Environmental Consequences of Alvarez Asteroid Collision Dinosaur Extinction Theory vs. Anthropogenic Environmental Problems of Today

Extinction Theory and Its Impact in Contemporary Society

The apparently sudden mass extinction of Dinosaurs marks the boundary between the Cretaceous and Tertiary periods. This catastrophic event has also triggered a large amount of interest in both scientific and general communities. Many speculations have thus been made regarding the reasons for the death of the dinosaurs. These include extreme changes in the global climate and sea levels, and supernova explosions.

During the 1980's notable new theories emerged regarding the mass extinction of dinosaurs. There has also been a concentrated effort to research these theories in terms of possible dangers to the human race. Luis Alvarez for example originated the idea of an asteroid striking the earth to cause the catastrophic demise not only of prehistoric reptiles, but also of most of the life forms present on the earth of the time.

According to the Alvarez theory, the environmental consequences of the alleged impact include a massive and catastrophic chain reaction. The asteroid striking the earth caused dust to cover the atmosphere on earth, resulting in continued darkness. This is referred to as "impact winter." The chain reaction involved the initial demise of plants, then of the animals depending on the plants for life, and finally the predators depending upon other animals. Other elements added to this theory include explosions, tsunamis, greenhouse warming, and global forest fires.

A second prominent theory contending with that of Alvarez was Dewey McLean's volcano-greenhouse theory. This theory is more in keeping with the current anthropogenic environmental problems experienced by the earth today.

In contrast to the Alvarez theory, the volcano-greenhouse theory is less cataclysmic and sudden in its impact. According to this, the mass extinction of a species is the result of the interaction between earth processes and the consequent evolution or indeed demise of life on the planet. The premise is that the earth and its revolutions on its own axis and around the sun directly affect bioevolution and extinction. Thus rather than seeking the reasons for extinction in extraterrestrial causes, McLean search for them within the earth itself. Rather than resulting from accidental causes, extinction, according to this theory, is the result of natural evolutionary processes. Thus McLean's work focuses on a link between Deccan Traps volcanism and the extinctions occurring during the Cretaceous period. This link further included variations in the earth's climate and its direct effect on the population dynamics of vertebrates. At the same time McLean is willing to incorporate all theories, including the impact theory, into his investigations.

The belief is thus that variations in the carbon cycle are linked to a physiological mechanism, and population dynamics are influenced by this system. This theory has far-reaching consequences for scientists and biologists during the 21st century. What McLean terms the "Mammalian Population Collapse Mechanism" and the "Vertebrate Physiological Killing Mechanism" are directly linked to events that are evident in the ecological dynamics of the world today.

Of course there is also the fact that dinosaurs were largely the victims of their world. They did not consciously manipulate the world to make life easier for themselves. Instead they were forced to adapt to whatever physiological changes their environment underwent at the time. Whether these were due to natural mechanisms or to the sudden impact of a an asteroid makes little difference to the extent of the reptiles' ability to continue life. Human beings today differ in that they are much more technologically advanced. What has set the human population apart from other forms of life is the ability to manipulate and build tools against the difficulties presented by the environment.

This ability has however also had some catastrophic consequences. Inherent in human intelligence is also the ability to destroy itself. Many of the environmental crises faced by all life on earth today are the result of the human effort to simplify life. Pollution and global warming are for example effects directly related to technological advances. These in themselves predict future tragedy and the possibility of extinction without the help of natural killing mechanisms or indeed extraterrestrial projectiles.

It can be argued that mass extinction is possible, even today, as it was during the time of the dinosaurs. There are three possibilities, if the above is taken into account. First, it is possible that an asteroid of vast proportions can collide with the earth, resulting in the mass extinction of several life forms, including human beings. The exact consequences listed by Alvarez have however proved to be inconclusive by further scientific study. A second possibility is of course the fact that changing dynamics on earth and the consequent bioevolution could prove fatal to the human race. Human beings are however very advanced technologically. Passively waiting for slow earth-induced extinction is a somewhat fantastic notion. Much more realistic is the third possibility - that human greed and ignorance may prove fatal to a race that is much too clever for its own well being.

There is however hope. While mass extinction on earth is certainly possible, one can say that it is not very likely. The reason for this is the very intelligence inherent in the human mind that can be so destructive. This intelligence can also be extremely beneficial. This can be considered in terms of all three extinction possibilities mentioned above.