Which of these statements is/are true regarding carbon dioxide?
◦ CO2 levels are now 31% higher than before the Industrial Revolution.
◦ The rate of increase is greater than any time in the last 20,000 years, while the total amount is greater than any time in the last 420,000 years.
◦ It is responsible for 64% of global warming.
◦ Global emissions in 2000 were 400% greater than in 1950, and the U.S. produced 24% of that total.
◦ They are all true.