For the last 3.5 billion years, living organisms have survived, blossomed, increased, and variegated to take place in each of Earth’s ecosystems.
The not-so-positive part about this thriving of new species is that species extinctions have taken place as well, as part of the evolutionary life circuit. However, these two processes are not always synchronizing. When the decline of species quickly exceeds the development of new species, this offset can be tilted sufficiently to provoke what is known as ‘mass extinction’ occurrences.
Today’s Biodiversity – a Mass Extinction?
A mass extinction is typically explained through a loss of approximately three-quarters of all existing species all over the Earth over a relatively short geological period. Considering the massive amount of time since life first developed on the planet, ‘short’ is established as anything less than 2.8 million years.
The Earth is at the moment going through an extinction crisis mainly because of the exploitation people are causing. However, this fitting the description of a mass extinction depends on whether the current extinction rate is higher than the ‘natural’ or ‘background’ pace that takes place between mass extinctions.
The background pace explains the speed of the disappearance process the species would be expected to follow in lack of human behavior, and it is mainly calculated utilizing the fossil record to measure how many species were annihilated between mass extinction events.
The most agreed-upon background rate calculated from the fossil record shows that the life of a species lasts for approximately one million years. However, the assessed pace is incredibly unreliable, spanning between 0.1 and 2.0 extinctions per mission species-years.
The fact that we are or not in a sixth mass extinction at the time depends on some extent on the correct numbers of this rate. If not, it is rather difficult to make a comparison between Earth’s situation today with the past.
A Sixth Mass Extinction
Scientists estimate it would take a few millions of years of natural evolutionary diversification to regain the Earth’s species to what they were before humans started to influence the planet negatively.
According to the number of declining vertebrate species listed in the International Union for Conservation of Nature‘s Red List of Threatened Species, 32 percent of all currently-existing species from all ecosystems and groups are declining in an astoundingly rapid manner. As a matter of fact, Earth has lost approximately 60 percent of all vertebrate individuals since 1970.
Even though biologists are still arguing over how much today’s extinction pace surpasses the background rate, even the most moderate evaluations depict an unusually rapid loss of biodiversity characteristic to a mass extinction event.
As a matter of fact, a few studies show that the cooperating conditions currently in place, such as accelerated climate change, changing atmospheric composition, which is man-made, and unnatural ecological stresses caused by human consumption of resources, is the definition of the beginning of an extinction event.
All these estimates and circumstances clearly show that the sixth mass extinction has already begun.