Key points are not available for this paper at this time.
Author Posting. © IOP Publishing, 2012. This article is posted here by permission of IOP Publishing. Re-use is limited to non-commercial purposes. The definitive version was published in Environmental Research Letters 7 (2012): 015301, doi:10.1088/1748-9326/7/1/015301.
Carmichael et al. (Wed,) studied this question.