Sharks are about 450-400 million years old. They were around 200 million years before the dinosaurs, and have outlasted them by 65 million years. They're older than the North Star, the rings of Saturn, the Atlantic Ocean, and trees.

And it took 60 million years for the trees to start rotting when they died, because the bacteria to break them down didn't exist. Those trees died, fell over, became peat, and then eventually coal. The trees that were dead and buried trapped carbon dioxide that had been in the atmosphere. 90% of the coal we burn today comes from the period when trees didn't rot, and we're re-releasing all that CO2 back into the atmosphere, from where it's been safely sequestered for 250 million years.