How cli­mate change will af­fect Pa­pua New Guinea agribusi­ness


Bob Hansen con­sid­ers the threats and op­por­tu­ni­ties to Pa­pua New Guinea from cli­mate change.

The world’s cli­mate is chang­ing and most of us are aware of this fact. The Earth has gone through very warm pe­ri­ods (22°C some 50 to 70 mil­lion years ago) and very cold pe­ri­ods (6°C some 600,000 years ago). The average global tem­per­a­ture is cur­rently 14°C.

His­tor­i­cally, most of this vari­a­tion was caused by the el­lip­ti­cal or­bit the Earth takes around the Sun or by the re­lease of car­bon by ex­treme vol­canic pe­ri­ods such as the up­lift of the Hi­malayas 60 mil­lion years ago. By study­ing the ef­fects of these his­tor­i­cal events, we have a good un­der­stand­ing of what the im­pacts of ris­ing global tem­per­a­tures caused by the re­lease of car­bon may have for the fu­ture of the Earth, and thus the im­pacts on in­dus­try.

Cli­mate pro­jec­tions

The his­tory of cli­mate sci­ence is rel­a­tively re­cent. The first sci­en­tist to pub­lish on the sub­ject was prob­a­bly Svante Ar­rhe­nius who, in 1896, pos­tu­lated that ‘the hu­man emis­sion of car­bon diox­ide would be strong enough to pre­vent the world en­ter­ing a new Ice Age’. Ar­rhe­nius’ green­house law is still used to­day.

More re­cently, the 1979 re­port by the United States Na­tional Academy of Sci­ence pre­dicted that car­bon diox­ide in the at­mos­phere would dou­ble from its pre-in­dus­trial lev­els by about 2035. (To­day, it’s ex­pected this will hap­pen by about 2050, de­pend­ing on the sce­nario or model.)

A dou­bling of car­bon diox­ide would lead to an average warm­ing of the planet of 2°C to 3°C. The po­lar re­gions would warm by ap­prox­i­mately 12°C and the trop­ics by less than 1°C. These pre­dic­tions are al­ready com­ing true, with record melt­ings of the Arc­tic Sea ice dur­ing sum­mer.

More re­cently again, the In­ter­gov­ern­men­tal Panel on Cli­mate Change’s models pre­dict a global average warm­ing of 1°C to 4°C by 2100.

The im­pact on PNG’s cli­mate

The 2011 Pa­cific Cli­mate Change Sci­ence Pro­gram re­port found that, for Pa­pua New Guinea: • Tem­per­a­tures would rise by be­tween 0.4°C and 1.0°C by 2030. • An­nual rain­fall would in­crease, with more ex­treme rain­fall events. • Sea lev­els are ris­ing at 7.0 mm a year in the vicin­ity of PNG,

dou­ble the global average of 2.8mm to 3.5mm a year. • The sea level is af­fected by the El Niño-South­ern Os­cil­la­tion

phe­nom­e­non. This is a rise of 140mm in the past 20 years.

Im­pli­ca­tions for PNG’s econ­omy

The ef­fects of these fore­casted changes are many and sig­nif­i­cant. Some of those changes are: • In­creas­ing in­ci­dence of malaria in the High­lands (Mueller, 2007),

now an an­nual event. • Re­gions like Lae will be wet­ter and there­fore the Lae roads, High­lands High­way and Wau/Bu­lolo road will re­quire in­creased main­te­nance due to wash-outs. The rain­fall in Lae has in­creased by ap­prox­i­mately 500mm per an­num or nearly 11%. This is con­sis­tent with pro­jected rain­fall for the trop­ics (Sea­ger, 2007 and IPCC, 2007) and rain­fall trends in North­ern Aus­tralia. • The pro­duc­tion re­gion for cof­fee and co­coa may ex­pand with in­creased rain­fall but there will also be in­creased dis­ease chal­lenges with higher hu­mid­ity in cur­rent pro­duc­tion re­gions. • Civil en­gi­neers will need to take into ac­count the in­creased river

flows in road and bridge de­signs, as wash-outs will in­crease. • Rub­ber farm­ing may be­come un­vi­able as the la­tex is washed out

of the cups on the trees. • Palm oil pro­duc­tion (Dun­can, 2007) will ben­e­fit from the in­creased pre­cip­i­ta­tion and the vi­able pro­duc­tion ar­eas will pos­si­bly ex­pand. Palm oil pro­duc­tion will be a po­ten­tial win­ner from cli­mate change. • The price of agri­cul­tural com­modi­ties will rise and be more volatile, as there will be in­creased de­mand and more weather events (too dry or too wet) im­pact­ing on the sup­ply chain dy­nam­ics. • In­creased rain­fall will raise river lev­els in the Sepik River, which

could af­fect the sup­ply of croc­o­dile eggs and hatch­lings. • The in­creased at­mo­spheric car­bon will ben­e­fit those crops that are C4 con­ver­tors such as maize, sorghum and sug­ar­cane, while C3 con­ver­tors such as wheat and rice will be sub­ject to yield de­clines. • Sea level rise will im­pact coastal com­mu­ni­ties. Houses and gar­dens will have to be moved to higher ground if pos­si­ble and is­land com­mu­ni­ties re­lo­cated to the PNG main­land. These will cre­ate so­cial prob­lems for many of these com­mu­ni­ties. A good ex­am­ple is the Sala­maua Isth­mus in Morobe Prov­ince, which has been sub­stan­tially eroded in the past 20 years.

In sum­mary, the im­pact of cli­mate change will have sig­nif­i­cant fi­nan­cial im­pli­ca­tions for PNG. There will be win­ners and losers and they are not all ap­par­ent presently. Ad­di­tional bud­getary funds will be re­quired for in­fra­struc­ture up­keep and re­lo­ca­tion of in­fra­struc­ture.

Bob Hansen is a for­mer Man­ag­ing Di­rec­tor of PNG agribusi­ness Main­land Hold­ings, and an Ad­junct As­so­ciate Pro­fes­sor at the Univer­sity of South­ern Queensland’s Aus­tralian Cen­tre for Sus­tain­able Business De­vel­op­ment.

Flood­ing along the Erap River in Morobe Prov­ince

In­creased rain­fall will raise river lev­els in the Sepik River, which could af­fect the sup­ply of croc­o­dile eggs and hatch­lings.

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