The Impact of Climate Change on Agriculture and Health Sectors in Tanzania: A review

The impact of climate change in Tanzania is dynamic and differs among regions as they are impacted in different ways. While other regions experience normal rainfall and temperature patterns, others have continued to experience temperature extremes, severe droughts, decline in crops production coupled with food insecurity, extreme weather episodes of heavy rainfall associated with floods, loss of lives and infectious disease outbreaks. Despite the effects of climate change being recognized in the country, awareness is limited among local people, in particular the vulnerable communities. Thus, this review aims to raise awareness by giving a broader picture of impacts of climate change on agriculture and health sector. It reveals that in many parts of Tanzania, agriculture and health sectors may continue to suffer from the effects of climate change aggregated with limited awareness among communities. It is expected, that outbreaks of infectious diseases including malaria and cholera may increase as they correlate positively with high temperatures and rainfall. As a result, health problems and deaths of people, and reduced crops production will continue. Therefore, it is recommended that, the best way to overcome climate change is to invest effectively on the irrigation agriculture; and the health sector's budget should be enough to improve health care services and prepare for outbreaks of climate change sensitive diseases. Most importantly, provision of climate change awareness to the vulnerable communities must be seriously considered. About 50 peer-reviewed articles, government and International reports published between 2000 and 2017 were reviewed.


I. INTRODUCTION
defines climate change as the long-term changes in weather conditions and patterns of unusual extreme weather events. On the other hand, IPCC (2001) describes a climate change as a change of climate which is attributed either directly or indirectly to anthropogenic activities that alter the global atmosphere composition and which is in addition to observed natural climate variability over comparable time periods. It is a global problem that defies and threatens global sustainable development, economy, food security, biodiversity, agriculture, human health and water availability as shown in Brown and Crawford (2008), Enfors Wu et al. 2016). All these activities produce high emission levels of greenhouse gases (GHGs) which include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) (Brown et al. 2007;IPCC, 2007;Mwakisunga et al. 2012). Thus mounting of GHGs concentration in the atmosphere is the leading cause of climate change (Hemp, 2009;IPCC, 2007). Several studies including IPCC (2001,2007), FAO (2013) and Shikuku et al. (2017) clearly show that the GHGs are positively correlated with the burning of fossil fuels, oils, forest destruction and agriculture. It has been indicated that, climate change takes place in the context of developmental stresses, poverty, food shortage, drought, outbreaks of infectious diseases, environmental change and land degradation (Brown and Crawford, 2008;Brown et al., 2007;Enfors and Gordon, 2007;FAO, 2013;IPCC, 2001 (Levira, 2009;URT, 2007). Its impact also accelerates food shortage, poverty, deforestation and forest degradation, poor livelihoods and occurrence of infectious diseases (Hatibu, 2003;NAPA, 2005;Wolbring, 2009;Wu et al. 2016). The poor and rural communities are particularly chiefly vulnerable owing to their complete dependence on subsistence agriculture and forests resources coupled with limited capacity to adapt to climate change (Brown et al., 2009). Researches have shown that more than 80% of Tanzanian population directly rely on agriculture for their livelihoods; thus, 10% decrease in rainfall would make most of areas unsuitable for cultivation (Hemp, 2009;URT, 2003URT, , 2007. Moreover, Craparo et al. (2015) reported that, a minimum temperature change in future will be severe in the interior regions of Tanzania and will considerably affect crops production and health sector. This review paper provides an overview of the impacts of climate change on agriculture and health sectors in Tanzania. Recommendations to overcome them have also been discussed. Shemsanga et al. (2010) asserted that the best way to explain the effect of climate change is to focus on the context of crops production and outbreaks of infectious diseases such as cholera and malaria. Crop yields have been used in many studies to justify the impact of climatic change (Burke et al. 2009;Hatibu et al. 2003;Shemsanga et al. 2010). This is because climate change influences crop yields by decreasing soil moisture content, increase drought and floods, and support diseases affecting crops.   (2008) report that, increase or decrease in temperature and rainfall patterns in some cities accelerates shortage of food. This is because many crops die as a result of high temperature that increases evapotranspiration and moisture loss (Rowhani et al. 2011;URT, 2003URT, , 2007. Furthermore, a decline in rainfall makes water inadequate for farming activities (Ojoyi, 2017), because many seasonal streams and rivers used for irrigation dry out (Craparo et al. 2015). For example, Rowhani et al. (2011) claim that, seasonal increase in temperature by 2 o C as projected by 2050 will reduce yields of rice, sorghum and maize by 7.6%, 8.8% and 13% respectively in Tanzania while a 20% increase in precipitation variability will decrease yields of rice, sorghum and maize by 7.6%, 7.2% and 4.2% respectively by 2050. In addition, increase in temperature between 2 o C and 4 o C will alter the ecosystem, causing ecosystem shifting (Rowhani et al. 2011). As a consequence, this will shift former areas suitable for cultivation of annual crops to perennial crops (Yanda et al. 2008). Severe droughts in Tanzania have been causing hunger as a result of dwindling in crops production. For instance, Shemsanga et al. (2010) reported that in Dodoma there was a decrease in harvest by 80% attributed to poor rainfall. In 2005, Kilimanjaro, Coastal and North-East regions experienced marginal rains, which led to food shortages and starvation. Besides, the food scarcity due to climate change, the phenomenon has also has resulted into an increase in malnutrition rate amongst children in the country (URT, 2005(URT, , 2007 ). Yet, livestock productivity, distribution and survival will continue to decline because of the present climate change variability, decrease in the quality of rangelands and prevalence of vector-born diseases.

