Man Made Climate Change

One thing that has often puzzled me about climate change, is that while a 2°C rise in global temperature is considered safe, a 5°C rise is thought to be catastrophic. In addition, several books I have read have reported that earth temperature has not risen more than 6°C warmer than it has now for hundreds of millions of years. The last time the climate warmed 6°C warmer than now was at the End-Permian mass extinction event, when 90% of species perished. The only vertebrates that survived were ugly pig-like animals that sheltered in pools. However, I read in another book that at the start of the Eocene era, the average temperature in London was 25°C, and that England was covered in rainforest. I thought maybe that was because England was further south, but apparently we were at the same latitude. In addition, crocodiles were living 100 miles from the North Pole, which meant that the water temperature there could never have fallen below 10°C. That sounds like an average temperature rise of well over 5°C. I know the poles are expected to warm up more equatorial area, and that due to trigonometry the surface area of the planet between 45° and 90° latitude is much less than the between 0° and 45°, but still, it seems like a rise well above 5°C.

 

Yes, but I still can't see how an average 5°C rise in average global temperature can produce a 15°C rise in temperature at a latitude of 51° (London) and all points north.

Anyway, after a lot of struggling, I think I found the surface area of the Earth above a certain latitude.

A = 2πR^2(1-sin(Θ))
R= 6371 km
29.3% of the Earth's surface is above 45° North and below 45° South. 11.1% of the Earth's surface is further north than London with another 11.1% on the other side of the planet. I suppose if you divide 5°C by 0.222 you get nearly 23°C, still it's a bit iffy. How much did it warm in the tropics?

 

Wow, I didn't know any of this. Where did you learn that? If it's a book, I want to read it! It's weird to think there was crocodiles up there and London was a rain forest! When was this Eocene era? Sorry, I am pretty much clueless about these types of things.

 

These were two books. One was Six Degrees by Mark Lynas, which is enough to give you nightmares at night. I think the other was called something like Eocene: From Greenhouse to Icehouse. It was a geology text book, not really about man-made climate change. It's main controversy was the exact ending of the Eocene epoch. The bit about the rainforest and crocodiles was at the start of the book, but on the whole it was more interested in the other end of the timescale when things were cooling down. There was a lot of talk about foraminiferans, I remember, which are tiny plankton with shells. The Eocene started about 55 million years ago and ended about 30 million years ago.

 

Oooh, wow. Now that you have said that books is enough to give you nightmares, I kind of want to read it haha. Going to have a look on Amazon for it. Sounds exciting. Will check out the other one too as I find this a really fascinating subject.

Thank you for sharing!

 

The other book was called The Eocene-Oligocene Transition by Donald R. Prothero. I am not sure I would recommend buying it as it is quite expensive for a paperback. Also, it is a bit dull. If you really want to read it, I will send you my copy, so long as you promise to send it back when you've finished.

 

Yes, it is scary. However, there are geo-engineering techniques which we could resort to. Geo-engineering is very, very contentious. A lot of people (well Greens, but a fair few climate scientists too) think it is total insanity to consider it. Personally, I suspect we may not have an option.

I have been reading Mark Lynas's latest book, The God Species. He discusses a number of environmental boundaries that he considers vital that we do not cross. These include greenhouse gases, freshwater, land use, biodiversity, toxins, aerosols, nitrogen fertilisers and ozone. Lynas is not really a Green. He thinks the Green movement has done a lot of damage to environmental causes by their opposition to technologies such as nuclear power, geo-engineering and GM crops. He also tends to think that the Green narrative of cutting back consumption and curtailing free-market economics has caused a political backlash. Ideology trumps science, incredibly enough. I am not sure I buy everything that Mark Lynas says, but he is right that pessimism is not an option. However difficult it is, we (well people with clout) have got to keep trying.

 

Awh thank you for that offer, think I'm going to stick to The six degrees book for now though. I'm going on holiday soon and this book looks like some perfect holiday reading for me. I will be sat on the beach reading about all the devastation that will soon be! It really does look scary!

 

I read an article in a paper that suggested it could be a brake on climate change. The algal blooms that result from the nutrients released from melting ice die and drop to the bottom of the sea.