Those who watched Fox News over the weekend were treated to a brief but ambitious science lesson on “Why CO2 Can't Cause Warming”:
Oh boy. Let's take these one at a time.
During the segment Fox's global warming expert, Joe Bastardi, who is employed by the WeatherBELL meteorological consulting firm, declared that the theory of human-induced climate change “contradicts what we call the 1st law of thermodynamics. Energy can be neither created nor destroyed. So to look for input of energy into the atmosphere, you have to come from a foreign source.”
It's not clear what to conclude from this except that Fox and Bastardi are not familiar with the greenhouse effect. Climate scientists aren't claiming that humans are creating energy. They're saying that humans are trapping more energy by increasing the concentration of greenhouse gases in the atmosphere. Duke University scientist William Chameides, who called Fox's claims “utter nonsense,” explained via email:
It is true that global warming requires a source of heat. In this case it comes from the sun. What CO2 does is trap a larger amount of the heat from the sun, preventing it from escaping and thus driving up temperatures. To argue otherwise is to argue that the greenhouse effect does not exist. In fact the existence of the greenhouse effect was established by scientists more than a century ago. It would be impossible to explain the temperatures of Mars and Venus, as well as the Earth, without invoking this effect.
Bastardi went on to claim Le Chatelier's Principle “says that any system in distress, physical or chemical in the atmosphere, tries to return toward normalcy. And that is why you're seeing temperatures level off.”
In fact the notion of a system moving toward “normalcy,” or more accurately, toward a new “equilibrium,” explains why greenhouse gases do cause warming, rather than “Why CO2 Can't Cause Warming.” By preventing infrared energy from efficiently escaping to space, increased greenhouse gases in the atmosphere make it more difficult for the earth to maintain its previous energy balance, and thus its previous temperature.
Kevin Trenberth, Senior Scientist at the National Center for Atmospheric Research, explained via email that the system “re-creates equilibrium” by heating up, since the surface and atmosphere radiate more at a higher temperature. As a result, “it reaches a new equilibrium but at a higher temperature,” he said, adding: “And of course we keep adding more CO2 so we have not reached that new state yet.”
Though it appears that Bastardi cites Le Chatelier's Principle in a general sense and not in reference to any specific process, the principle does have implications for “the uptake of fossil fuel carbon by the ocean,” according to David Archer of the University of Chicago's Department of Geophysical Sciences. He said, “Without Le Chatelier's principle, the climate crisis would be much worse than it is, but even with this buffering, the CO2 concentration in the atmosphere is rising and will continue to remain elevated for tens of thousands of years into the future. So to suggest that Le Chatelier's principle is going to save us is wrong.” And the principle certainly doesn't establish that “CO2 Can't Cause Warming.”
And that's not all Fox got wrong.
Bastardi claimed that human-induced climate change is implausible because “When you look at carbon dioxide, it increases 1.5 parts per million a year. We contribute 3 percent of that, which means the human contribution is 1 part per 20 million.” Chameides says it's “not true” that human activities represent such a small fraction of the annual increase in CO2, adding: “Isotopic data show that the increase is mostly traceable to burning of fossil fuel.”
And as the Congressional Research Service explained, the human CO2 contribution is important even if it makes up a small amount of the atmosphere because it affects the Earth's carbon cycle and “the oceans, vegetation, and soils do not take up carbon released from human activities quickly enough to prevent CO2 concentrations in the atmosphere from increasing ... As a result, the atmosphere contains approximately 35% more CO2 today than prior to the beginning of the industrial revolution.”
Bastardi also claimed that “We have warmed up overall over the last 20 to 30 years, over the last 200 years because of the sunspot cycles. You can trace it to the sunspot cycles and you can trace it to the movement of the ocean.” Chameides responds:
Bastardi attributes the warming to: a) sunspots - no there has been no secular trend in sunspots over the past 2 - 3 decades; b) the ocean - no, data show that the ocean has heated up over the past 20 -30 years; in other words the ocean has absorbed heat from the atmosphere not the other way around.
Lastly, Bastardi claimed that satellites allow us to “measure the temperatures without having to readjust things.” In fact, satellite temperature data do require adjustments, as Roy Spencer, who maintains the UAH satellite temperature record, has explained.