Cli­mate change: it’s hap­pen­ing faster than you think

The av­er­age tem­per­a­ture in­crease in South­ern Africa due to cli­mate change is tak­ing place at twice the global rate. The re­sult­ing lower rain­fall fig­ures and in­crease in the num­ber of heat­waves will see agri­cul­tural land­scapes shift­ing and veld fires growi

Farmer's Weekly (South Africa) - - Feature Climate Change - FW

The im­pact of cli­mate change con­tin­ues to have dev­as­tat­ing ef­fects on coun­tries across the globe, and South Africa has not been spared. The Western Cape has ex­pe­ri­enced one of its worst droughts in decades, while the Free State and North­ern Cape have seen sub­stan­tial de­ple­tion of live­stock as well as crop fail­ure due to per­sis­tent drought con­di­tions.

Prof Fran­cois En­gel­brecht, chief re­searcher for cli­mate stud­ies, mod­el­ling and en­vi­ron­men­tal health at the Coun­cil for Sci­en­tific and In­dus­trial Re­search (CSIR), says the in­crease in tem­per­a­tures across South­ern Africa over the last five decades can be directly at­trib­uted to the en­hanced green­house ef­fect, or an­thro­pogenic forc­ing.

“The ef­fects in­clude tem­per­a­tures in the in­te­rior re­gions of South­ern Africa that are in­creas­ing at about twice the global rate, and in­creases in the num­ber of high fire-dan­ger days and num­ber of heat­wave days. These in­creases in tem­per­a­ture on their own are im­por­tant due to the neg­a­tive ef­fects that ex­treme tem­per­a­ture events have on nu­mer­ous agri­cul­tural in­dus­tries, for ex­am­ple crop yields and live­stock pro­duc­tion.”

En­gel­brecht notes that over the win­ter rain­fall re­gion, an­thro­pogenic forc­ing has al­ready in­creased the like­li­hood of multi-year droughts.

“Over the sum­mer rain­fall re­gion, there is not clear ev­i­dence that cli­mate change has al­ready in­creased the like­li­hood for droughts to oc­cur, al­though events such as the 2015/2016 El Niño and re­lated drought is pro­jected to oc­cur more fre­quently un­der cli­mate change.”

El Niño is the warm phase of the El Niño–South­ern Os­cil­la­tion. Dur­ing this phase, the Pa­cific Ocean nor­mally warms up by 0,01%. But with global warm­ing, the tem­per­a­ture in­crease has climbed to 0,1% and it could pos­si­bly rise to 1% if global warm­ing con­tin­ues on its cur­rent path.

The warm­ing of the ocean in­ter­rupts the usual weather pat­terns and af­fects the global cli­mate. This could re­sult in droughts in one re­gion and in­tense storms in an­other.

In re­sponse to the chang­ing and of­ten er­ratic cli­matic con­di­tions seen over the past few decades, the De­part­ment of Science and Tech­nol­ogy launched the South African Risk and Vul­ner­a­bil­ity At­las (SARVA).

The se­cond edi­tion, pub­lished last year, urges plan­ners and de­ci­sion mak­ers to move from re­ac­tive cri­sis man­age­ment to proac­tive cli­mate change and dis­as­ter risk man­age­ment ap­proaches. This is es­pe­cially true for the 20 most vul­ner­a­ble mu­nic­i­pal­i­ties in South Africa, all of which are sec­ondary ci­ties and small towns.

SARVA states that ru­ral ar­eas are par­tic­u­larly vul­ner­a­ble due to their de­pen­dency on cli­mate­sen­si­tive re­sources such as wa­ter and an agrar­ian land­scape.

CHANGES IN FARM AC­TIV­ITY

En­gel­brecht notes that the sub­Sa­ha­ran cli­mate will be es­pe­cially af­fected by cli­mate change.

“South­ern Africa is pro­jected to be­come gen­er­ally drier, with more El Niño-re­lated droughts. East Africa is pro­jected to be­come gen­er­ally wet­ter. Op­pres­sive tem­per­a­tures and heat­wa­vere­lated events are pro­jected to oc­cur more fre­quently across the South­ern African re­gion.”

Con­se­quently, the eco­nomic en­vi­ron­ment will be af­fected, as shifts in farm­ing ac­tiv­i­ties are in­evitable. “South­ern Africa has been iden­ti­fied by the ‘Spe­cial Re­port on Global Warm­ing of 1.5°C’ as one of the re­gions in the world where cli­mate change will im­pact most neg­a­tively on eco­nomic growth, con­sid­er­ing the wide­spread im­pact on the agri­cul­ture sec­tor,” says En­gel­brecht.

“Should re­gional warm­ing reach lev­els of about 6°C to­wards the end of the se­cond half of the cen­tury, the col­lapse of the maize crop and live­stock in­dus­tries may plau­si­bly oc­cur in South­ern Africa.”

He adds that cli­mate change pre­dic­tions should play an in­te­gral role in or­chard plan­ning, as many of these crops pro­duce a re­turn on in­vest­ment only af­ter sev­eral years, and con­tinue pro­duc­ing a crop for decades. As tem­per­a­tures shift, many re­gions that were once suited to cer­tain crops might no longer pro­duce an ad­e­quate yield.

En­gel­brecht ad­vises that each agri­cul­tural in­dus­try plan care­fully to adapt to the im­pact of cli­mate change over the next few decades.

“For ex­am­ple, the likely oc­cur­rence of more fre­quent heat­waves and more fre­quent droughts sug­gests that dry­land agri­cul­ture will in­creas­ingly re­quire drough­tand heat-re­sis­tant crops.”

He adds that the south­west­ern part of the Western Cape is par­tic­u­larly vul­ner­a­ble in terms of sys­tem­atic rain­fall re­duc­tions and more fre­quently oc­cur­ring droughts.

