US EPA

1540611 

Journal Article 

Peatlands in the Earth's 21st century climate system 

Frolking, S; Talbot, J; Jones, MC; Treat, CC; Kauffman, JB; Tuittila, ES; Roulet, N 

2011 

Yes 

Environmental Reviews
ISSN: 1181-8700
EISSN: 1208-6053 

19 

371-396 

10.1139/A11-014 

WOS:000297028000018 

Peatlands occupy a relatively small fraction of the
Earth's land area, but they are a globally important carbon store because of their high carbon
density. Undisturbed peatlands are currently a weak carbon sink (similar to 0.1 Pg C y(-1)), a
moderate source of methane (CH4; similar to 0.03 Pg CH4 y(-1)), and a very weak source of nitrous
oxide (N2O; similar to 0.00002 Pg N2O-N y(-1)). Anthropogenic disturbance, primarily agriculture
and forestry drainage (10%-20% of global peatlands), results in net CO2 emissions, reduced CH4
emissions, and increased N2O emissions. This likely changes the global peatland greenhouse gas
balance to a C source (similar to 0.1 Pg C y(-1)), a 10% smaller CH4 source, and a larger (but
still small) N2O source (similar to 0.0004 Pg N2O-N y(-1)). There is no strong evidence that
peatlands significantly contributed to 20th century changes in the atmospheric burden of CO2,
CH4, or N2O; will this picture change in the 21st century? A review of experimental and
observational studies of peatland dynamics indicates that the main global change impacts on
peatlands that may have significant climate impacts are (1) drainage, especially in the tropics;
(2) widespread permafrost thaw; and (3) increased fire intensity and frequency as a result of
drier climatic conditions and (or) drainage. Quantitative estimates of global change impacts are
limited by the sparse field data (particularly in the tropics), the large variability present in
existing data, uncertainties in the future trajectory of peatland use, interactive effects of
individual impacts, and the unprecedented rates of climate change expected in the 21st century. 

peat; land use change; CO(2); CH(4); N(2)O