evidence: Instead, global sea level rose by about 14 centimeters, or 5.5 inches, from 1900 to 2000. That’s a substantial increase, especially for vulnerable, low-lying coastal areas. "The 20th century rise was extraordinary in the context of the last three millennia – and the rise over the last two decades has been even faster," said Robert Kopp, the lead author. [...] Global sea level has been rising for the past several thousand years, owing to the retreat of glaciers from the last ice age. The key issue is whether the rate of sea level rise is accelerating owing to anthropogenic global warming. It is seen from the figure above that the rate of sea level rise during 1930-1950 was comparable to, if not larger than, the value in recent years. The challenges to determining global sea level rise, particularly over the past 100 or 1000 years, are substantial. [...] Sea level rise is the main ‘danger’ from human caused climate change (any increase in extreme weather events is hypothesized rather demonstrated using historical data, with possible exception of heat waves in a few regions).