How to calculate the average annual rate of increase in CO₂ concentration between 423 ppm and the CO₂ concentration on my birthday?
a) Average Rate = (Final CO₂ - Initial CO₂) / Number of Years
b) Average Rate = Final CO₂ / Initial CO₂
c) Average Rate = (Initial CO₂ - Final CO₂) / Number of Years
d) Average Rate = Number of Years / (Final CO₂ - Initial CO₂)