A major challenge with climate change is predicting how it could cause myriad effects that ‘cascade’ through food chains and ecosystems. A new study about polar bear predation at Arctic bird colonies illustrates one way these knock-on effects can play out.

After observing bird breeding colonies in Greenland and Norway’s Svalbaard Archipelago for more than 40 years, scientists documented an increase in polar bear raids on bird nests in step with reductions in sea ice coverage.

In some years, b...