An example of this kind of surprise happened in relation to the Antarctic ozone hole, where unexpected chemistry on surfaces of
ice particles lead to much more efficient destruction of ozone in the polar vortex than had been expected, making an existing concern into a serious problem.
Year after year, as fallen snow added layers to the
ice sheet,
lead emissions were captured along with dust and other airborne
particles, and became part of the
ice - core record that scientists use today to learn about conditions of the past.