Future trends in emissions of N₂O from rivers and estuaries

Figures & data

Table 1. Global N₂O emissions from rivers and estuaries as estimates from total N (TN) or dissolved N (DN) in rivers, and using low or high emission factors.

Case	Rivers (Tg N/y)	Estuaries (Tg N/y)	Total (Tg N/y)
TN high^a	1.6	0.6	2.1
TN low^a	0.3	0.1	0.4
DN high^a	0.8	0.3	1.1
DN low^a	0.2	0.1	0.3
^aTotal dissolved N (DN) and total N (TN) export by rivers is 30 and 44 Tg N/y, respectively (Global NEWS output for the year 2000 (Mayorga et al. 2010; Seitzinger in press)).

Figure 1. Global emissions of nitrous oxide (N₂O) from rivers and estuaries in 1970, 2000, and four scenarios for 2050.

Figure 2. Global emissions of nitrous oxide (N₂O) from rivers and estuaries in 1970, 2000, and four scenarios for 2050 by continent. NB: Oceania includes Australia.

Table 2. Past (1970–2000) and future (2000–2050) trends in global emissions of nitrous oxide (N₂O) from rivers and estuaries by continent.

	2000	2050 GO	2050 OS	2050 TG	2050 AM
Africa	40	109	96	122	46
Europe	17	1	−12	−31	−32
N America	15	37	30	−1	3
S America	48	64	43	49	40
Oceania	119	54	38	32	9
Asia	173	49	26	−2	−25
Total	87	47	28	10	−8
Unit: The increase in percentage relative to 1970 (past) or 2000 (future).
Calculations are based on case DN high (Table 1).

Mayorga , E , Seitzinger , S P , Harrison , J A , Dumont , E , Beusen , A HW , Bouwman , A F , Fekete , B , Kroeze , C and Van Drecht , G . 2010 . Global nutrient export from watersheds 2 (NEWS 2): model development and implementation . Environ Model Software , 25 : 837 – 853 .

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