World population

The number of inhabitants on the planet is the result(profit) of an immense and fast progress realized by the man during these last 50 years. It is enough, to convince to look at the figures of the life expectation.
In 1900 in France, the life expectation was of 45 years for the men(people) and of 48 years for the women, in 2007 of 77,6 years and 84,5 years (source(spring): World Factbook CIA on 2007).
We are crossed(spent) by 250 million men(people) at the beginning of the Christian era in more than 6 billions in the 20eme century, it illustrates well the exponential increase of the world population which thus continues to increase dangerously at the rate of 1,17 % a year. The world population in 1970, was 3,696 billion inhabitants, in 2000 of 6,085 billions. This increase of 80 million inhabitants a year, amounts about, to add on our planet, the population of a country as Germany, and this every year.
But a fast decline of the fertility is running, in all the countries and in particular in the developing countries, Iran is crossed(spent) by a fertility of 6,5 children by woman in 1985 to 2 children in 2008, China in 1,75 child by woman, India is crossed(spent) 2,7 children by woman...
In spite of this decline of birthrate, it is very difficult to believe that the curve is going to be reversed in the years to come. Once more the human race will have to adapt itself quickly to the environmental context without reaching(affecting) the state of overpopulation which would produce a Malthusian disaster.
A Malthusian disaster indicates a demographic collapse which follows an exponential growth of the population and which is due to the depletion of resources, as a result of this growth.

The extensive agriculture and the wasting of the water, the raw materials, the fossil fuels as well as the plunder of seas, the destruction of the animal and vegetable species are not they going eventually exhaust the planet?
In 1798, Thomas Malthus notices that the alive sorts tend to have an exponential growth while the resources cannot grow in the same way. He deducts that from it a demographic disaster is inevitable unless preventing the population from growing.

Nota: the overpopulation is a demographic state characterized by an incapacity of the available resources to assure the perpetuity of a population and its descent, on a local, regional, national, continental or global territory.
It is for it that China adopted from the beginning 1970s a politics of regulation and birth control to end in 1979 in the politics of the unique child.
With an annual growth rate of only 1 %, a single couple gives birth to more than 40 000 descendants in a millennium, about a billion descendants in two millenniums and about 20 000 billion individuals in only three millenniums.
We notice today that the demand of global resources is superior to the renewable offer.

We are thus in this phase where it is necessary to find a reasonable level of balanced growth to allow the nature to renew its resources with the same rhythm as we consume them.
Malthusian disasters were already observed and studied in animal populations.
In 1944, 29 Rennes were introduced on the island of offshore St Matthew of Bering.
The food resources were plentiful and Rennes had no predator, thus the population exploded, reaching 6000 individuals in summer, 1963, that is a 30 % growth a year.
Some months after this peak, all the population of Rennes declined and there were only 42 females, Rennes starved because the vegetation had been seriously and durably degraded.
Certain observers of the human societies consider that the notion of accommodation facilities on Earth, must be also applied to the human populations and that an uncontrolled growth of the population can pull a Malthusian disaster.
World Wildlife Fund (world organization of environmental protection) in a report dated 2006, based on the notion of ecological footprint, the respect that the biological resources of the planet are exploited 25 % beyond their capacity of renewal.

The world population moves and concentrates in the cities which become more and more gigantic.
In 1975, a person only on three, on the planet, lived in urban zone. During the years 1975-2008, the urban population so increased that in 2008, it exceeded the rural population. This urban growth saw the emergence of megalopolises of more than 20 million inhabitants.
Between 1975 and 2008, the number of mega cities (more than 10 million inhabitants) is crossed from 3 to 30 among which 22 are situated in developing countries. The urbanization is a rough phenomenon, the city is 5000 well years old of age, but the urban revolution is recent. This process propagates now southward.
The demography and the urbanization are also going to affect their limit and to enter in crisis. In this space with problem, how to live, to feed, to circulate in the megalopolis of tomorrow, more particularly in these giants of Africa and Asia already profiled to more than 20 million inhabitants?

The world oil demand is going to continue very probably to increase in the next thirty years. According to the International Agency of the Energy (AIE) this growth could be 60 %, a forecast which remains however soiled by uncertainties, so much it is difficult to estimate the evolution of the populations, the savings, the ways of life, the technologies, even the geopolitical evolutions. All the forecasters agrees on the fact that the growth of the consumption will largely be fired by the most populated emerging countries, as China or India, which know a very steady economic growth.
The demand of these countries will increase three times as fast that that of the zone OECD to achieve near half of the total demand of petroleum the horizon 2030 (against 13 % in 1970).
The planet cannot credibly supply all the energy which we wish. A revolution is going to take place on our bulimic mode of consumption.

Image: Tep (thunders fuel oil equivalent)

It seems that the demographers have many difficulties estimating the world population. Figures are naturally only estimations because the margin of error is important, it is due to the difficulties of inventory of the populations. In certain countries a third party of the births gives place to no official declaration. Nevertheless, the demography remains galloping and plays an important role in the global warming, the other problem than the humanity has to settle for its survival. We notice, a dangerously fast rise of the temperature, confirmed by the summary of the GIEC on 2007 which described an increase in temperature of 0,74°C over 100 years, that is more than 25 % more than the increase of 0,6°C quoted during its 3eme report of 2001. What is certain, it is that we reject more and more CO2 and the other nauseous waste and it risks to continue, because needs in energy of the world population increases with the demography.

We notice at the same moment that the nature bursts out more and more violently and at the same time, that the world of the alive fights to adapt itself to these climatic fluctuations by abandoning the weakest sorts. Everything takes place as if we were not welcome on this " macro body " the Earth, which defends itself by pushes of "fevers" in reaction to an internal aggression which obliges it to activate certain immunizing mechanisms to find its "balance".
Let us hope simply that these mechanisms do not fight the man as if it was about a foreign infectious agent. The informed maintaining humanity has to prove that it is an appropriate and not foreign constituent of the planet Earth and for it to control its expansion.
Although needs in resources, of the humanity are more and more gigantic, it will be necessary to find a balance to be accepted on this magnificent solitary spaceship.