In News:

The World Meteorological Organization (WMO) has released its latest decadal climate forecast (2025–2029), warning of a continued trend of record-breaking global temperatures. This projection raises serious concerns about climate risks, sustainable development, and international climate commitments under the Paris Agreement.

Key Projections:

• Annual Global Temperature Rise: Each year from 2025–2029 is projected to be 1.2°C to 1.9°C above pre-industrial levels (1850–1900).
• Record Heat Likelihood:
  • 80% chance that at least one year will surpass 2024, currently the warmest year on record.
  • 86% probability that one year will exceed the 1.5°C threshold.
• Five-Year Mean Warming: 70% chance that the 2025–2029 average will be above 1.5°C, a sharp rise from 47% (2024–2028) and 32% (2023–2027).

Note: The Paris Agreement’s 1.5°C limit refers to long-term (20-year) averages, but short-term overshoots are now increasingly probable.

Regional and Thematic Insights:

1. Arctic Amplification: Arctic winters (Nov–Mar) are projected to be 2.4°C warmer than the 1991–2020 average—3.5× faster than the global rate.

2. Sea Ice Decline: Continued sea ice reduction is expected in the Barents Sea, Bering Sea, and Sea of Okhotsk, impacting marine biodiversity and indigenous livelihoods.

3. Precipitation Variability:

• Wetter-than-average conditions likely in:
  • Sahel region
  • Northern Europe
  • Alaska and Northern Siberia
• Drier conditions expected over:
  • Amazon Basin
  • Parts of South Asia

South Asia may witness generally wet years, though seasonal variability will persist.

Impact and Implications:

• Extreme Weather Events: Increased warming will fuel more intense heatwaves, extreme rainfall, droughts, and floods, stressing both urban systems and agriculture.
• Cryosphere and Ocean Changes:
  • Accelerated glacier and sea ice melt will raise sea levels.
  • Ocean heating contributes to acidification and marine biodiversity loss.
• Threat to Sustainable Development: Progress on SDGs, particularly food security, water availability, and health, is at risk in vulnerable regions.

Way Forward:

• Revise NDCs at COP30: Strengthen and align Nationally Determined Contributions (NDCs) with the 1.5°C goal.
• Accelerate Clean Energy Transition: Promote renewables, energy efficiency, and net-zero strategies to reduce GHG emissions.
• Adaptation and Resilience: Invest in climate-resilient infrastructure and early warning systems.
• Climate Monitoring & Forecasting: Enhance WMO-led regional forecasts and risk assessment tools.
• Preserve Natural Carbon Sinks: Protect forests, wetlands, and oceans to mitigate atmospheric CO?.

In News:

According to the WMO, the last time the earth had a similar CO2 concentration was 3-5 million years ago, when temperatures were 2-3°C higher and sea levels were 10-20 metres higher than they are now

Key Highlights:

• Record High Greenhouse Gas (GHG) Levels:
  • In 2023, annual mean carbon dioxide (CO2) levels rose by 2.3 parts per million (ppm), reaching a new record of 420 ppm.
  • This marks the 12th consecutive year with an increase of over 2 ppm in CO2 levels.
• Historical Context:
  • CO2 levels not seen in 3-5 million years, when temperatures were 2-3°C higher, and sea levels were 10-20 meters higher than they are today.
• Key GHGs at Record Highs:
  • The globally averaged surface concentrations of CO2, methane, and nitrous oxide all reached new highs in 2023.
• Contributors to the Increase in CO2:
  • Natural Variability: Natural factors such as large vegetation fires and reduced carbon absorption by forests contributed to higher CO2 levels.
  • Human Activity: High fossil fuel emissions from human and industrial activities also played a major role.
  • El Niño Phenomenon: The El Niño event led to higher temperatures and drier conditions, exacerbating the rise in GHG levels through increased wildfires and reduced carbon absorption by land sinks.
• Climate Feedback Loop Concerns:
  • The WMO warned of a vicious cycle:
    • Climate change could cause ecosystems to become larger sources of GHGs.
    • Wildfires could release more carbon, and warmer oceans may absorb less CO2, leading to more CO2 remaining in the atmosphere, accelerating global warming.
• Radiative Forcing:
  • Radiative forcing (the warming effect on climate) from long-lived GHGs has increased by 51.5% from 1990 to 2023, with CO2 contributing 81% of this increase.
• Methane Concerns:
  • Methane saw its largest three-year increase between 2020 and 2022.
  • This increase was linked to warmer temperatures and wetter land conditions during the 2020-2022 La Niña conditions, which caused an uptick in methane emissions from natural wetlands.
• Long-Term Impact of CO2:
  • Given CO2's long atmospheric lifetime, even with rapid emissions reductions, the warming effect will persist for several decades.