Road map to save en­vi­ron­ment

A global map high­lights re­gions where road con­struc­tion will have high en­vi­ron­men­tal costs

Down to Earth - - SCIENCE - MANUPRIYA

IN­DIA PLANS to con­struct over 0.8 mil­lion kilo­me­tres of roads by 2025 to con­nect ev­ery habi­tat in the coun­try, as per the tar­gets out­lined in the gov­ern­ment's Ru­ral Road De­vel­op­ment Vi­sion. World­wide, 25 mil­lion kilo­me­tres of roads are pro­posed to be con­structed by 2050—a 60 per cent in­crease in road length from 2010—and nine­tenths of this new con­struc­tion is ex­pected in de­vel­op­ing coun­tries such as In­dia. But con­struc­tion of roads of­ten harms bio­di­ver­sity and de­stroys wild habi­tat. To weigh the po­ten­tial ben­e­fits as­so­ci­ated with road con­struc­tion against their en­vi­ron­men­tal im­pact,Wil­liam Lau­rance,pro­fes­sor at James Cook Univer­sity, Aus­tralia, and col­leagues con­ducted a study and came up with a map that can help pol­i­cy­mak­ers take in­formed de­ci­sions on where to con­struct roads.

The map high­lights re­gions where road con­struc­tions will have high en­vi­ron­men­tal costs.It is based on two fac­tors: en­vi­ron­men­tal val­ues and road ben­e­fits. En­vi­ron­men­tal val­ues are mea­sured by in­te­grat­ing global data on three classes of pa­ram­e­ters: bio­di­ver­sity, key wilder­ness habi­tats and car­bon stor­age and cli­mate-reg­u­la­tion ser­vices of the lo­cal ecosys­tem. The re­searchers as­signed a value be­tween zero and one to each part of the globe. Re­gions with sen­si­tive en­vi­ron­ments and, there­fore, high en­vi­ron­men­tal value scored close to one on a scale of zero to one. Sim­i­larly, road ben­e­fits were de­fined on the ba­sis of po­ten­tial in­crease in agri­cul­tural pro­duc­tion re­sult­ing from bet­ter con­nec­tiv­ity of­fered by roads.

The two sets of data were com­bined to gen­er­ate a global map where ev­ery square kilo­me­tre (sq km) has been as­signed a colour (see map). Green ar­eas are those where road build­ing would have rel­a­tively high en­vi­ron­men­tal costs and only mod­est po­ten­tial ben­e­fits for agri­cul­ture, while red-shaded ar­eas have a high po­ten­tial to in­crease agri­cul­tural pro­duc­tion and low en­vi­ron­men­tal val­ues. Large parts of the In­dian

sub­con­ti­nent fall un­der this cat­e­gory. Black and dark-shaded ar­eas are “con­flict zones” with high val­ues on both the pa­ram­e­ters, whereas white and light-shaded ar­eas are of lower pri­or­ity for both en­vi­ron­ment and agri­cul­ture.

In coun­tries such as In­done­sia and Mada­gas­car, which have been as­signed “ex­cep­tional en­vi­ron­men­tal value”, the au­thors sug­gest adop­tion of al­ter­na­tive meth­ods,such as eco­tourism and har­vest­ing the for­est pro­duce, to meet eco­nomic de­vel­op­ment goals.

The au­thors note that roads are be­ing con­structed or are planned in re­gions that have high en­vi­ron­men­tal val­ues but only mod­est agri­cul­tural po­ten­tial.Th­ese re­gions in­clude the Ama­zon Basin,parts of the Asi­aPa­cific re­gion and high lat­i­tude forests in the North­ern Hemi­sphere.The map also shows that re­gions where road mak­ing is en­vi­ron­men­tally fea­si­ble ex­ist in ev­ery con­ti­nent.In to­tal 12.3 per cent of the global land area has been mapped red.Th­ese in­clude parts of cen­tral Eura­sia,the Irano-Ana­to­lian re­gion, African Sa­hel and the In­dian sub­con­ti­nent. The study was pub­lished in Na­ture on Au­gust 27

What ails In­dia

What does the study mean for coun­tries such as In­dia which the map says has a huge scope for con­struct­ing roads with min­i­mal en­vi­ron­men­tal im­pact? Ac­cord­ing to Lau­rance,road con­struc­tion even in such ar­eas will have en­vi­ron­men­tal im­pact (see ` Un­planned roads can cause a lot of dam­age'). There are sev­eral ex­am­ples to show this. San­jay Gubbi of Mysore-based non-profit Na­ture Con­ser­va­tion Foun­da­tion says 23 leop­ards have died in road ac­ci­dents in Kar­nataka in the past five years. He says en­vi­ron­men­tal im­pact as­sess­ments done be­fore lay­ing new roads of­ten ig­nore eco­log­i­cal is­sues re­sult­ing in loss of bio­di­ver­sity and an­i­mal habi­tat.But this can be eas­ily avoided.

Gubbi worked with the state gov­ern­ment to re­align a part of the MysoreManan­thavadi road pass­ing through the Na­gara­hole Tiger Re­serve. “The re­aligned road helps 'de­frag­ment' wildlife habi­tat in ad­di­tion to pro­vid­ing con­nec­tiv­ity to 11 vil­lages,”he says.

Source: Na­ture, Au­gust 27, 2014

Red shades high­light ar­eas where road con­struc­tion will ben­e­fit agri­cul­ture and have mi­nor en­vi­ron­men­tal costs, while green shades de­note ar­eas where roads will have high en­vi­ron­men­tal costs and low agri­cul­tural ben­e­fits

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