Multiple Choice
According to the figure below,how much has atmospheric carbon dioxide (CO₂) increased in parts per million (ppm) in approximately the last 50 years? 
A) from about 310 to 320 ppm
B) from about 360 to 400 ppm
C) from about 320 to 400 ppm
D) from about 380 to 400 ppm
Correct Answer:
Verified
Correct Answer:
Verified
Q6: Models used by the Intergovernmental Panel on
Q21: In the last few decades,global warming has
Q30: In the figure below,why is there a
Q30: Sedimentary sequences,which are bounded by unconformities,record global
Q31: Which greenhouse gas has the greatest total
Q32: How are carbon dioxide (CO₂)levels in the
Q35: Which of the following is an important
Q36: A blogger writes that global warming is
Q39: The reliable paleoclimate record from the Antarctic
Q51: Natural carbon sinks have generally matched the