The effect of climate change on ruminant livestock population dynamics in Ethiopia

Kefyalew Alemayehu and Tegegn Fantahun*

Bahir Dar university, college of Agriculture and Environmental Sciences, Department of Animal Production and Technology,
PO Box 2145, Bahir Dar, Ethiopia.
Kefyale@gmail.com
* Mizan-Tepi University, College of Agriculture and Natural Resources, Department of Animal Sciences, PO Box 260, Mizan-Teferi, Ethiopia.

Abstract

Climate change   affects the livestock population dynamics. The objective of this paper was therefore to quantify the effect of climate change on ruminant livestock population dynamics in Ethiopia. For these, the climate and ruminant livestock data were collected from literature reviews and pertinent organizations and   analyzed using SPSS 16.

Mean annual rainfall shows large spatial and temporal variation.  Data analyzed in selected stations indicated that temperature has been increasing by 0.37⁰C every ten years. Climate change projection models also indicated that the mean annual temperature in Ethiopia expected to increase from 0.9 -1.1°C by 2030, 1.7 - 2.1°C by 2050 and 2.7-3.4°C by 2080. The ruminant livestock population in Ethiopia show increasing trend. However, climate change has a negative impact on the population dynamics. In southern Ethiopia, droughts in the 1980s and 1990s caused 49% herd losses under the farmers’ condition and 57% of the cattle mortality under ranch management. As a whole except goats, other ruminant population dynamics were negatively affected by both temperature and rainfall distribution. Therefore, biodiversity conservation in general, reforestation and sustainable utilization of natural resources in particular will enable to tackle climate change and reduction in population dynamics of livestock.

Key words: climate change, Ethiopia, population dynamics, ruminants

Introduction

Livestock systems in developing countries are characterized by rapid change, driven by factors such as population growth, increases in the demand for livestock products as incomes rise, and urbanization (Delgado et al 1999; Thornton et al 2007). Livestock currently contribute about 30 percent of agricultural gross domestic product in developing countries, with a projected increase to about 40 percent by 2030 (FAO 2010) and is becoming the fastest-growing sub-sector of agriculture (Delgado 2005; FAO 2009). Livestock are an important component of nearly all farming systems in Ethiopia and provide draught power, milk, meat, manure, hides, skins and other products (Funk et al 2012). Currently, the population of livestock found in Ethiopia is estimated to be 53.4 million cattle, 25.5 million sheep and 22.78 million goats (CSA 2011).  

Ethiopia has a diversified climate ranging from semi-arid desert type in the lowlands to humid and warm (temperate) type (NMSA 2001). The size and diversity of major agro-ecological zones render it suitable for the support of large numbers and classes of livestock (Funk et al 2012).  However, the country has suffered from climatic variability and extremes (NMA 2007; Alebachew and Woldeamlak 2011). Climate related hazards in Ethiopia include drought, floods, heavy rains, strong winds, frost, heat waves (high temperatures) and lightning (NMA 2007). Consequence of the long-term climate related to changes in precipitation patterns, rainfall variability, and temperature has   increased the frequency of droughts and floods (NMA 2007; World Bank 2010).  Climate change influences are more severely felt by poor people who rely heavily on the natural resource base for their livelihoods (IPCC 2007; IFAD 2009). Of course, pastoral communities are the most vulnerable communities (Lautze et al 2003; IFAD 2009). It has been suggested that Ethiopia might see greater climate variability and extreme events in coming decades (IPCC 2007; NMA 2007).  

Climate change is also affecting the dynamics of livestock sector (Hoffmann 2010; Thornton and Gerber 2010). Studies had reported that there are correlations between rainfall variability and livestock population dynamics (Solomon 2001; Kgosikoma 2006; Abdeta 2011). Rainfall variability greatly influenced herd dynamics in terms of herd die-offs and lower birth rates, which also considerably affected milk production for household consumption (Solomon 2001; Abdeta 2011).  Indeed, the effect of climate changes on ruminant livestock population dynamics were not fully investigated and analyzed in Ethiopia. Consequently, awareness creations on effects of climate change on ruminant livestock population dynamics can provide appropriate management practices which enable to cope with the problems.  

