GS Paper - 3 (Environment)

Greenhouse gas concentrations in the atmosphere reached new record levels last year, the United Nations said on 25 October 2021 in a stark warning ahead of the COP26 summit about worsening global warming. The Greenhouse Gas Bulletin from the UN's World Meteorological Organization said the annual rate of increase last year was above the yearly average between 2011 and 2020 -- and the trend continued in 2021.

What WMO said

  1. The economic slowdown caused by the Covid-19 pandemic triggered a temporary decline in new emissions, but had no discernible impact on the atmospheric levels of greenhouse gases and their growth rates.
  2. The organisation said that as long as emissions continue, global temperatures will continue to rise.
  3. And given the long life of carbon dioxide (CO2), the temperature level already observed will persist for several decades even if emissions are rapidly reduced to net zero.
  4. COP26, the UN Climate Change Conference, is being held in Glasgow from October 31 to November 12.
  5. The Greenhouse Gas Bulletin contains a stark, scientific message for climate change negotiators at COP26.


  1. The three major greenhouse gases are CO2, methane and nitrous oxide.
  2. CO2 is the most important, accounting for around 66 percent of the warming effect on the climate.
  3. CO2 concentrations reached 413.2 parts per million in 2020, up 2.5 ppm, and are at 149 percent of the 1750 pre-industrial level.
  4. Around 40 percent of methane is emitted from natural sources such as wetlands, while 60 percent comes from human activity, including rice agriculture and landfills.
  5. Nitrous oxide averages reached 333.2 ppb, up 1.2 ppb, at 123 percent of 1750 levels.