Question

what does Al gore, author of An Inconvenient Truth, demonstrate about the level of atmosphere carbon dioxide levels?

1. Each year, The CO2 level rises and then falls. over the past 50 years ,it has steadily increased.

2.each year, the CO2 levels increase on a faster rate. Over the past 50 years, and has nearly doubled.

3.each year, the CO2 levels decreases. Over the past 50 years, it has steadily decreased