Ill ef­fects of ni­tro­gen over­dose

Ex­ces­sive use of ni­tro­gen is caus­ing prob­lems rang­ing from coastal dead zones to fish kills and global warm­ing.

The Star Malaysia - Star2 - - ECOWATCH -

NI­TRO­GEN continues to be used in­ef­fi­ciently as a plant nutrient in agri­cul­ture, ac­cord­ing to the United Na­tions En­vi­ron­ment Pro­gramme (UNEP) Year Book 2014.

The amount of us­able ni­tro­gen pro­duced by hu­mans is now about 190 mil­lion tonnes per year, greater than the 112 mil­lion tonnes cre­ated through nat­u­ral pro­cesses. As ni­tro­gen moves through the en­vi­ron­ment, the same ni­tro­gen atom can con­trib­ute to mul­ti­ple neg­a­tive ef­fects in the air, on land, in fresh­wa­ter and ma­rine sys­tems, and on hu­man health. This se­quence continues over a long pe­riod and is re­ferred to as the “ni­tro­gen cas­cade”.

Ex­cess ni­tro­gen in the en­vi­ron­ment con­trib­utes to many prob­lems, in­clud­ing:

> Coastal dead zones and fish kills due to se­vere eu­troph­i­ca­tion (a high con­cen­tra­tion of nu­tri­ents, which leads to ex­ces­sive plant growth and oxy­gen de­pri­va­tion). There are cur­rently over 500 known coastal dead zones in well-stud­ied ar­eas of the world, whereas in 2003 only around 150 such oxy­gen-de­pleted ar­eas were re­ported. Once other re­gions start reporting, it is es­ti­mated that 1,000 coastal and ma­rine ar­eas will be iden­ti­fied as ex­pe­ri­enc­ing the ef­fects of eu­troph­i­ca­tion.

> Ni­tro­gen emis­sions to the air, no­tably those of ni­trous ox­ide (N2O), con­trib­ute to cli­mate change. Some­times re­ferred to as the “for­got­ten green­house gas”, N2O is over 300 times more ef­fec­tive at trap­ping heat in the at­mos­phere than car­bon diox­ide over a 100-year pe­riod. Hu­man ac­tiv­i­ties such as agri­cul­ture, de­for­esta­tion and fos­sil fuel com­bus­tion are in­creas­ing the amount in the at­mos­phere.

Bet­ter man­age­ment prac­tices are es­sen­tial to re­duce ni­tro­gen losses to the en­vi­ron­ment from agri­cul­tural sources.

Ac­cord­ing to the UNEP-com­mis­sioned re­port, Our Nutrient World, a 20% im­prove­ment in global nutrient use ef­fi­ciency by 2020 will re­duce an­nual use of ni­tro­gen by an es­ti­mated 20 mil­lion tonnes.

The re­port also high­lights the haz­ards of fish farm­ing. Aqua­cul­ture A GLOBAL car­bon price of at least US$32 (RM104) per tonne is needed by 2015 to ap­ply an ef­fec­tive brake on global warm­ing – al­most five times to­day’s Euro­pean mar­ket rate.

A study co-au­thored by Bri­tish econ­o­mist Ni­cholas Stern, an author­ity on the costs of cli­mate change, re­viewed a widely-used model for as­sess­ing risk and found it led to a “gross un­der-as­sess­ment” of dan­ger.

This beefs up the case for strong cuts in green­house gas emis­sions, helped by a car­bon price “in the range of US$32 to US$103 per tonne of CO2 in 2015,” said the study car­ried by The Eco­nomic

Plant­ing rice in nan­garhar prov­ince, afghanistan. Wide ap­pli­ca­tion of fer­tiliser in agri­cul­ture has left huge amounts of ni­tro­gen in the en­vi­ron­ment, and con­se­quently, var­i­ous ad­verse im­pacts. — aFP pro­duc­tion has in­creased since the 1950s from 650 thou­sand tonnes to al­most 67 mil­lion tonnes, and to­day pro­vides half of all fish for hu­man con­sump­tion. Ma­rine aqua­cul­ture pro­duc­tion by vol­ume grew by 35% dur­ing the last decade, while pro­duc­tion in fresh and brack­ish wa­ter grew by 70% and 83%, re­spec­tively.

