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Part 2: East Africa appendix 1 - Climate data analysis

Rainfall in Turkana and Karamoja is, and has long been, very low and highly variable from year to year and place to place. There is no month in either territory when rainfall exceeds evaporation potential. Its scarcity and variability are the reasons why pastoralism is the dominant mode of production here and it is why agreements to share access to grazing and water between different territories and in safety are so important. The extensive grazing system involves mobility across often large distances a way of production that requires security arrangements to be largely maintained by herders themselves.

In the border zone, herds and families are sometimes scattered across open rangeland and sometimes gathered close around dry season waterpoints and in pasture reserves. Both the importance of mobility and the difficulty of securing people and herds explain why the rules of cooperation rely on sophisticated and historically evolved cultural, technical, and legal (customary law) norms and practices. The current generosity of Matheniko and Jie towards Turkana bringing herds out of the much dryer land of Turkana West into wetter Karamoja is a contemporary manifestation of a very old practice. It demonstrates how economic and social relations have a basis in climate and suggests that strategies for adapting to climate change will draw on these relations. In this research it was Turkana who talked most about the changing climate as their territory is significantly drier than Karamoja, and they must move across an international border to maintain their livelihood, where their citizenship of another state puts them at a disadvantage.

Men and women elders in Turkana said that the six months of wet season and six of dry that they remember has changed to more patchy rain at any time between the months of April and November:

It used to rain, six months in the dry season and six months in the wet season and when it rained, we got wild fruits from this and that tree. When it rained, we could plough. We got cheese and honey. And the cheese would let us survive the dry season.6

Their descriptions of the changing climate are in line with meteorological studies. Extreme drought events in Turkana have increased in recent decades, with only 29 per cent of drought occurrences falling in the two decades between 1950 and 1970 in contrast to 48 per cent of drought years occurring during the last two decades between 1990 and 2012 (Opiyo et al., 2013), yet rainfall is slightly higher than in the past (Opiyo, 2014). Turkana lies in a long valley that runs south-east to north-west and separates the Ethiopian from the Kenya highlands to the north and south respectively.

An investigation by climate scientists into the low-level jet stream that blows through this depression and is associated with the area’s aridity suggests that large-scale climate dynamics, including rising surface temperatures, has weakened the jet over the last 30–40 years. A weaker wind is associated with higher rainfall in the valley (King et al., 2021).

Among pastoralists these changes in temperature and rainfall distribution are understood to have come about because of changes in human and non-human activity including the ways in which rituals are maintained, land is looked after, and society behaves. For instance, one young herder noted that ‘when the conflict came, the drought got worse’. In Komio people spoke of a plethora of seers (ngimurok) emerging where there had once been few, all offering conflicting advice and instructions. One elder commented that all these competing ngimurok ‘mess up each other’s work’ on rain. ‘That is why now we have all this… That is why God is distant from us and that is why the sun is burning us. Ehh.’ The herder expressed a sense of loss which we heard quite often. It was one way in which climate change was affecting conflict – not by causing it, but by making it seem that old institutions had lost their way. It is these same institutions that declare war and peace and that arbitrate over justice in the traditional realm, so when their power is manifestly failing, their function in peace is undermined.

Karamoja is at a higher elevation than Turkana and has overall higher rainfall. Between 1979 and 2009 there was a progressive rise in temperature, with mean temperature across the sub-region increasing by 1.3°C and maximum temperatures by 1.6°C (Chaplin et al., 2017). Rainfall increased over the same period, but the increase is small and possibility not significant. Year-to-year rainfall variability increased between 1981 and 2015 (ibid). The very high quantitative variability is shown in the graph below for Karamoja. Variability within each month has increased and the overall season of rains has lengthened.

Rainfall, and therefore pasture and standing water variability is the reason why community agreements to share access to grazing and water are particularly important and why the cultural basis for them is so profound. The deep economic and social relations that span the Kenya–Uganda border in this region are rooted in climate and land, as much as in a shared heritage. Extending the findings of our ethnographic research across the geography, a climate analysis using satellite data adds a spatial and temporal grounding to the social and political analysis. In a first round, a team at Satellite Catapult generated maps of vegetation indices and surface soil moisture covering the study area and a period of 14 months. In a second round they extended the analysis back to 2017, showing change over a longer period.

Figure 6: Average monthly rainfall estimates for Karamoja, 1981–2015

Error bars represent standard deviation in average monthly rainfall estimates.

