Table 1.

Global annual GHG gas emissions according to the traditional and size-productivity weighted (SPW) approaches and three different global lake and impoundment size distributions.

			Lake Size Distribution
Gas	Data source	Upscaling approach1–†emission mechanism	Downing et al. 2006	Verpoorter et al. 2014	Messager et al. 2016
CO2 (Tg CO2-C y−1)	Tranvik et al. (2009)	Traditional	810	--	--
	This work	Traditional	740	899	542
		SPW	503 (468–541)	525 (491–562)	244 (227–262)
CH4 (Tg CH4-C y−1)	Bastviken et al. (2011)	Traditional - Diffusion	7	--	--
		Traditional – Ebullition	41	--	--
		Traditional - Total	69	--	--
	This work	Traditional - Diffusion	43	52	32
		Traditional - Ebullition	140	170	102
		Traditional - Total	204	248	149
		SWP - Diffusion	28 (17–48)	34 (21–57)	18 (11–13)
		SWP - Ebullition	67 (39–115)	84 (49–144)	47 (28–81)
		SPW - Total	112 (71–177)	139 (89–221)	78 (50–124)
N2O (Tg N2O-N y−1)	Soued et al. (2015)	Traditional	0.63	--	--
	This work	Traditional	0.22	0.27	0.16
		SPW	0.3 (0.19–0.45)	0.38 (0.24–0.55)	0.26 (0.16–0.38)

¹SPW estimates include lower and upper 95% confidence intervals in parentheses.

^†If not reported, emission mechanism is diffusion.