Three major global environmental problems

By Kardono

JAKARTA (JP): The changes in the stratospheric ozone, the global climate and population growth worldwide are the three most important global environmental problems currently facing the occupants of the Earth.

These problems have been discussed by many experts around the globe. The 1992 Environmental Summit held in Rio de Janeiro was just one indication of the level of concern. The United Nations Population Conference in Cairo last year was another. What we need now is to determine the causes and to become aware of how to prevent or correct these problems.

Ozone plays a peculiarly significant part in the chemistry of the earth's atmosphere, even though at first glance it might seem minor in terms of volume. The ozone exists primarily in the stratosphere, and is only about 3 mm thick if compressed to atmospheric pressure. The pollutants introduced into the stratosphere as a result of man's activities, which are eating holes in this layer, will take a lifetime to remove and have the potential to build up to globally damaging levels.

High temperature as a result of fuel combustion leads to the formation of nitric oxide (NO) by the fixing of atmospheric N2 and O2. The ordinary combustion products, CO2, CO and H2O, are also produced during this combustion process. Injection of these, especially of NO, into the stratosphere destroys the ozone. Nitrous oxide (N2O) from the troposphere is also the principal source of stratospheric NOx (NO2 and NO). Intensive use of fertilizers could lead to increased N2O production in the biosphere, the nitrogen fixed artificially in the manufacture of fertilizer being returned to the atmosphere through nitrification and denitrification processes. Nitrous oxide concentrations in the atmosphere are known to be increasing slowly (at a rate of 0.2 percent annually between 1976 and 1980).

It has been predicted that the concentration by the year 2000 will reach up to 5 percent to 7 percent above the 1980 figure, even if fertilizer use does not increase. With a world population of 6.5 billion and grain consumption of 400 kilograms per person per year, N2O production in the biosphere could double by the turn of the century.

Possible contributions to this concentration because of human activities could affect stratospheric ozone conditions. Moreover, fluorinated chlorocarbons (CFCs), particularly CFC12, or Freon 12, also have the capability of destroying ozone.

Ozone depletion results in the increase of solar ultraviolet radiation reaching the earth. The macromolecules, such as proteins and nucleic acids that are characteristics of living cells, are damaged by radiation of a wavelength shorter than 290 nanometers (nm).

Ozone has an unusually strong absorption ability at the critical wavelength (230-290 nm) so that it is an effective filter, in spite of its relatively small concentration.

Changes in ozone concentration could also have climatological effects because of altered stratospheric heating. Environmental worries about increased Ultraviolet-B (UV-B) radiation are concerned with the deleterious effects both on human beings and on all plant and animal species. Fear of cancer has made the incidence of human skin cancer the most publicized potential effect of ozone depletion.

Solution

The solution to be taken is immediate phasing out of such relatively frivolous and easily substitutable uses of CFCs as aerosol. Also, the control of producing and releasing NO from both naturally occurring combustion and conventional combustion. And safe agricultural practices should be undertaken to reduce the amount of N2O released from fields into the stratospehre.

The carbon dioxide (CO2) increase has come about almost entirely since the Industrial Revolution, as a direct result of man's activities. Increased CO2 emission is mainly caused by burning fossil fuels. Deforestation in the tropics and changing agricultural practices reduce the efficiency of COI2 recycling, thus causing and additional increase of CO2. At present, 1.9 x 10 kilograms of CO2 are being released into the atmosphere every year.

Concern about increasing CO2 levels is directed primarily toward the possible consequences for our climate due to radiation trapping.

It is not only carbon dioxide levels that have been increasing in recent years. Methane is another important greenhouse gas, and atmospheric methane levels have been increasing at the rate of 1.7 percent per year since 1965. The growth in rice paddy cultivation and in cattle farming could account for increased methane production. Input of nitrogen into crop land is expected to contribute t raising temperatures globally in the future.

The impact of all of this on global climatic conditions will be staggering for humanity and most other animal and plant species. The global increase in temperature could destroy the habitats of thousands of species of flora and fauna.

The solution to this problem is to find new and renewable energy sources to substitute for the conventional fossil fuel energy source. This can be done by renewed international research focused on improving the efficiency of such alternative energy sources as solar power and the perfection of such potential technological breakthroughs as hydrogen powered vehicles. Also, it requires the development of a series of external constituencies for climatic stability, including environmentalists, scientists, farmers and the nuclear and solar industries.

Population

Global population growth is considered one of the most important global environmental problems because environmental changes will directly affect the population. And, if global population growth remains high, at its current rate of 2 percent per year, the population will double in 35 years. This will destroy the environment.

It is vital that we apply the understanding that we have that human beings must maintain a balance with their environment if they expect to continue to obtain the food, oxygen and clean water that they need to survive.

The possible extent of future tragedy is being felt even today with roughly half of the people in the world suffering from inadequate nutrition. Protein deficits are most common. About one-third of the worlds' people do not get enough of the proteins that contain adequate proportions of all the essential amino acids.

The green revolution of vastly increased food production on the basis of new high-yielding strains was seen as necessary to solving the problem of nutritional deficits.

But this has resulted in heavier use of fertilizers and an increase in demand for water.

Water, which is used for so many other purposes, is now the prime resource for agricultural advancement. And our water sources are threatened by the agricultural widespread use of pesticides to the green revolution. The heavy use of fertilizer has contributed to the problem by resulting in eutrophication in rivers and lakes. In addition, the continued use of pesticides which are recalcitrant will result in greater pollution through the food chain processes.

There are two basics approaches to reducing the global population growth. The first is to change people's motivations so they want fewer children. The second is to provide couples who do not want children with the practical means to avoid unwanted births (contraceptives, etc.)

All of this can be done through education. So, education is a basic need. It is the basis for most effectively informing people about the need for contraceptives and other methods to limit population growth.

Curbing the growth of the human population is perhaps the most rational way of maintaining an environmental balance, which the most important principle of global environmental preservation.

Mankind, even at the population level the Earth bears now, has already proven its capability of overwhelming the natural restorative mechanisms that preserve the global environment.

The writer holds a Ph.D in air pollution which he obtained from the Environmental Engineering Sciences Department, University of Florida, U.S.A.