Pterosaurs

At http://wattsupwiththat.com/2012/06/02/so-dinosaurs-could-fly-part-i/ … an unusual post as far as subject is concerned. Andi Cockroft wonders aloud about paleo-climate as it seems Theresa Cole (see ColeTheresaN2011MSc.pdf) recently produced a graph that purports to depict an observed fall in global annual mean atmospheric pressure since 1916. This led to the dinosaurs and the idea they would not be able to fly nowadays as they are too heavy to get lift off from the ground. Were they helped by denser air? Denser air probably means a higher air pressure than today. If so how has the air pressure fallen – is the composition of the atmosphere changing? Did Earth have an atmosphere high with co2? After all, in the Carboniferous and the Permian there were dragonflies over two feet in wing span – and other giant insects. In the geological magazine, Down to Earth (June 2012) there is a picture of one of these dragonflies, one of two that was found by miners in a colliery in Bolsover in Derbyshire. It became known as the 'beast of Bolsover' and in modern times the term was transferred to the local MP for Bolsover, Dennis Skinner.