If you have read this blog for any length of time, you probably know that I am skeptical of the idea that human activities are changing climate on a global scale. I don’t think the data support such a notion. Climate is certainly changing, but that’s nothing new. The data strongly indicate that around 1000 AD, the Northern Hemisphere was significantly warmer than usual; this is generally referred to as the “Medieval Warm Period.” About 650 years later, the Northern Hemisphere was significantly cooler than usual, and that period is often called the “Little Ice Age.”1 The important question is whether or not the changes we are seeing today is unusual compared to events such as those. Based on the data I have seen, my answer would be, “No.”
At the same time, I hasten to add that global climate is incredibly complex, and we are not close to fully understanding how it works or even how to measure it in a detailed fashion. Indeed, there are various methods used to determine the “average global temperature” and how it has changed over time, and they each produce different results. So while I think that the data show there is nothing unusual about the way climate is changing right now, I think a lot more study needs to be done.
But what do most people think? When it comes to climate change, their beliefs vary over time. The percentage of Americans who think the earth is warming has been falling since 2007. Interestingly enough, however, there seems have have been a recent rebound, at least when the phrase “climate change” is used. What drives these changes? Are the data changing significantly? Are the proponents of one side “getting their message out” better?
Unfortunately, a recent study has provided insight into why some people change their mind on the climate issue, and the results are rather depressing.
The Granite State Poll conducts telephone interviews with a random sample of about 500 New Hampshire residents four times each year. It asks a variety of questions related to politics, including party affiliation. In April of 2010, it started specifically polling its subjects on climate change. One of the things the poll did was ask each subject whether or not he or she agrees with the following statement:
Climate change is happening now, caused mainly by human activities.
Not surprisingly, results varied over the two and a half years since that statement has been included in the poll.
Lawrence C. Hamilton and Mary D. Stampone wondered if the current weather had any effect on the observed change, so they looked at the average temperature in the state of New Hampshire on the days around which the poll was taken. The depressing results are shown in the graph at the top of the post. In general, those who identify themselves as Democrats are very likely to agree with the statement, and their agreement is not strongly affected by the temperature on the day the statement is made. Republicans, on the other hand, are very unlikely to agree with the statement, and their disagreement is also not strongly affected by the temperature. However, for those who identify themselves as independent, their reaction to the question is directly correlated with temperature: the warmer it is, the more likely they are to agree with the statement.2
Why do I find these results depressing? The study says that those who identify themselves as “independent” make up 18% of the sample. That means roughly one-fifth of the New Hampshire population is not even thinking when it comes to climate change. After all, climate change is a global phenomenon. What is happening in your little corner of the world is not at all indicative of global climate change! In addition, climate change is a long-term phenomenon. Even organizations that promote the concept of global warming typically claim that the past century has seen a rise of less than one degree Celsius. That is such a small, gradual change there is just no way to notice it in the local weather! Thus, the weather on a given day shouldn’t have any effect on a thinking person’s reaction to a statement regarding global climate change!
If we are ever going to come up with sane policies regarding climate change and other scientific issues that affect the general populace, people are going to have to start thinking!
1. B. Christiansen and F. C. Ljungqvist, “The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability,” Climate of the Past 8:765-786, 2012 (Available online)
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2. Lawrence C. Hamilton and Mary D. Stampone, “Blowin’ in the wind: Short-term weather and belief in anthropogenic climate change,” Weather, Climate, and Society, http://dx.doi.org/10.1175/WCAS-D-12-00048.1, 2013
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