The numbers I saw for the year 2007 were:
(remember, this number is an average of ocean temps, land station temps, etc. Thus, not very reliable as an indicator of CLIMATE)...........
Avg 2007:
-0.6 C
A worldwide drop of 3-5 degrees centigrade would be sufficient to trigger another ice age.
After the Toba eruption 75K years ago, worldwide temps fell by 10 degrees F.
The Earth was plunged into an ice age that lasted more than 1,000 years.
Thank you for providing the data, djf.