Sea levels are rising
[2007-11-01]

animation: Lisa Roberts
Sydney 2007

sea level data: John Church et al.
Understanding sea level rise: implications for the future (presentation)
World Climate Research Program, Greenhouse 2007

sound: Jack Colwell
Sydney, 2007

Data from tide guages
around the Australian coast
shows sea levels rising
over eighty years:

The most important reason

for sea level rise in the 20th century,

and we expect to be in the 21st century,

is oceans thermal expansion.

As the ocean warms the water expands,

sea level rises.

The second largest contribution

is from the melting of glaciers and ice caps,

so these are glaciers in places like Alaska,

the Himalayas, New Zealand, Switzerland, etc.,

and they've been melting,

and melting an increasing rate

over the past 50 years.

And the third contribution,

and potentially the largest contribution

on the longer timeframe,

but we don't think there's been a large contribution

in the last century,

are the ice sheets of Greenland and Antarctica.

Greenland contains enough water

to raise sea levels by about seven metres,

and Antarctica over 60 metres.

Dr John Church, 2007

CSIRO transcript:Sea level on the rise
World Climate Research Program, Greenhouse 2007