Why in news?

According to the World Meteorological Organization (WMO), the global atmospheric concentration of carbon dioxide (CO₂) rose by a record 3.5 parts per million (ppm) between 2023 and 2024, reaching 423.9 ppm, the highest level ever recorded. This increase far exceeds the average annual rise seen during 2011–2020.

The year 2024 also became the warmest year on record, with global temperatures 1.55°C above pre-industrial levels — the first time the 1.5°C threshold was breached for an entire year.

The data highlights the failure of the Paris Agreement framework to curb emissions effectively and signals a worsening climate crisis with potentially irreversible impacts if warming continues.

What’s in Today’s Article?

• Record Surge in CO₂ Concentrations: Understanding the Trends and Implications
• Why CO₂ Levels Rose Sharply in 2024: Natural and Human Factors Combined
• Methane and Nitrous Oxide Levels Rise in 2024, Though at a Slower Pace
• Rising Greenhouse Gases Highlight Growing Climate Crisis and Policy Failures

Record Surge in CO₂ Concentrations: Understanding the Trends and Implications

• According to the WMO, the CO₂ concentration in the atmosphere reached 423.9 ppm in 2024, marking a record annual increase of 3.5 ppm — the highest since measurements began in 1957.
• This level is now 152% higher than pre-industrial levels (278.3 ppm).
• Despite global efforts to curb emissions, CO₂ concentrations have risen continuously for over 40 years without a single year of decline.
• The rate of increase has tripled, from 0.8 ppm per year in the 1960s to 2.4 ppm between 2011–2020, before the current unprecedented spike.
• Natural vs. Man-Made CO₂ Emissions
  • CO₂ is released through both natural and human activities.
  • Natural sources: respiration, wildfires, volcanic eruptions, and decomposition.
  • Human sources: burning of fossil fuels, industrial emissions, and deforestation.
  • While natural processes absorb almost all the CO₂ they emit through photosynthesis and oceanic absorption, only half of human-induced emissions are absorbed.
  • The remaining half accumulates in the atmosphere, intensifying the greenhouse effect.
• CO₂’s Role Among Greenhouse Gases
  • CO₂ is the most abundant GHG, accounting for over 90% of accumulated GHGs in the atmosphere.
  • However, it is less potent than other gases like methane (CH₄) and nitrous oxide (N₂O):
    • Methane: ~25 times more heat-trapping capacity than CO₂, but lasts 12–14 years.
    • Nitrous oxide: ~270 times more potent than CO₂, remains 100–120 years.
    • CO₂: persists for hundreds to thousands of years, making its effect cumulative and long-lasting.
• Contribution to Global Warming
  • CO₂ is responsible for about 66% of total global warming since pre-industrial times, and about 79% of warming in the past decade.
  • Its persistence in the atmosphere ensures that even small increases have long-term climate impacts, reinforcing the urgent need for deep emission cuts to prevent irreversible warming.

Why CO₂ Levels Rose Sharply in 2024: Natural and Human Factors Combined

• The record 3.5 ppm rise in CO₂ levels between 2023 and 2024 was not caused solely by human emissions, according to the World Meteorological Organization (WMO).
• Variations in the natural carbon cycle also played a major role.
• In 2024, both oceans and land-based carbon sinks absorbed less CO₂ than usual, while widespread forest fires released additional carbon into the atmosphere.
• Global warming itself is weakening natural absorption systems:
  • Warmer oceans absorb less CO₂ due to reduced solubility.
  • Extreme droughts dry out forests and grasslands, limiting their ability to absorb carbon.
• These feedback effects — reduced absorption and increased emissions — reinforce one another, worsening the CO₂ imbalance and accelerating atmospheric buildup.

Methane and Nitrous Oxide Levels Rise in 2024, Though at a Slower Pace

• In 2024, atmospheric concentrations of methane (CH₄) and nitrous oxide (N₂O) continued to increase, though below the decade’s average growth rate, according to WMO data.
  • Methane (CH₄): Rose by 8 parts per billion (ppb) to 1,942 ppb, compared to the decadal average increase of 10.6 ppb per year.
  • Nitrous oxide (N₂O): Increased by 1 ppb to 338 ppb, slightly lower than the average annual rise of 1.07 ppb in the last decade.
• Cumulatively, CH₄ contributes about 16% and N₂O about 6% of total global warming since pre-industrial times, with the remaining share arising from CO₂ and other greenhouse gases.

Rising Greenhouse Gases Highlight Growing Climate Crisis and Policy Failures

• The WMO Greenhouse Gas Bulletin underscores the worsening challenge of curbing greenhouse gas (GHG) accumulation, as both human activities and destabilised natural systems now drive atmospheric increases.
• Natural processes that once absorbed carbon — such as forests and oceans — are becoming less effective under global warming, amplifying gas buildup.
• Meanwhile, human-controlled emissions continue to rise despite international commitments.
• Even after a decade of the Paris Agreement, global emissions remain high, and the 2030 reduction targets are unlikely to be met.
• With global temperatures surpassing 1.5°C in 2024, the data reveal a deepening climate crisis and the failure of existing frameworks to reverse the trend.