What does Al Gore, author of An Inconvenient Truth, demonstrate about the level of atmospheric carbon dioxide levels?
Each year, the C*O_{2} level rises and then falls. Over the past 50 years, it has steadily increased
Each year, the C*O_{3} level increases at a faster rate. Over the past 50 years, it has nearly doubled
Each year, the CO2 level decreases. Over the past 50 years, it has steadily decreased