While the eyes of the world are on Paris, where nations are hammering out an agreement to do something about the reality of climate change, the Senate Subcommittee on Space, Science, and Competitiveness once again held a hearing on Tuesday to debate whether climate change is for real. Subcommittee Chairman Ted Cruz (R-Tex.), who is running for his party’s presidential nomination, convened the hearing titled “Data or dogma? Promoting open inquiry in the debate over the magnitude of human impact on Earth’s climate.”

Senator Cruz brought in four witnesses to testify, mostly chosen from the usual suspects that have participated in similar hearings in the past. There were two of the very small handful of climate scientists who express doubts about human responsibility for climate change—Georgia Tech professor and blogger Judith Curry and John Christy from the University of Alabama in Huntsville. William Happer, a retired Princeton physicist and chairman of the George C. Marshall Institute, a conservative think-tank, was also invited to speak. The fourth person brought in to talk climate science was conservative radio host and columnist Mark Steyn. (The last two were keynote speakers at this year’s Heartland Institute conference for climate “skeptics.”)

Senator Cruz opened the hearing with some ironic remarks. “This is a hearing on the science behind the claims of global warming. Now, this is the Science Subcommittee of the Senate Commerce Committee, and we’re hearing from distinguished scientists, sharing their views, their interpretations, their analysis of the data and the evidence. Now, I am the son of two mathematicians—two computer programmers and scientists—and I believe that public policy should follow the actual science, and the actual data and evidence, and not political and partisan claims that run contrary to the science and data and evidence.”

John Christy, who has helped develop the UAH satellite temperature dataset favored by climate “skeptics” because it shows slower warming in portions of the troposphere than we see in surface records, made his pitch for why we just don’t know what has caused recent warming. That explanation involved highlighting his graph of tropical mid-troposphere (rather than global surface) model projections and observations that frequently appears in the comments on stories like this one—a graph other climate scientists take issue with—and claiming that emissions cuts would have a minimal impact on climate change. While claiming that research funding is biased, he proposed setting aside five to 10 percent of federal climate research funding for a “Red Team” like the CIA section tasked with outside-the-box analyses that challenge the status quo. This Red Team would “produce an assessment that expresses legitimate, alternative hypotheses” for climate change.

Judith Curry echoed Christy’s complaints, claiming that climate science has fallen victim to “groupthink”—a conclusion she says she reached after reading the quote-mined “Climategate” e-mails between scientists in 2009. (A pile of subsequent independent investigations found no evidence of scientific misconduct.) The rest of Curry’s testimony entailed claims that the science of anthropogenic climate change is unsettled, which she has spoken and written about at length over the years.

Mark Steyn’s testimony focused on his accusations that climate science is fraudulent and oppresses contrarians. Steyn’s claim to climate fame is that he’s being sued for defamation by Penn State climate scientist Michael Mann, whom Steyn has repeatedly accused of fraud.

William Happer used most of his time to argue that rising concentrations of carbon dioxide are good for the planet, claiming that there is “not much dispute” that there is too little CO 2 and too much oxygen for plants right now. He also seemed to like Christy’s “Red Team” idea, as he said climate science lacks an “adversarial process” to check if the science is right. (Of course, “an adversarial process” isn’t a bad description of peer review or the work of thousands of independent researchers.) “I would like to argue very strongly that we set aside some fraction of funding for climate research that is designed to be for the other side,” Happer said. That would run counter to the way funding is granted today, which is based on the hypothesis and the quality of the test rather than what the resulting conclusion is going to be.

Happer became a story in his own right earlier in the day, when Greenpeace released e-mails with Happer in which they had pretended to represent a foreign energy company. They asked Happer if he would produce a report extolling the virtues of CO 2 but without disclosing their financial support, and Happer agreed this was something he could do. Happer explained that Peabody Coal Company had paid him $8,000 to testify at regulatory hearings in Minnesota. That fee went to the tax-exempt CO­­ 2 Coalition, which he said pays his travel expenses but no salary. Just before Tuesday’s hearing, someone from Greenpeace filmed a heated exchange with Happer asking whether he had been paid to testify. Happer seemed to indicate that the CO 2 Coalition “took some of my fee” before rising out of his chair and angrily replying, “I haven’t taken a dime, you son of a bitch.”

Finally, there was testimony from a witness invited by committee Democrats—former Navy Rear Admiral and current Penn State meteorology professor David Titley. Titley calmly attempted to explain the basics of climate science, highlighting the fact that nothing is ever 100 percent certain in science, yet we understand how to act on risks despite imperfect knowledge.

A question-and-answer portion followed this testimony, which at one point devolved to Senator Ed Markey (D-Mass.), Steyn, and Curry pretty much shouting at each other. But there was also some discussion about satellite temperature data sets. (Curiously, this involved no questions for John Christy, who helps run one.) Senator Cruz is fond of claiming that one of the satellite data sets shows “no warming for 18 years” while ignoring longer-term trends and the fact that all surface temperature data sets show warming over that period.

After Senator Cruz pushed Titley to answer a question about the satellite records, which he claimed “the global warming alarmists don’t want to talk about,” Titley let loose. “Let’s talk about the satellite measurements,” Titley said. “Let’s talk about orbital decay. Let’s talk about overlapping satellite records. Let’s talk about stratospheric temperature contamination. I think Dr. Christy and Dr. [Roy] Spencer, when they’ve put this out, they have been wrong, I think, at least four consecutive times. Each time the data record has had to be adjusted upward. There have been several sign errors. So, with all due respect, sir, I don’t know which data, exactly, your staff has, whether it’s the first or second or third or fourth correction to Dr. Christy’s data. We used to have a negative trend, and then we had no trend, and now we begrudgingly have an upward trend.”

To be fair, Senator Cruz was pointing to a competing data set run by Remote Sensing Systems in California that, until recently, showed an even smaller 18-year warming trend than the University of Alabama in Huntsville data set. And the latest version of that UAH data set, which is in beta, reduces that trend once again.

In a curious moment, William Happer chimed in to state that these satellites measure temperatures “the same way as hospitals do today,” with devices that measure infrared radiation. In fact, these satellites measure microwave radiation, and doctors aren’t trying to simultaneously determine temperatures of various layers inside you when they pop a thermometer in your ear.

Senator Cruz also accused scientists of deliberately manipulating land surface temperature data to create the appearance of warming over the 20th Century. (Quality-control adjustments to sea surface temperature data, which obviously involve a much larger portion of the globe, actually make the overall effect a decrease in global 20th Century warming.) When asked about this, Judith Curry didn’t quite support Senator Cruz’s accusation but did comment, “To me, the error bars should really be much bigger if they’re making such a large adjustment, so we really don’t know too much about what’s going on.”

In contrast to this talk of uncertainty and scientific skullduggery, Senator Gary Peters (D-Mich.) opted for some remedial physics in his opening comments. “By burning fossil fuels, humans are releasing carbon into the atmosphere that would have otherwise remained locked away. This process creates carbon dioxide, a greenhouse gas that traps heat that otherwise would have been radiated off into space. We know that by the law of conservation of energy, that additional heat can’t just magically disappear. Instead, it causes our planet to get warmer.”