We are all aware of, indeed seriously concerned about, the climate change and global warming. The large majority of scientists – environmentalists, climatologists, atmospheric physicists, geophysicists, geochemists, oceanographers and experts of hosts of associated disciplines – as well as overwhelming proportion of human population unanimously hold the view that significant climate change is indeed taking place and that is all due to human activities. But then a small but powerful section of the population, mostly in America, reject this contention and assign changes to just natural activities. Obviously, these people have vested interests in deflecting away human activities.
It is blatantly obvious that human activities are the root causes of climate change. Of course, nature may be reacting to adverse conditions created by human beings, but the initial cause is human activity. One may ask, why is it that earth is reacting so disastrously over the last few decades when it existed in stable conditions for millions of years? The answer is undoubtedly ‘WE ARE’, there are too many of ‘US’ – human beings on the surface of the earth demanding, exploiting and extracting earth’s resources ruthlessly without any regard to its stability and sustainability.
Some 200 years ago or even 100 years ago we were doing what we are doing now – spewing out carbon dioxide and other global warming gases into the atmosphere – but that did not change climatic conditions irreversibly, because not enough of us had been doing the abusive actions. But now more than 7,500 million of us abusing the earth and probably pushed the earth to the threshold or beyond its sustainability.
The large human population of the present day is causing the problems. The United Nations’ estimation of human population from 1050 to 2017 is shown in Figure 1, where the past numbers had been compiled from human records and best estimate values. At no time until 1850 the global human population exceeded 1.0 billion. Around 1750, when Industrial Revolution took place, the Western World started using coal and other natural resources to improve living conditions and consequently the population started to grow significantly. From that time on, not only the standards of living started to improve but also better hygiene and improved medical sciences managed to bring down the death rate and thereby help increase population growth. At the moment the global population is 7.5 billion and growing at the rate of 80 million every year and this number is also growing! Since 1970, the global population had gone up by two-fold!
In 1960s and 1970s there were intense debates about the sustainability of the world population beyond about 3.5 billion, particularly with regard to food production. As estimated at that time that in about 12 to 15 years the population would grow by more than a billion (about 30% of the prevailing population). If so, could the food production be increased by about 30% in that time scale? The global population had been going up at that rate ever since despite all the measures taken to curtail it.
As the population grows, there are extra demands for housing and other socio-economic facilities and consequent shrinkage of arable land. But human ingenuity prevailed – multiple crop production, better yielding crop, crop rotation, disease resistant seeds and now GM crop etc – had improved food production. In fact, food production had been improved so much that food supply for the population is no longer an issue. But that had created more serious problems, particularly environmental problems, which need to be tackled.
The United Nations have also produced a population growth projection for the years 1950 to 2100, as shown in Figure 2. Many factors affect population growth and incorporating various assumptions in those factors produce widely varying outcomes. The middle thick green line is the outcome based on best estimate values, whereas the top and bottom lines are those with 95% level of confidence in various assumptions. If corrective actions such as proper family planning, better education and social responsibility of the population etc. are taken, the population growth could be limited to 9.6 billion in 2100, whereas unbridled growth will show a figure of 13.6 billion! The difference between two extremes in population numbers in 2100 is about 4 billion, more than 50% of the present population! That is an alarming prospect indeed!
Population distribution is not uniform round the world, as shown in Figure 3. At the moment over 60% (4.6 billion) of world population is in Asia and Africa constitutes 1.4 billion (less than 20%). But by 2100 the Asian population may remain same or even decline, whereas African population will shoot up to 4.4 billion, more than three times of the present population. This drastic increase will place enormous burden on the continent and may even lead to violent responses, unprecedented population migration to other continents etc. This situation will arise on top of ensuing environmental deterioration – global warming, extreme weather conditions etc.
It is interesting to note that China’s present population of over 1.42 billion would come down to about 1.06 billion by 2100, whereas India’s population would grow from 1.35 billion to 1.46 billion in the same time scale, as shown in Figure 4. China’s drastic reduction in population is due to lower fertility rates which arise due to older population group. China had imposed two-child policy right from its inception and gradually it is bearing fruit.
As already mentioned, population growth is multifactorial. But a very important factor is the economic condition of the country. A run away population growth stunts the economic growth of the country and at the same time a low economic growth tends to encourage higher population growth. A family tends to produce more children in a poverty-stricken country so that the children can look after the parents at their old ages. Thus, population growth and poverty form a vicious circle. Examples are Pakistan and Nigeria where large population growths are anticipated. On the other hand, Bangladesh is the country which has broken out of this vicious circle.
Let us get back to the aforementioned theme that climate change is primarily due to the presence of vast population. Coal extraction and its use by limited number of people catering for one or two billion people in the Western World in the 18th or 19th century was not that damaging to the climate. But, as deprived population of the East as well as other decolonised countries’ population are striving to improve living standards from abysmal depths, demand for natural resources like coal, gas, oil as well as minerals have gone up exponentially and environmental degradation followed the suit.
Nature has an inbuilt mechanism of correcting itself when there is any deviation or offset from the norm, which is commonly known as negative feedback. If there is an increase in temperature in the summer, more water from the sea would evaporate and subsequent rain would cool down the area. There are lots of factors acting in opposite phase to the initial condition to stabilise the natural conditions and that is the negative feedback.
But there may be situations when moderate negative feedback condition could breakdown and violent response would ensue. If due to excessive increase in global temperature, arctic and Antarctic ice caps melt, then there would be no seasonal cold stream of water, no moderation of summer temperature etc. In some areas the temperature would become so high that there would be almost spontaneous fire – as in Australia, California and even in Siberia. Condensation would be restricted to limited areas giving large increase in rainfall – as in England now – causing unprecedented floods etc.
So, either we pull ourselves back from the precipice by limiting and then reversing the damage that had already been inflicted to the nature or let nature go berserk threatening the very existence of human life or for that matter any form of life on earth.
- Dr A Rahman is an author and a columnist