Geological Society says emitting more CO2 "likely to be unwise"

The Geological Society has prepared a position statement on climate change, focusing specifically on the geological evidence. As you would expect, it takes the long view. It considers:

What is climate change, and how do geologists know about it?
What are the grounds for concern?
When and how did today’s climate become established?
What drives climate change?
What is the Greenhouse Effect?
What effect do natural cycles of climate change have on the planet?
Has sudden climate change occurred before?
Are there more recent examples of rapid climate change?
How did levels of CO2 in the atmosphere change during the ice age?
How has carbon dioxide (CO2) in the atmosphere changed over the longer term?
How has carbon dioxide in the atmosphere changed in recent times?
When was CO2 last at today’s level, and what was the world like then?
When global temperature changed, did the same change in temperature happen everywhere?

and, finally,

In conclusion - what does the geological record tell us about the potential effect of continued emissions of CO2?

The answer:

"it is reasonable to conclude that emitting further large amounts of CO2 into the atmosphere over time is likely to be unwise, uncomfortable though that fact may be."