People tend to blame the last straw for breaking the camel's back, but each individual straw shares equal responsibility. When a tree falls, the rain that loos

People tend to blame the last straw for breaking the camel's back, but each individual straw shares equal responsibility. When a tree falls, the rain that loosened the soil around the roots, the wind that pushed upon the end of the trunk-lever, and the beetle that damaged the bark such that the tree became less flexible are all responsible. When it comes to icebergs calving from glaciers, warming is a contributing factor, but so is a snowfall upon the glacier further up the slope. Ice above pushes ice below away from the support of land, and like many crystalline minerals, water-ice has far less strength under tension than it has under compression.