Fears of accelerating sea level rise (SLR) due to anthropogenic global warming (AGW) are rampant nowadays—often the primary phenomenon in people’s minds when they think of potential ill effects of AGW. The image above, created by NASA to show what lands would be inundated by a hypothetical 70-foot SLR, thought by some to be in store for “future generations” if global average temperature (GAT) rises by 2C, causing the complete melt of the Greenland and West Antarctic ice sheets, is typical of the kinds of scares. The 70-foot (22-meter) SLR was arrived at by comparison with sea level Pliocene interval, when atmospheric CO2 concentration and temperature were comparable to what is projected with a 2C rise in GAT. The roof of my own home in south Florida, the slab of which is at 8 feet above sea level, would then be about 40 feet underwater. Such predictions are indeed frightening—though far less so when people are told that it will take thousands of years to reach that state.
Yet empirical evidence indicates no acceleration in global SLR, and no acceleration in local SLR that can be tied to any global phenomena, which suggests even less to worry about.
Sea level and SLR are far more complicated matters than most people imagine. For those who want to gain a good understanding, a series of articles by Kip Hansen underway at WattsUpwithThat.com is highly instructive. The first installment introduces the topic and lays groundwork. The second focuses on tide gauges and the intricacies of gaining accurate information relative to both local and global sea level and SLR. We look forward to future installments.