How much have greenhouse gas concentrations increased?
The concentration of carbon dioxide is approximately 30 per cent greater than it was in the 18th century, before the industrial revolution. It has increased from around 280 parts per million (ppm) to approximately 360 ppm today. Although carbon dioxide comprises only 0.036 per cent of the air, its warming effect is significant. Methane levels have risen from a pre-industrial concentration of about 700 parts per billion (ppb) to 1700 ppb. However, the rapid growth of methane has slowed considerably since the 1980s. Nitrous oxide concentrations have increased from approximately 275 ppb to 315 ppb. There is strong evidence that ozone concentrations in the lower atmosphere are greater than in pre-industrial times, especially in the northern hemisphere. CFCs didnt exist 200 years ago. However, the concentrations of many of them are now starting to fall, thanks to international agreements to protect the ozone layer.
Greenhouse gas graphs The concentration of carbon dioxide is approximately 30 per cent greater than it was in the 18th century, before the industrial revolution. It has increased from around 280 parts per million (ppm) to approximately 360 ppm today. Although carbon dioxide comprises only 0.036 per cent of the air, its warming effect is significant. Methane levels have risen from a pre-industrial concentration of about 700 parts per billion (ppb) to 1700 ppb. However, the rapid growth of methane has slowed considerably since the 1980s. Nitrous oxide concentrations have increased from approximately 275 ppb to 315 ppb. There is strong evidence that ozone concentrations in the lower atmosphere are greater than in pre-industrial times, especially in the northern hemisphere. CFCs didn t exist 200 years ago. However, the concentrations of many of them are now starting to fall, thanks to international agreements to protect the ozone layer. Human activities do not directly change atmospheric w
