A recent study has shown that dust from areas in the Arctic that lack snow and ice could play a significant role in climate change affecting the region. Elevated dust levels assist in the creation of ice crystals within clouds, which reduces the clouds’ capability to hold more liquid droplets, particularly as the Arctic continues to warm.
The Arctic is heating up at a rate two to four times higher than the global average. Researchers in Japan recently discovered that dust from areas devoid of snow and ice in the Arctic may significantly influence climate change in that area. The results of this study were shared in the journal npj Climate and Atmospheric Science.
One viewpoint suggests that rising temperatures in the Arctic could result in clouds holding more liquid droplets rather than ice crystals. This change can lead to thicker, longer-lasting clouds that are more effective at reflecting sunlight, potentially cooling the region during the summertime (known as temperature feedback).
On the other hand, this new research indicates that as the Arctic experiences warming, the extent of snow- and ice-free regions increases, leading to a rise in dust emissions. This dust seems to encourage the development of ice crystals within clouds. Consequently, the higher presence of ice crystals may be resulting in thinner and less persistent clouds that reflect less sunlight, potentially contributing to warming in the summer (known as emission feedback).
“An increase in dust due to the warming Arctic may lead to effects contrary to the typical understanding of changes in ice crystals,” stated Associate Professor Hitoshi Matsui from Nagoya University, the study’s lead author. “Our previous research found that a significant quantity of Arctic dust is found in the lower troposphere (below around 3 km altitude) during the summer and early fall, serving as a very effective nucleus for ice formation in clouds during that time.”
To assess the influence of Arctic dust on the region’s cloud formations, Matsui and Dr. Kei Kawai from Nagoya University collaborated with researchers from the National Institute of Polar Research and Hokkaido University, utilizing the CAM-ATRAS global aerosol-climate model in their study.
The researchers first analyzed how the amount of dust released from the Arctic land surface has changed over the last 40 years, from 1981 to 2020. Their simulations revealed a 20% increase in dust emissions during this period due to warming in the Arctic. This rise in dust levels promotes ice nucleation in clouds within the lower troposphere, diminishing clouds’ ability to hold more liquid droplets and fewer ice crystals as the region warms. Increased dust also enhances ice crystal formation, which overcomes the reduction in ice crystal formation due to temperature feedback in 30% of the region on an annual basis, and 70% during the summer months.
“Many climate models have not factored in the impacts of dust from Arctic land surfaces,” noted Matsui. “Our findings indicate that it is crucial to consider both temperature and emission feedbacks together to enhance the precision of climate change forecasts in the Arctic.”
