Despite numerous studies and climate models, the sharp temperature increase of 0.2 degrees Celsius remained unexplained. At first glance, this may seem like a minor figure, but its impact on ecosystems and climate stability is substantial.
Researchers from the Alfred Wegener Institute (AWI) have found a possible explanation: a decrease in the Earth's ability to reflect sunlight—known as planetary albedo.
What is albedo and why is it decreasing?
Planetary albedo is a measure that indicates what percentage of sunlight the Earth reflects back into space. When this measure declines, more solar energy remains in the atmosphere, intensifying warming.
According to AWI, in 2023, albedo reached its lowest levels in decades, coinciding with record temperature increases. The primary reason for this is the reduction in low-level clouds, particularly over the North Atlantic.
Disappearance of low clouds
Low clouds play a crucial role in cooling the planet: they reflect sunlight without trapping heat in the atmosphere. A decrease in their numbers leads to a loss of this "cooling effect."
Research indicates:
- The most significant reduction in low cloud cover occurred in tropical latitudes and over the North Atlantic—regions where abnormal temperatures were recorded.
- Changes in cloud cover at mid and high altitudes were minimal.
Impact of anthropogenic factors
One reason for the decline in low cloud cover is attributed to the decrease in atmospheric concentrations of anthropogenic aerosols. These particles, released into the air as a result of human activity, play a vital role in cloud formation. Stricter environmental regulations, particularly for marine fuel, may have significantly impacted this process.
Natural fluctuations and feedback from the oceans may also have contributed.
A new threat of warming
Dr. Helge Hesling from AWI emphasizes that global warming itself can reduce the amount of low clouds. This creates a feedback loop where warming exacerbates factors that lead to further temperature increases.
If this trend continues, humanity may face an acceleration of climate changes, with the critical threshold of 1.5 degrees Celsius being surpassed sooner than anticipated.
Conclusion
The decrease in planetary albedo has become a new challenge for climatology. This discovery highlights the need for a comprehensive approach to studying the consequences of human activity and natural changes.