• It has been observed that there is an imbalance in the atmospheric carbon-oxygen cycle.
• CO is released directly into the atmosphere by incomplete combustion.
• About 40% of CO in the atmosphere is contributed by the burning of fossil fuel.
• CO level in southern hemisphere in around 50 ppb and in northern hemisphere it is 120 ppb.
• Is the major portions CO produced form combustion?
  NO! from the oxidation of methane generated by anaerobic bacteria in swamps and paddies.

Why there is a climate change?

• Due to the change in CO₂ level.
• Deforestation in recent days is the main cause for the accumulation of CO₂ in the biosphere.
• Changes in land used by human beings contribute around 1 Gt(C)/yr CO₂ to atmosphere.
• Global carbon cycle involves exchange of atmospheric CO₂ with carbon reservoir in ocean and biosphere in several time scales.
• It has been predicted that the freezing of current emissions would not really solve our problem immediately.
• CO₂ emission does not impact atmospheric chemistry directly but changes the temperature and circulation, which indirectly changes the chemistry and climate.