Climate Change: A Real Danger to Human and Animal Survival

Abstract

Some countries in Southern Africa where hit by either a storm or cyclone or both in 2019 alone manifesting a changing climate. Infrastructure and cropping land was destroyed, both animal and human lives were lost due to the flooding events. Drought is a common phenomenon in this region, often occurring once in three years. This has affected food, feed and nutritional security of both humans and livestock. Saline soils unsuitable for agriculture, other animal and plant life are expanding fast due to insufficient precipitation. Soil degradation is on the rise, leaving soils with poor water holding capacity to support sustainable agriculture. Climate change is changing the environment and new pests and diseases for both crops and livestock are emerging. World governments, industries and general populace should find better ways of reducing air pollution by greenhouse gases which have a net effect of damaging the ozone layer and increasing atmospheric temperatures. At the same time, plant and animal breeding should aim at improving crop cultivars and animal breeds that resist to the constraints such as drought and heat stress brought by climate change. The human population is increasing at an alarming rate and need both food and nutritional security.

1. Introduction

The whole earth’s climate systems are changing in the atmosphere, the oceans, ice floes and on the land. Some of the changes such as increases in temperature, rise in carbon dioxide, drought and floods are already in motion now, while others like continued sea level rise are already irreversible for centuries to millennia ahead. The impact of climate change makes lives of both humans, animals, and plants unbearable. The main drivers of climate change are attributed on human activities in the following economic sectors, transport (road, air, rail, and sea), energy industries (electricity, heat, power) and agriculture [1]. Agriculture alone contributes to almost 32% of all greenhouse gases that contribute to climate change. Human population is increasing in the world and assuring an increase in demand for food, shelter, water, and clothing.

Africa is one of the world’s most vulnerable regions due to the fragility of its economies. It is now evident that global warming in the 21st century will be more intense in Africa compared to the rest of the world [1, 2], Global warming and increased climate variability will severely affect crop and livestock production systems in Africa. Some of the harsh realities of climate change has been felt in Southern Africa in recent years but the worst scenarios of Storm Desmond (January 23, 2019, in central Mozambique), Cyclone Idai (March 14, 2019, in central Mozambique, Zimbabwe, Malawi and northern Madagascar) (Cyclone Idai: Wikipedia) and cyclone Kenneth (April 25, 2019). A total of 100,000 homes were destroyed and more than 1000 people were killed during the cyclones and storm. Figure 1. shows the areas that were affected by cyclone Idai in southern Africa while Figure 2. shows some of the damage done in Mozambique.

Figure 1.

Areas in southern Africa which were affected by cyclone Idai in march 2019, destroying infrastructure and crops as well as killing people and animals (source: Cyclone Idai: Wikipedia).

Figure 2.

Flooded villages and destroyed crop lands in Mozambique in 2019 (source: Cyclone Idai: Wikipedia).

Villages, towns, infrastructure, cropped land were destroyed, and livestock died during the cyclone events. One in every five years, agricultural and ecological drought often affects most countries in southern Africa, sometimes leading to 100% crop failure depending on timing, intensity, and severity. Definition of drought varies with for different water users. Meteorological, Hydrological and Agricultural drought is a prolonged period with shortage of precipitation/below average precipitation, surface water or soil moisture. Climate change effects develop slow over time and their impact underestimated—negative impact on vegetation, animals, and people. Livestock and wild animals also suffer from crop and veld failure. The natural production of water (water cycle) is intensified by climate change and brings intense rainfall and associated flooding and intense drought in some regions. The rainfall patterns and distribution are affected. Significant economic (loss of employment, decreased agricultural and industrial production) and social disasters, such as famine, forced migration, and conflict over few remaining resources, health related- lack of water, poor nutrition and famine are some of the negative effects of drought.

Climate change causes warming up of the earth resulting in severe heat waves in some regions. Hotter days by 6 to 15°C are expected in some countries while other will suffer colder days. All the changes in temperature and environment give rise to new pests and diseases for both humans and animals. Serious crop and animal yield losses to emerging pests and diseases will lead to starving populations.

Climate change affects prediction of the future and is an indication that the past is over. It is still difficult to assess the extent and nature of such changes in the future.

2. Agriculture and climate change

Agriculture in its various forms anchors the core component of human life. Vital is crop and livestock production to the agricultural sector. Worldwide, agriculture is the largest economic sector and in Africa as well as Asia employs between 70 and 90% of the total labour force as well as supplying up to 50% of household food requirements and household incomes [3].

2.1 Livestock and crop production in Africa

Livestock production contributes between 30 and 50% of agricultural gross domestic production, mainly from the production of beef cattle, dairy cattle, goats, sheep, and chickens [4]. Africa has about 250 million Tropical Livestock Unit (TLU) equivalents [3] that support 70% of the rural livelihoods and provide income to over 200 million people. Livestock production is increasing throughout Africa, due to rising human population, urbanisation, and demand for meat. Total human population in the world is expected to reach 8.6 billion by 2035 and 9.8 billion by 2050 [5]. In addition to provision of food security and income, livestock provide draught power, transport, and manure in mixed crop-livestock systems. Also, livestock is socially and culturally important for payment of dowry, celebrations, and gifts to family members, and as a means of savings [6].

The livestock sector is widely constrained by a lack of regulation, which leads to negative externalities such as land degradation, water pollution, loss of biodiversity and emission of greenhouse gases (GHGs). Greenhouse gasses are the major causes of climate change, and the consensus is that climate change and global warming are real due to increased GHG emissions into the atmosphere.

2.2 Impact of climate change on livestock and crop/forage yields and quality

Livestock production depends on natural resources, which in much of Africa, primarily means pasture and water [7, 8]. The transition towards drier and hotter regimes with climate change is expected to have several adverse impacts on the quantity and quality of animal feeds. Grazing areas will be affected by changes in herbage growth brought about by changes in atmospheric carbon dioxide concentrations and temperature [9]. In terms of field crops, climate change has affected yield in several places. Some crop yields have increased in some places and decreased in others. Yield of some crops such sorghum has increased by 0.7% in sub-Saharan Africa and 0.9% in Asia due to favourable environments created by climate change [10]. In other instances, yield of some world staples such as rice and wheat are reducing on average by 0.3 and 0.9% respectively. In some studies, climate change was reducing food calories by 1% for the top 10 global crops. The food calory reduction is happening throughout the world, both in rich industrialised countries and poor countries.

2.3 Effects of heat stress

Heat stress is defined as the rise in air temperature above a threshold level for a significant amount of time to cause damage to normal growth and development [11]. Heat stress limit plant growth and productivity even in the presence of adequate soil moisture. Just like drought, heat stress can happen at any stage of crop growth and its negative effect varies with the onset, intensity, and duration during plant growth. Field crops which give flowers, pollen, tassels, silking, grain filling, storage root formation and bulking are most susceptible to heat stress at reproductive stages due to flower drop. Yield losses can reach 100 percent depending on intensity and duration of the heat. In addition, an increase in air temperature results in raised soil temperatures which can be higher than air temperature when soil moisture is limited. Root development is severely affected in both field crops and forage/pastures for animals.

The vulnerability of livestock to heat stress varies according to species, genetic potential, life stage and nutritional status. The projected warmer temperatures expected in sub-Saharan Africa are likely to cause heat stress in beef cattle raised under extensive production systems. Heat stress in extensive beef cattle production systems will likely reduce foraging time, feed intake, growth performance and carcass quality. Reproductive performance will also be compromised, for example, conception rates will decrease, calving intervals will increase, and spermatogenesis and semen quality will be impaired. Heat-induced reduction in feed intake will result in a decline in milk yields in dairy cattle [12].

The effect of heat stress is not likely to be as adverse in small ruminants, due to the small body weight, well developed water retention in the kidney and lower metabolic rates of smaller ruminant species. Goats are more likely to cope with, and adapt to, the increasingly hot and dry conditions expected in the region compared to sheep and cattle, because of their low feed and water requirements, ability to exploit low quality forage and disease resistance. Goats can survive harsher climates than cattle and require less space [12].

2.4 Availability of water and its usage

Climate change will amplify existing stress on water availability in agricultural systems of semi-arid environments [13]. Rising temperatures may increase irrigation water requirements of major crops [14] and drive-up water demand by livestock [9, 15]. For example, the increased reliance on groundwater in the future in Botswana for the cattle sector could lead to problems associated with the sustainability of water resources in the country [16]. Global warming and accompanying hydrological changes are also likely to affect soils in complex ways, including soil fertility and propensity for erosion [14]. Additionally, much prime agricultural land located in the coastal plains of Southern Africa might be lost to rising sea-levels [17]. Most of staple foods consumed in sub-Saharan Africa are grown under rain fed conditions largely by small scale farmers who have limited capacities to effect supplementary irrigation in cases of drought. Southern Africa and West Africa have a one rainfall season in a year and suffer drought episodes.

2.5 Disease and pest outbreaks on livestock and crops

Several studies have shown that the impact of climate change on the transmission and geographical distribution of animal diseases will vary according to the ecosystem, the type of land use, disease-specific transmission dynamics, susceptibility of the populations at risk and sensitivity of the pathogen to temperature and humidity [3, 18]. Climate change is expected to alter transmission rates between hosts by affecting the survival of the pathogens or parasites or the intermediate vectors, but also by other, indirect, forces that may be hard to predict with accuracy. For example, a series of droughts in East Africa between 1993 and 1997 resulted in pastoral communities moving their cattle to graze in areas normally reserved for wildlife. This resulted in cattle infected with a mild lineage of rinderpest transmitting disease both to other cattle and to susceptible wildlife such as buffalo and impala, causing severe disease, and devastating certain populations [19].

Climate change is also expected to affect the abundance or distribution of hosts or the predators of vectors and influence patterns of disease in ways that cannot be predicted from the direct effects of climate change alone [20]. Climate change-related disturbances of ecological relationships, driven perhaps by agricultural changes, overgrazing, deforestation, construction of dams and loss of biodiversity, could give rise to new mixtures of different species/strains, thereby exposing hosts to novel pathogens and vectors and causing the emergence of new diseases [21].

2.5.1 Influence on pathogen diversity and virulence

Higher temperatures may influence some pathogens and parasites through accelerated development on their life cycle outside their hosts. Pathogens and parasites that are sensitive to moist or dry conditions may be affected by changes to precipitation, soil moisture and the frequency of floods [20]. Changing wind patterns could affect the spread of certain pathogens and vectors, particularly the infective spores of anthrax and blackleg, the wind-borne dermatophilosis [22].

2.5.2 Influence on animal and crop hosts

Climate change may bring about substantial shifts in diseases distribution, and outbreaks of severe diseases could occur in previously unexposed animal and plant populations. While livestock often have evolved genetic resistance to diseases to which they are commonly exposed, they may be highly susceptible to ‘new diseases’ [3]. For example, mammalian cell immunity level may be suppressed following a sharp exposure of light of ultraviolet B nature because of expected ozone layer depletion [23]. Ultraviolet B depletes specific lymphocyte cells and animals become susceptible to some pathogens such as viruses; rickettsia (such as Cowdria and Anaplasma, and some bacteria, such as Brucella [18]. Continued depletion of ozone layer would, therefore, possibly impact some animal diseases in future. Endemic stability of animals is likely to be disrupted for tick borne diseases such as anaplasmosis, babesiosis and cowdriosis that exhibit endemic stability [24]. If climate change drives such diseases to new areas, non-immune individuals of all ages in these regions will be newly exposed, and outbreaks of severe disease could follow [18].

2.5.3 Influence on disease vectors

Changes in moisture and temperature regimes may impose limits on the distribution and the abundance of vectors. Often, low temperatures limit vector distribution because of high winter mortality and a relatively slow rate of population recovery during warmer seasons [20]. This is different with high temperatures as, limiting occurs when there is excessive moisture loss. Therefore, cooler, and high-altitude regions which were previously too cold for certain vectors may begin to allow them to flourish with climate change. Warmer regions could become even warmer and yet remain permissive for vectors if there is also increased precipitation or humidity. For example, biting midges and mosquito-borne diseases outbreaks have been linked to the occurrence of ENSO [25, 26, 27].

2.5.4 Additional effects of climate change on animal and crop productivity

Climate change, in conjunction with other forms of land use fosters the emergence of new diseases as it changes the structure of the ecosystems in relation to species composition and diversity in favour of livestock pathogens and vectors [28]. Similarly, the preponderance of diseases due to climate change occurs through tendencies of animals to migrate in masses, overgraze and congest around pastures, during times of droughts, a common phenomenon during this climate change era [3]. High rains on the other hand positively correlate with disease outbreaks in both livestock and crops. In field crops, diversity will be lost, and pathogens will rely on a few crop species, leading to increases in diseases such as leaf spots, root rots, blights, and cankers. In livestock production, apart from increases in internal and external parasites, diseases like dermatophytosis, anthrax and foot rot will rapidly occur and spread. This way, areas with limited disease occurrences may end up experiencing high crop and livestock disease occurrences. Changing international trade patterns, local animal and crop transportation, farm size and human migrations are all factors that may be driven in part by climate change, and which may impact negatively on disease transmission.

3. Strategies for adaptation to climate change in the livestock sector

For long, there have been widely publicised calls to mitigate and adapt to climate change issues and efforts are evident worldwide, however, this may be at the expense of natural ways of adaption and fears are that there could be the possibility of the emergency of new unforeseen challenges on the environment [3]. Adaptation typically refers to longer-term changes in behaviour and practices which are more likely to reduce underlying vulnerability to climate change [29]. Commonly documented livestock adaptation strategies include diversifying livestock activities, diversifying livestock types, supplementing livestock feed, and developing niche markets to preserve indigenous breeds.

3.1 Niche breeding of locally adapted animals

Indigenous livestock breeds have an adaptive to their native localities advantage than the exotic ones. Characteristics such of drought resistance, disease tolerance are crucial for sustainability of livestock in the face of climate change and indigenous breeds are inherently superior in this regard. In Africa, there are higher levels of inbreeding of local breeds and these animals are often found in small-scale and pastoralist farming setups. Apart from having an adaptive advantage, knowledge of the ways of survival of such breeds ensures an effective way of maintaining the natural environments in which they dwell in with limited chances of negatively affecting them. The success of pasture and rangeland conservation lies in part on the availability of livestock breeds that can effectively utilise the environment [30].

3.2 Animal diversification at farm level

Diversification of animal species provides a means through which a broad range of plant species may be utilised. As climate change influences temporal and spatial variations in the vegetation nature with respect to species diversity, quantity and quality of the biomass and having a diversified herd of animals may help to close this gap. Places rich in shrubs for example may be better suited for goats while those with grasses may be well suited for cattle and diversification in this scenario offers complete utilisation of the available vegetation [31].

3.3 Adopting livestock production as an adaptation strategy

The integration of livestock farming with crop production, where some of the crops grown at the farm serve as livestock feed has been a common practice across the globe. This however in most cases depends is a function of matching the correct livestock type with the feed available, the ability of the animal in question to survive on crop residues or disease resistance.

Poultry production has since been one of the enterprises engaged by many farmers in collaboration with crop production in many countries, [32]. Poultry can effectively utilise crop-based feeds such as soya beans and maize with high production success rates. Many indigenous chicken breeds can even survive under free range production systems with little or no feed supplementation. Similarly, locally adapted breeds have high disease resistance rates corresponding to a limited need for prophylactic and therapeutic disease management. Poultry are particularly especially in Africa a means of controlling the effects of climate change as they require minimal production space and can thrive on household waste.

3.4 Reviving and creation of markets for indigenous breeds

The maintenance of local adapted breeds plays a pivotal role to produce breeds adapted to the changes in climate in future. These advantages are however now being eroded by the rising need by breeders to produce breeds with high performing traits, especially characteristics of economic importance. About 11 and 2% of mammalian and avian breeds, respectively have been reported to be extinct in recent years with a further 210 cattle breeds and 179 sheep breeds classified under the critically endangered species [33]. Maintaining local breeds requires a multi-pronged approach, starting with respect for the rights of local custodians of these breeds and support for their production systems.

The quest of maintaining local breeds is inevitable in the face of climate change however for these breeds to be competitive, niche markets through improving production; processing and value addition of their products is an area of prime focus. Such markets are already in existence although there is still much to be done to smoothen the intervention. Performing SWOT analysis is an important strategy for driving the evolution towards identification of promising niche markets. The most important domain of the process is to organise local people who have the breeds of interest and ensuring that they are directly involved in the process.

4. Adaptation strategies in the crops sector to climate change

Apart from agronomic measures such as water harvesting, irrigation, mulching and growing of well adapted crops and varieties, plant breeding offers more sustainable and widespread answers to a changing climate. Plant breeding goals should meet the changing climate. Major goals should include the following:

4.1 Minimization of postharvest losses

Plant breeding programs should include postharvest durability in their product profiles. Huge losses of between 40 and 70% of cereals and legumes harvested in the world are lost to grain pests mainly weevils and moths. In fruit and vegetable sector, 25–50% of the produce is lost at postharvest stage, while 20–40% of cassava is lost to post physiological deterioration and sweetpotato to moulds. The control or management of postharvest losses is the easiest way to double food availability in Africa. With increased temperatures due to climate change, anticipated losses could be higher than mentioned.

4.2 Heat tolerance

Heat stress during reproductive, grain filling, storage root formation and root bulking leads to severe yield losses in field crops. Heat stress has damaging effects irrespective availability of other factors required for normal plant growth. Breeding for heat tolerance in field crops is one of the strategies of coping with high temperatures induced by climate change. Climate model predictions and simulations pointed to an increase between 1.8 and 4 degrees Celsius in temperature in the 21st century with high increases in southern Africa and Southeast Asia [2].

4.3 Drought tolerance

Climate change alters the precipitation amount, patterns, and distribution. The occurrence of drought and its severity has already been felt in some regions of the world and is expected to significantly rise soon. Food and nutrition security is threatened by frequent droughts in Southern Africa. The release of cultivars with improved tolerance to drought will reduce the impact of drought on many nations in southern Africa whose economies are already struggling from COVID-19 pandemic and political disturbances. Many methods and techniques are available for breeding programs to utilise in the development of drought tolerant cultivars. Genomic selection tools and emergence of different bodies ready to capacitate breeding programs in modernization and operational excellence would help in the identification of drought tolerant genotypes for respective. Water use efficiency is one mechanism for drought tolerance which should be explored in breeding programs.

4.4 Salinity tolerance

The earth is receiving lesser rainfall than before and experiencing more evaporation making it impossible to dilute salts in the soil. In addition, sea encroachment is recorded due to rising seas and is depositing a lot of salt in agricultural land. Breeding for salt tolerance should be considered high priority in nations receiving less precipitation due to climate change.

4.5 Tolerance to low soil fertility especially nitrogen and phosphorus requirements

Soils are continuously depleted and there is higher need for crops with high efficiency in the use of nitrogen and phosphorus. Legume crops with high capacity of nitrogen fixation bred and released for commercialization should be compatible with free living N fixing bacteria, Rhizobia. This helps restore nitrogen in the soils which could benefit staple cereal crops in subsequent crop rotations.

4.6 Pest and disease resistance

Climate change brings in new pest and diseases in a similar manner to livestock. Plant breeding need to continuously match the evolving pests and diseases that would reduce crop productivity and produce quality.

4.7 Recommendations

Communities as well as nations are likely going to fight for water resources, pastures, and other few comfortable places to live due to diminishing natural resources particular rainfall and water. There is an on-going tension between Egypt and Ethiopia over water resources from Nile River. Conflict resolution skills and techniques should be endowed in leaders at all levels and should be taken seriously. Focussed niche breeding especially for targeted production environments should be encouraged in both animal and crop breeding programs. Global campaigns to reduce emissions of greenhouse gases should be led by governments and multilateral companies. Innovative ways of food and feed conservation should be developed and adapted to reduce post-harvest losses.

5. Conclusions

Climate change is a reality and solutions to reduce its effect on humans, animal and the environment should be put in place and be adapted by all nations. In summary, Africa’s agricultural sector and human population will suffer the effects of climate change in a multitude of ways:

• frequent droughts caused by reduced precipitation and shifts in growing seasons particularly in Southern Africa.

• occasional floods caused by too much rainfall with short periods of time. This is witnessed more in Southern Africa most affected countries being Madagascar, Mozambique, Zimbabwe, and Malawi.

• rise in temperatures and becoming uncomfortable for life for both humans and animals. Crop and animal growth will be affected severely reducing productivity and production.

• forced migrations by both animals and humans. This will exert a lot of pressure on habitable environments and economies.

• emergence of new diseases and pests to both humans and animals which might be difficult to cure.

• the cost of food and feed will increase due to decreased productivity and production in certain environments.