The general objective of the paper was therefore, to analyze the climate and ruminant livestock data and quantify the effect of climate change on ruminant livestock population dynamics in Ethiopia

The specific objectives of this paper were:-

• To overview the  trends of climate change and ruminant livestock population dynamics  in Ethiopia
• To  correlate and quantify  the effects of climate  change  and ruminant livestock population dynamics  in Ethiopia

Climate change and livestock population dynamics

Methodological approaches  

To quantify the effect of climate change on ruminant livestock dynamics livestock, climate data were gathered from literature reviews and   the National Meteorological Services Authority (NMSA).  The ruminant livestock data were collected from literature reviews released by the Central Statistical Agency of Ethiopia (CSA), the database of Food and Agriculture Organization of the United Nations (FAO) and National Meteorological Services Authority (NMSA). Trends of both for climate and livestock data were analyzed using regression analyses and the effect of climate change on ruminant livestock dynamics were quantified using correlation analyses. In both cases, SPSS 16 (2007) was used for analyses. 

Climate variability and trends  

Climate is a key natural resource which influences food production, water and energy availability. It sets the stage for the establishment of habitats, affects the pace of primary productivity, and influences species density and distribution. Temperature, wind and rain all affect the biophysical environment. Climate is often described by the statistical interpretation of precipitation and temperature data recorded over a long period of time for a given region or location (NMA 2007). 

Rainfall variability and trends 

In Ethiopia, rainfall during a year occurs in different seasons. Unlike most of the tropics where two seasons are common (one wet season and one dry season), three seasons are known in Ethiopia, namely Bega (dry season) which extends from October-January, Belg (short rain season) which extends from (February-May), and Kiremt (long rain season) which extends from June-September (NMSA 2007). Mean annual rainfall distribution over the country is characterized by large spatial variation which ranges from about 2000 mm over some pocket areas in the southwest to less than 250 mm over the Afar and Ogaden low lands (NMSA 2007). Ethiopia receives most of its rain between March and September. Rains begin in the south and central parts of the country during the Belg season, then progress northward, with central and northern Ethiopia receiving most of their precipitation during the Kiremt (winter) season. Rainfall totals of more than 500 mm during these rainy seasons typi­cally provide enough water for viable farming and pastoral pursuits (Funk et al 2012). Baseline climate information was developed using historical data of temperature and precipitation from 1961- 1990 for selected stations. Mean annual rainfall shows large spatial and temporal variation (Figure1). The country has experienced both dry and wet years over the last 50 years. Years like 1965 and 1984 were extremely dry while 1961, 1964, 1967, 1977 and 1996 were very wet years. NMSA (2001) has confirmed that there is a link in ElNino and LaNina Phenomena with Ethiopian rainfall (NMSA 2001).

Figure 1. Year to year variability of annual rainfall over Ethiopia expressed in normalized deviation adapted from (NMSA 2001).

From the analyses of 1971- 2000 data of temperature and precipitation in 42 selected stations, it was possible also to see the year-to-year variation in rainfall over the country (NMA, 2007) (Figure 2).  It was also revealed  that between the mid-1970s and late 2000s, Belg and Kiremt rainfall, decreased by 15–20 percent across parts of southern, southwestern, and southeastern Ethiopia (Funk et al  2012). As a whole, annual rainfall remained more or less constant when averaged over the whole country, decreased in Northern half of the country and southwestern and in central Ethiopia (NMSA 2001; NMA 2007). The country does not, therefore, face a cata­strophic national failure of rainfall, but rather regional hot spots with a tendency towards more frequent droughts. Although these droughts will tend to affect most pastoralists and agro-pastoralists living in cli­matically marginal areas, improved yields in climatically secure areas could help mitigate the impact of those effects (Funk et al 2012).

Temperature variability and trend 

In Ethiopia, temperatures are very much modified by the varied altitude exist. Mean annual temperature distribution over the country varies from 10^oC over the highlands of northwest, central and southeast to 35^oC over north-eastern lowlands (NMA 2007). The year to year variation of annual minimum temperatures expressed in terms of temperature differences from the mean and averaged over 40 stations. The country has experienced both warm and cool years over the last 55 years from 1971- 2000 for selected stations (Figure 3). Temperature has been increasing about 0.37⁰C every ten years (NMSA 2007).

Figure 3. Year to year variability of annual minimum temperature over Ethiopia expressed in temperature difference, adapted from (NMSA 2007).

