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The world’s population
Growing, growing, gone? Trends Prof Yash
Pal THIS UNIVERSE
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The world’s population
Growing, growing, gone? It is about to pass the seven billion mark; by the end of the century, it could reach 15 billion, with the number of people in Africa trebling. How much more can the planet take? The UN calculates that the global population, which on 31 October 2011 is estimated to reach seven billion people, will hit 9.3 billion by 2050 and more than 10 billion by the end of the century. But it warns that, if fertility rates in Africa do not begin to fall from present levels as demographers predict, then the global population in 2100 could reach as high as 15 billion, more than twice the present level. John Cleland, a demographer at the London School of Hygiene and Tropical Medicine, is quoted in the report as saying that the reason why the focus is on population growth in Africa is clear. “The escape from poverty and hunger is made more difficult by rapid population growth,” Dr Cleland said. Much of the global population increase this century will come from “high-fertility” countries where women have on average many more babies than the 2.1 replacement rate. There are 30 high-fertility countries in Africa, nine in Asia, six in Oceania and four in Latin America, the UN report showed. Fertility rates worldwide have fallen dramatically since 1950. In Central America, for instance, the rate has fallen from 6.7 children per woman to 2.6, while in East Asia it fell from six to 1.6, helped largely by China’s draconian “one-child” policy. The State of World Population 2011, published yesterday, adds: “In some parts of Africa, there has been only a modest drop in total fertility, which today remains at more than five children per woman.” Asia will remain the most populated region of the world this century, due largely to the two most populous nations, China and India, but Africa is catching up, with its present population of one billion expected to rise to 3.6 billion by 2100, the report says. “Africa’s population has been growing at 2.3 per cent per year, a rate more than double that of Asia’s population (1 per cent per year). The population of Africa first surpassed a billion in 2000 and is expected to add another billion in just 35 years (by 2044),” the report says. This growth in Africa’s population will continue despite an expected fall in average fertility rates from the present level of about 4.6 children per woman to about three children per woman by 2045, it says. But in some African countries, such as Niger, Mali and Uganda, fertility rates will remain far higher than the African average. An extrapolation of future population trends found that, if existing fertility and mortality rates remained unchanged — which is highly unlikely — then by 2300 the global population would reach a staggering 3.5 trillion people, which is far too high to be sustainable. Joseph Chamie, former director of the Population Division of the United Nations Department of Economic and Social Affairs, said that, if Africa’s fertility rates remained unchanged over the coming decades, its population alone would reach three billion by 2050 and 15 billion by 2100. “Globally, it now seems likely that Africa will be the last continent to advance through the demographic transition: that is, the progression from high to low rates of birth and death,” Mr Chamie said. And there’s room for 10.9m more in the UK... The UK is on course to outstrip Germany and France to become the most populous nation in the European Union by 2043, the Office for National Statistics (ONS) said, with the UK’s population estimated to reach 74.4 million that year, more than Germany’s 73.7 million. Statisticians said this could be partially explained by lower fertility rates in Germany. Only three countries — Luxembourg, Cyprus and the Republic of Ireland — are projected to grow faster than the UK over this period. The ONS also said more than two-thirds of the UK’s population increase would be a result of immigration. —
The Independent
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Trends
CAPE CANAVERAL, Florida: NASA evacuated astronauts and scientists participating in an underwater space simulation in the Florida Keys over concerns about Hurricane Rina, officials said on Wednesday. Six astronauts and scientists participating in the NASA Extreme Environment Mission Operations, or NEEMO, program left the Aquarius Undersea Laboratory after five days. “Northern Lights” show as far south as Atlanta MINNEAPOLIS: The fiery glow of the Northern Lights could be seen as far south as Atlanta on Monday night thanks to a combination of a large cloud of gas and magnetic field ejected from the sun, and lucky timing, weather experts said. The cloud ejected from the sun Saturday arrived on Monday more intensely and quickly than people were expecting, said Doug Biesecker, a physicist and researcher for the Space Weather Prediction Center of the National Weather Service. U.S. researchers raise cannon from Blackbeard’s ship WILMINGTON, North Carolina:
Archeologists raised another cannon on Wednesday from the sunken wreck of pirate Blackbeard’s legendary ship off the coast of North Carolina. The eight-foot (2.4-meter) cannon, which had rested at the bottom of Beaufort Inlet since the ship Queen Anne’s Revenge sank in 1718, was covered in a cement-like shell of sand, salt and sea life. China says to launch unmanned space-docking craft BEIJING:
China said on Wednesday it will launch within weeks its first spacecraft capable of docking with a module it put into orbit last month, in what will mark a crucial test of its growing space program. The unmanned Shenzhou-8 spacecraft, carried by the Long March-2F rocket, will blast off in early November, state media reported, and will later try to dock with the Tiantong-1, or “Heavenly Palace-1” space laboratory module China launched in September. — Reuters
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THIS UNIVERSE Why don’t birds and other flying animals get shock when they sit on a high power electric wire? The primary reason for their safety is their small size compared to the distance between the live and the neutral wires of the electrical supply. If they touch both of them simultaneously the electric current would be able to pass through them and they would be incinerated. In some rural congested areas the supply wires run close to each other and an occasional large bird, not pulling in its wings in time, does get badly burnt and die. When an aeroplane flies high, why does it feel stationary for the passengers sitting in it? When a large plane is cruising high up, above the level of clouds, there is no turbulence. The speed of the plane is constant and there is no acceleration. A coin standing on its edge will remain standing. The noise in the plane is also muffled. Without any acceleration we will not be aware of the fact that we are in uniform motion in a straight line and not stationary! Why does earth not collide with sun? Both the sun and the earth are too small compared to the distance between them. Yes we know that there is an attractive force of gravity between them. You could say that the earth is continuously falling towards the sun, but it does not collide with it because it happens to be moving fast in a transverse direction. We call this drama as orbital motion of the earth around the sun! If sugar in water is in a solution, then why it scatters a beam of light? Just because sugar molecules are in solution, they do not disappear. We can even taste these molecules. Therefore it is not surprising that a light beam passing also detects them. Readers wanting to ask Prof Yash Pal a question can e-mail him at palyash.pal@gmail.com
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Africa will struggle to escape from poverty and hunger this century because its rapidly expanding population will continue to grow significantly faster than any other region of the world, says a United Nations report. Every continent has seen the stabilisation of their populations, with Asia’s expected to peak in the middle part of the 21st century, but the number of people living in Africa by 2100 is likely to treble, the report says.