Your claim is true. According to a study done by Virginia Tech, 24 of the 32 coastal cities in the US are sinking more than 2 millimeters a year, and half of those cities have areas sinking faster than global sea levels are rising. While these numbers don't seem like much, the researchers explained that when combined with the rapid rise in sea level, it culminates in a big change. Furthermore, to help readers better understand the situation, the paper used this analogy: “Imagine you are in that boat with a steady leak, slowly causing the boat to sink. That leak symbolizes sea-level rise or broadly flooding. What would happen if it also starts raining? Even a minor rainfall or drizzle would cause the boat to sink more quickly than you thought it would. That’s what land subsidence does — even imperceptible millimeter land subsidence exacerbates existing coastal hazards.”
