Vital Ozone Graphics 3

02 Most people know nitrous oxide as laughing gas that dentists use as an anaesthetic. But this is only a minor source of emissions. Deforestation, animal waste and bacterial decomposition of plant material in soils and streamsemituptotwo-thirdsofatmosphericN 2 O.Unlikenatural sources, emissions from human-related processes are steadily increasing, currently boosting the atmospheric concentration of N 2 O by roughly one percent every four years. nitrous oxide the culprits 13

1,75286 2;,'( $ 0$-25 &8/35,7 $)7(5

NITROUS OXIDE: A MAJOR CULPRIT AFTER 2010

7KRXVDQG 2'3 7RQQHV (PLVVLRQV

³:H KDYH FDOFXODWHG WKH R]RQH GHSOHWLQJ SRWHQWLDO RI 1 2 WR EH URXJKO\ SHUFHQW ODUJHU ZKHQ FKORULQH OHYHOV UHWXUQ WR WKH \HDU OHYHO´ 7R XQGHUVWDQG ZK\ 5DYLVKDQNDUD VD\V LW KHOSV WR NQRZ KRZ &)&V DQG 1 2 GDPDJH R]RQH 6RODU XOWUDYLROHW UDGLDWLRQ EUHDNV &)& PROHFXOHV DSDUW FUHDWLQJ FKORULQH DQG FKORULQH R[LGHV 7KHVH DUH ZKDW GHVWUR\ R]RQH KH VD\V QRW WKH SDUHQW &)&V 6LPLODUO\ 1 2 GRHVQ W GLUHFWO\ GDPDJH R]RQH &KHPLFDO UHDFWLRQV LQ WKH VWUDWRVSKHUH PXVW ILUVW VWULS DZD\ RQH RI WKDW PROHFXOH V QLWURJHQ DWRPV ² IRUPLQJ QLWULF R[LGH RU 12 7KLV VWULSSHG GRZQ PROHFXOH KH H[SODLQV LV ZKDW DFWXDOO\ ZUHDNV KDYRF ZLWK R]RQH ³1LWURJHQ R[LGHV DQG FKORULQH R[LGHV NLQG RI RSSRVH HDFK RWKHU LQ GHVWUR\LQJ VWUDWRVSKHULF R]RQH ´ WKH VFLHQWLVW H[SODLQV ³,Q RWKHU ZRUGV 1 2 RIIVHWV WKH DELOLW\ RI FKORULQH R[LGHV WR GHVWUR\ R]RQH $QG YLFH YHUVD ´ 6RXUFH -DQHW 5DORII 1LWURXV R[LGH ILQJHUHG DV PRQVWHU R]RQH VOD\HU 6FLHQFH1HZV $XJXVW WK

&)&V

&DUERQ WHWUDFKORULGH DQG 0HWK\O FKORURIRUP +DORQV

1 2

6RXUFH $ 5 5DYLVKDQNDUD -RKQ 6 'DQLHO 5REHUW : 3RUWPDQQ 1LWURXV R[LGH 1 7KH 'RPLQDQW 2]RQH 'HSOHWLQJ 6XEVWDQFH (PLWWHG LQ WKH VW &HQWXU\ 6FLHQFH $XJXVW * Tonnes multiplied by the ozone depleting potential of the considered gas. Source: A. R. Ravishankara, John S. Daniel, Robert W. Portmann, Nitrous oxide (N 2 0): The Dominant Ozone-Depleting Substance Emitted in the 21st Century , Science, August 2009. ... MOSTLY RELEASED BY AGRICULTURE ... MOSTLY RELEAS D BY AGRICULTURE 7RQQHV PXOWLSOLHG E\ WKH R]RQH GHSOHWLQJ SRWHQWLDO RI WKH FRQVLGHUHG JDV

Annual global emissions have been estimated at about 2 000 million tonnes of CO 2 -equivalent and in 2010, the ODP of N 2 O was estimated at 0.017. Now the main threat to the ozone layer, nitrous oxide is also a greenhouse gas. Limiting its emis- sions yields a double benefit. With a global warming potential (GWP) of about 300, N 2 O accounts for almost eight per cent of GHG emissions. Nitrous oxide is not regulated by the Montreal Protocol, but falls under the Kyoto Protocol. An unwanted side effect of the Montreal Protocol in stalling CFC emissions is that N 2 O can now develop its ozone destructive potential more ef- fectively. (See explanation in the graph). Together with the rising concentrations this could slow the ozone layer’s recovery. options for control Because many N 2 O releases are diffuse, limiting them will be much more challenging than simply controlling indus- trial processes. Farming is a growing source of N 2 O emis- sions. Widespread and often poorly controlled use of ani- mal waste as a fertilizer also causes substantial emissions. Applying fertilizer dosages in line with demand and what the soil can absorb significantly reduces N 2 O emissions and at the same time addresses high nitrate levels in drink- ing water supplies and eutrophication in estuaries. Infor- mation campaigns for farmers should focus on the optimal form and timing of fertilizer application. 0267/< 5(/($6(' %< 7+( $*5,&8/785$/ 6(&725 0DQXUH )HUWLOL]HUV ,QGXVWU\ DQG WUDQVSRUW %LRPDVV EXUQLQJ 0LOOLRQ WRQQHV 1LWURXV R[LGH DQWKURSRJHQLF HPLVVLRQV 0HDW FRQVXPSWLRQ JURZWK PRUH PDQXUH SURGXFHG %LRIXHO FURSV DUHD H[WHQVLRQ PRUH IHUWLOL]HUV XVHG 0RUHRYHU 1 HPLVVLRQV LQ WKH DJULFXOWXUDO VHFWRU DUH SURMHFWHG WR LQFUHDVH GXH WR 0 6 5 4 3 2 1 7

Million tonnes Nitrous oxide anthropogenic emissions

N 2 0 emissions in the agricultural sector are projected to increase due to:

+DUPIXO IRU WKH R]RQH OD\HU 1LWURXV R[LGH LV DOVR D JUHHQKRXVH JDV 7KHUHIRUH OLPLWLQJ LWV HPLVVLRQV LV D GRXEOH EHQHILW 1LWURXV R[LGH LV XQUHJXODWHG E\ WKH 0RQWUHDO 3URWRFRO Growth in meat consumption (more manure produced)

Agriculture represents almost 80 % of all anthropogenic N 2 O emitted

Manure

Biofuel crops area extension (more fertilizers used)

Fertilizers

$JULFXOWXUH UHSUHVHQWV DOPRVW RI DOO DQWKURSRJHQLF 1 2 HPLWWHG

Industry and transport Biomass burning

Source: Eric A. Davidson, The contribution of manure and fertilizer nitrogen to atmospheric nitrous oxide since 1860, Nature Geoscience, August 2009. Source: Eric A. Davidson, The contribution of manure and fertilizer nitrogen to atmospheric nitrous oxide since 1860 , Nature Geoscience, August 2009.

6RXUFH (ULF $ 'DYLGVRQ 7KH FRQWULEXWLRQ RI PDQXUH DQG IHUWLOL]HU QLWURJHQ WR DWPRVSKHULF QLWURXV R[LGH VLQFH 1DWXUH *HRVFLHQFH $XJXVW