There did not used to be any rainfall in these parts, but now there is and it mixes with meltwater which runs through their nesting grounds. When the water comes into contact with the incubating eggs, it drops their temperatures so that the embryos die within their shells. Or worse; if the chicks have hatched, their down can soak up the icy water and they either die of cold or drown.
Also, in certain parts of the Antarctic, warming has reduced the sea ice fields which juvenile krill and silverfish need to survive. This means that over the past forty years or so, there has been a drop in the food supply for Adélies. The consequence of climate change has been the complete eradication of many of the Adélies’ breeding colonies. The scientists call them "ghost rookeries".
