Carolyn Kaster, Associated Press
From left, Sen. Tom Carper, D-Del., Senate Minority Leader Charles Schumer of N.Y., Sen. Sheldon Whitehouse, D-R.I., and Sen. Ben Cardin, D-Md., talks as they arrive on Capitol Hill in Washington, Wednesday, May 24, 2017, for a news conference on the Paris Climate Agreement.

President Trump is building a “great” wall around his luxury golf course in Ireland to protect it from storms and rising sea level. When it affects his things, Trump is a believer in the science that measures weather extremes and sea level rise. It is important for the public to know what science is since science is such an important part of everyday life. Science is not a thing. It is a method of learning about the natural universe. The “scientific method” is based on three things: 1) curiosity and designing testable ideas (hypotheses), 2) careful observation of experimental evidence to evaluate the ideas, and 3) thoughtful and logical conclusions based on the evidence. The practice of science adds a fourth element: review of conclusions by knowledgeable peers before publication in journals.

The basis of science is observation — of evidence or of experimental results. An error occurs when the standard for acceptance of an idea is set so high that an actual "truth" is rejected (say for 95 percent confidence, 19 out of 20 observations of evidence or experimental results support the conclusion, meaning we reject it based on only one negative indication out of 20). Scientists call this type of error, rejecting something real, a “Type I error.”

Another type of error occurs when the standard is set so low that something not real is accepted (say 60 percent or some other lower value, meaning we will accept a falsehood as real with only 6 out of 10 positive indications). Either one is an error that occurs because 1) human beings are involved and 2) an arbitrary level of confidence is used to arrive at conclusions.

Human beings have only our perceptual observations available and therefore we have no other means of ascertaining reality. While science may use a high standard of acceptance (95 percent is typical for acceptance of scientific explanations of natural phenomena; prone to Type I errors), when the consequences of public policy are very great as in the case of climate change, it is better to apply a lower standard and make a Type II error (thus risk being wrong about cause) than to demand such a high level of proof that we make a Type I error and reject a real human cause that leads to a devastating future for the planet and human life on it.

Congress and the public seem to want answers to be either true or false, i.e. 100 percent confidence in the result. Such an impossible standard is highly prone to Type I errors. People need to realize that while scientists use a 95 percent confidence level among themselves for acceptance of scientific conclusions, when the issue is one with great consequences if we get it wrong (for example climate damage due to human causes), the public and public officials must not insist on such a high level. Ninety-seven percent of serious scientists have evidence that gives them great concern about climate damage. This ought to be sufficient for the public and any legislator.

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Type I and Type II errors do occur in Congress and in legislatures, often with serious consequences. According to the best conclusions of climate science, the consequences of making a Type I error regarding climate damage are very serious and delaying making changes to reduce these consequences is devastating. Public action must get that message across to politicians. Economic and social changes may be inconvenient, but waiting much longer may take us to a point where corrections are no longer possible and terrible consequences become inevitable.

If we put the same emphasis on developing non-polluting energy sources in the next decade that we did to put a man on the moon in the 1960s, we would have the human contribution to climate damage under control in 10 years. And the effort will generate millions of long-term jobs in new and sustainable industries.

Cameron Mosher is a local geologist, author, instructor at SLCC and member of the Citizens Climate Lobby.