A new study on Africa's live­stock emis­sions chal­lenges IPCC's es­ti­mates, trig­ger­ing a call to in­cor­po­rate data from lo­cal live­stock sys­tems


The IPCC may have got it wrong in es­ti­mat­ing African live­stock emis­sions

THE DE­BATE over the amount of live­stock emis­sions con­tribut­ing to global green­house gases ( ghg) has al­ways been con­tentious. In­dia had ear­lier chal­lenged the cal­cu­la­tions of the In­ter­gov­ern­men­tal Panel on Cli­mate Change ( ipcc) say­ing that it is un­eth­i­cal to com­pare sur­vival emis­sions with emis­sions from the in­dus­try. Now a new study has fur­ther shaken the pot. Method­olo­gies adopted by the ipcc in es­ti­mat­ing live­stock emis­sions in Africa are now un­der the scan­ner.

Sci­en­tists at the In­ter­na­tional Live­stock Re­search In­sti­tute ( ilri) in Nairobi, Kenya, have found that African live­stock emit as much as two times lower than the ipcc es­ti­mates. The study found that as com­pared to ipcc’s es­ti­mates, fae­cal meth­ane emis­sions are two times lower, 10-20 times lower for fae­cal nitrous ox­ide (NO ) and two times 2 lower for urine NO (see ‘In­flated?). 2

The study is sig­nif­i­cant as nearly 65 per cent of Africa’s pop­u­la­tion de­rives its liveli­hoods from farm­ing, live­stock and fresh­wa­ter fish­eries. Ac­cord­ing to ipcc es­ti­mates, though live­stock emis­sions ac­count for only nine per cent of global car­bon diox­ide (CO ), 2 it gen­er­ates 65 per cent of hu­man-re­lated nitrous ox­ide and 35 per cent of meth­ane, the global warm­ing po­ten­tial of which is 296 and 23 times that of CO re­spec­tively. 2

Ig­nor­ing lo­cal con­di­tions

The sci­en­tists mea­sured ghg emis­sions from live­stock waste in Kenya, us­ing two com­mon breeds of cat­tle—the na­tive Bo­ran and the ex­otic Friesian. They stud­ied whether diet could af­fect emis­sions in any way. Cat­tle were fed dif­fer­ent di­ets, con­sis­tent with those fre­quently used in small­holder farms in east Africa. The re­searchers then used these lo­cally de­rived fac­tors to es­ti­mate emis­sions. The find­ings were pub­lished in the

peer-re­viewed Jour­nal of En­vi­ron­men­tal Qual­ity in June 2016.

The re­searchers blame the dis­crep­ancy in the “Tier 1” model used by the ipcc to cal­cu­late emis­sions, which is pri­mar­ily based on stud­ies car­ried out in Europe and North Amer­ica. “The con­di­tions un­der which live­stock are reared in Europe, the feeds, cli­mate and breeds most prob­a­bly have led to this in­con­sis­tency,” says David Pel­ster, lead author of the study.

“In Kenya and most African coun­tries, we have wet, dry, cool and hot sea­sons, and this changes the kind of feed that an­i­mals con­sume in dif­fer­ent sea­sons. Hence, the amount of emis­sions in cat­tle ma­nure varies. An­i­mals used to low-qual­ity feed tend to de­velop highly-ef­fi­cient di­ges­tive sys­tems to get the most out of the food,” says Pel­ster.

Iron­i­cally, the ipcc col­lects lit­tle or no data from the devel­op­ing world for live­stock, bar­ring Brazil. The real ghg emis­sion sce­nario could pos­si­bly be very dif­fer­ent from what the ipcc has pro­jected, says Lutz Mer­bold, a sci­en­tist with ilri. The sci­en­tists sug­gest that global av­er­ages for emis­sions must take into ac­count the dif­fer­ent live­stock sys­tems in dif­fer­ent parts of the world. This, they say, will en­able gov­ern­ments and global agen­cies to de­sign ac­cu­rate mit­i­ga­tion mod­els to com­bat ghg. “Get­ting the right data for ghg emis­sions in dif­fer­ent live­stock sys­tems will also mean that it would be pos­si­ble to know the stage at which the most-ef­fec­tive in­ter­ven­tion mit­i­ga­tions can be made,” adds Pel­ster. So there may be a need to de­velop a “Tier 2” ap­proach to mea­sure emis­sions based on lo­cally col­lected data.

For ac­cu­rate mit­i­ga­tion

Gov­ern­ments, on the other hand, may have to change the way they mea­sure live­stock ghg since they are now un­der obli­ga­tion to re­port to ipcc ev­ery four years, and there is pres­sure to en­sure that the emis­sions are kept un­der check to de­velop mit­i­ga­tion strate­gies. Wil­bur Ot­tichilo, a cli­mate ex­pert and mem­ber of the En­vi­ron­ment and Nat­u­ral Re­sources Com­mit­tee of Kenya’s na­tional as­sem­bly, agrees on the need to in­cor­po­rate lo­cal emis­sion fac­tors in ghg es­ti­mates. “Sci­en­tists should blend both lo­cal fac­tors as well as those of the ipcc,” he says.

He em­pha­sises the need for devel­op­ing coun­tries to con­duct more lo­cal stud­ies to gen­er­ate data that can stand up to in­ter­na­tional scru­tiny. “There have been reser­va­tions in many coun­tries that the ipcc may be over­stat­ing emis­sions from live­stock. So con­duct­ing sci­en­tif­i­cally sound lo­cal stud- ies could help in cor­rect­ing the es­ti­mates,” he adds.

“These find­ings call for fur­ther sci­en­tific stud­ies to es­tab­lish the ac­cu­racy of ipcc data on emis­sions based on var­i­ous live­stock pro­duc­tions sys­tems, thereby im­prov­ing knowl­edge and re­duc­ing un­cer­tainty,” adds Mer­bold. The sci­en­tists hope the study will trig­ger more de­bate on the sub­ject within the sci­en­tific com­mu­nity and lead to more in­ves­ti­ga­tions. “This is just the first crack,” as­serts Pel­ster. “We need to in­vest in more stud­ies in dif­fer­ent lo­ca­tions,” he adds.

Evans Ki­tuyi, se­nior pro­gramme spe­cial­ist, cli­mate change, at the Sub-Sa­ha­ran re­gional of­fice of the In­ter­na­tional De­vel­op­ment Re­search Cen­tre in Nairobi agrees with the study’s con­clu­sions, adding that a “Tier-2” method would be ac­cept­able for Africa. A con­sen­sus on live­stock emis­sions within the sci­en­tific com­mu­nity could also help African na­tions to chart out a de­vel­op­ment path, not weighed down by the weight of emis­sions from live­stock. “Coun­tries pre­par­ing their In­tended Na­tion­ally De­ter­mined Con­tri­bu­tions could then take in­formed de­ci­sions on where and what they need to re­duce.”

African live­stock emis­sions could be as much as two times lower than IPCC es­ti­mates

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