Not only does the Earths magnetic field wander around on time scales of a century or so, but every 100,000 years or so it completely changes direction, with the north (magnetic) pole becoming the south (magnetic) pole. (dotearth.blogs.nytimes.com)
Export of carbon to the deep sea and sea floor is an important process in the global carbon cycle that can sequester atmospheric CO2 over time scales of centuries or greater. (rstb.royalsocietypublishing.org)
Analysis of sea level changes during Eemian time, the last interglacial, show changes of several meters in time scales of a century. (dotearth.blogs.nytimes.com)