Global greenhouse gas concentrations hit record highs in 2025, with CO2 at 426.8 ppm, methane at 1,948 ppb, and nitrous oxide at 339.1 ppb, according to the WMO Greenhouse Gas Bulletin.

Over the last decade, Korea has seen higher-than-global-average increases in greenhouse gases, rising by about 2.7 ppm CO2, 9 ppb methane, and 1.2 ppb nitrous oxide per year.

The WMO bulletin also notes a headline signal of warming that goes beyond a short-term blip, underscoring urgency to cut emissions.

Researchers, including Dr. Peter Sperlich and Dr. Sara Mikaloff-Fletcher, emphasize that this signal is significant and urgent for emissions reductions.

A temporary rise in wildfire-derived methane points to a climate-change feedback, linked to human warming and a strong El Niño that increased fires and reduced wetlands.

Hydrogen, while not a greenhouse gas, can indirectly slow methane removal if leaks occur, potentially offsetting some climate benefits.

Experts warn that higher concentrations persist for decades to centuries and entrench future temperature increases, calling for rapid, deep emissions cuts and net-zero with negative emissions where needed.

Despite alarming trends, there are signs of progress: renewables outpaced coal in 2025, and growth in electricity demand did not fully offset gains from renewables and efficiency.

Sulfur hexafluoride (SF6) concentrations have risen over decades, representing a long-lived and highly potent greenhouse gas threat.

COP31 banners warned that some forecasted growth in emissions remains, but the emissions outlook continues to hinge on rising atmospheric warming potential if no stronger actions are taken.

The Paris Agreement remains central, aiming to keep warming well below 2°C and pursue 1.5°C where possible alongside peak-and-reduce trajectories.

A temporary moderation in 2024–2025 growth is noted due to land carbon-sink recovery and fewer fires after the 2023–2024 El Niño, with projected increases in 2026 tied to fossil fuels and a powerful El Niño.