Thread by @ncdave4life

@ClimateOpp [1/14] @ClimateOpp why did you tell @jdickerson & @60minutes that "sea level rise is accelerating," when all the best long measurement records show that coastal sea-levels trends have NOT significantly accelerated in >90 years?
sealevel.info/MSL_graph.php?…

@ClimateOpp @jdickerson @60Minutes [2/14] The Dutch, for obvious reasons, have been paying close attention to sea-level for a very long time. Their measurements show that there's been no significant acceleration in rate of sea-level rise in response to rising CO2 levels:

@ClimateOpp @jdickerson @60Minutes [3/14] Venice is one of the very few sites which have measured a statistically significant change in rate of sea-level rise: it DECELERATED slightly (probably because they curtailed groundwater pumping in the 1980s, to reduce subsidence).

@ClimateOpp @jdickerson @60Minutes [4/14] "The secular trend in MSL at venice during the twentieth century was a factor or two greater than at Trieste, which is almost certainly related to local anthropogenic effects including ground water pumping, see for example several publications by P.A.Pirazzoli." -PSMSL

@ClimateOpp @jdickerson @60Minutes [5/14] Trieste, Italy has a typical sea-level trend. As you can see, there's been no significant acceleration in the rate of sea-level rise.

@ClimateOpp @jdickerson @60Minutes [6/14] The "global" (i.e. average) sea-level trend is slightly up. But it's so slight that In many places it's dwarfed by local factors, like erosion, sedimentation, and vertical land motion.
@GretaThunberg 's town is one such place. There the land rises >3x as fast as the ocean.

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [7/14] The place recording sharpest acceleration is Brest, France. Even there it's nearly negligible, for practical purposes. The trend was 0.0 mm/yr in 1800s, but +1.5 mm/yr since 1900 (six inches/century), & no significant acceleration since 1900 (only 0.00483±0.01121 mm/yr²).

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [8/14] If you look at places with little or no vertical land motion, the sea-level trends look like these:

● sealevel.info/MSL_graph.php?…

● sealevel.info/MSL_graph.php?…

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [9/14] Measuring sea-level is straightforward. It's been done accurately for >200 years, in some places.
It's not driven by AGW. CO2 levels have risen (rapidly) for 70 yrs. Temps have been rising (slowly) for 40 yrs. It has NOT measurably affected coastal sea-level trends.

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [10/14] Wherever you look, the story is the same: regardless of whether the local sea-level trend is positive or negative, it hasn't accelerated significantly since the 1920s, or before.

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [11/14] Local sea-level trends vary, due mostly to varying rates of local vertical land motion (subsidence or uplift). But they all show the same lack of significant acceleration in response to rising CO2 levels:

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [12/14] Even at New York City's Battery Park, where land subsidence approximately doubles the rate of sea-level rise, there's been no significant acceleration in rate:

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [13/14] Where there's no vertical land motion (subsidence or uplift), the trend looks about like this: perfectly linear for at least nine decades, with no detectable effect from rising CO2 levels:

@ClimateOpp @jdickerson @60Minutes @GretaThunberg [14/14] @ClimateOpp as a matter of integrity you need to correct your statement to @jdickerson & @60minutes, and tell them that coastal sea level rise is NOT significantly accelerating, neither at Venice nor anywhere else. #DoTheRightThing

sealevel.info/MSL_graph.php?…

@ClimateOpp @jdickerson @60Minutes @GretaThunberg @ThreadReaderApp unroll it, please.