The impacts of climate change on livestock and livestock systems in developing countries: A review of what we know and what we need to know

Abstract

Despite the importance of livestock to poor people and the magnitude of the changes that are likely to befall livestock systems, the intersection of climate change and livestock in developing countries is a relatively neglected research area. Little is known about the interactions of climate and increasing climate variability with other drivers of change in livestock systems and in broader development trends. In many places in the tropics and subtropics, livestock systems are changing rapidly, and the spatial heterogeneity of household response to change may be very large. While opportunities may exist for some households to take advantage of more conducive rangeland and cropping conditions, for example, the changes projected will pose serious problems for many other households. We briefly review the literature on climate change impacts on livestock and livestock systems in developing countries, and identify some key knowledge and data gaps. We also list some of the broad researchable issues associated with how smallholders and pastoralists might respond to climate change. The agendas of research and development organisations may need adjustment if the needs of vulnerable livestock keepers in the coming decades are to be met effectively.

Introduction

Livestock systems in developing countries are changing rapidly in response to a variety of drivers. Globally, human population is expected to increase from around 6.5 billion today to 9.2 billion by 2050. More than 1 billion of this increase will occur in Africa. Rapid urbanisation is expected to continue in developing countries, and the global demand for livestock products will continue to increase significantly in the coming decades (Delgado et al., 1999). The potential impact of these drivers of change on livestock systems and the resource-poor people who depend on them for their livelihoods is considerable. These impacts will be influenced by both supply-side shifts in natural resource use as well as market-led demand changes. Given the complexity of livestock (and in most cases crop–livestock) systems in developing countries, a mix of technological, policy and institutional innovations will be required. On the technology side, improvements will be linked to a combination of feed and nutrition, genetics and breeding, health and environmental management options, with different combinations appropriate to different systems.

At the same time, the climate is changing. Significant changes in physical and biological systems have already occurred on all continents and in most oceans, and most of these changes are in the direction expected with warming temperature (Rosenzweig et al., 2008). For the future, there is considerable uncertainty, but recent “best estimates” of temperature increases from the IPCC in the Fourth Assessment Report (AR4) are in the range 1.8–4 °C in 2090–2099 relative to 1980–1999, depending on the scenario of future greenhouse-gas emissions that is used to drive the climate models (IPCC, 2007). The impacts of temperature increases at even the lower end of this range will be far-reaching. At the lower end of the range of temperature rise (1–3 °C), global food production might actually increase but above this range would probably decrease (IPCC, 2007). However, broad trends will be overshadowed by local differences, as the impacts of climate change are likely to be highly spatially variable. Climate change will alter the regional distribution of hungry people, with particularly large negative effects in sub-Saharan Africa. Smallholder and subsistence farmers, pastoralists and artisanal fisherfolk will suffer complex, localised impacts of climate change, due both to constrained adaptive capacity in many places and to the additional impacts of other climate-related processes such as snow-pack decrease, particularly in the Indo-Gangetic Plain, and sea-level rise (IPCC, 2007). Furthermore, changes in the frequency and severity of extreme climate events will have significant consequences for food production and food security; it is not only projected mean climate change that will have an impact. Increasing frequencies of heat stress, drought and flooding events are estimated to be likely, even though they cannot be modelled in any satisfactory way with current levels of understanding of climate systems, but these will have adverse effects on crop and livestock productivity over and above the impacts due to changes in mean variables alone (IPCC, 2007).

Of the planet’s 1.3 billion poor people, at least 90% of them are located in Asia and sub-Saharan Africa, and climate change will have major impacts on the more than 600 million people who depend on livestock for their livelihoods (Thornton et al., 2002). These impacts will include changes in the productivity of rain-fed crops and forage, reduced water availability and more widespread water shortages, and changing severity and distribution of important human, livestock and crop diseases. Major changes can thus be anticipated in livestock systems, related to livestock species mixes, crops grown, and feed resources and feeding strategies, for example.

The challenges for development are already considerable, and there is now general concern that climate change and increasing climate variability will compound these. However, there is only limited knowledge about the interactions of climate with other drivers of change in agricultural systems and on broader development trends. Such work is increasingly important for evaluating how farming systems may evolve in the future. Part of this work involves trying to understand the likely impacts of climate change on vulnerable people through its effects in and on other sectors. These include impacts on water resources and other ecosystems goods and services, and human health and nutrition, for example. Enhanced understanding is needed of the likely impacts of climate change on the vulnerability of the resource-poor, so that resilience to current climate variability as well as to the risks associated with longer-term climate change can be gauged, and appropriate actions set in place to increase or restore resilience where this is threatened. (The long term here refers to the next three to five decades, while the short term refers to 3–5 years into the future.)

In this paper, we briefly review some elements of the complex relationship between livestock and climate change in developing countries. Livestock globally play a considerable role in climate change, in terms of their contribution to greenhouse-gas emissions. This has been reviewed and extensively discussed by Steinfeld et al. (2006), and is not dealt with here. Section 2 provides a brief overview of a classification of livestock systems in developing countries, which is used as a framework for the review. Section 3 reviews the literature on what is known concerning the impacts of climate change on livestock. Many of the relationships are two-way (for example, livestock have obvious impacts on water resources and biodiversity, as well as these things being affected by climate change and having impacts on livestock), but that is not the focus here. Some of the livestock-related responses to climate change are considered in Section 4, in terms of possible researchable issues related to adapting to climate change and to mitigating the livestock-related impacts on climate change. Some final remarks are made in Section 5.