The average annual minimum temperature over the country has been increasing by 0.25⁰C every ten years while average annual maximum temperature has been increasing by 0.1⁰C every decade. It is interesting to note that the average annual minimum temperature is increasing faster than the average annual maximum temperature (NMSA 2001) (Figure 4 and 5).

Figure 4. Year to year annual mean maximum temperature variability and trend over Ethiopia, adapted from (NMSA 2001).

Figure 5. Year to year annual mean minimum temperature variability and trend over Ethiopia, adapted from (NMSA 2001).

Projected climate change over Ethiopia 

Climate change is not possible to predict precise future climate conditions, but the scientific consensus is that global land and sea temperatures are warming under the influence of greenhouse gases, and will continue to warm regardless of human intervention for at least the next two decades. On average, global temperatures will likely increase worldwide by 0.2 degrees per decade. There will be fluctuation in precipitation, increase in droughts and floods (IPCC 2007). For the IPCC mid-range emission scenario, the mean annual temperature in Ethiopia expected to increase from 0.9 -1.1°C by 2030, 1.7 - 2.1°C by 2050 and 2.7-3.4°C by 2080 as compared to the 1961-1990 conditions.  Unlike the temperature trends, it is very difficult to detect long-term rainfall trends in Ethiopia, due to the high inter-annual and inter-decadal variability. A small increase in annual precipitation is expected over the country (NMA 2007). 

Trends of ruminant livestock population in Ethiopia  

Many sources profess to provide data on the numbers and distribution of Ethiopian livestock. A major problem is the lack of conformity in these sources which have most often used information gathered in various ways, at various times and using various procedures. The most commonly used sources are the information provided on an annual basis by the Central Statistical Agency of Ethiopia (CSA), the database of Food and Agriculture Organization of the United Nations (FAO) and National Meteorological Services Authority (NMSA). 

Data on number of ruminant livestock in Ethiopia from1981-1997 were adapted from NMSA (2001). In addition, 12 years (1996; 1997; 1998; 1999; 2000; 2001; 2004; 2005; 2006; 2007; 2010 and 2011) date on cattle, sheep and goat were taken from Central Statistical Agency(CSA) of Ethiopia ( Figure 6 and 7).

Figure 6. Trends of ruminant livestock number in Ethiopia from1981-1997 (Analyzed from the data adopted from NMSA 2001).

Figure 7. Trends of ruminant livestock number in Ethiopia from 1996-2011.

Correlation of climate change and ruminant livestock population  

Livestock production both contributes to and is affected by climate change (Hoffmann 2010).

Livestock production systems may be affected in various ways, and changes in productivity are inevitable (Thornton and Gerber 2010; Hoffmann 2010).  Generally, climate change affects the sector directly through temperature increases and shifts in rainfall amounts and patterns and through ecosystem changes, changes in crop yield, quality, and types, alter the distribution of animal diseases, and increased competition for resources indirectly (IPCC 2007; Thornton et al 2007; Hoffmann 2010).  

The IPCC predicts that by 2100 the increase in global average surface temperature may be between 1.8°C and 4.0°C. With increases of 1.5°C to 2.5°C, approximately 20 to 30 per cent of plant and animal species are expected to be at risk of extinction (FAO 2007a) with severe consequences for food security in developing countries (IFAD 2009).  

Studies conducted in Ethiopia showed that climate change have a negative impact on livestock population dynamics. In southern Ethiopia, cattle numbers dropped by 37% after the drought of 1983 to 1985. The herd then quickly grew to about 85% of the previous peak size by 1990. Another crash occurred in the early 1990s with a 42% reduction in cattle numbers, but interestingly the corresponding change in annual rainfall was less apparent in the early 1990s compared to that observed in 1983 to 1985 (Solomon 2001; Solomon and Coppock 2002). In this region, it was shown that cattle population dynamics resembled a “boom and bust” pattern where longer periods of gradual herd growth were punctuated by sharp crashes in 1983 to 1985, 1991 to 1992, and 1998 to 1999 when 37 to 62% of the cattle population perished (Solomon 2001) (Figure 8). Another study in Borana, Ethiopia showed that rainfall variability greatly influenced herd dynamics under the communal and ranch management in terms of herd die-offs and lower birth rates, which also considerably affected milk production for household consumption.  Droughts of the 1980s and 1990s caused 49% herd losses under the communal land use, while 57% of the cattle mortality under ranch management was attributed to droughts of the 1990s (Abdeta 2011). Cattle herd dynamics is strongly determined by rainfall variability in southern Ethiopia (Abdeta and Oba 2007) (Figure 8).

