'The oldest records date back to the 1890s and the average rise for 225 tide gauges spread around the world is 1.48 mm per year. This is close to the generally accepted 1.72 mm per year for tide gauges.' - 'There has been no acceleration of the rate of rise during the 20th century. Data are available from satellite observations since 1993. These show a rise of about 3.2mm per year with indications of a recent decline in the rate. Nobody seems to be able to explain why it is about twice the tide gauge rate.'