Thanks for your replies.

Of course the science offered on the BBC program may not be the most recent on the topic.

At good video on the snowball earth with the latest in the science on the matter is:
http://www.agu.org/meetings/fm09/lectures/lecture…

Caution, this presenter is very high bandwidth! It is a talk given at the American Geophysical Union by Dr. Richard Alley.

Here's another example of CO2 being a temperature regulator from earth's history.

There is one event, I'm sure you are aware of, the PETM (about 55 million years ago) when the spike in CO2 from natural sources was similar to the spike in CO2 we are seeing today. The CO2 went directly into the oceans causing them to acidify and the land temperatures increased rapidly. Bottom line, 95% of the species on the world died.

The oceans are 30% acidic over baselines right now and this number is growing.

This event gets as close to the rapidity of the CO2 increase in our atmosphere today as the natural world can get. It's happening faster today, about 10 times faster. And we are the new volcanoes on the planet. We release about 100 times as much CO2 into the atmosphere as all the current volcanoes combined.

So in the past things happened much slower because natural forces work on their own time. Today we are making things happen much faster.

We are committed to 2 C warming right now because we have about 450 ppm equivalent CO2 in the atmosphere. We are at about .74 C over baseline right now and getting hotter.

The sulphur you talk about would cool the globe … in fact is that not what people are thinking about blowing into our upper atmosphere to provide a heat shield for the planet?

Indeed, many people are very concerned over this issue because physics is physics. It does not matter what anyone cares, believes or wants to happen. We are committed to a much hotter world in the near future and we as a species and all the other species alive today have, like us, no experience with these kinds of changes.

Increased CO2 causes plants to uptake fixed nitrogen faster which reduces the fixed nitrogen in the soil. After certain concentrations are reached, on a per species basis, production falls off. Add to this problem the one of heating and drying of our 'breadbaskets' and we will be faced with food underproduction problems. Of course, we can use man made nitrogen fertilizer made from …. you guessed it …. natural gas. Heating, drying, CO2 pollution and flooding …. its a deadly mix for a population that will be running out of resources over the next 100 years and be 30% larger than today.

Looks like to me our species is in for a 'spanking'.

Regards to all.

You are saying that CO2 causes global warming by increasing after the temperature increases!

Calm down fella, and start thinking.

The problem most of us have is with the CO2 story. It isn't doing anything much to the climate yet we are supposed to stop burning stuff to reduce an already tiny trace gas , 0.038% of our atmosphere. The global dislocation of doing so is immense and yet we are supposed to "believe" in CAGW caused through CO2 on the grounds that " we can't find anything else".

They tell you how it happened, what evidence they have that it DID happen and how they THEORISE that the world warmed up again… The theory of recovery, however, is NOT based on CO2 creating a feedback and warming the globe.
The scientists in the programme came to the conclusion that it was the massive amounts of airbourne sulphur dioxide and sulphurous soot covering the ice, all spewed from volcanos, which eventually allowed the globe to warm (they did actually mention CO2 but disregard it as not a powerful enough greenhouse gas to have been responsible).
Another theory floating around is that the snowball scenario was caused by the solar system passing through an area of galactic debris, causing solar diming, and when we came out the other side, the world warmed accordingly.

From the first post, CO2 is always going to be our buddy. It acts as fertiliser for every plant, tree, bush, etc. on this planet; The higher the concentration, the better the plants grow. Ask your local plant nursey what gas they pump into their greenhouses.
For all that you can expect a tiny amount of warming because of it's concentration doubling.

Bargain if you ask me