The geological record shows what happens when carbon increases in the atmosphere

March 1st, 2012 by Richard Lord

Dr Bryan Lovell, President of the Geological Society of London, discusses what the geological record tells us about past global warming events with Andrew C. Revkin of DotEarth blog.

Below are some of the comments Dr. Lovell makes.

“Within the last ten years we have been able to look at past episodes of global warming on the human scale.”

A paper published in Nature in November 1999 looked at a 55 million year old warming event. The beauty of looking at the rock record is you don’t have to run a computer model about what is going to happen. You see the whole thing.

When you put 2000 gigatonnes of carbon into the atmosphere rapidly a certain number of things happen.

It gets hot. The oceans get acid, they run short of oxygen and as a result a large number of species become extinct.

The rock records the extinction event, and the carbon from the atmosphere, which is manifested on the floor of the ocean as the development of a carbon-rich mud-stone.

Earth itself has run the global warming experiment several times – 183 million years ago something very comparable happened.

“Other past warming events where we get these black mud stones we find that whatever the starting conditions, you get the same outcome.”

“The Geological Society of London is a mixture of academics and oil men. We are a professional body and we are a learned body. We thought it was time for us to make a public statement about things we agree as a group of geologists that are established beyond reasonable doubt.”

“No one doubts that we have already dump several hundred gigatonnes of carbon into the atmosphere – that’s observational science.”

All the geological evidence points to what happens during a warming event.

“Which bit of this observational science do you quarrel with and why?”

“We are now quite confident that it is unwise to go on doing what we are doing.”

“Our code of conduct broadly states that if you don’t know what you’re talking about, shut-up. It’s a standard code of conduct for a professional society.”

“The rock record tells us we have a problem. We have got to stop doing what we’re doing now or we’re going to risk a repetition of these past events. The Earth will be fine. We might not be.”

Geologist are trying to establish an independent line of argument. Climate science is tricky and not everything is understood.

You look at the full 200,000 year cycle and there’s an eerie repetition of events. This looks like a pretty substantial trigger you pull on the planet and then you get this outcome. It sweeps away the detail….

“I think it is really important that the oil industry plays a part in helping us solve this problem.”

“As far as the public argument goes, the fact that Shell have said, for them, the climate change debate is over is very important.

I think the geological argument is quite effective. We geologist need to think about how we can deploy it on the political sphere.

“I would like us to behave around the planet now in a way that makes it very tough to spot the anthropocene in the future geological record.”

“We’ll put down a little bit of stinky black mud stone in the world’s oceans but may be not enough for it to be a distinctive geological epoch.”

You ask about anthropocene.  I hope we won’t have to define it.”


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