Global Greenhouse Gas (GHGs) Levels

Generals Studies Paper-3 

Context: Recently, the National Oceanic and Atmospheric Administration (NOAA) revealed that global carbon dioxide levels reached a record high in 2023.

About the Carbon Dioxide (CO₂):

• It is an important heat-trapping gas, also known as a greenhouse gas, that comes from the extraction and burning of fossil fuels (such as coal, oil, and natural gas), from wildfires, natural processes like volcanic eruptions, and land use changes like deforestation, peat emissions, and agricultural activities.
• Since the onset of industrial times in the 18th century, human activities have raised atmospheric CO2 by 50% – meaning the amount of CO₂ is now 150% of its value in 1750.
• This human-induced rise is greater than the natural increase observed at the end of the last ice age 20,000 years ago.

Global Carbon Dioxide Levels (Current Status):

• The global average atmospheric carbon dioxide was 419.3 parts per million (ppm) in 2023, which is more than 50% higher than pre-industrial levels.
  • This increase was the third-largest in the last decade.
• The increase between 2022 and 2023 was 2.8 ppm — the 12th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm.
• The 2023 increase was the third-largest in the last decade and is likely a result of an ongoing increase of fossil fuel carbon dioxide emissions, coupled with increased fire emissions possibly as a result of the transition from La Nina to El Nino.
  • El Nino and La Nina are the warm and cool phases of a recurring climate pattern across the tropical Pacific called the El Nino-Southern Oscillation (ENSO).
• In March 2024, the CO₂ levels at Mauna Loa Observatory, Hawaii, were recorded at 425.38 ppm, up from 420.99 ppm in March 2023.
  • It has the longest record of direct measurements of CO2 in the atmosphere.

Global Methane Levels (Current Status):

• Methane is emitted during the production and transport of coal, natural gas, and oil.
  • Methane emissions also result from livestock and other agricultural practices, land use, and by the decay of organic waste in municipal solid waste landfills.
• Despite being less abundant than CO₂, Methane is more potent at trapping heat in the atmosphere.
• Methane levels in the atmosphere are now more than 160% higher than their pre-industrial level.
  • It first rose in the 1980s, and nearly stabilised in the early 2000s before rapidly increasing again in 2007.
  • It went up to an average of 1922.6 parts per billion (ppb) in 2023 — a 10.9 ppb jump over 2022.
  • The year 2023 marked the fifth-highest since 2007.
• More than 85% of the increase from 2006 to 2021 was due to increased microbial emissions generated by livestock, agriculture, human and agricultural waste, wetlands and other aquatic sources.
  • The rest could be coming from fossil fuel emissions.

Global Nitrous Oxide Levels (Current Status):

• Nitrous oxide is emitted during agricultural, land use, and industrial activities; combustion of fossil fuels and solid waste; as well as during treatment of wastewater.
• It is the third-most significant human-caused greenhouse gas, and its concentrations are 25% higher than the pre-industrial level of 270 ppb.
  • The current levels climbed by 1 ppb to 336.7 ppb in 2023.
• This increase in recent decades is being traced back to the use of nitrogen fertiliser and manure from the expansion and intensification of agriculture.

Impact of Rising Levels:

• Without carbon dioxide, Earth’s natural greenhouse effect would be too weak to keep the average global surface temperature above freezing.
  • By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise.
• The rising CO₂ levels have put us in a precarious position, mirroring atmospheric conditions from the Pliocene epoch, a period roughly 4.3 million years ago.
• During that geological period, sea levels were approximately 23 metres higher than today, and the average temperature was higher than in pre-industrial times.
• If the current level of emissions persists, there is a 50% chance that global warming of 1.5°C will be exceeded in nine years.
• This is the opposite trend needed to reverse climate change.

Conclusion:

• CO₂ is the single most important greenhouse gas leading to human-induced climate change.
• Although other GHGs are more powerful per molecule in warming the planet than CO₂, the CO₂ emissions stay in the atmosphere for hundreds to thousands of years, making CO₂ the biggest challenge in combating climate change.
• The increasing levels of carbon dioxide in our atmosphere are a clear indication of the urgent need for action.
• The data from NOAA highlight the critical state of earth’s carbon cycle and underscore the importance of reducing greenhouse gas emissions.