Projections of rapidly rising surface temperatures over Africa under low mitigation

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Date
2015Author
Engelbrecht, Francois
Garland, Rebecca
Adegoke, Jimmy
Bopape, Mary-Jane
Naidoo, Mogesh
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Show full item recordAbstract
An analysis of observed trends in African annual-average near-surface temperatures over the last five
decades reveals drastic increases, particularly over parts of the subtropics and central tropical Africa.
Over these regions, temperatures have been rising at more than twice the global rate of temperature
increase. An ensemble of high-resolution downscalings, obtained using a single regional climate
model forced with the sea-surface temperatures and sea-ice fields of an ensemble of global circulation
model (GCM) simulations, is shown to realistically represent the relatively strong temperature
increases observed in subtropical southern and northern Africa. The amplitudes of warming are
generally underestimated, however. Further warming is projected to occur during the 21st century,
with plausible increases of 4–6 °Cover the subtropics and 3–5 °Cover the tropics by the end of the
century relative to present-day climate under the A2 (a low mitigation) scenario of the Special Report
on Emission Scenarios. High impact climate events such as heat-wave days and high fire-danger days
are consistently projected to increase drastically in their frequency of occurrence. General decreases in
soil-moisture availability are projected, even for regions where increases in rainfall are plausible, due
to enhanced levels of evaporation. The regional dowscalings presented here, and recentGCM
projections obtained for Africa, indicate that African annual-averaged temperatures may plausibly rise
at about 1.5 times the global rate of temperature increase in the subtropics, and at a somewhat lower
rate in the tropics. These projected increases although drastic, may be conservative given the model
underestimations of observed temperature trends. The relatively strong rate of warming over Africa,
in combination with the associated increases in extreme temperature events, may be key factors to
consider when interpreting the suitability of global mitigation targets in terms of African climate
change and climate change adaptation in Africa
URI
http://hdl.handle.net/10394/18779http://dx.doi.org/10.1088/1748-9326/10/8/085004
http://iopscience.iop.org/article/10.1088/1748-9326/10/8/085004