What is Holocene?
To study the history of life on our planet, scientist requires a relative scale so that they can place important events. Such as the first land vertebrates, or the first evidence of flowering plants in the perspective of geological time. Such a scale is provided by the science of geology. Geologists have subdivided the history of our planet into time intervals of varying duration. The largest periods of time are divided into Eons. An example is the Phanerozoic Eon (visible life), representing the period of geological time from approximately 550 million years ago to the present day.
The Phanerozoic covers that period of time when fossils first become abundant, reflecting the obvious presence of life. Eons are divided into Eras, such as the Cenozoic Era that covers the last 65 million years (sometimes called the Age of Mammals). Eras are broken down into Sub-eras and further divided into Periods. Hence well-known sections of geological time such as the Jurassic and the Cretaceous. Periods are further sub-divided into Epochs. The last 10,000 years of geological time is known as the Holocene (recent time). Roughly reflecting the adoption of sedentary farming and domestication of livestock by people.
What is mass extinction?
Mass extinction is the rapid destruction of the major living thing in a wide range of the location on earth. Mass extinction is an event called a biotic crisis, is a vast and rapid elimination in the biodiversity on Earth. Such an event can be identified by a distinct negative change in the diversity and distribution of multicellular organisms. The example is Permian Mass extinction (251.94Ma), Ordovician mass extinction, Cretaceous mass extinction in which dinosaurs have vanished. The recent Holocene mass extinction (Sixth Mass Extinction) is coming soon.
What Causes the Holocene mass extinction (Sixth Mass Extinction)?
Scientists use information sources such as ice cores and micro-fossil studies to investigate the history of the earth. It seems that the Earth’s climate has been more stable than during any other 10,000-year interval in at least the last 200,000 years or so. For much of this time, the human population has grown steadily. It is only in the last 200 years or so that the human population has grown dramatically. The growing demand for resources from the increasing human population, in conjunction with rapid climate change, has been identified in the United Nations (UN) report. This may be a causal factor in the dramatic decline of animal and plant species.
However, one of the conclusions in a United Nations (UN) report due to be released this week, is that animal and plant species are becoming extinct faster than ever before. A rapidly growing human population in combination with an increasing demand for natural resources represents a grave threat to all. The increasing economic activity and industrialization of countries such as India, China, and Brazil are adding to environmental threats.
By the middle of this Century, the human population is estimated to have grown from today’s level of approximately 6.8 billion to over 9 billion. That is an increase of 2.2 billion (32% increase in just forty years). Two-thirds of the population will live in cities it has been predicted, in China alone over 400 new cities with populations greater than 1 million will have to built to accommodate this increasing population.
The increased demand for natural resources plus the adverse effect on the global climate will have a dramatic impact on the diversity of life on Earth. Scientists are aware of a natural extinction rate, a sort of background rate of extinction. This background rate represents low levels of extinction as a result of evolution and adaptation plus some local or restricted climate/environmental change. The fossil record, although far from complete shows evidence of larger extinction events. There have been a number of extinction events recorded in the fossil record.
For instance, many people may be aware of the Cretaceous mass extinction event that ended the reign of the dinosaurs, but a number of lesser extinction events are associated with the Cretaceous. Paleontologists have identified five major mass extinctions in the Phanerozoic. The history of life on our planet has been punctuated by a series of mass extinctions, mass extinctions being defined in a number of ways, but normally they relate to the number of marine and terrestrial genera that die out in a relatively short period of geological time. Most scientists agree about the “big five” mass extinction events, but some scientists are arguing that the Holocene epoch should also be defined as a mass extinction event – the sixth mass extinction.
The Scale and Speed of Extinction
Although it is difficult to accurately assess the decline of fauna and flora, if mammals and birds are examined in isolation, an alarming picture is revealed. There are approximately 14,000 species of mammals and birds today. These types of animals are dying off at a rate of approximately 10,000 times faster than the standard background extinction rate. The United Nations report uses data gathered from 120 countries, it concludes that the magnitude of damage to ecosystems is much bigger than previously reported. This UN report will show that no country has succeeded in halting the decline in biodiversity. Eighty-nine percent of those countries that submitted data had identified climate change as a major cause. For our species, the consequences could be dire.
We, humans, are at the top of the food chain and very reliant on robust and dynamic ecosystems. The loss of a single species, the honey bee, for instance, would have a significant and detrimental impact on our ability to produce food. Approximately, one-third of all the vegetable and fruit crops grown on a commercial scale by humans, are pollinated by bees.
Given the current economic difficulties being experienced by many countries, it is likely that this report and its conclusions will not be given the prominence that it and the conclusions deserve. The fossil record in two million years’ time could show one of the most dramatic and rapid extinction events in the history of life on Earth.