Impact of climate change on health sector
It is not relatively simple to assess the effect of climate change on human health. This is because human health may be impacted due to extreme changes in cold and heat, droughts and floods. Other human health impacts may get up from ecological or social system alterations caused by climate change. The climate change affects the health sector in Tanzania by persistent burdens of diseases (Kibona, 2008;URT, 2007). This includes the basic elements of good health such as adequate food, clean air, safe water, adequate shelter, and health environment (Hulme et al. 2001). Climate change further impacts on health of people by multiplying the present health problems (Wu et al. 2016). Strong weather associated with heavy rainfall, landslides and floods destroy the infrastructures of health care services infrastructure and hence affect the health sector (URT, 2005;Yanda, 2005). In addition, it causes injuries and deaths, water supplies contamination, decrease in food production and disease outbreaks (Costello et al., 2009). The health sector is impacted in diverse ways, for example, the impact on food, system efficiency of local sewerage and the accessibility of fresh water supplies (Kibona, 2008). Furthermore, a decrease in food production also affects health of many people in form of malnutrition (FAO, 2013). A deficiency of water in most places of the country leads to consumption of unsafe water. This increases the chance of water borne disease outbreaks, a threat to health. There are many climatically sensitive illnesses in Tanzania; and they are very common during heavy rains, drought and flooding (Mboera et (Mboera et al. 2011). This review focuses on two major climatic sensitive diseases (Cholera and malaria), however, other climatic infectious disease are also discussed in briefly.

Cholera
Cholera is a disease associated with climate change also reported a significant relationship between cholera incidences and temperature in the country. He further showed that, initial risk of cholera increased by 15% to 19% for every 1 o C temperature increase. Additionally, he projected that in Tanzania by 2030, the total costs of cholera attributable to climate change variability will be in the range of 0.32% to 1.4% of national GDP. Similarly, Traerup et al. (2011) showed that the seasonal patterns that existed between June and October had the lower cholera cases which corresponded with lower minimum or maximum temperatures and total rainfall (Fig 2). Treatment and handling costs of people suffering from cholera as well as controlling the disease burden the country's economy. This is because more funds are injected in the health sector to combat it. In addition to the economic consequences, the disease also decrease labour force (URT, 2003; Yanda, 2005).