A bar and line graph showing average monthly rainfall estimates for Karamoja, 1981–2015

Analysis of satellite data recording vegetation greenness allows a view of changing patterns of pasture over time and space, in a geospatial register. Vegetation cover in the study area shifts from one part of the territory to another, except along some permanent watercourses. Figure 7 shows the vegetation at three sites, Kobebe in the south of the study area, Nakapelimoru, 45 kilometres to the north-east and Kalapata 120 kilometres to the north, using the Normalised Difference Vegetation Index (NDVI).7 Each colour shows the ‘greenness’ of the vegetation for a different year between 2017 and 2022. The individual graphs demonstrate the high degree of variability in the same site from year to year. Comparison of the three graphs demonstrates the variability between the sites in any one year. While there is a clear dry and rainy season (dryer from October to March and wetter from April to September) the graphs demonstrate how pastoralists accessing the pasture must make decisions to move into an area or away from it at different times each year.

Figure 8 shows how the greenness changed across the whole study area (100km x 200km) month by month between November 2021 and December 2022. It indicates the extremely large variation across the territory and month by month.

In Figure 8, the mosaic can be seen across the whole study area (approximately 20,000 km2 ) over a period of 14 months. It demonstrates why the changing mosaic of pastureland is not subdivided to different owners, but shared between large groups who negotiate access. In Figure 9, homing in on a 5km radius of Kobebe dam at the centre, the variation in pasture levels across the years is shown in a comparison of cover between November 2021 and November 2022. It suggests why pastoralists are not transhumant in the sense of having fixed summer and winter grazing areas. The decision as to where to move is based on where there is grass, and where an agreement can be made to graze. The satellite coverage for the years 2017 to 2022 shown in the graph demonstrates the variability over a longer period, indicating further the complexity of movement patterns needed in different years.

The mosaic pattern of pasture helps us see the events at Kobebe described in this paper in their geographical context. Pastoralists had gathered by the dam in large numbers because the drought in other areas was intense, an unusually extreme series of annual dry seasons particularly on the Turkana side. The response of the military authorities to the presence of so many herders in one place, many of whom were carrying guns, was therefore not surprising.

Figure 7: NDVI for Kobebe, Nakapelimoru and Kalapata

 Three line graphs showing the Normalised Difference Vegetation Index for Kobebe, Nakapelimoru and Kalapata

Figure 8: NDVI for the study area November 2021 to December 2022

Modified Copernicus Sentinel data 2023 Sentinel Hub. Satellite imagery and analysis by Satellite Catapult.

A series of images showing vegetation coverage in the study area from November 2021 to December 2022

Figure 9: NDVI for Kobebe (5km radius) November 2021 and November 2022

Twi images showing the reduction in vegetation cover from November 2021 to November 2022

Pastoralist mobility and capability for making natural resource sharing agreements is an adaptive response to low and variable rainfall patterns. Mobility takes a variety of forms, including moving to more distant pastures, to protected dry season grazing reserves, negotiating with neighbouring pastoralists for access to their reserves, distributing small stock among extended family, while other techniques include exchanging grain for stock with farmers, drying milk, and collecting bush foods. Different ways of dealing with the new rainfall patterns have included increasing the number of times that a herd moves, splitting the herd into more smaller sections and scattering them to different locations or keeping a smaller herd and relying on other sources of livelihood, including cropping and/or food aid. Recent adaptations have also added to the repertoire of dry season management, including selling animals to buy imported food in markets (Derbyshire et al., 2021). People’s responses to climate change are entwined with their response to many other changes. Their repertoires have been influenced by new infrastructure, livelihood opportunities, settlements, and markets. Pastoralists move, for instance, to take advantage of price differentials between markets on different sides of the international border.

Herders, women, and elders pointed to the ways in which the ever more uncertain climate had strengthened the need for security and agreement with neighbours. These agreements must be honoured even if a government intervenes to undermine them. One Jie kraal leader reminded us that in 2016 the Uganda government asked Turkana to leave Karamoja. But the Jie moved their herds out of Kotido into neighbouring Abim and Lango and invited Turkana to bring in their herds to graze on the pastures they had left. In 2022–23 the communities made similar agreements. A changing climate only increases the need for a reliable system of sharing, in which security of people, herds and agreements is central, and in which not only laws and practices, but also beliefs, are essential elements.

Footnotes

6 Interestingly, an elder recorded by a team of anthropologists in Turkana East said almost the same thing, see Derbyshire et al. (2021).

7 NDVI is an index for quantifying green vegetation. It normalizes green leaf scattering in Near Infra-red wavelengths with chlorophyll absorption in red wavelengths. The value range of the NDVI is -1 to 1. Negative values of NDVI (values approaching -1) correspond to water. Values close to zero (-0.1 to 0.1) generally correspond to barren areas of rock, sand, or snow. Low, positive values represent shrub and grassland (approximately 0.2 to 0.4). It is a good proxy for live green vegetation. Source: Sentinel Hub (2023).