For those observing Arctic climate change from afar, the picture often seems simple: Warming is a harmful process that leads to melting glaciers and rising sea levels. But as is often the case, the truth is much more complex.

A group of Japanese researchers studying the intricacies of the Arctic have provided further evidence of this complexity. When considering the Arctic climate, one fact emerges: Everything is warming rapidly. The region’s warming rate is two to four times the global average. In this context, an important question arises: What is the reason for the rapid temperature increase in the Arctic?

This phenomenon, known as Arctic expansion, is not only changing the local environment but also affecting global climate systems. Unraveling the reasons for this requires looking not just at ice and temperature, but also at less obvious factors like Arctic dust.

Arctic Dust: An Unexpected Player

In a world where we often think of dust as nothing more than an inconvenience, researchers have found that dust plays a significant role in warming the Arctic. According to a recent study, dust (especially dust from snow- and ice-free regions of the Arctic) has been linked to accelerated warming in the region.

According to popular understanding, warming in the Arctic is generally believed to be due to more liquid droplets and fewer ice crystals filling clouds in the region. It is believed that this combination will create thicker, longer-lasting clouds that are more likely to reflect sunlight, thus potentially cooling the region during the summer months. This is what is often called temperature feedback.

Expansion of snow and ice-free areas

However, Japanese researchers paint a different picture. Their studies showed that warming in the Arctic is associated with the expansion of areas free of snow and ice. This increase also causes an increase in dust emissions, which contributes to the formation of ice crystals in clouds. Thinner, less durable clouds are a result of cloud ice crystals, which means less sunlight is reflected and the Arctic is warmer during the summer months. The researchers called this “emission feedback.”

Voice of researchers

The lead author of the study, Professor Hitoshi Matsui from Nagoya University, provides valuable insight into this complex phenomenon.

“The increase in dust due to warming in the Arctic may cause a phenomenon that is opposite to the conventional understanding of changes in ice crystals,” he said. “Our previous work showed that large amounts of Arctic dust are distributed in the lower troposphere (below about 3 km altitude) in the region during the summer and early autumn months, and that the dust acts as a very effective nucleus for cloud ice formation at this altitude season”.

I’m looking back, I’m looking forward

Professor Matsui, Dr. Kei Kawai and colleagues from the National Polar Research Institute and Hokkaido University used the global aerosol climate model CAM-ATRAS for their study. They examined how dust emissions from the Arctic land surface changed over four decades, from 1981 to 2020. The results show that dust emissions increased by 20% during this period as the Arctic continued to warm.

Formation of arctic dust and ice crystals

Increased Arctic dust emissions contribute to the formation of cloud ice in the lower troposphere, weakening the cloud’s ability to transport more liquid droplets and fewer ice crystals as the Arctic warms. The researchers found that in 30% of the region annually and 70% in summer, the increase in ice crystal formation due to increased dust outweighed the decrease caused by temperature feedback.

“Most climate models do not take into account the impact of Arctic surface dust. Our study shows that feedbacks on balancing temperature and emissions need to be taken into account to improve the accuracy of Arctic climate change predictions,” said Matsui.

So, as we continue to grapple with the realities of climate change, these findings underscore the need to recognize the subtle relationship between Arctic warming and Arctic dust. It’s a reminder of how interconnected our world is, and how a deeper understanding of these connections can help us make better predictions and perhaps better decisions about the future of our planet. The full text of the research was published in the journal npj Climate and Atmospheric Science.