Syllabus:

GS-3: Conservation, environmental pollution and degradation, environmental impact assessment 

Context: According to the WMO’s Greenhouse Gas Bulletin 2024, Carbon dioxide (CO₂) levels saw their steepest-ever increase, rising by about 3.5 parts per million (ppm) between 2023 and 2024.

Key Findings of the Bulletin

• Unprecedented Rise in CO₂ Levels: CO₂ growth rates have tripled since the 1960s, with the annual average increase accelerating from 0.8 ppm per year to 2.4 ppm per year in the decade from 2011 to 2020.
• Long-Term Concentration Trends: Global CO₂ levels have risen from 377.1 ppm in 2004 to 423.9 ppm in 2024, a 12.5% increase in just two decades, reflecting sustained emissions and weakened natural absorption.
• Methane and Nitrous Oxide at Record Highs: Methane (CH₄) and nitrous oxide (N₂O), the second and third most significant long-lived greenhouse gases, have reached unprecedented concentrations.
• Role of Methane: Methane accounts for about 16% of the total warming effect on the planet and remains in the atmosphere for approximately nine years, highlighting its potent short-term impact on climate warming.
• Nitrous Oxide Trends: The globally averaged N₂O concentration reached 338.0 parts per billion (ppb) in 2024, marking a 25% increase over pre-industrial levels and indicating sustained agricultural and industrial emissions.

Factors responsible for rise in Greenhouse Gases 

• Human-Induced Emissions: Continued emissions from industrial operations, transportation, and energy generation remain the leading causes of elevated CO₂ concentrations.
• Wildfires and Natural Feedbacks: Large-scale wildfires released massive amounts of carbon into the atmosphere in 2024, compounding human emissions.
• Reduced Carbon Sink Efficiency: The natural carbon-absorbing capacity of land and oceans has declined, with forests and vegetation absorbing less due to drought and heat stress.
• Impact of the El Nino Phenomenon: El Nino conditions in 2024 significantly reduced the efficiency of terrestrial carbon sinks. Drier vegetation and intensified fires in regions such as the Amazon and southern Africa worsened atmospheric CO₂ buildup.
• Methane Source Distribution: Roughly 40% of methane emissions originate from natural sources like wetlands, while 60% stem from human activities including livestock farming, rice cultivation, fossil fuel extraction, landfills, and biomass burning.

About Greenhouse Gas Bulletin (GGB) 

• The Greenhouse Gas Bulletin is an annual publication by the World Meteorological Organization (WMO) since 2004. 
• It provides authoritative global assessments of surface concentrations of key greenhouse gases including CO₂, CH₄, and N₂O. 
• The bulletin serves as a vital scientific reference for policymakers, helping track progress toward international climate agreements such as the Paris Accord and guiding mitigation strategies. 

Sources:
Down To Earth
Indian Express
India Today