A) The steady rise of sea level for the past 100 years
B) ENSO
C) Random change observed in the past 15 years of coastal flooding
D) The steady loss of sea ice in the summer in the Arctic Ocean

A) Only because of deforestation
B) Only because of fossil fuel burning
C) Because of a and b, and other sources
D) None of the above

A) Increased the same amount over the past 100 years, irrespective of latitude
B) Increased along a straight-line trajectory over the past 100 years
C) Increased much more at the Equator and much less along the poles
D) Increased differently at different locations and at different decades in the past 100 years