Environmental Science
Atmospheric CO₂
Quick fact
The concentration of atmospheric CO₂ has increased by over 50% since the Industrial Revolution, from about 280 parts per million (ppm) to over 420 ppm today—a level not seen in millions of years.
Why this is interesting
You breathe it out every second, but the tiny amount of CO₂ in the air—just 0.04%—holds the key to Earth's climate. How can such a small fraction cause such enormous changes?