I hope you’re all sitting down as you read this. As some of you may have heard, the planet’s temperature has been rising recently, and according the very wise Bloodsucking Monster Lobby, we just can’t possibly know the cause. As you all know, I’ve just been so unsure what to say about all of this. Well, thankfully, the good folks at the Woods Hole Oceanographic Institute seem to have figured it out. It turns out that humans are the ones doing it! More specifically, it’s the stuff we’ve been burning for energy!
New research provides clear evidence of a human “fingerprint” on climate change and shows that specific signals from human activities have altered the temperature structure of Earth’s atmosphere.
Differences between tropospheric and lower stratospheric temperature trends have long been recognized as a fingerprint of human effects on climate. This fingerprint, however, neglected information from the mid to upper stratosphere, 25 to 50 kilometers above the Earth’s surface.
“Including this information improves the detectability of a human fingerprint by a factor of five. Enhanced detectability occurs because the mid to upper stratosphere has a large cooling signal from human-caused CO2 increases, small noise levels of natural internal variability, and differing signal and noise patterns,” according to the journal article, “Exceptional stratospheric contribution to human fingerprints on atmospheric temperature,” published in the Proceedings of the National Academy of Sciences (PNAS). Noise in the troposphere can include day-to-day weather, interannual variability arising from El Niños and La Niñas, and longer-term natural fluctuations in climate. In the upper stratosphere, the noise of variability is smaller, and the human-caused climate change signal is larger, so the signal can be much more easily distinguished.
“Extending fingerprinting to the upper stratosphere with long temperature records and improved climate models means that it is now virtually impossible for natural causes to explain satellite-measured trends in the thermal structure of the Earth’s atmosphere,” the paper states.
“This is the clearest evidence there is of a human-caused climate change signal associated with CO2 increases,” according to lead author Benjamin Santer, an adjunct scientist in the Physical Oceanography Department at the Woods Hole Oceanographic Institute (WHOI) in Massachusetts.
“This research undercuts and rebuts claims that recent atmospheric and surface temperature changes are natural, whether due to the Sun or due to internal cycles in the climate system. A natural explanation is virtually impossible in terms of what we are looking at here: changes in the temperature structure of the atmosphere,” added Santer, who has worked on climate fingerprinting for more than 30 years. “This research puts to rest incorrect claims that we don’t need to treat climate change seriously because it is all natural.”
Jokes aside, this is important research.
I don’t know if this is the piece of climate science I wished more people knew, but it’s up there. See, if the warming was caused by an external source, like solar activity, or cosmic radiation, then the upper atmosphere would be warming as fast, or faster than the bits nearer the surface. If, on the other hand, the warming is due to greenhouse gases, then the extra heat is being trapped here. That means that less heat reaches the outer atmosphere. If the climate scientists have been right all these years, then the outer atmosphere should be cooling, and shrinking. We’ve had evidence that this is happening for a bit now, but the clearer the picture, the harder it is to refute, and this research plugs some holes in the existing data:
Although these earlier studies considered global-mean temperature changes in the middle and upper stratosphere, roughly 25 to 50 kilometers above Earth’s surface, they did not look at detailed patterns of climate change in this layer. This region can be better studied now because of improved simulations and satellite data. The new research is the first to search for human-caused climate change patterns – also called “fingerprints” – in the middle and upper stratosphere.
“The human fingerprints in temperature changes in the mid to upper stratosphere due to CO2 increases are truly exceptional because they are so large and so different from temperature changes there due to internal variability and natural external forcing. These unique fingerprints make it possible to detect the human impact on climate change due to CO2 in a short period of time (~10 – 15 years) with high confidence,” stated co-author Qiang Fu, a professor in the Department of Atmospheric Sciences at the University of Washington.
“The world has been reeling under climate change, so being as confident as possible of the role of carbon dioxide is critical,” said co-author Susan Solomon, Martin Professor of Environmental Studies at the Massachusetts Institute of Technology. “The fact that observations show not only a warming troposphere but also a strongly cooling upper stratosphere is unique tell-tale evidence that nails the dominant role of carbon dioxide in climate change and greatly increases confidence.”
Santer said that although it is intellectually gratifying to be able to extend fingerprinting higher up into the atmosphere to test the prediction by Manabe and Wetherald, it is also deeply concerning.
“As someone who tries to understand the kind of world that future generations are going to inhabit, these results make me very worried. We are fundamentally changing the thermal structure of Earth’s atmosphere, and there is no joy in recognizing that,” Santer said.
“This study shows that the real world has changed in a way that simply cannot be explained by natural causes,” Santer added. “We now face important decisions, in the United States and globally, on what to do about climate change. I hope those decisions are based on our best scientific understanding of the reality and seriousness of human effects on climate.”
It’s honestly pretty remarkable the degree to which, by the time I started paying attention to this stuff, climate scientists really did know what was going on, and the “rebuttals” of the corporate-backed denial campaign have all turned out to be bullshit. Maybe I’m being too generous, but you’d think they’d get at least something right, right? Apparently not.
I’m with Santer on not finding joy in this information, obviously. We already knew the house was on fire, and while it’s nice to have more details on the exact nature of that fire, they won’t matter much in the long run if we don’t take steps to put it out. It’s hard not to feel like every new piece of research that comes out, only really serves as another piece of evidence to be presented at a trial of our “leaders” that will never come. There was no reasonable doubt as to the cause of climate change, immediately prior to the publication of this research. There was no reasonable doubt, if we’re honest, when I was born almost 40 years ago.
That’s why this climate blog focuses so much on politics, and social justice, and organizing – because our biggest lesson of the last 50 years must be that simply having the facts on your side is not enough, even if we’re risking human extinction. Most of the world is already on our side, in wanting more action. When it comes to the powerful few who stand in our way (and their servants), persuasion is a waste of time. We can convince them after we win.