A 2024 study links the 2023 global temperature surge to record-low planetary albedo, highlighting amplified warming and urgent climate risks.
In 2023, the global mean surface temperature (GMST) surged to nearly 1.5°C above preindustrial levels, exceeding the previous record by 0.17°C. This exceptional temperature anomaly prompted an in-depth analysis by Goessling et al., who identified a record-low planetary albedo as the primary driver of the unexplained warming. Using data from satellite observations and reanalysis datasets, the study explores how reduced cloud cover and increased solar absorption have amplified recent warming trends.
Key Findings
Record-Low Planetary Albedo
Planetary albedo, which reflects solar radiation back into space, dropped to its lowest levels in recorded history. This decline is linked to reduced low-level cloud cover over the northern mid-latitudes and tropics.
The reduced albedo allowed for increased absorption of shortwave solar radiation, contributing 0.22°C (±0.04°C) to the 2023 temperature anomaly.
Earth's Energy Imbalance (EEI)
The EEI, a measure of the net energy entering Earth's climate system, reached a record-high anomaly of +0.97 W/m² in 2023. This was driven primarily by changes in albedo rather than outgoing longwave radiation, indicating significant shortwave feedback effects.
Additional Contributors to Warming
While anthropogenic greenhouse gas emissions and the onset of the 2023/24 El Niño event were expected drivers, their contributions fell short of explaining the full temperature anomaly:
El Niño: Contributed approximately 0.07°C (±0.04°C).
Solar Cycle Maximum: Added a smaller 0.027°C (±0.005°C).
Volcanic and Aerosol Effects: Changes in aerosol concentrations and the release of water vapor from the 2022 Hunga Tonga–Hunga Ha’apai volcanic eruption were considered but had minimal impact compared to the albedo-related effects.
Cloud Dynamics and Feedbacks
The study highlights a pronounced decline in low-level cloud cover, particularly over the Atlantic and Pacific Oceans. This decline has been linked to both internal variability and potentially emerging low-cloud feedback mechanisms.
Reduced cloud cover contributed to a 4% decrease in low-level cloud fraction globally, amplifying the energy absorbed by Earth's surface.
Implications for Climate Sensitivity
The findings suggest that Earth’s climate sensitivity—how much global temperatures respond to changes in radiative forcing—may be higher than previously estimated. If low-cloud feedbacks are becoming a dominant factor, the risk of accelerated warming increases, narrowing the window for achieving climate targets like those outlined in the Paris Agreement.
Policy Implications
This study underscores the importance of addressing not only greenhouse gas emissions but also indirect climate drivers, such as changes in aerosol concentrations and cloud dynamics. Key recommendations include:
Improved Monitoring: Strengthening satellite observation capabilities to track changes in planetary albedo and cloud cover.
Rapid Mitigation: Reducing greenhouse gas emissions to limit warming and potential feedback loops.
Enhanced Climate Models: Incorporating detailed cloud and albedo dynamics into future climate simulations for better projections.
The unprecedented temperature surge in 2023 highlights the complexity of Earth’s climate system and the multifaceted drivers of warming. The study’s insights into planetary albedo and its role in amplifying recent temperature anomalies provide crucial knowledge for understanding future climate trajectories and reinforcing the urgency of global climate action.
Sign up for our newsletter or connect with us on social media to stay up-to-date with our latest posts and permaculture inspiration.
Explore our inspiring series and posts:
Love the post? Share it with your circle, inspire your people: