DUE to human energy-driven consumption of fossil fuels and anthropogenic activities, the global carbon emission rate is higher than at any point in the history of mankind, disrupting the global carbon cycle and contributing as a major cause of global warming, with air and ocean temperatures rising dangerously over the past century.
With more frequent extreme weather events, including increased temperatures, climate change presents both direct and indirect challenges for livestock health and production.
The health of livestock is affected by heat stress, metabolic disorder, oxidative stress and immune suppression, resulting in an increased propensity for disease incidence and death.
The indirect health effects for livestock relate to the multiplication and distribution of parasites, reproduction, virulence and transmission of infectious pathogens and/or their vectors. Managing the growing crossbreeding livestock industry in Zimbabwe is also at the coalface of the emerging impacts of climate change, with unknown consequences for the incidence of emerging and re-emerging diseases.
Alongside agriculture, the livestock sub-sector in Zimbabwe is an important and integral part of the socio-economic sector with beef, dairy, small ruminants, pigs, poultry, apiculture and aquaculture together with other small and emerging stock making up the livestock industry, which contributes about 19 percent to the agricultural GDP and is a major part of food security for Zimbabwe.
The livestock herd size has declined nationally by about 20 percent for beef, over 83 percent for dairy, as well as 26 and 25 percent for pigs and small ruminants respectively.
The productivity of smallholder cattle herds remains very low in Zimbabwe, with average calving rates of about 45 percent against a potential of 60 percent, and off-take rates of about six percent against a recommended rate of 20 percent.
Thus, the successful transformation of the smallholder livestock sub-sector into a fully commercialised system with increased output and productivity, to meet the increased demand for animal protein and surplus for export, requires a more appropriate policy environment which should take climate change into consideration.
Climate change is the complex and multi-dimensional change in global and regional climate patterns, which pose significant risks for human and natural systems. The most complex multi-factor global challenge which jeopardises human and natural system, similarly threatens livestock productive performance and production.
The Intergovernmental Panel on Climate Change (IPCC) projected that global mean surface temperature will increase by about 3.7°C – likely in the range of 2.6°C-4.8°C – by 2100.
The changes to the frequency, intensity and duration of extreme weather events are already evident climate changes will directly and indirectly impact the health and production aspects of livestock which include a complex set of interacting biophysical consideration that influence growth and performance, meat and milk yield (egg yield) as well as quality, weight and quantity, reproductive performance, metabolic, health status and carcass traits.
The direct health impact for livestock due to climate change are temperature-related illness, changes in metabolic functions and morbidity due to extreme weather events.
This, coupled with the indirect impact on livestock health, make livestock in general vulnerable to unprecedented diseases, some of which are hard to predict.
A vast number of studies on livestock and climate change have clearly demonstrated impaired reproductive health and the adverse effects on the animal immune system that can be compromised with the distribution, growth and incidence of diseases.
Heat load and subsequent heat stress (HS) alone can result in economic losses and health management costs. These economic losses in the US amount to over US$900 million a year for the dairy industry and over US$300 million a year for beef and swine industry.
The United Nations Department for Economic and Social Affairs (UNDESA) projects the world population to grow by 33 percent from 7,2 to 9,6 billion by 2050.
Hence, it is estimated that up to 70 percent increases in agricultural productivity will be required to meet the future demand and food security.
For example, to meet the predicted global demand for milk and meat for 2050 requires an estimated production of 1 077 tonnes milk up from 664 million tonnes produced during 2006 while in the same way, meat production will have to double from 258 to 455 million tonnes in 2050.
Global climate change represents a major challenge to achieving the predicted productivity growth required to meet these future demands.
Additionally, climate change in the agricultural sector impacts directly on the livelihoods of the poorest populations in the world, which is currently estimated to employ 1,1 billion people.
Any impact on this sector directly affects the most vulnerable populations.
Climate change is expected to have adverse effects on a variety of socio-economic sectors that are closely linked to the Millennium Development Goals (MDGs). Climate-induced water stress threatens to decrease the quantity and quality of drinking water in rural and urban areas, reduce the run-off necessary to sustain the country’s hydro-electric power supply and contribute to declining agricultural productivity.
The United Nations Framework Convention on Climate Change (UNFCCC), recognises that Africa is one of the most vulnerable regions in the world due to widespread poverty, limited coping capacity and its highly variable climate.
Zimbabwe, with a unique geographical location, is classified as a sub-tropical area.
It is particularly vulnerable due to its heavy dependence on rain-fed agriculture and climate-sensitive resources. Agriculture’s sensitivity to climate-induced water stress is likely to intensify the existing problems of declining agricultural outputs, declining economic productivity, poverty and food insecurity, with smallholder farmers and livestock producers particularly affected.
Extreme weather events, notably drought, flood and tropical storms, are also likely to threaten development gains across a variety of sectors and intensify existing natural hazard burdens for at-risk populations in both rural and urban areas.
In Zimbabwe, livestock and agriculture resources are considered an important part of food security for the nation.
This sector contributes to animal protein production, predominantly milk, meat and eggs and their by-products.
Changing climate is considered a threat to livestock production because of the impact on the quality of concentrate and roughage feeds, availability of clean drinking water, meat and milk production, disease prevalence and incidence, reproduction as well as biodiversity. Globally, it is estimated that livestock disease reduces productivity by 25 percent, with the heaviest burden falling on the poor.
Consequently, climate change presents risks to lives as well as livelihoods at the individual level and to the economy and infrastructure at the regional and national levels. Climate change adaptation is, therefore, a principal development challenge in Zimbabwe.
Dr Tony Monda BSc, DVM, DPVM, is currently conducting veterinary epidemiology, and agro-economic research in Zimbabwe. For views and comments, email: tonym.MONDA@gmail.com