginning, wind power maybe assigned a price 15% lower than that for energy from traditional sources.

Seven different proposals are before Congress to provide incentives for new wind-turbine purchases. Surprisingly, the energy industry itself is divided on the value of such incentives. Turbine manufac­turers believe that wind should prove itself competitive without further special assis­tance. But utilities would like a tax credit to make investment more attractive.

Additional technological advances now on the drawing board are likely to make wind power even more appealing. Engineers plan to boost the towers in some areas higher than they are at present so that the machines can escape ground turbulence and tap more consistent winds. Lighter materials could reduce the cost of building the towers And researchers are looking into ways to store excess energy produced during windy periods so that it could be banked for use on calmer days or during peak energy demand.

If wind power does not fulfill its prom­ise as a major energy source by the end of the century, it will not be a failure of technology. It will be a failure of vision on the part of society to make the necessary commitment.

Vocabulary

conduct – conduct a survey/experiment/inquiry–to carry out a particular process to get information;to conduct an orchestra; to conduct sb about; conduct yourself –behave in a particular way;conduct (n); conductor (n)

deploy – to organize people or things, especially soldiers, military equipment so that they are in the right place ready to be used; deployment.

enhance –improve sth; enhancement (n):much needed enhancement.

tamper – tamper with –to touch sth or make changes to it without permission, especially in order to deliberately damage it; tamper-evident/tamper-resistant – a package or a container made so that you can see if someone had opened it before; tamper-proof – made so that to prevent opening it before it is sold.

nurture –to feed and take care of a child or a plant while it is growing; to help a plan idea, feeling to develop; nurture (n) – education and care that you are given as a child, and the way it affects your later development and attitudes; nurturance – loving care and attention

prod –1. push with a finger; 2. To strongly encourage someone to do sth:to prod sb into doing sth; prod (n): give sb a prod.

escape –to get away from some place, somebody, something: to escape sb’s clutches; to escape from/through/into; escape sb’s attention/notice; the name/date/title escapes me; there’s no escaping (the fact); escape(n):an escape of gas/liquid etc.; a lucky escape.