Selecione seu idioma

sexta-feira, 21 de outubro de 2011

The time bomb of overpopulation

The American biologist Paul Ehrlich reveals how the degeneration of the environment and major epidemics can progress rapidly if not slow the population growth of the planet, which is in the rhythm of an additional billion people every 11 years.
A scientist reveals how the degeneration of the environment and major epidemics can have an explosive issue.

For Flavio Dieguez and Rene takes off  -

When he published the book The Population Bomb in 1968, the American biologist Paul Ehrlich of Stanford University, San Francisco, California, lit the wick of a huge controversy. A veteran analyst of aggression to the environment and deep knowledge of ecology, he was not concerned with the mere lack of space in a crowded world. Even then, it anticipated the tremendous headaches for years 80 and 90.Greenhouse effect, acid rain, AIDS, famine, destruction of the ozone layer, reduction of biodiversity and tropical forests. All this, he argued, is part of a major disruption of nature on a planetary scale. Ehrlich, remember, this alert launched in 1968, when the current disaster scenarios were just science fiction. But population growth was taking off in a way undreamed of earlier decades. You can see that every year 80 million new people were added to the existing 3.5 billion. Most important was the speed of growth, humanity had spent tens of thousands of years to earn his first billion people, a fact that occurred around 1800. But then, it took just 130 years to double that number, so that in 1930, 2 billion people spread across the planet.
The next step took even less time, 30 years and so on. In the 90 growth enters its most intense phase when 11 years are enough to produce 1 billion people, but if nothing is done to contain it, the explosive pace will continue until the middle of next century. This is kind of outrage that could lead mankind to a dead end, since it will not have a healthy future is to double its amount from the current 5.5 billion to more than 10 billion. Three decades ago Ehrlich's argument was simple: if population growth was not restrained, nature itself commissioned to tell him. Nothing more didactic than the stifling example of food: as you increase the number of mouths it becomes increasingly difficult to produce food for everyone. And that raises the mortality rate.
Less obvious but just as revealing as the previous example, the case of epidemics: the overcrowding leads to the proliferation of microorganisms and hinder the provision of prevention and treatment of diseases. Is it possible that a man so proud of his mastery over nature is carried away with this sort of ecological apocalypse? Ehrlich thinks so. So much so that almost 25 years later, he returns to the subject by means of a new book, published in 1990 and not yet published in Portuguese. Its title means just population explosion that the bomb exploded after envisioned in 1968.
A lot of evidence in its favor was the outbreak of AIDS and other epidemics whose strength goes far beyond what the experts thought a little more than a decade. For Ehrlich, this was a foreseeable threat, at least in outline, and many leading scientists, in retrospect, agree. It's a perfect statement of the American virologist Howard Temin, Nobel laureate in Medicine in 1975, about AIDS: What surprises me is that there is only one such epidemic. It is certainly not easy to assess the extent to which Stanford biologist is right, especially because their predictions are only qualitative, ie, can not be put in numbers or even accurate statements.
But an outline of its main arguments help to understand why a scientist feels so sure of himself. A major focus of attention is the so-called immune environment that is all that can create more or less easily to the outbreak and disease transmission. His conclusion is that the situation becomes more precarious each year. A basic motif, very striking in the Third World, is the increasing number of people living in cities. This accumulation, combined with delicate and deplorable sanitary conditions, causes people to become ideal target for old and new epidemics.
The AIDS virus is just one of many deadly microorganisms, as difficult to control, which has surprised experts in recent years. But he is exemplary because it may have triggered a mechanism of the type predicted by Ehrlich, through which nature raises the mortality rate and population growth offsets. In Africa, at least, computer simulations indicate that the disease will promote a significant decrease in the rate of increase of the population by the year 2000.Some regions Central African newcomers to earn a rate of 3% per year, so that, after 12 months, a country of 10 million people will have 10.3 million.
Instead, the rate would drop to 2% and the number of inhabitants would rise to 10.2 million, 100,000 fewer people than in the previous calculation. This forecast is even bleaker by the fact of taking into account only 25 years of spread of the virus from 1975 (graph). The global food crisis ends like possibility, Ehrlich points out. And much more complicated, because chronic hunger now affects nearly 800 million people and perhaps to become more acute where it is not as serious today. Anyway, due to starvation epidemiological environment will become even more precarious. Another complication is that the emission of pollutants is committed to agriculture in the future.
The essential data are the Worldwatch Institute, based in Washington, the United States on world trends in agricultural production. Ehrlich compared the population curve with the production of basic grains. The result suggests that the total amount of food hardly increase, quite unlike the population.
From the mid 80's, seems to have exhausted the so-called Green Revolution American program whose goal was to pass modern technology to poor countries. In some African countries, the revolution was simply devoured by tribal strife and political chaos. Just below the Sahara, for example, the yield may even have increased, but the amount per person has fallen 20% since 1970. This trend holds true for all countries, although the percentage drop is smaller. But the problem is most severe in Africa, where crop failure, among other coi-ture, led to the death of more than 5 million children.
