Michael D. Lemonick’s “Climate Heretic” seems to suffer from a common misconception. Lemonick tends to avoid any distinction between skepticism and denial when referencing so-called climate skeptics. At the same time, he makes much of the rigidity so evident among some in the majority. Such portrayal does an injustice to serious proponents on all sides of the issue. To refer to all those in disagreement as “skeptics” implies that the vast majority of climate scientists then are credulous. 

Skepticism—true skepticism, not the intractable bias characteristic of denial—is absolutely fundamental to the scientific method. I would submit that if but a single attribute can be said to characterize climate science in the hostile public policy milieu of recent years, it is surely skepticism.

Whatever their position on a topic or their bias toward a conclusion, true skeptics will ultimately follow the evidence where it leads. Deniers, on the other hand, interpret that same evidence only as it might support their foregone conclusions. The gulf between these mind-sets is wide. In an age already rife with misinformation and scientific illiteracy, that difference should be acknowledged by scientists and journalists alike and at every opportunity.

Dom Stasi
Studio City, Calif.

Lemonick replies: Those who do not accept the general scientific consensus on climate change span an enormous range, from people who have legitimate scientific disagreements on some of the details all the way to people who distort the facts to people who declare the whole thing a socialist plot (or, alternatively, a money-making scam). It is certainly inappropriate to lump them all together, and while my piece was not primarily focused on distinguishing between the different categories, I hope it did not create the impression that I consider skepticism and denial to be equivalent. I agree that true skepticism is an integral part of the scientific method—but want to emphasize that it is practiced by those who do accept the consensus, not just by those in opposition.

Michael Moyer’s “Window Shopping for Electric Cars” [Advances] got me doing just that, but I did not compare electric cars with other Japanese or U.S. cars. Rather I looked to German-made cars sold in the U.S.

I own a 2004 VW turbodiesel station wagon. On a recent 600-mile trip on the interstates, I averaged 52 miles per gallon. I am told the latest version of this model—which sells for only $16,000—­would have made 57. Why would I want to buy a Toyota Prius when I can get two Jettas for the same money?

In Europe, about half of all new cars sold are now diesels, some of which are more fuel-efficient than a Prius. The irony is that both GM and Ford make respectable turbodiesels in Europe but declined to make any of them in North America, presumably because they feared the high EPA cleanliness standard that VW, Mercedes and BMW were able to meet. Surely it would make more sense for them to license clean diesel technology from VW and produce those cars here.

John Fitzhugh Millar
Williamsburg, Va.

In David Biello’s “Darwin Was a Punk” [Advances], Greg Graffin is quoted as saying that there are no good songs about science, but he ignores the work of Monty Python in their seminal “Galaxy Song.” It may not appeal to Graffin’s punk preferences, but not only is the song’s science apparently plausible, it is also tuneful and the best song I know that begins and ends with the performer in a refrigerator.

Nigel Taylor
New York City

THE EDITORS REPLY: Numerous readers reacted to Graffin’s assertion by sending us great examples of science songs. In addition to Monty Python’s immortal song, others include “Mammals” by the band They Might Be Giants, John Bos­well’s album “Science Is the Poetry of Reality” and many songs by Tom Lehrer. Presumably none of the songs satisfies Graffin’s taste to qualify as “good.”

In “Dark Worlds,” Jonathan Feng and Mark Trodden explain that the dark matter candidates called super-WIMPs interact only through gravity. That means they cannot undergo the type of collisions that dissipate energy (or hardly any collisions at all) the way ordinary particles do, primarily turning kinetic energy into electromagnetic energy, in the form of photons.

“When created, super-WIMPs would have been moving at a significant fraction of the speed of light,” the authors write, adding that “they would have taken time to come to rest.” In purely gravitational interactions, energy is nearly conserved. The only possible mechanism for individual super-WIMPs to lose kinetic energy is to convert a tiny bit of it into gravitational radiation. If super-WIMPs essentially cannot interact, how can they come to rest?

Van Snyder
La Crescenta, Calif.

FENG AND TRODDEN REPLY: If the universe were not expanding, super-WIMPs would indeed have no way of slowing down. In an expanding universe, however, all matter comes to rest eventually, meaning that its motion ultimately is owed entirely to the expansion of the universe (technically, this means that it comes to rest in co-moving coordinates, which expand with the expansion of the universe). Thus, this is the sense in which super-WIMPs slow down. Incidentally, the same principle applies to the slowdown of WIMPs. The weak interactions that WIMPs possess (and super-WIMPs lack) do not have any appreciable impact on how long they take to come to rest or how well they seed galaxy formation.

I read with interest in Mary Carmichael’s “Halting the World’s Most Lethal Parasite” the idea of vaccinating mosquitoes by using a human carrier to pass the vaccine on to the mosquito. Couldn’t you use other mammals such as livestock instead, thereby eliminating the ethical dilemma of vaccinating people who will not directly benefit?

Paul Sidhu
Smethwick, U.K.

CARMICHAEL REPLIES: Vaccinating animals is an intriguing idea and one that is clearly more applicable for vector-borne diseases with nonhuman reservoirs (for example, vaccinating dogs to control both canine and human visceral leish­maniasis transmission). Still, the two major human malaria parasite species, Plasmodium falciparum and P. vivax, are re­stricted in their “choice” of vertebrate host. Also, to reiterate one of the points made in the article, a vaccination campaign using only a malaria-transmission blocking vac­­cine (TBV) would indeed confer direct benefit to the immunized individual. The benefit is not immediate but simply delayed. No one is envisioning using TBV alone, however. It would most likely be used in combination with antimalarials and other vaccines.