The contribution of rice agriculture and livestock pastoralism to prehistoric methane levels

Abstract

We review the origins and dispersal of rice in Asia based on a data base of 443 archaeobotanical reports. Evidence is considered in terms of quality, and especially whether there are data indicating the mode of cultivation, in flooded ('paddy' or 'wet') or non-flooded ('dry') fields. At present it appears that early rice cultivation in the Yangtze region and southern China was based on wet, paddy-field systems from early on, before 4000 bc, whereas early rice in northern India and Thailand was predominantly dry rice at 2000 bc, with a transition to flooded rice documented for India at c. 1000 bc. On the basis of these data we have developed a GIS spatial model of the spread of rice and the growth of land area under paddy rice. This is then compared with a review of the spread of ungulate livestock (cattle, water buffalo, sheep, goat) throughout the Old World. After the initial dispersal through Europe and around the Mediterranean (7000-4000 bc), the major period of livestock expansion is after 3000 bc, into the Sub-Saharan savannas, through monsoonal India and into central China. Further expansion, to southern Africa and Southeast Asia dates mostly after 1000 bc. Based on these two data sets we provide a quantitative model of the land area under irrigated rice, and its likely methane output, through the mid to late Holocene, for comparison to a more preliminary estimate of the expansion of methane-producing livestock. Both data sets are congruent with an anthropogenic source of later Holocene methane after 3000 bc, although it may be that increase in methane input from livestock was most significant in the 3000-1000 bc period, whereas rice paddies become an increasingly significant source especially after 2000 bc.

Pathways of Rice Diversification across Asia

“…4). In others words there is a spectrum from wet to dry (Weisskopf et al 2014;Fuller et al 2011). In some cases upland rice may be grown in slash-and-burn systems.…”

“…The evolution of genes connected to productivity under temperate summer conditions may well be related to the subsequent dispersal of rice to other northern regions such as the Korean Peninsula (ca. 1500 BC) and Japan (after 1000 BC) (Silva et al 2015;Fuller et al 2011).…”

“…While this research began with critical reflections and debate surrounding the initial cultivation of rice in China (Fuller, Harvey and Qin 2007) and India (Fuller 2006), it has expanded into better documenting the evidence for morphological change during domestication ), the characterisation of variable wet and dry ecologies of early rice cultivation Fuller and Weisskopf 2010;Weisskopf et al 2014), and to tracking the spread of rice through the compilation and analysis of a large database of archaeobotanical evidence (Silva et al 2015). We have completed more than six years of research supported by major NERC (Natural Environment Research Council) grants (Grant NE/G005540/1 "The Identification of Arable Rice Systems in Prehistory" (2009)(2010)(2011)(2012); Grant NE/ K003402/1 "The impact of evolving rice systems from China to Southeast Asia" (2013)(2014)(2015)(2016)), developing and deploying new methods for establishing the past ecology of rice cultivation and its potential impact not just on social change, but also on the global environment through methane emissions produced by methanogenic bacteria that thrive in the warm stagnant water of paddyfields (Fuller et al 2011). The time is right for assessing what we now know and which hypotheses require further archaeobotanical testing.…”

The Checkered Prehistory of Rice Movement Southwards as a Domesticated Cereal—from the Yangzi to the Equator

“…Incipient wet rice field complexes date back to almost 5,000 BC at Tianluoshan ). Fuller et al (2011) suggest that by 3,000 BC, the system was highly productive, capable of supporting the huge population of the Liangzhu phase in the lower Yangzi valley. 2 The elongated Liangzhu wet rice fields at Maoshan, for instance, dating from c.3,200-2,400 BC, were separated by long paralleled bunds of fired soil about 20 m apart and covered an area of at least 50 by 700 m, according to phytolith analysis (Qin Ling, Peking University, personal communication 2011).…”

An Son Ceramics in the Neolithic Landscape of Mainland Southeast Asia

“…This could be responsible for the appearance of a similar Neolithic expression, inclusive of incised and impressed decoration on the ceramics, alongside rivers in MSEA (Higham 2004;Bellwood 2005: 131-134;Rispoli 2007). While there is archaeobotanical evidence for the terra australis 45 dispersal of rice cultivation along coastal lowlands and coastlines in Southeast Asia (Fuller et al 2010;Fuller et al 2011), there is currently a lack of ceramic evidence to support this. On the other hand, particularly if multiple waves of cultigens entered Southeast Asia (Fuller 2011), there may be no reason to expect a direct correspondence between rice and ceramic origins.…”