A recent study indicates that dust from areas in the Arctic that lack snow and ice may significantly impact climate change in that region. Increased dust levels can encourage the creation of ice crystals within clouds, which reduces the clouds’ ability to hold more liquid droplets, a process that is further exacerbated by warming in the Arctic.
The Arctic is warming at a rate two to four times faster than the global average. Research conducted by scientists in Japan has revealed that dust from snow- and ice-free regions in the Arctic might play a crucial role in climate change affecting the area. These findings were shared in the journal npj Climate and Atmospheric Science.
One perspective suggests that rising temperatures in the Arctic may increase the presence of liquid droplets in the region’s clouds while decreasing the number of ice crystals. This can lead to thicker, more persistent clouds, which are better at reflecting sunlight and could potentially help to cool the area during the summer months (temperature feedback).
In contrast, the new research indicates that as the Arctic continues to warm, the expansion of snow- and ice-free zones results in rising dust emissions. This dust may facilitate the creation of more ice crystals in the clouds. Consequently, the presence of additional ice crystals may cause clouds to become thinner and have shorter lifespans, which means they reflect less sunlight and could contribute to warming in the region during the summer (emission feedback).
“The increasing levels of dust due to Arctic warming might lead to an outcome that contradicts the traditional understanding of changes in ice crystals,” explained Associate Professor Hitoshi Matsui of Nagoya University, who led the study. “Our earlier research demonstrated that a significant amount of Arctic dust is found in the lower troposphere (below about 3 km altitude) over the region during the summer and early fall, serving as an efficient nucleus for ice formation in clouds at that altitude.”
To measure the effect of Arctic dust on local clouds, Matsui and Dr. Kei Kawai from Nagoya University, alongside researchers from the National Institute of Polar Research and Hokkaido University, utilized the CAM-ATRAS global aerosol-climate model for their investigation.
They initially analyzed data on dust release from the Arctic land surface over the last 40 years, from 1981 to 2020. Their simulations revealed a 20% increase in dust emissions during this timeframe, resulting from the warming of the Arctic. This surge in dust contributes to ice nucleation in clouds in the lower troposphere, diminishing the ability of these clouds to maintain more liquid droplets and fewer ice crystals as temperatures rise. The increase in dust levels promotes the formation of ice crystals, overriding the reduction in ice crystal formation due to temperature feedback in 30% of the region annually and 70% in summer.
“Most climate models have not taken into account the influence of dust from Arctic land surfaces,” Matsui noted. “Our findings suggest that accounting for the opposing temperature and emission feedbacks is essential for enhancing the accuracy of climate change forecasts in the Arctic.”
