Climate Change, Land Use and Agriculture

Agriculture is a very important aspect of many people’s livelihoods in Africa, and my previous blog explored the impacts of climate change on agriculture and the vulnerability of Africa’s population to these impacts. Addressing the impacts is definitely an important aspect to maintain people’s livelihoods, but now I am interested in exploring the future of Africa’s agricultural sector in terms of land use change. How does climate change influence the way land is used? What are the drivers for land use change and to what type of land use is being used? What are the implications on hydrological processes and water availability if land is increasingly being used for agriculture? These are some questions that I would like to explore.

Land use change and climate change are both factors that contributes to global environmental change, however, both of these factors affect each other (Dale, 1997). Firstly, land use change and patterns influences climate change due to changes in the atmospheric flux of CO2 and secondly, land use can be altered by climate change due to unfavourable conditions for certain human uses and activities. Hence, land use can be seen as a causal factor to climate change, but it can also be seen as an adaptive measure to climate change (Dale, 1997).

The World Bank estimates that as of 2013, approximately 43.86% of land in Sub-Saharan Africa is used for agricultural purposes. Agricultural transformation in Africa has an important role for economic transformation and in recent years Africa has seen large increases in investment by governments in this sector. Africa Agriculture Status Report (2016) explains that Africa’s agricultural sector is driving changes in Africa’s economic prosperity, and hence these socio-economic drivers will continue intensify the changes in land use for agricultural purposes. I will not go into detail about the history and development of Africa’s agricultural sector in this blog, but instead, I would like to highlight another an alternative driver of land use change in Africa. 

Ahmed et al. (2016) highlights the importance of climate change as another important factor in shaping agricultural land use. As previously mentioned, Dale (1997) explains that there is a dual relationship between land use change and climate change, and Ahmed et al. (2016) models both socio-economic and climate change factors as the drivers of Africa’s agricultural future. The study found that a reduction in crop yields caused by climate change, alongside an increasing demand for food in the future will inevitably result in an increase in land used for agriculture in West Africa to meet these demands. The eastern region of West Africa will experience a decline in both forests and grassland covers to cropland covers, whereas the western region will experience a larger decline in forest cover overall. The study projected that for Nigeria, average cropland cover will increase from 39.4 to 84.5% as a result of climate change, and an increase in crop cover of 37.3-40.9% is likely to occur along the Gulf of Guinea. These results show that under a purely climate change scenario, land use change will move from natural vegetation to crop cover, however, these results were determined without accounting for the adaptive capacities of farmers and communities. This study does mention these limitations and it was useful in attempting to show how much land will change as a result of climate change, but we cannot simply ignore the combination of other socio-economic factors and adaptive strategies of farmers to climate change scenarios, which this study concludes as the largest factor in driving land use change.

Changing land from one land cover to another is likely to have large implications on water resources, and especially in arid and semi-arid regions of Sub-Saharan Africa. Evaporation and runoff components of a catchment are usually influenced the most by land-use change, which in turn influences runoff and recharge rates into aquifers. A case study in southwest Niger shows that the water table has been increasing for many decades, despite there being a decline of 23% of the monsoonal rainfall seasons (Favreau et al., 2009). This was because land clearing of natural savannah to be used for millet crops had significantly increased surface runoff; the study modelled runoff and concluded that runoff had increased by threefold the normal rate, irrespective of climate conditions. Higher rates of runoff leads to higher recharge rates, the study found that recharge rates increased to 7mm/area after land was cleared compared to a rate of 2mm/area before land was cleared for crops. Not only does land use change influence rates of recharge and runoff, it also affects the quality of groundwater resources whereby there was a rising trend in nitrate concentrations by 4% (Favreau et al., 2009). Hence, when decisions are made to convert natural land to agricultural land crops, the impacts of this change needs to be carefully considered, especially because of the impacts of water resources and if these impacts will infringe upon the sustainability of that resource.

Concluding thoughts:

Land use change, climate change and water resources has more complicated drivers, interactions and consequences than has been explored in this blog. In this blog, I wanted to focus on the climate perspective of land use change and the consequences of this change, but despite making attempts to just focus on this perspective, I could not ignore the socio-economic drivers that influences land use change. Indeed, when analysing the drivers and consequences of land use change, one should look at both the human and climate factors of this change. Undoubtedly, land use change will have consequences on water resources such as groundwater levels and the quality of water resources and so farmers will need to carefully consider why they are changing land-use for agricultural purposes and if it will outweigh the consequences of water resources.