Figure 8. Relationship between inter-annual rainfall variability and cattle herd dynamics, adapted from Abdeta and Oba (2007).

Substantial warming across the entire Ethiopia has exac­erbated the dryness. An important pattern of observed existing rainfall declines coincides with heavily populated areas of the Rift Valley in south-central Ethiopia, and is likely already adversely affecting crop yields and pasture conditions.  Rapid population growth and the expansion of farming and pastoralism under a drier, warmer climate regime could dramatically increase the number of at-risk people in Ethiopia during the next 20 years (Funk et al 2012). 

A correlation analysis was used to quantify impacts of    temperature and rainfall on livestock population dynamics. The   analyses revealed that   sheep (r =0.535, P < 0.05) and cattle (r =0.669, P < 0.001) were negatively affected by climate change. Where as goats were having positive relationship (r = 0.789, p < 0.001) (Table 1 and 2). 

However, there was a significant correlation between ruminant livestock population dynamics and climate variability. As the average maximum temperature steadily increases, the population dynamics ruminant livestock fluctuated after the year 1996. The population of goat shown boom after that year and the population of sheep and cattle shown dramatic increase and revived again   (Table 2 and Figure 9). 

Figure 9.  Trends of ruminant livestock dynamics and climate change

In general, climate change is likely to present significant problems for production systems where resource endowments are poorest and where the ability of livestock keepers to respond and adapt is most limited (FAO 2007b).  The impact of climate change is expected to heighten the vulnerability of livestock systems and reinforce existing factors that are affecting livestock production systems, such as rapid population and economic growth, rising demand for food (including livestock) and products, conflict over scarce resources (land tenure, water, bio-fuels, etc). For rural communities, losing livestock assets could trigger a collapse into chronic poverty and have a lasting effect on livelihoods (IFAD 2009). Rift valley fever, which afflicts people and livestock, is closely related to heavy rainfall events, which are predicted to increase with climate change. An outbreak in 1997 associated with an El Niño event killed up to 80 percent of the livestock in Somalia and northern Kenya (World Bank 2010). Adaptations are perceived as measures to improve livelihoods, the environment and rehabilitation of natural resources. Reforestation, water harvesting, use of irrigation, and improved productivity of crops and livestock are the common adaptation measures perceived by the different communities (World Bank 2010). 

Conclusion

• From the results, it was possible to conclude that climate change affected livestock population dynamics in Ethiopia. It was possible also to see the year-to-year variation in rainfall, annual minimum and maximum temperatures over the country. However, the average annual minimum temperature is increasing faster than the average annual maximum temperature. Years like 1984, 1965 and 1996 were extremely dry and affected negatively the population dynamics of livestock in particular and agriculture in general. Cattle and sheep were more affected by climate change than goats. It was possible also to predict that the mean annual temperature in Ethiopia expected to increase from 0.9 -1.1°C by 2030, 1.7 - 2.1°C by 2050 and 2.7-3.4°C by 2080. Following these predictions, the population dynamics of the livestock expected to be affected as climate change increases. Therefore, biodiversity conservation through sustainable utilization of natural resources and reforestations are mandatory to tackle the holistic effect of climate change and strengthening the green economy that the Ethiopia launched.

References

Abdeta A and Oba  G 2007  Relating long-term rainfall variability to cattle population dynamics in communal rangelands and a government ranch in southern Ethiopia. Agricultural Systems 94,715-725.

Abdeta A  2011  Effects of drought on cattle herd dynamics and its implication on local livelihood systems in Borana, Ethiopia. Food Security Center (FSC) Brief No 1, 1-6.

Alebachew  A and Woldeamlak  B 2011 A Climate Change Country Assessment Report for Ethiopia. Submitted to Forum for Environment. Epsilon International R&D. Addis Ababa, Ethiopia.

