About the Sixth Extinction

Most species that have ever lived over the 3.7 billion years of life's history are extinct. Extinction is a fact of life. Species become extinct because they were outcompeted for resources or poorly adapted when their environment changed. According to the fossil record, on average species exist for about 2 million years.

The fossil record -- all the fossils catalogued in all the musuems and scientific establishments around the world -- also record five periods when the extinction rate was much higher than average. These brief, dramatic periods are known as mass extinctions. (One place to read about them is here.) In a mass extinction, more than 50 percent of the species become extinct. There are five mass extinctions in the fossil record. Two notable ones were 250 million years ago, when 96% of species became extinct, and 65 million years ago, when an asteroid struck the Yucatan peninsula, setting off a chain of events that ultimately led to the final extinction of the dinosaurs. 

There is now abundant evidence that we are in a "sixth extinction". The major causes of the sixth extinction are habitat destruction, pollution, introduction of invasive species, over-exploitation (over-hunting and over-fishing) and climate change. These are all human factors so some scientists are referring to the latest geological period as the "Anthropocene" to reflect the enormous impact humans have had on the biosphere. 

The present extinction rate is estimated to be 100 to 1000 times the so-called background extinction rate, or in numbers, we're losing about 100 species per day. Over a year, that's 30,000 species, and over one hundred years that's 3,000,000 species. By the middle of the 21st century, we could lose half of Earth's biodiversity. This is a human crisis. Humans can solve it by understanding how our behavior is causing species loss and making changes. We should see ourselves as the stewards of the planet, not the conquerors.   Being a steward requires responsibility and the ability to see that other species deserve our respect, for they have a right to this planet just as we do.

The time to put a halt to this extinction is NOW.