# More on climate

1. May 13, 2005

### wolram

http://arxiv.org/PS_cache/astro-ph/pdf/0505/0505245.pdf [Broken]

Title: A climatic thermostat making Earth habitable
Authors: Peter D. Ditlevsen
Comments: 4 figures, Proceedings, NORDITA conf. Astrobiology 2004

The mean surface temperature on Earth and other planets with atmospheres is determined by the radiative balance between the non-reflected incoming solar radiation and the outgoing long-wave black-body radiation from the atmosphere. The surface temperature is higher than the black-body temperature due to the greenhouse warming. Balancing the ice-albedo cooling and the greenhouse warming gives rise to two stable climate states. A cold climate state with a completelyice-covered planet, called Snowball Earth, and a warm state similar to our present climate where greenhouse warming prevents the total glacition. The warm state has dominated Earth in most of its geological history despite a 30 % fainter young Sun. The warming could have been controlled by a greenhouse thermostat operating by temperature control of the weathering process depleting the atmosphere from $CO_2$. This temperature control has permitted life to evolve as early as the end of the heavy bombartment 4 billion years ago.

Last edited by a moderator: May 2, 2017
2. May 13, 2005

### Andre

Yes those two states. Greenhouse - Ice house with a lot of positive feedback forcing the climate either cool or warm, nothing in between, a flip flop.

It's also projected on the Pleistocene and it's the root of the global warming myth. Here is an excellent overview how that myth was born:

http://www.physicstoday.org/vol-56/iss-8/p30.html [Broken]

Anyway, when I had discovered this, some suggestions came that I may well had discovered the flawed roots of that global warming discovery sequence. So I decided to start the mega project. I'm in the process of reviewing all abstracts under sciencemag.org sciencedirect.com and AGU.org that contain the string "Younger Dryas" for datable warm-cold indications, glacier advances and retreats and of course arid-humid changes. 200 abstracts down, some 300 to go.

Extremely interesting result.

Last edited by a moderator: May 2, 2017
3. May 13, 2005

### wolram

Hi andre.

I found the remark about a, 30% fainter sun quite remarkable.