Historically, an Unusual Aspect of the Recent Rise in CO₂

Question

Historically, an unusual aspect of the recent rise in CO₂ levels is that
A)there is no known mechanism for its occurrence.
B)CO2reacts so quickly with other compounds that it should not be occurring.
C)it has occurred relatively slowly.
D)it has occurred relatively rapidly.

Accepted Answer

The recent rise in CO₂ levels has occurred relatively rapidly compared to historical trends. While CO₂ levels have fluctuated in the past, studies indicate that the current increase in CO₂ levels is occurring at a rate that is unprecedented in at least the past 800,000 years.