Last year I wrote a couple of posts about a paper by Valentina Zharkova and colleagues, which suggested that global warming was partly due to the Earth moving closer to the Sun as the Sun moves around the Solar System barycentre. If you read my posts, the comments, and this pubpeer thread you’ll notice a number of people pointing out that this was wrong; the Earth-Sun distance doesn’t change as the Sun goes around the Solar System barycentre.
Recently, an editorial response and comments from two reviewers have been released, as has a response from the authors. They’ve also released an erratum. You can find some discussion of this on Geoff Sharp’s post.
Unsurprisingly, the editorial response and the recviewers agree with the criticisms of the paper. The editor says:
There is a legitimate, and based on my reading, completely correct concern about the Earth-Sun distance calculation.
Similarly, reviewer 1 says:
Earth is orbiting about the sun and the barycentric motion of the sun is irrelevant for computing/predicting Earth’s temperature. In a simpler term, the Sun is very close to being the prime focus of the Earth orbit.
In their erratum, the authors acknowledge that they were wrong to suggest that the Earth-Sun distance changed as the Sun goes around the Solar System barycentre. However, they then go on to claim that there is still quite a substantial change in the Earth-Sun distance on century timescales. However, as pointed out in Geoff Sharp’s post, what they’ve done is to consider only the perihelion distance. This is the distance between the Sun and the Earth when the Earth is closest to the Sun. It’s well known that there is a slow change in the eccentricity of the Earth’s orbit; it goes from being almost circular, to being slightly elliptical.
This does indeed then lead to a slow change in the perhelion distance. However, there is an equivalent, but opposite, change in the aphelion distance, so that the average distance remains unchanged. This is illustrated in the figure in this comment. So, despite acknowledging a pretty fundamental error when discussing the motion of the Sun around the Solar System barycentre, they’ve gone on to make another pretty fundamental error.
I don’t know what the outcome of this is yet. It’s the authors who have released the editorial response, reviewers comments, and their erratum. Their erratum is still not published and it may be that it goes through further review. Would certainly hope so.