Central Statistical Authority (CSA) 2011  Agricultural sample survey 2010-2011. Report on livestock and livestock characteristics, Vol. II. Statistical Bulletin No. 505. Addis Ababa, Ethiopia.  

Delgado  C,  Rosegrant  M, Steinfeld  H, Ehui S  and  Courbois  C 1999 Livestock to 2020: the next food revolution. Food, Agriculture and the Environment. Discussion Paper. 28. IFPRI/FAO/ILRI, Washington, DC, USA.

Delgado  C 2005  Rising demand for meat and milk in developing countries: implications for grasslands based livestock production. In McGilloway, D.A.(ed), Grassland: a global resource. pp. 29-39. Wageningen Academic Publishers, Wageningen, The Netherlands.

FAO  2007a  Adaptation to Climate Change in Agriculture, Forestry, and Fisheries: perspective, framework and priorities. Food and Agriculture Organization of the United Nations, Rome, Italy.

FAO  2007b  Global Plan of Action for Animal Genetic Resources and the Interlaken Declaration. Food and Agriculture Organization of the United Nations, Rome, Italy.

FAO 2009  Preparation of national strategies and action plans for animal genetic resources. Animal Production and Health Guidelines, No. 2. Food and Agriculture Organization of the United Nations, Rome, Italy.

FAO  2010  Breeding strategies for sustainable management of animal genetic resources. Animal Production and Health Guidelines, No. 3. Food and Agriculture Organization of the United Nations, Rome, Italy.

Funk C, Rowland J, Eilerts G, Kebebe E, Biru N, White L and Galu G 2012  A climate trend analysis of Ethiopia. Climate change adaptation series. U.S. Geological Survey. Famine Early Warning Systems Network-Informing (FEWSNET). Fact sheet  3053. 6p.

Hoffmann I 2010 Climate change and the characterization, breeding and conservation of animal genetic resources.  Animal Genetics 41(Suppl.1), 32-46.

IFAD 2009  Livestock and climate change. Livestock Thematic Papers Tools for project design. International Fund for Agricultural Development, Rome, Italy.

Intergovernmental Panel on Climate Change (IPCC) 2007  Climate change 2007: impacts, adaptation and vulnerability. Summary for policy makers. (Available at http://www.ipcc.cg/SPM13apr07.pdf 

Kgosikoma  O E 2006 Effects of climate variability on livestock population dynamics and community drought management in Kgalagadi, Botswana M.Sc.thesis, Norwegian University of Life Sciences, Norway. 57p.

Lautze S, Yacob A, Raven-Roberts A, Young H, Girma K and  Leaning J 2003 Risk and vulnerability in Ethiopia: learning from the past, responding to the present, preparing for the future. A report for the U.S. Agency for International Development. 249 p.

National Meteorological Services Agency (NMSA) 2001  Initial national communication of Ethiopia to the United Nations Framework Convention on Climate Change (UNFCCC), edited by Abebe, T.  Addis Ababa, Ethiopia.

National Meteorological Agency (NMA) 2007 Climate change national adaptation program of action of Ethiopia, edited by Abebe, T.  Addis Ababa, Ethiopia.

Solomon D  2001 Cattle population dynamics in the southern Ethiopian rangelands. Research brief -01-02. The GL-CRSP Pastoral Risk Management Project (PARIMA). Utah State University, Logan, Utah, USA.

Solomon D and Coppock D L 2002 Cattle population dynamics in the southern Ethiopian rangelands, 1980–97. Journal of Range Management 55(5), 439-451.

Statistical Package for Social Sciences (SPSS) 2007  SPSS Statistical 16.0 .USA.

Thornton  P, Herrero M, Freeman A, Mwai O, Rege  E, Jones P and McDermott J 2007 Vulnerability, climate change and livestock – research opportunities and challenges for poverty alleviation. International Livestock Research Institute (ILRI), Nairobi, Kenya. SAT eJournal Vol. IV, Issue 1.

Thornton PK  & Gerber P J 2010  Climate change and the growth of the livestock sector in developing countries. Mitigation Adaptation Strategy of Glob Change 15,169-184.

World Bank  2010  The social dimensions of adaptation to climate change in Ethiopia. Development and climate change discussion papers No. 14. Washington, DC. USA.

Received 14 September 2012; Accepted 19 September 2012; Published 1 October 2012

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