Scientists claim to have directly measured carbon dioxide warming the Earth

carbon-dioxideThe scientific press is hyping research by Lawrence Berkeley National Laboratory that claims to have, for the first time, measured radiative forcing by carbon dioxide. Even if they have, it’s no big deal because such forcing is assumed from basic physics. They also claim that their measurement provides proof of anthropogenic global warming. But, as we shall see, they may be putting effect before cause.

Seth Borenstein, the Associated Press’ chief climate alarmist, writes “Scientists have witnessed carbon dioxide trapping heat in the atmosphere above the United States, chronicling human-made climate change in action.”

The Berkeley press release is titled “First direct observation of carbon dioxide’s increasing greenhouse effect at the Earth’s surface.” The paper, published in Nature, is somewhat more modest in its claim: “Observational determination of surface radiative forcing by CO2 from 2000 to 2010.”

Within the press release, one of the scientists is quoted as saying, “”We see, for the first time in the field, the amplification of the greenhouse effect because there’s more CO2 in the atmosphere to absorb what the Earth emits in response to incoming solar radiation.”

First, some background on what was done.

The scientists measured down-welling infrared radiation using Atmospheric Emitted Radiance Interferometer spectra from two stations located in Oklahoma and Alaska over the period from 2000 to 2010 during which atmospheric carbon dioxide increased by 22 parts per million. They claim to have 3300 measurements from Alaska and 8300 measurements from Oklahoma. Keep those numbers in mind.

They found that the down-welling radiation increased during that period and attribute that increase to the rise of carbon dioxide.

Some possible problems:

I wonder why the specific time period was chosen. In 2010 a strong La Nina produced a relatively cool tropospheric temperature, while in 2010 a strong El Nino produced a relatively warm tropospheric temperature. The difference was about half a degree Centigrade. A warmer atmosphere will intrinsically produce more down-welling infrared radiation regardless of its composition. So, was the increased down-welling radiation due to increased CO2 or increased temperature? I think they may be confusing cause and effect.

Also curious is that another study (See Evidence that CO2 emissions do not intensify the greenhouse effect ), using the same type of instruments, made 800,000 measurements during the period 1996 to 2010 and found a significant decrease in down-welling infrared radiation.

The Berkeley researchers claim that only about 10 percent of their increased down-welling radiation came from carbon dioxide. As far as I can tell, however, the emissions from carbon dioxide fall within the spectra emitted by water vapor, but the researchers claim a mathematical manipulation allows them to distinguish the 10 percent of radiation from carbon dioxide versus the 90 percent from water vapor and other gases in the atmosphere.

There is still a question about whether they saw what they claimed to have seen. This may be an example of confirmation bias, they saw what they wanted to see based on equivocal evidence.

But in the end, to paraphrase a prominent politician: what difference does it make at this point in time?