500ma organisms were adapted differently to what they are now and had time to adapt to the new conditions, there is concern that many species wont be able to adapt given how rapidly these levels are escalating.
I should have made my point clarer in the last post, co2 isnt the only pollutant generated by burning fossil fuels, particulate matter has been found to significantly shorten the lives of many even in brisbane and sydney, god knows what its doing in china, if curbing fossil fuel use reduces pollution in other forms that it generates I think that is worth it
