As I've been writing for a long time now, the reason that only a tiny minority of scientists are Republicans is obvious: Republican elites routinely endorse things so scientifically preposterous that they cause a strong adverse reaction in the scientific community. We saw this when Jonathan Chait wrote a piece taking apart George Will and Charles Krauthammer, whose (violently wrong) beliefs about climate change straightforwardly imply they should reject all scientific reasoning of any kind.
Josiah Neeley, who sometimes contributes to The Week, replies with "so's your old man," arguing in The Federalist that past statements and writings of White House science advisor John Holdren cast doubt on his predictions, and by extension his alarming predictions about the likely effects of future climate change. This is worth examining in detail, because it's another way that conservatives have managed to alienate scientists.
Let's get one thing out of the way first: This is an ad hominem piece. There is no attempt to disprove Holdren's predictions in detail, or even to say what they are. There is just the view that because Holdren has X history, he must be wrong about whatever else he's saying. Now, that's not always out of bounds, but it is a dangerous path to tread.
With that, let's look at the specifics.
Point 1: Holdren blames the recent cold winter on climate change. Did he say this? Yes, he made a video explaining how a warming Arctic might weaken the winter polar vortex, thereby cooling the continental U.S. while warming the Arctic. (It's a case for how overall global warming might make some regions colder some of the time.) It's plausible, though speculative; other scientists disagree, saying that the warming effect of climate change will predominate. However, the context that is missing here is that he made the video in response to the sadly typical round of conservative pundits gleefully arguing that climate change must be fake because winter is cold. Does this affect the case for climate change generally? It does not. It's a completely marginal issue.
Point 2: Holdren wrote an essay worrying about global cooling and environmental damage back in 1971. Apparently yes, this essay does exist and contains some speculation about global cooling along with warming, though I can't find the text of it aside from blockquotes from highly suspect denier blogs and WorldNetDaily. But until I can get hold of the text, the basic reality is that this is also a marginal issue. George Will has been recycling the same half-dozen 70s news articles about cooling for the past 20 years and it's been a complete crock from the start. There was never a scientific consensus in favor of global cooling, and even if there had been, it wouldn't speak to the credibility of the warming case now.
Point 3: Holdren said alarming things about overpopulation and forced sterilization. This is the meat of the case, since it makes Holdren sound like something from the fever dreams of the Bundy militia. Here's how Neeley quotes it [his emphasis]:
Holdren mused about adding sterilizing agents to the water supply, argued that "compulsory population-control laws, even including laws requiring compulsory abortion, could be sustained under the existing Constitution if the population crisis became sufficiently severe to endanger the society," and suggested that "it would even be possible to require pregnant single women to marry or have abortions, perhaps as an alternative to placement for adoption, depending on the society." [The Federalist]
Now this is an cheap attack. After some digging, I found the section of the book in question, which is called Ecoscience (not Ecosystems, as per Neeley's source), and discovered two huge things left out here. First: Holdren was not the sole author; in fact, he's the third one. Second, this is a textbook, and the sections Neeley quotes are explanations, not endorsements. This section envisages a potential ecological crisis brought on by overpopulation, and these solutions are discussed as emergency measures.
It's true that the overpopulation anxiety of many '70s environmentalists hasn't aged well. I've written at length about why I don't personally buy it. But to quote these sections as if Holdren alone were personally in favor of them frankly verges on a deliberate smear, especially when the authors' real preference is clearly stated at the end of the section: "A far better choice, in our view, is to expand the use of milder methods of influencing family size, while redoubling efforts to ensure that the means of birth control, including abortion and sterilization, are accessible to every human being."
This whole sorry mess was hashed out during and after Holdren's confirmation hearings back in 2009, and the criticism was so baseless that he got confirmed unanimously. David Vitter asked him about whether he thought government should be concerned with population control. "No, Senator, I do not," he replied.
Thus we're brought back, again, to conservative culpability in the partisanship of climate science. Articles like this say to scientists: If we disagree with your political leanings, we're going to root through your life's work, cherry-pick the most objectionable things you've written, take them out of context, and try to destroy your reputation. In other words, join team Democrat.