Probability Assessments of an Ice-Free Arctic: Comparing Statistical and Climate Model Projections

TL;DR

This paper compares statistical forecasts and climate model projections of Arctic sea ice decline, finding a higher likelihood of an ice-free Arctic in the 2030s based on statistical analysis of satellite data.

Contribution

It introduces a statistical modeling approach for Arctic sea ice projections and compares it with climate model forecasts, highlighting earlier ice-free conditions.

Findings

Statistical models predict an accelerating decline in sea ice.

Probability assessments show a 60% chance of an ice-free Arctic in the 2030s.

Climate models suggest a slower, more gradual loss.

Abstract

The downward trend in the amount of Arctic sea ice has a wide range of environmental and economic consequences including important effects on the pace and intensity of global climate change. Based on several decades of satellite data, we provide statistical forecasts of Arctic sea ice extent during the rest of this century. The best fitting statistical model indicates that overall sea ice coverage is declining at an increasing rate. By contrast, average projections from the CMIP5 global climate models foresee a gradual slowing of Arctic sea ice loss even in scenarios with high carbon emissions. Our long-range statistical projections also deliver probability assessments of the timing of an ice-free Arctic. These results indicate almost a 60 percent chance of an effectively ice-free Arctic Ocean sometime during the 2030s -- much earlier than the average projection from the global climate models.