Imagine if our world had a diary and on the interesting days, someone pulled out a big book and wrote about it. Day 103 was such a day.
It was about 300 million years ago, just a regular 22.5 hour day and on that lovely sunny morning, on the plains of a future Siberia, a Thursday perhaps, the recent rumblings and shaking of the ground took a turn for the worse.
The newly evolved reptiles had developed into millions of species and the air was filled with insects, some absolute monsters.
The oxygen in the atmosphere had been building up now for quite a while, a far higher concentration than the modest levels that would eventually be the norm for the apes of the future who will enjoy a 24 hour day at 21%, no the oxygen level on this lovely sunny morning was about 35%-40%. A lot of oxygen is a good thing, right?
Well, yes, in the same way your plane’s full tank of fuel is a good thing, right up to when it catches fire, then maybe not so good.
Well, all this oxygen made it possible for creatures that get their oxygen through this skin, insects for example, to grow and grow they did. On this fine sunny morning, there were dragonflies with wingspans like eagles filling the air and let’s not think too much about the local equivalent of mosquitoes.
But aside from the rumblings, life was getting on with what life does and there was no thought for the huge twin asteroids that were already on their way to crash into a future Canada. No matter, that was still a few millions years to go, so certainly no bother for the reptiles and insects.
The first sign of trouble was the smoke and gas arising from a patch of rather large trees. At that moment, the first of many mini volvanos broke the surface over thousands of kilometres of forest. There was going to be trouble and it was not just the trees that were burning and causing all that smoke that blocked out the sun, it was the coal. Vast clouds of thick black choking smoke rose into the upper atmosphere, blocking out the sunlight and quickly spreading around the world.
Yes, the coal, just under the ground, stretching to the horizon in all directions and hundreds of feet thick, was on fire. All that oxygen was not helping either, but why was there so much coal, nearly two million square kilometres of it, as it happens?
The answer to that is, ‘termites’. Well not exactly, more the lack of termites. What had happened it seems, was that as plant life evolved on land, feeding on sunlight as it does, those that could grow taller got the most sunlight and lived to pass on this trait.
The only way to compete was to grow taller and so lignum had been invented, well, evolved actually a couple of hundred million years before this fine sunny morning. It’s a woody substance that stiffened up the stems of plants and in those days, allowed them to eventually to become trees.
Now here was a problem. You see, lignum is very, uhm, woody and hard to break down, to digest. As it hadn’t been around before, there was no creature large or small, that had evolved the dental hardware to handle it. No bacteria could touch it and termites were millions of years away, so the trees grew and grew, got old and died. That’s all the happened, they just lay there, intact. More trees fell on top and more on top of them, until vast swathes of the earth was covered with dead trees that got compressed and turned in the massive coal deposits of the world as we know it.
As the volcanic action spread across the land, lava flowed and coal burned, for centuries. For a few thousand years, the earth was dark and very cold. There was no sunlight to sustain the plants and most creatures on land and most in the oceans too, turned up their toes in one of the great extinction events we now call the Permian extinction.
Eventually, the lava flows stopped in many places and the fire burned out and the sun came back, just long enough to make use of all the recently released carbon dioxide to heat up the earth, in a hot house of global warming as never seen before. What life had managed to survive the dark and cold was now faced with soaring temperatures and bright sunlight. Actually, it was just a trick and the lava began to flow once more and the whole earth was turned back into a cold dark night that lasted for a few more centuries before doing it again, perhaps as many as seven horrible cycles over several thousand years of hot and cold, dark and light.
Yep, day 103 was a big one and it was all because of those dam termites.
(You can see ALL the interesting days in The Magnificent Science Poster which you can download for tuppence.)