Buckle up your belts, I am going to take you all way back in time, in fact to a great expanse of time that had elapsed since the big bang. In order to think about it, let’s compress the whole timeline of our Universe since the big-bang till now into a single year, what we call it a cosmic calendar. We are now in the early morning of 23rd December. About 350 million years back in time.
About 350 million years ago, our world was a mere 4 billion years old. Earth was so different back then. You might not even know the place. The stars wouldn’t have helped, even the constellations would have been different back then. The dinosaurs were still more than 100 million years in the future. There were no birds, no flowers. And the air was different too. The atmosphere had more oxygen than any other time in the earth’s history before or since. This allowed insects to grow much larger than they do today.
Insects don’t have lungs. Life-giving oxygen is taken in through the porous openings in the outside of their bodies and transported through a network of tubes. If an insect were too large, the outer reaches of the tube would have absorbed all the oxygen before it could get to its internal organs.
But as I told you, during this carboniferous period, the atmosphere had almost twice the oxygen as today. Insects could then grow much bigger and could still get enough oxygen into their bodies. During this time, The dragonflies were nearly big as an eagle and the millipedes were almost the size of alligators.
So why there was so much oxygen back then…?
It was produced by a new kind of life.
So what kind of life could have changed the Earth’s atmosphere so dramatically…?
Plants that could reach for the sky.
Trees, in their competition for sunlight, trees evolved a way to defy gravity. Before trees, the tallest vegetation was only about our waists high. And then something incredible happened.
A plant molecule evolved that was both strong and flexible, a material that could support a lot of weight yet bend in the wind without breaking. Lignin made trees possible.
Life could now build upward and this opened up a whole new territory, a three-dimensional matrix for communities far above the ground. Earth became the planet of trees.
But lignin had a downside. It was hard to swallow. Nature’s demolition crew, yes I am talking about the fungi and Bacteria. Whenever they tried to eat anything with lignin in it, they got a really bad case of indigestion. And termites didn’t evolve for at least another 100 million years.
But what to do with all the dead trees?
It took the fungi and bacteria millions of years to evolve the biochemical means to consume them.
Meanwhile, the trees just kept springing up dying, falling over and getting buried by the mud that built up over eons. Eventually, there were hundreds of Billions of trees entombed in the Earth. With buried forests all over the Earth. What possible harm could emanate from that.
If you could get to the cliff in Nova Scotia, Eastern Canada. You can find the death mask of those trees, which were cast by minerals that replace the original wood cell by cell. Yes, these are fossils. The trees surrendered it’s organic molecules to the environment long ago.
When these trees were alive, it took in carbon dioxide and water and used to sunlight to turn them into an energy-rich organic matter, trees gave off oxygen as a waste product. That’s what trees and other plants still do.
When plants die, they decay and this reverses the transaction. Their organic matter combines with oxygen and decomposes putting carbon dioxide back into the air.
But If the trees are buried before they could decay, two things happen.
They take the carbon and the stored solar energy with them and leave the oxygen behind to build up in the atmosphere. This is what exactly happened about 300 million years ago.
And what became of all that buried carbon?
It lay there for Eons before dealing life on Earth.
There are places on this planet where you can walk through time and read the history written in the rocks……………………….