“NOAA Scientist Rejects Global Warming Link to Tornadoes,” blares Fox News. In a classic example of misreporting the threat that carbon pollution poses to the United States, Fox News reporter James Rosen asked climate experts the wrong questions and then confused the answers he received into a he-said, she-said faux controversy. Rosen claimed that a “top official at the National Oceanic and Atmospheric Administration (NOAA)” — Greg Carbin, the warning coordination meteorologist at NOAA’s Storm Prediction Center — “rejected claims by environmental activists that the outbreak of tornadoes ravaging the American South is related to climate change brought on by global warming”:
Asked if climate change should be “acquitted” in a jury trial where it stood charged with responsibility for tornadoes, Carbin replied: “I would say that is the right verdict, yes.”
In fact, the “environmental activist” Rosen interviewed — Sarene Marshall, Managing Director for The Nature Conservancy’s Global Climate Change Team — did not accuse global warming of spawning the tornadoes. She said that greenhouse pollution is “connected to the increased intensity and severity of storms.”
In an interview with ThinkProgress, NOAA’s Greg Carbin said that it was a mistake to interpret his remarks as being in conflict with those of Sarene Marshall, Managing Director for The Nature Conservancy’s Global Climate Change Team. Like Marshall, he believes that global warming is real, is manmade, and is influencing extreme weather — but that scientists like himself do not have enough data to understand how a warming world affects tornadic storms. When it comes to warning people about deadly risks, he said, the “jury trial” standard is not appropriate.
“All the science points to warming being due to anthropogenic forcing,” he said. “We don’t know how that warming has an influence on the small scale.” There has been a clear increase in precipitation in the United States as the planet has warmed, he said, and the science of how greenhouse pollution influences large-scale events like droughts and floods is robust. However, the climatology of tornadoes is much more challenging, given sparse historical data and the complexity of super-cell thunderstorm physics. Although the number of recorded tornadoes has risen dramatically in the last few decades, that could simply be an artifact of improved record keeping. “We just don’t know with respect to tornadoes. We are continuing to do the research.”
It is important for people to understand that tornadoes are not the primary extreme weather risks that most people should worry about, Carbin said, despite the obvious and terrible destruction they can cause. Tornado outbreaks that cause mass casualties are extremely rare and localized, he said, in contrast to the heat waves, floods, and droughts that have strong links to global warming pollution.
Asked if he applies the “jury trial” standard to his own work of warning Americans about the threat of tornadoes and severe storms, Carbin replied, “Absolutely not.”
“We use probabilistic methods to predict the threat of severe weather,” because it would be foolhardy to require absolute certainty when dealing with matters of life and death. Their predictions are usually of the form of a 45 percent risk of a tornado appearing within a 25-mile region of a given point. However, the conditions that bred these deadly twisters were “unbelievable,” Carbin said. The modelling predicted that multiple tornadoes would form, hours in advance, with over 95 percent probability, and extreme tornadoes with over 90 percent probability.
Fox News wants to make off limits any discussion of any connection with climate change to extreme weather in the United States, precisely because they are the sorts of connections that real people might actually care about.
Tornadogenesis is influenced by the jet stream and different air masses interacting, all of which are influenced by global warming. “Sea surface temperatures across the Gulf of Mexico have been warmer than normal for about a month and a half,” AccuWeather’s Heather Buchman explains. “Warm, humid air is a necessary ingredient for severe thunderstorm development, and the Gulf of Mexico is a major supplier of it. The warmer sea surface temperatures are across the Gulf of Mexico, the more warm and humid the air is above it. “