If you have followed the climate conversation for any length of time, you have seen the same drumbeat over and over. Satellite data shows a shocking acceleration in sea level rise, which validates climate projections and proves that human activity is driving global change. You have seen headlines like “Satellite Data Reveals Shocking Acceleration in Sea Level Rise” and “Global sea levels are rising faster and faster…” that are designed to leave no room for doubt.
But something crucial has been missing from the coverage. Tide gauges are the instruments bolted to coasts that measure the water where people actually live. They are our oldest and most direct record of local sea level. A new peer-reviewed paper compares local projections with local observations and tests for acceleration at sites around the world. The authors find that about ninety-five percent of suitable tide gauge records show no statistically significant acceleration in the rate of sea level rise. The few sites that do show acceleration are plausibly explained by local non-climatic factors like land motion. On average, the projections used for design are biased high by about two millimeters per year compared with what the gauges record.
That single result should matter to anyone who cares about sound risk and honest planning. It also sits very awkwardly next to the most amplified satellite analyses. One widely cited satellite study claims the global rate has more than doubled since the early nineteen nineties and projects about one hundred sixty-nine millimeters more rise by the middle of the century if that trajectory continues.
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