One of the scariest effects of climate change might already be happening — and it'd mean our projections are way off - Business Insider

This is the Mertz Glacier in January 2017. Warm waters are pooling underneath Antarctic glaciers in a way that's causing glaciers to melt more rapidly and preventing the formation of cool water beneath Antarctica, according to a new study. This could slow ocean currents and potentially lead to a rapid sea-level rise event known as a pulse. Such an event could be devastating, causing sea levels to rise by more than 10 feet by the end of the century.
http://www.businessinsider.com/antarctic-glacier-melting-could-warm-seas-and-cause-ice-shelf-collapse-2018-4