“More fre­quently oc­cur­ring El Niño events and droughts may also im­pact in­creas­ingly on the sum­mer rain­fall re­gions as we move deeper into the 21st cen­tury. En­hanced schemes for trad­ing food be­tween South­ern African coun­tries may also be im­por­tant.”

PLANT AND AN­I­MAL HEALTH

Tiaan Pool, a veld­fire man­age­ment ex­pert at the Nel­son Man­dela Uni­ver­sity’s Saasveld cam­pus, says that the

warmer and wet­ter con­di­tions with higher drought oc­cur­rence will in­crease plant pests and dis­eases, as drought-stressed veg­e­ta­tion is more sus­cep­ti­ble to such com­pli­ca­tions. Alien in­vaders tend to adapt eas­ily, so they will sur­vive, while planted crops strug­gle. This will make it more dif­fi­cult to com­bat weeds.

Pool adds that a higher level of car­bon diox­ide in the at­mo­sphere cre­ates more plant growth, but lower ni­tro­gen and pro­tein con­tent.

“This re­sults in slower de­com­po­si­tion, so there’s a big­ger build-up of fuel and lower soil car­bon. This could cre­ate a pos­si­ble neg­a­tive ef­fect on an­i­mal feed as live­stock would need to eat more to get the same nutri­tion.” De­spite these neg­a­tive ef­fects, cli­mate change can also in­tro­duce new op­por­tu­ni­ties for farm­ers. En­gel­brecht notes that re­gional warm­ing has al­ready re­sulted in a de­crease in the num­ber of frost days over the Highveld re­gions of South Africa. This im­plies that tomato farm­ing, for ex­am­ple, may be­come more fea­si­ble in this re­gion in a warm­ing cli­mate.

IN­CREASED DAN­GER OF FIRES

The in­crease in the num­ber of dev­as­tat­ing fires across South Africa has been at­trib­uted to cli­mate change. Ac­cord­ing to Pool, cli­mate change has re­sulted in a change in fire regimes, with the fre­quency, sever­ity, size, type and sea­son be­ing al­tered. “With drought events on the in­crease and ex­tended pe­ri­ods of be­low-av­er­age rain, there’ll be 31% more heat­waves, re­sult­ing in more veld fires.

“Fur­ther­more, with rain fall­ing over shorter pe­ri­ods, the wa­ter doesn’t in­fil­trate the soil. This means we’re left with rain­fall that is less ef­fec­tive, which has a ma­jor im­pact on veg­e­ta­tion and the preva­lence of veld fires.”

The size of the ar­eas that burn each year is on the in­crease as all the com­po­nents that cre­ate run­away fire con­di­tions are de­pen­dent on the cli­mate.

“In the forestry in­dus­try, we’re al­ready ex­pe­ri­enc­ing a longer fire sea­son, with heat build­ing up rapidly in sum­mer. There is no longer a grad­ual spring

af­ter win­ter, or an au­tumn that lingers. Due to the sud­den in­creased heat and lower rel­a­tive hu­mid­ity, veg­e­ta­tion be­comes com­bustible ear­lier in the sea­son.”

Farm­ers and foresters need to care­fully con­sider how they would cope if their wa­ter were elim­i­nated.

“Be­sides wa­ter­ing our crops, find­ing ways to com­bat the in­crease in fires with­out us­ing wa­ter will be im­per­a­tive.”

MIT­I­GA­TION

En­gel­brecht says that while the South African gov­ern­ment has been proac­tive in try­ing to mit­i­gate cli­mate change, the onus is on the in­dus­tri­alised North­ern Hemi­sphere coun­tries, pri­mar­ily the US and China, to re­duce emis­sions.

“To avoid global warm­ing of 1,5°C or more, car­bon diox­ide emis­sions need to be re­duced glob­ally by 45% by 2030 with re­spect to 2010 lev­els. To achieve this, the world needs to rev­o­lu­tionise the way en­ergy is gen­er­ated on the planet, with a ma­jor shift re­quired from the use of fos­sil fuels to al­ter­na­tive forms of en­ergy. Science tells us that it’s still pos­si­ble for a global cli­mate change mit­i­ga­tion ef­fort to be suc­cess­ful.

“The De­part­ment of En­vi­ron­men­tal Af­fairs (DEA) in South Africa leads a strong African pres­ence in the cli­mate ne­go­ti­a­tions of the UN. Through ini­tia­tives such as the Long-Term Adap­ta­tion Sce­nar­ios Project, the Third Na­tional Com­mu­ni­ca­tion on Cli­mate Change, and the Na­tional Adap­ta­tion Strat­egy, DEA poli­cies have been strongly in­formed by the most up-to­date cli­mate change science avail­able for the South­ern African re­gion. This pro­vides South Africa with an op­por­tu­nity to re­spond timeously to the chal­lenges posed by cli­mate change,” says En­gel­brecht.

• Email Tiaan Pool at [email protected], or

Prof Fran­cois En­gel­brecht at fen­gel­[email protected]

PROF FRAN­COIS EN­GEL­BRECHT

TIAAN POOL

ABOVE:A shift in tem­per­a­tures is af­fect­ing sow­ing times for farm­ers. While maize is tra­di­tion­ally planted in Oc­to­ber in Mpumalanga, last year the plants were af­fected by un­char­ac­ter­is­tic frost im­me­di­ately af­ter they emerged.

BE­LOW: Agri­cul­ture is re­spon­si­ble for pro­duc­ing 5% of green­house gas emis­sions, com­pared with the 14% pro­duced by the trans­port in­dus­try. Ini­tia­tives such as ‘Meat­less Mon­day’ will make a neg­li­gi­ble dif­fer­ence to cli­mate change.

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