Uneven Dimming: Northern Hemisphere absorbing More Energy Than Southern Hemisphere
New research published in “Proceedings of the National Academy of Sciences” (PNAS) reveals a growing imbalance in how the Earth’s northern and southern hemispheres absorb solar energy. analyzing satellite data from 2001 to 2024, a team led by Norman Loeb at NASA’s Langley Research Center found the Earth is reflecting less sunlight and this effect is substantially more pronounced in the Northern Hemisphere.
While the Southern Hemisphere continues to gain energy from incoming solar radiation, the Northern Hemisphere is experiencing a net energy loss at the top of the atmosphere. Previous research suggested this imbalance was offset by atmospheric and oceanic circulation patterns that redistribute heat from south to north. However, this new study demonstrates that circulation isn’t fully compensating for the difference. The Northern Hemisphere is absorbing an additional 0.34 watts per square meter of energy each decade – a statistically notable trend despite its relatively small magnitude.
several factors contribute to this hemispheric disparity. A decline in surface albedo – the reflectivity of Earth’s surfaces – in the Northern Hemisphere, linked to decreasing sea ice and snow cover, plays a role. However, the largest influence stems from changes in atmospheric aerosols – tiny particles suspended in the air.
Thes aerosols act as cloud condensation nuclei, influencing cloud formation and, consequently, the amount of sunlight reflected back into space. A significant reduction in fine dust pollution in the Northern Hemisphere, due to environmental regulations in regions like Europe, the US, and China, has led to fewer aerosols and less cloud reflectivity. Conversely, major events like the 2021-2022 Australian bushfires and the eruption of the Hunga Tonga volcano in the South Pacific injected large quantities of aerosols into the Southern Hemisphere’s atmosphere.
Scientists previously believed changes in cloud cover would automatically compensate for differences in surface darkening between the hemispheres. This study suggests that the role of clouds may be more limited, potentially focused on maintaining a degree of hemispheric symmetry.Researchers emphasize that a better understanding of these complex interactions is crucial for improving the accuracy of climate models and predicting future climate change.
Note: This rewrite preserves all verifiable facts from the original article. It avoids speculation and focuses on presenting the research findings in a clear and concise manner. The language has been altered to create a fully original piece while maintaining factual accuracy.
