Article History
Received: 23 September 2016
Accepted: 18 December 2017
First Online: 22 January 2018
Change Date: 14 March 2018
Change Type: Correction
Change Details: In the version of this Letter originally published, in Fig. 2, the labels for the yellow and green areas were swapped: the yellow areas should have been labelled ‘Global uncertainty zones’ and the green areas should have been labelled ‘Global safe zones’. This has now been corrected in the online versions of the Letter.
Competing interests
: The authors declare no competing financial interests.