One of the great benefits of modern civilization is the tremendous amount of information that is available for us to learn from, argue about, or misunderstand.
It’s easy to filter this information so we can stress just the things that support what we already believe. The recent revelation of email sent by scientists studying climate change is the latest example of this.
The weather may be a safe subject to talk about with strangers on an elevator, but climate change is something else. It’s turned into a subject to avoid, unless you like arguing in circles and straining relationships.
If the theory of human-induced climate change is correct, then we are going to have to change the way we live. No one wants to do that. Instead, we’ve been questioning the theory. If it’s wrong, we don’t have to change.
The result has been a lot of hot air that may only be making the problem worse.
With arguments of this sort, both sides look for the ultimate weapon, a simple and convincing argument that can’t be denied. It doesn’t help if you have volumes of information and piles of data to support you, if no one else can understand it.
In 1998, climate change scientists came up with a “hockey stick” as the best way to visually explain what was happening. It’s a graph that shows the Earth’s temperature over the past thousand years. The lines wiggle a lot as they move from left to right, but at the very end they shoot up.
There’s more than one line on the graph because the climate change scientists looked at different ways of calculating historical temperatures. The most reliable line is the record of instrumental measurements taken over the past 150 years. The other lines are based on measurements of tree rings or chemical compositions of ice, coral, and rock. Scientists look at how these things change and compare them against actual temperature measurements, and then extrapolate backwards. Some scientists disagree about the correlations between these things and what goes into the formulas used to create a graph like this.
The graph was published in 1998 in an article called “Northern Hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations”. It has come to be accepted as the key visual to identify climate change, and has been subjected to intense scrutiny, peer review, and criticism of the methods used. A 2006 National Research Council report (commissioned by the U.S. Congress) raised questions about the methodology but had a high level of confidence that the warming over the last few decades was unmatched over the past four centuries.
The problem with a graph like this is that it becomes the topic of discussion, rather than a tool used to discuss an issue. It takes on an unnecessary importance. When we start relying on graven images, we get ourselves into trouble.
The emails seem to show that some of the scientists involved in this work were opinionated and willing to ignore, hide, or tweak its shortcomings. It looks like they wanted the graph to fit their beliefs, or promote them to others.
When scientists get selective about the data they use and how they use it, they are no longer practicing good science.
I’m also disappointed in the reaction of the skeptics. Their argument has been that we don’t have enough information to act. They have been demanding more thorough and conclusive studies. But they seem perfectly content to accept a handful of emails that show scientists are just as human as the rest of us. As if that solves the problem of climate change.
Some people think scientists don’t get to have opinions. But the truth is, you don’t discover anything unless you’ve got an opinion about it first. You call it an hypothesis and then you test it.
When Columbus sailed west to find the East, he did it knowing the Earth was round. He also thought that the Earth was a lot smaller than it really was.
Eratosthenes had calculated that the world was 42,000 km in the second century BC. (It’s actually 40,000 km.) But Columbus relied on the calculations of Marinus of Tyre, leading to an Earth that was only 25,000 km around.
Columbus navigated by dead reckoning. He relied on a compass and carefully tracked how far he sailed each day.
His logs show that he kept two sets of numbers. For centuries, it was assumed that he did this so his crew wouldn’t fear that he had sailed too far from Spain. In 1983 James E. Kelley figured out that Columbus was converting the log between Italian and Portuguese Leagues.
Columbus also used lunar eclipses to measure how far he had sailed. This is a method that was used by Alexander the Great. If you know what time an eclipse occurs in two separate places, you can calculate how many degrees of longitude separate the two locations. It’s a little harder to do without clocks, but was a well known method at the time.
Columbus reported the times of two eclipses, but made huge errors in his measurements. One of the eclipses may have been impossible to observe, since the log indicates there was a heavy storm.
But the real reason for the errors was that he could only be confirmed as Viceroy of the newly discovered lands if they were in the region of the Indies. In order to protect his fortune, Columbus lied about the eclipses.
This didn’t change the size of the Earth or the importance of his voyage.
Warmergate doesn’t prove anything, and has not invalidated the basic truth of climate change.
We’re still left with some indisputable facts: the Earth has gotten warmer over the past few decades than it has been in recorded history, and probably warmer than it has been since civilization began 11,000 years ago. There is more carbon dioxide in the atmosphere than at any point in the past 500,000 years, and it’s gone up faster than at any previous time. Increased CO2 leads to increased warmth, and that correlates with our measurements, as well as observations of the polar ice caps. Given the warming trend, arguing about hockey sticks will get us nowhere.
