DATE: February 27, 2019
SNIP: The Arctic Ocean could become ice-free in the summer in the next 20 years due to a natural, long-term warming phase in the tropical Pacific that adds to human-caused warming, according to a new study.
Computer models predict climate change will cause the Arctic to be nearly free of sea ice during the summer by the middle of this century, unless human greenhouse gas emissions are greatly reduced.
But a closer examination of long-term temperature cycles in the tropical Pacific points towards an ice-free Arctic in September, the month with the least sea ice, on the earlier side of forecasts, according to a new study in the AGU journal Geophysical Research Letters.
There are different climate models used by researchers to predict when the first ice-free Arctic September will occur. Most models project there will fewer than 1 million square kilometers of sea ice around the middle of this century, but projections of when that will occur vary within 20-year windows due to natural climate fluctuations.
The climate model used in the new study predicts an ice-free Arctic summer sometime between 2030 and 2050, if greenhouse gases continue to rise.
By accounting for a long-term warming phase in the tropical Pacific, the new research shows an ice-free Arctic is more likely to occur on the earlier side of that window, closer to 2030 than 2050.