“By denying scientific principles, one may maintain any paradox.”
—Galileo Galilei
Galileo has always been one of my scientific heroes. He was versatile as a scientist and an expert in the areas of physics, mathematics, astronomy and even philosophy. He is considered by many to be the Father of Modern Science. (If you ever get the chance to visit Florence in Tuscany, don’t miss the Museo Galileo where you can learn much about him and see telescopes he built himself. You can even see the middle finger from his right hand. And once you’re done there, not too far away you can visit his tomb in the Santa Croce church.)
The main reason I’m so fond of Galileo is because he took Copernicus’s view of the solar system—that the Earth went around the sun and not the other way around—and he proved it was correct. With his new invention the telescope (a modification of the spyglass used for observing ships coming over the horizon), he was able to observe four moons orbiting Jupiter, now known as the Galilean moons or satellites. He also observed that Venus went through phases similar to our own moon. These observations made it quite clear that not everything went around the Earth, as was the common knowledge at the time. His conclusions were that planets like Jupiter and Venus went around the sun as did Earth, and moons went around planets.
This was considered heresy and caused trouble between Galileo and the Roman Catholic church. He ended up being forced to recant his findings, and lived out the remainder of his days—almost thirty years—under house arrest. Given the overwhelming evidence that came along in time proving Galileo was right, the Catholic church eventually came to its senses and admitted that it had been wrong. Galileo eventually received a formal apology from the Pope posthumously, too late for Galileo to ever know the church acknowledged he was right. (Really late in fact: the pope giving the apology was John Paul II and the year was 1992! Makes me wonder if the upright middle finger on display at the Museo Galileo is giving a message!)
So what does Galileo have to do with North Carolina? Nothing directly, but he was a hero because he received persecution and punishment for describing what science told him, despite it not being popular with the authorities. Just because someone doesn’t like what science teaches us doesn’t make the science go away. And scientists in North Carolina are now facing the same kind of hurdle.
It would appear that the legislators in North Carolina today are thinking the same thing the Catholic church thought 400 years ago. Following in their footsteps, North Carolina legislators have passed a law stating that it’s illegal to use methods of extrapolation to estimate future sea-level rise. Why did this even come up for discussion? The North Carolina Coastal Resources Commission received a report from a state-appointed board of scientists that predicted more sea-level rise than the state was comfortable with. It seems twenty counties in North Carolina are on the coast, and the possibility that they may flood over the next few decades doesn’t help property values very much.
A group of legislators from these coastal counties didn’t like the report. So how do you deal with information you don’t like, even if it’s scientific? By sticking your head in the sand, that’s how. In House BIll 819, they describe how they want to deal with predicting rates of sea-level rise: “These rates shall only be determined using historical data, and these data shall be limited to the time period following the year 1900. Rates of sea-level rise may be extrapolated linearly. …”
Linear extrapolation means that things will increase in a straight line at the same rate they always have, explaining why historical data is reasonable for such predictions. Problem with that in this case is that sea levels are expected to rise exponentially, not linearly.
In case you don’t know the difference between these two terms, take a look at the graph to the left. Some things increase at a linear rate. If a tree grew a foot a year every year, that would be linear growth. Your age increases linearly by one each year.
Exponential growth means it will increase by more each year rather than by the same amount. Many things increase exponentially: computer microprocessing speed, nuclear chain reactions, and even life itself, whether bacteria in a culture plate or human beings on a planet. Such a rate of growth tends to stop once resources are depleted but up until then, there’s nothing to stop two becoming four becoming eight, and so on.
If you predict sea level rise linearly based on historical data, you have the very best-case scenario. Good if you want to minimize the risk to property values on the North Carolina coast. Bad if you want to know how to prepare for what’s coming. That’s all science is trying to do, but in what I think should now be called the Galileo Bill, North Carolina is making it illegal to do so. So nobody has the ability to publicly state what they think is a worst-case scenario, or even a likely scenario.
The reason most scientists think sea-level rise will be exponential is because of the feedback loops that are in effect. Warmer oceans will have larger volumes leading to even more sea ice melting. The loss of glaciers and ice shelves will add even more. It’s difficult to know exactly how much each of these mechanisms will have an impact, especially when they are interdependent.
When planning for possible future disaster, it’s best to have a range to work with, from best- to worst-case. The above graph shows that none of the projections are linear, even the best-case. (This information comes from a paper written by Vermeer and Rahmstorf, published in 2009. Too complicated to cover here, but the link is there if you’d like to explore it further.)
It’s time for authorities—whether religious, political or economic—to stop stifling science. Facts and evidence can’t be changed just because they’re inconvenient or not giving you the answers you want. The Roman Catholic church took about 380 years to own up to their egregious mistake. I wonder how long it will take the North Carolina legislature to come to the same conclusion.
Sometimes you can’t do experiments to investigate a hypothesis, however. One reason would be that it’s unethical to do so. We’ve proven that smoking causes cancer because of careful observations over many decades, but it would be difficult as well as unethical to design a clinical trial where nonsmokers were randomized to either become smokers or remain nonsmokers, and then follow their health over the years. When such data needs to be obtained, we do our best to observe smokers and nonsmokers and compare how they do, and try to account for any other possible confounding variables that might affect the outcomes such as level of education, socioeconomic status, etc… Continue reading 
