He writes: "climatologists have debated whether the earth is experiencing global warming and, if so, why. Science is an ongoing search to understand the world around us. It is not surprising that as the search continues, scientists sometimes disagree about the direction in which truth lies" (my emphasis).
No, there is not a debate among climatologists about whether the earth is experiencing global warming. Global warming is a fact which even those who made a living denying it have had to acknowledge, while they move on to other ways of stalling action to lessen it.
And no, there is no debate about why global warming is occurring. The basic science has been known since the late 19th century.
So why is this rubbish in his text? (It was in the previous edition as well, and likely in many earlier ones.)
If Mankiw wanted a reasonable example related to climate change, he could explain the debate around 'climate sensitivity' – how much global warming could be expected if carbon dioxide concentrations were twice their preindustrial level. this value is critical in determining where and how fast temperatures in the earth system are headed.
