Climate Change and Distribution of Date Palms Figure 11. Comparison of the location of wet stress in some selected regions for date palm growth between current time and 2100. These areas were selected on the basis of large changes in wet stress in the future. doi:10.1371/journal.pone.0048021.g011 Arabia earned 3621 and 1378 U.S. dollars/tonne, respectively, in 1995 from exporting dates. The large disparity in price was due to their strategies in targeting different countries and the differences in date quality [11]. However, this study indicates that large areas of Algeria and Saudi Arabia may become climatically unsuitable and may not be able to cultivate this profitable crop to the same extent in the future. The results are in line with current observations of a decline in date palm production in Middle Eastern countries from 1990 to 2000 [4,5]. Consequently, the results of this paper provide some advance awareness for countries which rely on income from exporting dates. Furthermore, by making some strategic plans, many economic disadvantages can be prevented. This information is particularly important for some countries in northwestern Africa and the Middle East. Conversely, the results indicate that some areas which are climatically unsuitable at present may become suitable for date palm cultivation in the future. These outcomes may well be useful in making informed choices about the location of date palm farms and associated industries in advance. Benin, Ghana, Cameroon, Nigeria, Venezuela and China may have the opportunity to cultivate date palms and export its produce in the future. Under future climate, P. dactylifera may be able to be cultivated in areas that are currently too cold or wet; this can be seen in the improved climatic suitability for Florida, Mexico, northern Venezuela, and eastern Brazil in the Americas; South Sudan and Guinea in Africa; and Spain and France in Europe. These countries should be prepared to make use of these opportunities since, climate-wise, these areas may become highly suitable for this plant. Specifically, these maps could be used by agricultural organizations in various countries to make strategic, long-term plans. This may include research into alternative crops in areas where climate will become unfavorable for date palms. In interpreting these results, the following should be considered: i. The modeling was performed based only on climate; it does not take into consideration other factors such as land uses, soil types, biotic interactions, diseases and competition. ii. This research was based on currently available broad-scale climate data; therefore, it only shows broad-scale shifts. iii. It is indicative because a certain level of uncertainty is associated with future levels of greenhouse gas emissions. In conclusion, this research has demonstrated broad-scale shifts in areas conducive to date palm cultivation and how different areas of the world may be affected due to climate change based on broad regional-scale changes over the next hundred years using coarse scale climate data. Some regions were projected to be climatically unsuitable as a consequence of only one stress for date palm growth, such as wet stress in northern Angola. However, some regions were projected to be unsuitable as a consequence of a combination of multiple stresses; for example, the combination PLOS ONE | www.plosone.org 11 October 2012 | Volume 7 | Issue 10 | e48021