The billion-mark was reached only after 1800 AD. When Jesus was born, there are thought to have been around 300 million people on earth.
In the days ahead, a baby will be born who will take the global population above 7 billion for the first time, and in all probability that birth will take place in China or India, the two countries with more than a billion inhabitants.
No one is sure. There may already be 7 billion passengers on spaceship earth, as no statistician would be prepared to say exactly when this event of largely symbolic significance takes place.
The United Nations has fixed October 31 as the date of the fateful birth, but events have so often proved demographers wrong in the past that the expectation is that it will be sooner rather than later The rate of population growth has soared over the course of recorded history: When Jesus was born, there are thought to have been around 300 million people on earth.
The billion-mark was reached only after 1800. As many as a billion have been added in the eleven years of the 21st century alone, and predictions on future population growth are now treated with the same caution and scepticism as long-range weather forecasts.
David Bloom of the Harvard School of Public Health says that the multitude of unpredictable factors means that taking a global view is problematic.
“Among them are infectious diseases, war, scientific progress, political change and our capacity for global cooperation,” he says.
The general expectation is, however, that population growth will tail off, with U.N. predictions for 2050 ranging from 8.0 to 10.5 billion.
What is clear is that the proportions will shift between the continents, driven by high birth rates in Asia and Africa. Soon India, with 1.2 billion currently, will take the lead from China, with 1.3 billion, as the world’s most populous nation.
Read More :http://www.thehindu.com/sci-tech/science/article2412108.ece
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