A new study by an international team of scientists (h/t No Tricks Zone) gathered detailed daily sea level measurements at three locations along the coast of Peru where the rapid sea level increases predicted by the IPCC would cause major problems, if they actually happened. Turns out (stop us if you’ve heard this before) the models were wrong. While sea levels have gone up compared to the 1950s, they peaked in the 1980s and have gone down since. And the overall rate of rise over 1961-2010 turned out to be far lower than IPCC predictions. So if Bill Gates decides to build mansions for himself all down the Pacific Coast, at least the ones in Peru will be safe.
The article discusses all the complications associated with trying to measure sea level rise. First there are the daily tides, which in the case of the Peruvian coast yield not one but two daily highs and lows. Then there are winds off the mountains that affect the shape of the ocean surface. Then there is the movement of the land itself: rising land makes it look like the seas are going down. There are also regular cycles in large-scale atmospheric pressure systems like the El Niño oscillation which squeeze and release vast reaches of the ocean. Amidst all these factors, which cause swings of up to several meters of sea level on a daily or weekly basis, scientists are trying to measure if there is a trend measured in millimeters per year. The IPCC says yes, and along Peru they predicted, back in 2007, that the rate of rise would be between 1.8 and 2.0 mm/year over the 1961 to 2010 interval.
Actually the decadal average sea level did rise, by about 8 mm, from the mid-1950s to the mid-1990s. But then it dropped by between 1 and 5 mm over the next 20 years. And when the authors computed trends in the data, they found the 1961 to 2010 trends to be 0.7 and 1.7 mm per year, well below the IPCC predictions.
Now on the one hand you might tell us not to nitpick, one little prediction gone wrong, who cares? But IPCC predictions are treated as evidence these days, whereby if some climate model somewhere predicts any bad event some time over the next 100 years it’s considered proof of a crisis we have to drop everything to fix. So if the alarmist crowd is going to throw model predictions and scary charts at us and expect us to panic whenever they do, we get to ask how the models did in the past. And in this case they were all wet. Or rather dry.