Malaria Ahern et al. (2005) and Haines and Patz (2004) have
shown that, incidences of malaria are highest during heavy rainfall and high temperature. The increase in precipitation and temperature is associated with global warming and therefore makes mosquitoes' habitats (such as ponds, pools, wells or bores, streams, rivers and canals) suitable breeding sites (Harrus and Baneth, 2005). Consequently, they grow and increase in population capable of spreading parasite causing malaria, Plasmodium falciparum (Lindsay et al. 2000;Kibona, 2008). Development rates of parasites and vectors are affected by temperature whilst mosquitoes' breeding sites are affected by the availability of rainfall (Craig et al., 2004;Zhou et al., 2004). Kibona (2008) in their study conducted in Lushoto district, Tanzania, reported that malaria cases were prominent during high rainfall seasons. For example, 249.1 mm of rainfall in April were associated with the increase of mean malaria cases in the same month (Fig 3). This is similar in other months in each rain season. Kibona (2008) also reported an increase in malaria cases were linked with increased temperature (Fig 4). Largely, malaria cases tend to correspond with annual and monthly rainfall seasons and temperature (Lindsay et al. 2000). This correspondence is due to the temperature and rainfall patterns that favour the breeding and distributions of mosquitoes (Kibona, 2008;Ostfeld and Brunner, 2015;Reiter, 2001). This happens especially if the infrastructures such as pools, ponds, canals, streams and rivers are present to support their existence (Rodó et al., 2013). The burden of malaria on the health sector is very huge, it slows the health sector to provide better health care services. This is because the budget allocated in the sector is diverted to treatment and purchasing of malaria medicines every year. IPPC (2007) reported that a part from causing morbidity, malaria kills many children, elderly and pregnant women more than other diseases on the planet.

IV. CONCLUSIONS
Human health is impacted by climate change directly or indirectly. Direct effects can cause mortality due to extreme heat and cold waves, flooding, droughts, and cyclones. Indirect effects are associated with increased health problems due to contaminated food and water, and malnutrition due to reduced food production. However, in Tanzania, mortality cases due to direct impacts are mainly caused by floods and droughts. In order to reduce the impacts of climate change on agriculture and health sectors, the government and other stakeholders should set up early warning system mechanisms and demonstrate optimal preparedness owing to the dynamic nature of climate change impacts. Preventive adaptation and mitigation measures against infectious diseases should be introduced, for example, good infrastructures for water and sanitation, and health service centres. These must be supplemented with Tanzania national goals of universal water and hygiene coverage. In agriculture sector, it is recommended that the best solution to overcome climate change is to effectively invest in the irrigated agriculture and also biotechnology whereby crops tolerant to various climate changes such as drought can be bred to ensure food security. It is also critical to provide education to farmers and livestock keepers about climate change adaptation and mitigation strategies. Most importantly, the government should massively sensitize and build the capacities of rural communities, who are also the chief victims of climate change, to practise sustainable and environmentally friendly agricultural technologies such as conservation agriculture, farrowing, agroforestry, afforestation, integrated plant nutrient management, integrated pest management etc. that have the capacity to increase resilience to, or mitigate effects of climate change. On a macro level, governments should consider investing in technologies with lower greenhouse gas emissions in key sectors of manufacturing, automobile, health and agriculture. Consequently, various global initiatives and agreements exist aimed at reducing climate change (effects), to which is Tanzania is a signatory, and must therefore remain committed to achieving such goals as Sustainable Development Goal(s) 13 (Climate Action). In accordance with this review, it is envisioned that the climate will continue to have impacts on both agriculture and health sectors. These impacts will extend to socioeconomic aspects of rural communities which are most vulnerable to climate change. It must be noted that, climate change does not occur in void, as its effects and resulting environmental alterations interact with agriculture and health sectors.