=+67. El Nio. Concern over the weather associated with El Nio has increased interest in the possibility

=+67. El Niño. Concern over the weather associated with El Niño has increased interest in the possibility that the climate on Earth is getting warmer. The most common theory relates an increase in atmospheric levels of carbon dioxide 1CO22, a greenhouse gas, to increases in temperature. Here is a scatterplot showing the mean annual CO2 concentration in the atmosphere, measured in parts per million (ppm) at the top of Mauna Loa in Hawaii, and the mean annual air temperature over both land and sea across the globe, in degrees Celsius (C).

16.500 16.575 16.650 16.725 16.800 325.0 337.5 350.0 CO2

(ppm)

Mean Temperature ( °C)