With one crucial detail: even when malnutrition was not the direct cause of deaths, was the medium that favors the development of lethal diseases. In Latin America, also, cereal production per person has fallen since 1981, a decline of around 10%. Another alarming trend: large areas are failing to produce food according to needs.
Before World War II, Asia, Africa, Latin America and North America were exporters of food.Today, the situation is reversed: three quarters of grain exports come from North America and around 100 countries depend on them, in one form or another since turned to industrial production, relegating agriculture to a secondary plane. To make matters worse, Americans themselves are beginning to encounter insurmountable natural obstacles: there, in 1988, due to a devastating drought, lost a third of the grain harvest. For the first time since the 50s, the country consumed more grain than harvested, and the fraction lost corresponded to 100 total exports to those countries.
The drought of 1988 explains why the big question of the future, according to Ehrlich, is the effect of climate on crops. This must be impaired, above all, by an acute shortage of water on the planet, since the global warming of the atmosphere is the most important climate change. Reduced availability of water, in turn, will lead to a smaller amount of grain.
Then a chain of effects must be associated in a complex manner. Starving populations will become a full plate for epidemic diseases, and these raise mortality rates. Large cities will target certain disorders, as they will quickly looms in poor regions. This leads us to predict from homelessness to seemingly trivial services like garbage collection. The latter, in some countries, is beginning to take titanic stature.
Thus, it is difficult to predict gloomy political outlook. Faced with so many obstacles, democratic forms of government face increasing challenges, the constant risk of extinction.National governments may find themselves weakened, prophesy Ehrlich. In some cases it is replaced by a combination of feudalism and tribalism. Another fairly concrete is the proliferation of religious fanaticism. It may not be an exaggeration to see a sign of this trend in a well known fact: the Arab countries, where some of the world record in population growth, are also home to the strongest extreme sectarian movements linked to religion.
If this scenario materializes, represents a historical regression of humanity into a political and social organization similar to that which prevailed in the Middle Ages. But it would be gravely unjust to ignore the fact that Ehrlich often talks about trends, none of this needs to happen, necessarily. As an experienced scientist never a candidate for the prophet, he knows the limits of solid arguments presented. So is perfectly aware that the negative trends can be reversed through attitudes more rational and better informed by the various governments.
This effectively has happened due to the decrease in the Cold War, which pitted the United States to the former Soviet Union. Then there was a relaxation of political tension, making it less likely the ignition of a nuclear conflict. Ehrlich himself deserves credit for this change because it was an ardent critic of the war, against which he helped to write a compelling scientific study, known as nuclear winter. This work, in 1983, considered the fate of mankind after a possible nuclear confrontation, showing how it could reduce the level of civilization to the pre-history.
The risk is not entirely clear, but is not so great.Likewise, it is perfectly possible to correct the existing environmental missteps, and Ehrlich has what he thinks is the best way to fix it. The first measure is clear: reduce the rate of population growth as quickly as possible. His idea is to initiate a broad program of birth control, able to fix a ceiling set for the world's population. This may not be so great that it can be sustained by available resources at any given time. The sustained expression for Ehrlich, means that everyone should have a life of good quality and productive.
The economic system should also be refurbished to reduce consumption in richer countries. This measure is essential to preserve the environment and not wasting non-renewable resources of the planet. Besides, the scientist recommends the use of alternative technologies, ie, that harm nature as little as possible. After all, the greatest danger in all this story, seems to be the slowness of the great natural phenomena, compared to human existence. So, are not easily perceived, unless already advanced.
It is clear that the remedial measures must be implemented according to a well thought out plan, which must also be corrected step by step over time. Therefore, Ehrlich created an equation to describe the environmental effect of population explosion. This equation has the form I = PCT, where I is environmental impact, P is population, average consumption per person C and T level of technology. The example of China helps to understand how it works. There, the population was tightly controlled. Statistics of the United Nations (UN) show that it grew 2.22% between 1970 and 1975. Controlled, that rate dropped to 1.24% between 1980 and 1985 and 1.19% between 1985 and 1990. The impact on the environment, therefore, should reduce, but does not decrease due to the development in this case, represented by the consumption of water, the item C of the equation.
The total cost of water is immense, since China is the world's most populous country. But the per capita consumption is still small, about a fifth of U.S. consumption. Still, demand is growing rapidly due to significant social change. By the year 2000, the industry must absorb twice as much water consumed today, and urban centers will quadruple its quota. As a result, we expect water shortages in 450 of 644 major Chinese cities by the end of the century. This example is even more instructive because it reveals a clear need for greater solidarity between countries, so that some have better life through technological progress, others have to give up excess resources and often exaggerated. After all, there may be the root of the problem: to reach an agreement on how best to distribute the wealth of the world, humanity has made great strides toward a future worth living.