HIGHEST ATMOSPHERIC CARBON IN 800,000 YEARS

The choice to curb--or not to curb--carbon emissions in the near term   
will affect populations across the globe for centuries to come, says a   
new report from the National Research Council. The amount of carbon in   
the atmosphere is currently higher than at any point in the last   
800,000 years.   
CO2 doesn't displace easily. The amount could triple by the end of the   
century depending on the sorts of emissions reductions choices   
individuals and policy makers enact today. Even if emissions stabilize,   
CO2 concentrations in the atmosphere would continue to increase as the   
amount in the air already exceeds what the earth can absorb.   
The report details how small changes in temperature would change   
rainfall patterns and water availability: Rain in the North American   
southwest and the Mediterranean would decrease by as much as 10%, and   
crop yields could decrease by 15% for every one degree (Celsius) of   
warming according to the report.   
SOURCE: National Research Council 
http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12877