29.03.2015 Views

Mapping climate vulnerability and poverty in Africa - CGSpace Home

Mapping climate vulnerability and poverty in Africa - CGSpace Home

Mapping climate vulnerability and poverty in Africa - CGSpace Home

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

mean<strong>in</strong>gful way, so current ra<strong>in</strong>fall CV <strong>and</strong> changes <strong>in</strong> ra<strong>in</strong>fall amounts were used as proxies<br />

for future conditions. We also carried out cont<strong>in</strong>ent-wide analyses of the possible changes <strong>in</strong><br />

probability of season failure, for the cropp<strong>in</strong>g areas of sub-Saharan <strong>Africa</strong>. For that analysis,<br />

we omitted both very dry <strong>and</strong> very wet areas. These various analyses are described below.<br />

4.1 Data <strong>and</strong> analysis<br />

For look<strong>in</strong>g at different scenarios of <strong>climate</strong> change to 2050, the data set TYN SC 2.0 was<br />

used, k<strong>in</strong>dly supplied by its orig<strong>in</strong>ator, Timothy D Mitchell (Mitchell et al., 2004). The<br />

variables used from this data set were the diurnal temperature range, precipitation <strong>and</strong><br />

average daily temperature on a monthly basis. The data cover the global l<strong>and</strong> surface at a<br />

resolution of 0.5 degrees latitude <strong>and</strong> longitude, <strong>and</strong> cover the period 2001 to 2100. There<br />

are 20 <strong>climate</strong> change scenarios <strong>in</strong> the complete data set. The <strong>climate</strong> change scenarios are<br />

made up of all permutations of five Atmosphere-Ocean General Circulation Models<br />

(AOGCMs) (HadCM3, CSIRO2, CGCM2, PCM, ECHam4) <strong>and</strong> four SRES scenarios (A1FI,<br />

A2, B1, B2). The five models used <strong>in</strong> this data-set (see Table 1) were among the set of stateof-the-art<br />

coupled <strong>climate</strong> models used by the IPCC (2001) <strong>in</strong> the Third Assessment Work<strong>in</strong>g<br />

Group 1 Report. A summary of their features may be found <strong>in</strong> IPCC (2001). The month-tomonth<br />

<strong>and</strong> year-to-year variations are superimposed on top of the averaged <strong>climate</strong> changes<br />

taken from the models; these are taken from the gridded observations <strong>in</strong> a companion dataset,<br />

CRU TS 2.0 (New et al., 2002). The two data sets together thus provide complete timeseries<br />

for the period 1901-2100.<br />

Details of the SRES scenarios can be found <strong>in</strong> IPCC (2000), <strong>and</strong> these are summarized <strong>in</strong><br />

Table 2. The “A” scenarios have more of an emphasis on economic growth, the “B”<br />

scenarios on environmental protection. The “1” scenarios assume more globalisation, the “2”<br />

scenarios more regionalization. The SRES scenarios have come <strong>in</strong> for some criticism, partly<br />

to do with the fact that the projections for human population have become out-of-date<br />

surpris<strong>in</strong>gly rapidly. While some have criticized the population <strong>and</strong> economic details, the<br />

scenarios are generally <strong>in</strong>ternally consistent <strong>and</strong> constitute a very useful set of st<strong>and</strong>ards, <strong>and</strong><br />

the range of future greenhouse gas emissions is undisputed (Tol et al., 2005).<br />

21

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!