A blue Arctic within a decade
For decades climate models have been predicting that without a reduction in CO2 emissions the sea ice in the Arctic would disappear entirely in the summer months. The latest generation of climate models from CMIP6 confirm the expectations from previous assessments: without any radical change in human emissions of CO2 we will regularly have ice-free summers in the Arctic by the late 2020s / early 2030s.
This is the September sea ice extent in CMIP6 and CMIP5 climate models. The blue colours indicate the percentage of models that agree there is sea ice at a given location (in a 10yr running-mean), the red line shows where half the models agree that there is ice there.
While there is a long tail to the projections of sea ice extent with some models still having summer sea ice until late into the 21st century, more than half the models have no sea-ice in the summers from the late 2020s and early 2030s. There is some dependency on the initial conditions here: some models have overly thick ice or too-large extents compared to observations which causes a delay in the disappearance of summer sea ice. There are also different physics schemes used to describe the dynamics and thermodynamics of ice in the different models, so some models are better than others at capturing important surface coupling processes which can accelerate ice loss.