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Wildfire smoke impacts Arctic ice thousands of miles away

By investigating the differences between climate models, a team of researchers led by the University of Colorado Boulder and the National Center for Atmospheric Research (NCAR) has found that Arctic sea ice and wildfires may be more interconnected than previously thought.

According to the experts, soot and other burned biomass from wildfires in the Northern Hemisphere can eventually reach the Arctic, where they affect how much – or how little – sea ice persists at any given time. This can cause ripple effects on climatic patterns all over the globe, reinforcing a previously unobserved feedback loop between these two systems.

“This research found that particles emitted from wildfires where people live can really impact what happens in the Arctic thousands of miles away,” said study lead author Patricia DeRepentigny, a postdoctoral fellow in Climate and Global Dynamics at NCAR.

“Sometimes the Arctic can be seen as this region that we shouldn’t care about because it’s so far away from where we live … but the fact that there’s this back-and-forth of what happens here with the wildfires can affect the sea ice, and a diminishing sea ice can then lead to more wildfires here, connects us with the Arctic a little bit more.”

Governments and other organizations have often used climate models that simulate how different parts of the climate interact to help guide future climate change policies. By examining one of these models – the NCAR-based Community Earth System Model version 2 (CESM2) – Dr. DeRepentigny and her colleagues found that the model identified a drastic acceleration of Arctic sea ice loss towards the end of the 20th century that was not seen in other models. Further investigations revealed that, by contrast to previous models, this one took into account biomass burning emissions.

When aerosols released by wildfires interact with Arctic clouds non-linear effects can emerge. For instance, during heavy fire years, when many aerosols are released, clouds in the Arctic get thicker, whereas in lighter fire years, those clouds are thinner and allow for more solar radiation to get through and melt more ice. Thus, surprisingly, smoke from wildfires could actually help protecting Arctic ice.

“When we think about climate, everything’s really interconnected, and this is really a great example of that,” said study co-author Alexandra Jahn, an associate professor of Atmospheric and Ocean Sciences at CU Boulder. “When we’re thinking about climate processes, it’s really a global problem, and we can’t study it in any isolated fashion. We really always have to look at the global picture to understand all these different interactions.”

Further research is needed to pinpoint the effects of specific wildfires and to fine-tune the existing climate models. “The goal that we’re trying to achieve here is to have these climate simulations be more reliable and give us projections that can then inform policy makers and societal choices,” Dr. DeRepentigny concluded.

The study is published in the journal Science Advances

By Andrei Ionescu, Staff Writer  

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