What’s worse than legislating the size of a soda cup? Legislating the scientific facts, of course. In 1897, the Indiana state legislature tried to pass a bill restricting the value of pi to one of three numbers, none of them the real value of pi.

That bill didn’t pass, but one equally stupid is under consideration by the state legislature of North Carolina. It mandates the way that scientists are to calculate the rate of sea-level rise due to global warming. Replacement House Bill 819 requires that there be only one way to calculate sea-level increase: by linear extrapolation of the increase since 1900. Here’s the relevant portion of the bill:

The problem is that sea level isn’t supposed to rise linearly with time. As Scott Huler’s Plugged In site at Scientific American notes (link above):

It goes on, but there’s the core: North Carolina legislators have decided that the way to make exponential increases in sea level rise – caused by those inconvenient feedback loops we keep hearing about from scientists – go away is to make it against the law to extrapolate exponential; we can only extrapolate along a line predicted by previous sea level rises. Which, yes, is exactly like saying, do not predict tomorrow’s weather based on radar images of a hurricane swirling offshore, moving west towards us with 60-mph winds and ten inches of rain. Predict the weather based on the last two weeks of fair weather with gentle breezes towards the east. Don’t use radar and barometers; use the Farmer’s Almanac and what grandpa remembers.

So what does the linear extrapolation yield? A rise of less than 16 inches by the end of this century. That’s far less than what the real data tell us, which suggest a more-than-linear increase: to about one meter.

An article in the Charlotte [North Carolina] Observer suggests that economic forces are behind this change:

The calculation [of a 1-meter rise], prepared for the N.C. Coastal Resources Commission, was intended to help the state plan for rising water that could threaten 2,000 square miles. Critics say it could thwart economic development on just as large a scale. A coastal economic development group called NC-20 attacked the report, insisting the scientific research it cited is flawed. The science panel last month confirmed its findings, recommending that they be reassessed every five years. But NC-20, named for the 20 coastal counties, appears to be winning its campaign to undermine them. The Coastal Resources Commission agreed to delete references to planning benchmarks – such as the 1-meter prediction – and new development standards for areas likely to be inundated. The N.C. Division of Emergency Management, which is using a $5 million federal grant to analyze the impact of rising water, lowered its worst-case scenario from 1 meter to 15 inches by 2100.

Don’t like the science? Ignore it. But, as the old saying goes, “You can’t fool Mother Nature.” Nor can you legislate her away.