Greenhouse gas levels surge to a new record in 2023: WMO
- Planet-warming greenhouse gas (GHG) levels surged to a new record in 2023, with annual mean levels of carbon dioxide (CO2), the most important GHG in the atmosphere, rising by 2.3 parts per million (PPM) between 2022 and 2023.
Highlights:
- Global levels of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), reached unprecedented highs, with CO₂ at 420 ppm.
- This marks the 12th consecutive year with an increase of more than 2 ppm in CO₂ levels, a new record for greenhouse gases.
Historical Context and Implications:
- CO₂ levels today mirror those from 3-5 million years ago, a period when temperatures were 2-3°C higher and sea levels were 10-20 meters above current levels.
- The report suggests these increased GHG levels could have lasting effects, with today’s temperatures expected to persist for decades even if emissions drop.
Natural Factors and Anthropogenic Impacts:
- The slight rise in CO₂ from 2022 to 2023 was driven by high fossil fuel emissions, wildfires, and reduced forest carbon absorption.
- El Niño conditions in 2023, with higher temperatures and reduced rainfall, dried vegetation and triggered more wildfires, which released additional CO₂, amplifying warming effects.
Potential for Vicious Cycle Due to Climate Feedbacks:
- WMO cautions about a feedback loop where natural systems, such as forests and oceans, might increasingly emit GHGs instead of absorbing them.
- As the planet warms, forest fires, decreased ocean CO₂ absorption, and thawing wetlands could worsen the greenhouse effect, keeping more CO₂ in the atmosphere.
Methane’s Rising Contribution:
- Methane saw its most significant three-year increase from 2020 to 2022, attributed to warmer and wetter conditions from La Niña, which increased methane emissions from wetlands.
- Methane, although present in smaller quantities than CO₂, is a potent greenhouse gas with higher short-term warming potential.
Radiative Forcing and Long-term Warming Impact:
- Since 1990, the radiative forcing—or warming effect—of GHGs has increased by 51.5%, with CO₂ contributing around 81% to this rise.
- The WMO’s findings emphasize that the warming influence of GHGs will remain long-term due to the persistence of CO₂ in the atmosphere, regardless of near-term emission reductions.
Prelims Takeaways
- Planet-warming greenhouse gas (GHG)
- El Nino