Methane Module (53_methane)¶

• Table of contents
• Methane Module (53_methane)
  • Description
  • Interfaces
    • Input
    • Interface plot
  • Realizations
    • (A) off
    • (B) ipcc1996 (default)
    • (C) ipcc_1996_2006_dec14
  • Definitions
  • Developer(s)
  • See Also
  • References

Description¶

The methane module calculates methane emissions ($CH_4$) according to 1996 IPCC Guidelines of National Grennhouse Gas Inventories¹.
Methane emissions before technical mitigation ($vm\_btm$) are then handed on the 57_maccs module to calculate emissions after technical mitigation.

Interfaces¶

Input¶

Name	Description	Unit	A	B	C
$vm\_area(j,kcr,w)$	agricultural production area	mio. ha		x	x
$fm\_feeding\_convergence(t\_all)$	feeding convergence scenario	-		x	x
$vm\_prod\_reg(i,k)$	regional aggregated production	mio. ton DM		x	x
$vm\_dem\_feed(i,kli,kbio)$	regional feed demand including byproducts	mio. ton DM			x
$fm\_GE\_content(kbio)$	gross energy content	GJ per ton DM			x
$vm\_btm\_reg(i,emis\_reg)$	emissions before technical mitigation	Tg N2O-N CH4 and CO2-C	x	x	x

_{The last columns of the table indicate the usage in the different realizations (numbered with capital letters)}

Interface plot¶

Figure 0: Information exchange among modules

Realizations¶

(A) off¶

Methane emissions are set to zero.

\begin{equation}
vm\_btm\_reg.fx(i,emis\_ch4) = 0
\end{equation}

Limitations
CH4 emissions are fixed to zero

(B) ipcc1996 (default)¶

This module realization estimates $CH_4$ emissions from paddy rice cultivation, enteric fermentation from ruminant animal husbandry and from animal waste management systems. These are total $CH_4$ emissions calculated before technical mitigation ($vm\_btm\_reg$). Technical mitigation options are applied on these baseline emissions in the module 57_maccs.
Emission factors are based on the 1996 IPCC Guidelines for National Greenhouse Gas Inventories¹ (IPCC 1996). Emission factors are multiplicatively connected to the cultivated area of rice $vm\_area(j,\text{"$rice\_pro$"},w)$ or on the amount of livestock production $vm\_prod\_reg(i,kli)$.
In some scenarios, it is assumed that the productivity and the management of the livestock sector changes from current practices to industrialized practices; therefore the parametrization of the regional livestock sectors are assumed to converge to the European values. The emission factors in this module converge to the European levels too.
For rice, one mitigation option would be to produce rice only on rainfed areas. Drainage would reduce methane emissions. However, paddy rice does not necessarily require blue water, but can also exclusively use green water. Moreover, LPJ does not simulate paddy rice, but irrigated normal rice, so we are not certain about the yield differential. Therefore, we only use total rice area and assume that the share of paddy rice in the world regions (from IPCC Guidelines¹ (IPCC 1996)) stays constant.

CH4 emissions are calculated as follows:

enteric fermentation:

\begin{equation}
vm\_btm\_reg(i,\text{"$ent\_ferm\_ch4$"}) = \sum_{kli} (vm\_prod\_reg(i,kli)*ic53\_emis\_ch4\_liv\_1996(\text{"$ent\_ferm\_ch4$"},i,kli))
\end{equation}

animal waste management:

\begin{equation}
vm\_btm\_reg(i,\text{"$awms\_ch4$"}) = \sum_{kli} (vm\_prod\_reg(i,kli)*ic53\_emis\_ch4\_liv\_1996(\text{"$awms\_ch4$"},i,kli))
\end{equation}

rice:

\begin{equation}
vm\_btm\_reg(i,\text{"$rice\_ch4$"}) = \sum_{cell(i,j),w} (vm\_area(j,\text{"$rice\_pro$"},w)*f53\_emis\_ch4\_rice1996(i))
\end{equation}

Limitations
IPCC 1996 guidelines should be updated to 2006 guidelines.

(C) ipcc_1996_2006_dec14¶

This realization is the same as ipcc1996 realization for animal waste management and rice emissions. The $CH_4$ emissions from enteric fermentation are estimated based on the GE (energy content) in ruminant feed, the approach from IPCC 2006 Guidelines for National Greenhouse Gas Inventories, Tier II methods [2].

\begin{align*}
vm\_btm\_reg(i,\text{"$ent\_ferm\_ch4$"}) = \sum_{k} & [vm\_dem\_feed(i,\text{"$livst\_rum$"},k)*fm\_GE\_content(k)*f53\_ef\_entferm(k) \\
&+ vm\_dem\_feed(i,\text{"$livst\_rum$"},k)*fm\_GE\_content(k)*0.065] / 55.65
\end{align*}

The factor 1/55.65 t/GJ is the energy content of methane.
The factor 0.065 is the share of GE in feed released as methane for dairy cattle.
$f53\_entferm$ is 0.035 for concentrates and 0.065 percent for fodder, pasture, scavenging, and crop residues.

Limitations
$CH_4$ emissions from animal waste management may be inconsistent with $CH_4$ emissions from enteric fermentation

Definitions¶

Name	Description	Unit	A	B	C
$i53\_scen\_emis\_ch4\_liv\_1996(t,emis\_ch4,i,kli)$	$CH_4$ Emission per $t$ livestock product (methodology 1996) after feed conversion	CH4/t		x	x
$ic53\_emis\_ch4\_liv\_1996(emis\_ch4,i,kli)$	value of $i53\_emis\_ch4\_liv\_1996$ in the current timestep	CH4/t		x	x
$f53\_emis\_ch4\_rice1996(i)$	$CH_4$ Emission per ha (methodology 1996)	CH4/ha		x	x
$f53\_emis\_ch4\_liv\_1996(emis\_ch4,i,kli)$	$CH_4$ Emission per $t$ livestock product (methodology 1996)	CH4/t		x	x
$f53\_ef\_entferm(kbio)$	percentage of gross energy in feed that is released as methane for beef cattle	%			x

_{The last columns of the table indicate the usage in the different realizations (numbered with capital letters)}

Developer(s)¶

Benjamin Leon Bodirsky

See Also¶

Overview, 57_maccs, 70_livestock, 30_crop

References¶

¹ * IPCC (1996) Volume 2: Workboook, Chapter 4: Agriculture, in: Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories, Institute for Global Environmental Strategies (IGES), 1996.

² * IPCC (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 10, Table 10.12. Prepared by the National Greenhouse Gas Inventories Programme.