Looking at the continent as a whole, we have already seen an increase in temperatures in recent decades that is significantly higher than what was expected under natural variability. Due to the likely anthropogenic impact on the climate, it is important to consult models that integrate 'Representative Concentration Pathways’ (emission scenarios) when predicting future temperatures.
Africa is a key warming region - expected to have a faster rise in temperatures over the 21st century than the global mean projection. The figure below (Niang et al, 2014) shows the temperature increases in different African regions , expected under the RCP8.5 pathway(exceeding 4 C over most land areas!).
Using the CIMP5 global climate model ensemble, Diffenbaugh and Giorgi (2012) examined climate-change "hot spots", and identified the Sahel and tropical West Africa as such. Other studies focusing on particular semi-arid regions of Africa (e.g. Ethiopia by Conwayand Schipper, 2011) highlight the likelyhood of large temperature increases during all seasons.
How does this link back to water?
Generally, higher temperatures will raise the proportion of freshwater lost to evapotranspiration, and reduce the physical water resource availability from annual precipitation. The evidence I provided shows that all of Africa will be experiencing a water loss to evapotranspiration under the future scenarios. Relating back to my diagrams in the last post - this is especially dramatic if the renewable freshwater formation depends on the seasonal rain pulse (as in the semi-arid regions). And indeed, the regions with the projected greatest warming year-round ("Hot spots") are those that have a precipitation scheme similar to what was represented in my schematic diagrams. Therefore we expect these (already highly adapted, vulnerable) environments, and populations, to encounter the greatest pressures on blue water resources (alone from temperatures and not yet taking precipitation projections into account!).
Your blog is making use of some very well chosen journal articles - well done. On the subject of blue water, see another comment below. I also encourage you to explore the non-linear implications of warming outlined in the Wit and Stankiewicz Science paper.
ReplyDeleteThe frequency of your posts could certainly be improved. It is not always necessary to compose long posts. Consider short posts that raise a question or make a clear point. Perhaps make links to items in the news on new research or policy.
Also try to encourage greater interaction on your blog by getting some GEOG3038 fellow students to comment and you can comment on theirs in return. The exchanges can be very good for developing your further and more critically.