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Rapid changes in the Arctic are forcing the region into an entirely different climate state according to environmental scientists, as its once-frozen landscape continues to heat up. New research published in the journal Nature Climate Change from the National Center for Atmospheric Research (NCAR) has found that year-on-year increases in temperature have moved well beyond changes seen in the region’s history, indicating that this “new Arctic” may now be its new norm.
Weather patterns have always shifted in the region, with some variability in sea ice, temperature, rainy seasons, and snowfall being expected. The new study led by NCAR scientist Laura Landrum and co-author and NCAR scientist Marika Holland used detailed computer simulations based on Arctic climate observations to map scenarios for the region. Using this they were able to statistically define the upper and lower climate limits of the “old Arctic” versus the “new Arctic” to look at whether human-linked warming has created a rift between the two scenarios.
They were able to check the reliability of their model by using it to reliably “predict” current climate based on past climate information. The paper notes however that their results incorporated high-end estimates regarding future emissions of greenhouse gases, stating that a significant reduction in these could change the outcome. They looked at air temperature, ice volume, and the shift from rain to snow throughout the year and found that, as the model stands, in some respects the Arctic has already moved into a new climate state.
Changes in Arctic climate have seen the average amount of sea ice in September, when it reaches its annual minimum, drop by 31 percent since the first decade of the satellite era (1979-88). According to their models, the reduction in summer ice has meant that even an unusually cold year will no longer preserve the amount of ice that existed as recently as the mid-20th century throughout the summer months. This represents a significant threat to many Arctic species such as polar bears that rely on summer sea ice to hunt. Existing research has predicted that the Arctic could see ice-free summers as early as 2035.
Autumn and winter air temperatures will also move into a new climate state by the middle of this century according to their model, which will be followed by a seasonal change in precipitation as many more months of the year will see rainfall instead of snow.
"The rate of change is remarkable," said Landrum in a statement. "It's a period of such rapid change that observations of past weather patterns no longer show what you can expect next year. The Arctic is already entering a completely different climate than just a few decades ago."
"The Arctic is likely to experience extremes in sea ice, temperature, and precipitation that are far outside anything that we've experienced before. We need to change our definition of what Arctic climate is."
