I have been toying with the idea of writing this post for some time. I am well aware that discussions about climate change can generate a lot of heat and not much light (pun intended), but this is a question that has been bugging me for quite a while. So I am willing to withstand the brickbats in order to harvest the wisdom of the crowd.
I have witnessed conversations which involve one person saying that global warming isn’t happening at all, on saying it is happening and it is all down to human action and another saying it is happening and it is all down to increased sun activity. I stood by and just listened.
Let’s start at what I believe I know. When I learned about the dinosaurs I was told that they were the dominant life form on Earth for over 150 million years, which is a period that makes the humans’ time on Earth negligibly short. They were reptiles and therefore cold blooded and depended on significantly higher air temperatures than we have now in order to survive.
As our distance from the Sun hasn’t significantly changed, so it is reasonable to assume that there is an expected average temperature that a planet should expect when it is 150 million KM from the Sun. Venus is a bit closer and a bit hotter and Mars a bit further and a bit colder.
This leads me to the big question, how hot is the Earth supposed to be? On average?
For 150 million years until about 65 million years ago it was much hotter than it is now, over the fairly recent past it has been much cooler than it is now, but which is closer to the average mean temperature for the whole history of the planet. If the mean is a higher temperature than we are currently experiencing, could recent global warming be at least partially explained by reversion to the mean?
Newslinks for Saturday 25th May 2013
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