Palaeoclimate: A southern misfit .
For far too long the climate science community has grappled with an inconvenient truth: the vast majority of the datasets used to constrain temperature trends of the recent past come from the Northern Hemisphere. Over a dozen reconstructions of Northern Hemisphere temperature spanning the past millennium exist and have played a critical role in distinguishing natural from anthropogenic climate change. However, the extent to which recent temperature variations in the Northern Hemisphere resemble those in the Southern Hemisphere remains unclear. Such information is critical to a complete understanding of the mechanisms of global, rather than hemispheric, climate change. Writing in Nature Climate Change, Raphael Neukom and co-authors1 present a new, millennium-long reconstruction of Southern Hemisphere temperature by combining information from a wide variety of palaeoclimate sources. Although the new reconstruction resembles the Northern Hemisphere reconstructions in some key aspects — the anomalous nature of twentieth century warming being one of them — it also suggests that temperatures in the two hemispheres may have differed more than they have agreed over the past millennium.