The other day, I saw a Vancouver Sun article called “Meteorologists split on global warming“.
I was struck in particular by the sub-headline: “Fewer than one in five specialists in the U.S. see human influence as the only driver”.
At first glance, may seem like a garden-variety example of climate change skepticism from experts in fields other than climatology. People who are experts in one area often have misplaced confidence about their expertise in others.
On second reading, the sentence betrays considerable ignorance about the subject of climate. If “19 per cent of U.S. meteorologists saw human influences as the sole driver of climate change in a 2011 survey” then at least 19% of U.S. meteorologists have no idea what they are talking about.
Nobody is arguing that human behaviour – or CO2 emissions exclusively – is the only thing that affects the climate. Look up the concept of ‘radiative forcing‘ and you will quickly learn that scientists have studied many of the causes of climate change in detail. The work of the Intergovernmental Panel on Climate Change (IPCC) has involved consideration of other things. They looked at impacts from changes in ozone, albedo (the reflectiveness of the Earth’s surface), aerosols, linear contrails, and changes in the energy output of the sun. When you look at all of these factors, you see that greenhouse gases are simply the most important cause of change in the climate right now, and we are poised to emit vast additional quantities of them as the world continues to burn fossil fuels.
I note that the article has no link to the original survey and so it is hard to know whether the ignorance in question comes from meteorologists, surveyors or journalists. In my experience, few survey questions about climate change attribution really understand the issue and how it is quite possible for more than 100% of recent warming to be attributed to human influences. I strongly suspect that there are problems at all three stages.
The failure of the journalist is evident in this section: “Most U.S. meteorologists – 82 per cent in a 2011 survey – are convinced that the climate is changing, but many say it’s changing because of natural causes, or human and natural causes combined. / That contrasts with about 95 per cent of climate scientists who are convinced that climate change is occurring and that human activities, particularly the burning of fossil fuels, are a key driver.” While both stats are presumably correct, the fact the journalist tries to contrast them shows that she doesn’t realise there is a logical difference between “key driver” and “human causes alone”. This doesn’t take scientific training, simply a familiarity with logic.