There have been five mass extinction events throughout Earth’s history:
The first great mass extinction event took place at the end of the Ordovician, when according to the fossil record, 60% of all genera of both terrestrial and marine life worldwide were exterminated.
360 million years ago in the Late Devonian period, the environment that had clearly nurtured reefs for at least 13 million years turned hostile and the world plunged into the second mass extinction event.
The fossil record of the end Permian mass extinction reveals a staggering loss of life: perhaps 80–95% of all marine species went extinct. Reefs didn’t reappear for about 10 million years, the greatest hiatus in reef building in all of Earth history.
The end Triassic mass extinction is estimated to have claimed about half of all marine invertebrates. Around 80% of all land quadrupeds also went extinct.
The end Cretaceous mass extinction 65 million years ago is famously associated with the demise of the dinosaurs. Virtually no large land animals survived. Plants were also greatly affected while tropical marine life was decimated. Global temperature was 6 to 14°C warmer than present with sea levels over 300 metres higher than current levels. At this time, the oceans flooded up to 40% of the continents.
I just finished The Sixth Extinction: An Unnatural History by Elizabeth Kolbert. It is a chronicle about what homo sapiens (us humans) are doing to the planet. The short version is we are literally killing our planet. Climate change, species extinction and increasing ocean acidity, all caused by us at such a fast rate that species are going extinct faster than ever before, destabilizing the weather, causing droughts, floods and wild temperature variations. And with ocean acidity rising, coral reefs are dying and some species of marine life will certainly go extinct. I would like to say there is a silver lining somewhere but the rate of species extinction, climate change and ocean acidity, the human race may find itself in a predicament that leaves cock-roaches to inherit the earth.
I wake each morning to the trees, clouds, dogs, cats, deer, skunk, possum, squirrel, owl,hawk, bear, coyote, bobcat, you get picture. I’m fortunate to have nature this close to me. I feel her presence close to me. The idea of losing even one member of our family makes my heart sad.
“We Have Met The Enemy and He Is Us”
– Walt Kelly
“Dear future generations: Please accept our apologies. We were rolling drunk on petroleum.”
― Kurt Vonnegut