Who is at stake? Earth or Homo sapiens!

Earth Day is the largest, most widely celebrated international environmental event. It is observed on April 22 to inspire awareness and appreciation for the Earth's environment. The scope of earth day is wider than other environmental days such as Arbour day or Habitat day which are specific to a particular aspect of environment. Due to gravity of the situation several days, years and even decade are celebrated to sensitize the stakeholders. United Nations declared the period from 2005-2014 as the decade of education for sustainable development. The present year is being observed as the International year of Biodiversity. A sustained effort like this bears positive impacts. People are now more aware and sensitive towards environmental issues and challenges.   

Let us go through a brief history of earth to know when and how humans started disturbing the environment. Most of the scientists believe that the universe was formed 13.7 billion years ago with what physicists call a big bang. The age of earth is about one third of the age of the universe.  Immense geological and biological changes have occurred on earth since its formation. It is speculated that life originated on earth about four billion years ago. Several mass extinctions have occurred on earth since then and the evolution of modern humans or Homo sapiens.  Homo sapiens are believed to have originated around 200,000 years ago or earlier in Africa. Throughout more than 90% of their history, Homo sapiens lived in small bands as nomadic hunter-gatherers.  Gradually language evolved and the ability to remember and communicate developed.  Due to which ideas could be exchanged quickly and passed down the generations. Cultural evolution started outpacing biological evolution.  Somewhere around 7500 BC, humans began systematic husbandry of plants and animals. Since then humans began to affect the environment as never before. The next phase of tinkering with environment began after European Renaissance leading to the scientific and industrial revolutions. Since then the change has continued at a rapid pace. Modern technological developments include sophisticated weapons, computers, genetic engineering and nanotechnology. Several of the environmental impacts faced by humanity are directly or indirectly caused by energy extraction, conversion and utilization. Economic globalization spurred by advances in communication and transportation technology has influenced everyday life and surroundings in many parts of the world. Human-caused climate change has risen as the world population increases. The present level of temperature is 0.3-0.6 degree higher than what it was 100 years ago. The frequent abnormal weather conditions are reported to be an outcome of global warming. Carbon dioxide which is one of the most prevalent green house gas (GHG) in the atmosphere is rising due to combustion of fossil fuel and changes in land use.  

In modern times climate change has become serious threat to society affecting environment, terrestrial ecosystems and biodiversity. The human dominance in Noosphere has resulted in widespread ongoing extinction of other species. At current rate about 30% of species are at risk of extinction in next 100 years. This extinction is the result of habitat destruction, the widespread distribution of invasive species, hunting and climate change.  More than a third of the land surface has been modified by human actions.

 Nature, however  is capable of taking care of itself. Earth’s survival is not at stake. Going by the history of earth we know that Nature may help in evolution and nurture of new species in new circumstances. It is the survival of Homo sapiens that is at stake. The consequences of present environmental crisis could be anything from a decline in biodiversity, proliferation of opportunistic species such as pests and weeds. Novel species may also emerge. However, no new species of existing large vertebrae are likely to arise and food chains will likely be shorter. Earth day may be observed with the slogan and spirit of ‘Save Homo sapiens by respecting other forms of life’.