From Malcolm Hunter
Why should it be surprising that Pluto is continuing to get warmer as it moves farther from the Sun (19 October, p 25)?
One plausible explanation is that we are seeing “greenhouse” warming. Once Pluto gets close enough to the Sun for its atmosphere to start to regenerate and thicken, surely any greenhouse gases in the atmosphere, such as methane, will lead to a positive feedback loop: the thickening atmosphere will lead to further warming, and hence further thickening of the atmosphere. This effect might be expected to outweigh the cooling effect of reduced energy input from the Sun, at least initially.
Leicester, UK
