An interesting graphic from NOAA
The unobservant might well look at this graph and say:"There you are! The sea level is rising, just as global warming theory predicts!
But look at the calibrations. The graph goes back to 1850, showing that the sea level was rising long before global warming was thought of. And the rate of rise has been smooth, unlike the accelerated rise in recent times that would be expected from anthropogenic global warming
Relative Sea Level Trend: The Battery, New York
The relative sea level trend is 2.84 millimeters/year with a 95% confidence. interval of +/- 0.09 mm/yr based on monthly mean sea level data from 1856 to 2017 which is equivalent to a change of 0.93 feet in 100 years.
The plot shows the monthly mean sea level without the regular seasonal fluctuations due to coastal ocean temperatures, salinities, winds, atmospheric pressures, and ocean currents. The long-term linear trend is also shown, including its 95% confidence interval. The plotted values are relative to the most recent Mean Sea Level datum established by CO-OPS. The calculated trends for all stations are available as a table in millimeters/year and in feet/century (0.3 meters = 1 foot). If present, solid vertical lines indicate times of any major earthquakes in the vicinity of the station and dashed vertical lines bracket any periods of questionable data or datum shift.