While progress has been made to­wards mak­ing ma­rine aqua­cul­ture more sus­tain­able, en­vi­ron­men­tal con­cerns re­main. Fish farms can re­lease nu­tri­ents, undi­gested feed and vet­eri­nary drugs to the en­vi­ron­ment. They can also in­crease risks of dis­eases, par­a­sites and harm­ful al­gal blooms. In some coun­tries, cer­tain forms of shrimp farm­ing have de­stroyed large ar­eas of coastal habi­tats, such as man­grove forests.

Healthy ma­rine ecosys­tems are fun­da­men­tal to se­cur­ing food and pro­vid­ing jobs. En­vi­ron­men­tally sound de­vel­op­ment of the ma­rine aqua­cul­ture sec­tor is needed to avoid the loss of im­por­tant ecosys­tem ser­vices. Tech­ni­cal in­no­va­tions, the grow­ing skills of aqua­cul­ture pro­duc­ers, and im­proved knowl­edge of en­vi­ron­men­tal im­pacts pro­vide hope for a sus­tain­able ma­rine aqua­cul­ture sec­tor.

The re­port also says that air qual­ity is de­te­ri­o­rat­ing in most cities. The World Health Or­gan­i­sa­tion (WHO) es­ti­mates that in 2012, air pol­lu­tion led to around seven mil­lion pre­ma­ture deaths (one out of eight to­tal global deaths), more than dou­ble pre­vi­ous es­ti­mates. It is the leading cause of en­vi­ron­men­tally re­lated deaths. The WHO guide­line for aver­age an­nual fine par­tic­u­late mat­ter is 25 mi­cro­grammes per cu­bic me­tre. Cities in low- and mid­dle-in­come coun­tries far ex­ceed this level. For ex­am­ple, in Kath­mandu, Nepal, par­tic­u­late mat­ter (PM2.5) lev­els of over 500 mi­cro­grammes per cu­bic me­tre have been mea­sured.

The cost of air pol­lu­tion to the listed a global car­bon price as one op­tion for tack­ling the chal­lenge. It warned tem­per­a­tures could rise by up to 4.8°C this century and sea lev­els by 26cm to 82cm on present emis­sions trends.

The In­ter­na­tional Mon­e­tary Fund and World Bank have also this year called for the in­tro­duc­tion of a uni­ver­sal price on car­bon – the most com­mon green­house gas blamed for cli­mate change.

For the mo­ment, car­bon prices are de­ter­mined by na­tional or re­gional sys­tems – ei­ther as a tax on emis­sions or as a cap-and­trade scheme that al­lows com­pa­nies to sell un­used al­lot­ments.

The Euro­pean Union Emis­sions world’s most ad­vanced economies, plus In­dia and China, is es­ti­mated at US$3.5tril (RM11.3tril) per year in lives lost and ill health. In Or­gan­i­sa­tion for Eco­nomic Co-oper­a­tion and De­vel­op­ment coun­tries, the mon­e­tary im­pact of death and ill­ness due to out­door air pol­lu­tion is es­ti­mated to have been US$1.7tril in 2010. Re­search sug­gests that mo­torised on-road trans­port ac­counts for about 50% of that amount.

In light of the high costs re­lated to the health and en­vi­ron­men­tal ef­fects of air pol­lu­tion, all coun­tries should in­vest in clean air poli­cies, the re­port says. — UNEP Trad­ing Scheme (ETS), the most am­bi­tious cap-and-trade sys­tem in the world, has seen prices drop dras­ti­cally from a peak of about 30 eu­ros (RM133) per tonne eight years ago to 5.7 eu­ros (RM25) to­day – partly due to coun­tries is­su­ing too many al­lowances.

The Stern-Di­etz re­port said the stan­dard model used to cal­cu­late eco­nomic risks from cli­mate change, also by stud­ies in­cluded in the IPCC’s lat­est re­port, used un­re­al­is­tic val­ues and un­der-es­ti­mated the po­ten­tial dam­age.

The up­dated model, “strength­ens the case for strong cuts in emis­sions of green­house gases,” Di­etz said in a state­ment. – AFP

Bad ef­fects:

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