It is estimated that anatomically modern humans have been on Planet Earth for around 200,000 years and that Planet Earth has been in existence for over 4.5 billion years. The human imprint upon the planet we inhabit has therefore been an extremely recent phenomenon but it has been quite pronounced nevertheless. Indeed, it’s becoming increasingly hard to find oneself somewhere that doesn’t bear the hallmarks of human endeavor. Take a look around and the chances are that you will see buildings, roads, land that has been converted for farming, and telegraph poles snaking their way even through our most remote wildernesses.
The extent of the change that our species has wrought and the degree of damage that we have inflicted upon our environment is a matter of much debate. There is an increasing concern in the scientific community that the effects of industrialization, deforestation, and high energy consumption have led to an abnormal increase in greenhouse gases which, in turn, are causing our planet’s climate to become dangerously unbalanced. Sceptics still remain, however, who argue that the projected global warming either won’t happen or is part of the planet’s natural cyclical climate pattern.
Whatever one’s beliefs on the global warming debate, there is no doubt that man’s evolution has resulted in changes to the planet. Some of the main changes include:
Deforestation:
Deforestation is amongst the most obvious of the changes that humans have delivered. Over the course of many centuries, humans have cut down trees for fuel, to build houses, make paper, and to make way for farm land. Humans have short life-spans and tend to only be able to grasp changes that they see happen over their lifetimes. Many people are therefore ignorant of just how dramatic this process of deforestation has been. The United Nations Environment Programme (UNEP) estimate that “about half of the forest that was present under modern (i.e. post-Pleistocene) climatic conditions, and before the spread of human influence, has disappeared, largely through the impact of man’s activities.” (1)
Of most concern is the ongoing loss of acreage in the rainforests of South America, Africa, and South East Asia. Deforestation is causing increasing amounts of carbon dioxide to be released into the environment and is also having a devastating impact upon our planet’s biodiversity. Research at Harvard University has postulated that a “quarter or more of all species on Earth could be exterminated within 50 years due to the removal of habitat with destruction of the rainforests”. (2) Quite apart from the inherent tragedy of species extinction, this will prove detrimental to humans as the rainforests are our prime source of pharmaceutical advancement.
Biodiversity and predator/prey balance:
All life exists within an ecosystem, that contains predators and prey and requires a certain amount of balance to avoid collapse. Humans originally would have occupied a fairly low place on the food chain, preying on small animals but, in turn, being preyed upon by the larger carnivores. Our rise to being the alpha predator throughout the planet was dramatic and exceptionally comprehensive.
Corresponding with our rise to power, has been a significant decline in the health of other predator species. Some, such as the sabre tooth cats, have gone extinct, whilst the ranges and population size of others has decreased substantially. To give an example, lions, wolves, and bears used to be commonplace across Europe and early man (and Neanderthals) found themselves in competition for resources.
We have also influenced the evolution of other species either by turning them into working animals (dogs, horses, etc) or pets (dogs, cats, etc), or by farming them for meat or by-produce (cattle, sheep, etc). Through animal husbandry and cross-breeding initiatives, we have domesticated many species and caused significant changes in their physical appearance and traits.
Pollution, over-farming, and warfare:
Mankind has had an insatiable desire to become bigger, better, more advanced, richer. This has manifested itself in technological developments such as transport (cars, trains, planes, ships, etc), and the production of all manner of products and services that require to be manufactured in smoke-billowing factories. For the vast majority of modern humanity, very little thought has gone into minimizing the harmful side-effects of this activity, with the result that our rivers and seas have become polluted (as well as over-fished), our polar ice-caps are shrinking, and (in some cases) farm land has become decreasingly fertile.
Human activity is contributing (in some regions) to a process whereby deserts are claiming former farm land, causing drought and untold hardship for both human and animals populations.
On top of all this, humans have also developed and deployed the capability to substantially damage the environment through modern warfare and/or the misuse of nuclear power. The bombing of Hiroshima and Nagasaki, during the Second World War, not only caused large-scale loss of life but also emitted harmful radiation. Similarly, the Chernobyl Nuclear Power Station disaster, in 1986, also caused significant radiation poisoning and the effects are still being felt in the area today.
Summary:
Our species, Homo Sapiens, has risen to an unprecedented position of power and influence on our planet, and the imprint that we have left on our environment is becoming increasingly clear. Humans have the capability to work together for a common good but, unfortunately, more often our actions are either intentionally or unintentionally damaging for the eco system that we are part of.
Indeed, mankind in his arrogance, often forgets that we are part of an eco system and that our continuing prosperity and existence is intrinsically tied to the health of our planet and the species that we share this planet with. We would do well to reflect on the fact that we are a very recent institution on Planet Earth and previous dominant species (such as the dinosaurs) discovered that the world would not always remain conducive to their way of life. Whether we agree with the global warming predictions or not, all of us should strive to reign in the worst excesses of our behavior so that we act as custodians of our planet rather than parasites.
Sources:
(1) http://www.unep-wcmc.org/forest/original.htm
(2) http://www.nytimes.com/1992/03/03/news/talks-seek-to-prevent-huge-loss-of-species.html
