malaria in Kenya

In large tracts of Africa, malaria is one of the most common diseases, and in Kenya, this disease accounts for 1/3 of outpatient consultants and 1/5 of deaths of children under 5. Malaria's worldwide economic cost is estimated at billions of dollars. The scope and the lethality of this disease make it a priority for a variety of international health organizations, such as the World Health Organization (WHO) and the Gates Foundation, including high-profile efforts to develop a vaccine.

Malaria is a caused by transmission of a Plasmodium parasite, which are spread exclusively through Anopheles mosquitoes. There are four parasite species that differ in their lethality, so death rates are variable depending on parasite species and treatment availability. Even if an individual survives, malaria can lead to anemia, which is quite dangerous for pregnant women. Additionally, children who survive severe malaria can have mental disabilities.

Worldwide malaria transmission rates; from DPDx

Water is a critical factor in malaria transmission, because completion of the Plasmodium life cycle requires sufficient rainfall to generate pools of water for Anopheles breeding. The timing of rainfall is particularly important: for example, more Anopheles-friendly water bodies form in an intense short-term storm than if the same amount of rainfall falls over a few days. In addition to insufficient rainfall, temperature is also important: too-high temperatures can hinder Anopheles development, whereas intermediate temperatures can accelerate Anopheles development.

Current malaria risk in Kenya. from DataDredger. 

This dependence of Anopheles on water and temperature means that malaria transmission in Kenya will be substantially affected by climate change. More intense-short term storms could mean more breeding areas for Anopheles mosquitoes, but changing temperatures are also an important variable. Most projections rely on changes in temperature and indicate that malaria cases will shift their distribution with climate change. Projections suggest that malaria incidence will decrease in most of lowland Africa, where temperatures will become too cold, but will increase in highland areas where temperatures will become warm enough to support Anopheles. Such changes have already been observed in Kenya, with malaria moving up into the formerly too-cold highlands of central Kenya.

Less work focuses on the role of changes in precipitation in changing malaria incidence rates. Prior work shows that droughts tend to reduce incidence rates, and high rainfall increases Anopheles population sizes. However, uncertain predictions of changes in rainfall in Kenya make incorporating these predictions quite difficult. Most climate models predict a decrease in rainfall (see the first blog post), suggesting that rates of malaria will decrease, but it seems possible that increased variability in precipitation could change the seasonality of malaria infection.

Eradication of malaria is possible with aggressive prevention tactics. Up until the last century, malaria was common across the world, including Europe and North America, but was successfully eradicated, suggesting the same can be done in African countries such as Kenya. There have already been successes in parts of Africa, with frequency reduced by 50% in 1/3 of countries where malaria is endemic; this reduction is due in part to global health organizations such as the Global Malaria Action Plan, the Roll Back Malaria Partnership, and WHO.

Tactics to reduce incidence of malaria are fairly straightforward, and there is much room for improvement in Kenya. First, prompt diagnosis and treatment is critical; the most lethal strain of malaria is lethal within the first 24 hours. In the Lake Victoria area, 1/2 of parents do not seek treatment when their children under 5 years develop a fever, and only 1 out of 10 children is given a blood test for malaria. Two-thirds of medical facilities do not even have the capacity to diagnose malaria via a blood test. In terms of treating the disease, more than half the mothers in the coast area have not heard anything about the most common antimalarial medicine.

A woman and child underneath a mosquito net; from Healing Hearts. 

In addition to rapid diagnosis and treatment, use of insecticides and mosquito nets is critical to preventing malaria. Spraying residences with insecticides reduces the instance of malaria, but only 1 out of 10 children under 5 years sleeps in an insecticide-treated residence. The use of insecticide-treated bed nets to protect people from nighttime bites also drastically decreases incidence of malaria. However, the proportion of Kenyans owning insecticide-treated nets has stagnated since 2007, and in malaria-endemic areas, there is only 1 net for every 5 Kenyans (the nationally-recommended ratio is 1 to 2).

National efforts to prevent the spread of malaria with climate change have focused on improved prediction of outbreaks as a function of climate data, which is critical in an region of changing incidence rates. Improved prediction will allow healthcare providers to take preventative measures such as distributing nets or spraying for mosquitos, thus increasing the capacity for dealing with outbreaks in susceptible areas. For example, in the highland areas near the Mount Kenya region, where malaria has been rare historically, workers have focused on disseminating mosquito nets to people with little experience of the disease.

Administration of a malaria vaccine; from the Guardian Express. 

One of the most heartening advances in the fight against malaria in Kenya in particular and Africa in general is the recent development of a vaccine, which was tested in seven African countries, and may be ready for approval by WHO by 2015. This vaccine is effective against the most virulent Plasmodium parasite, but is not currently licensed for use as a malaria control tool.

Changes in precipitation and temperature with climate change will shift the distribution of malaria incidence in Kenya, with rates increasing the highland and decreasing in the lowlands. Given the relative unfamiliarity of highland Kenyans with this disease, as well as low rates of preventative measures, it is critical to develop effective preventative and mitigation strategies in these susceptible areas, both at the national and international level.

women and water

Girl collecting water in Kenya;
from The Water Project. 

For many Kenyans, climate change has very real consequences for daily life: many people will have to hours to get drinking water from increasingly scarce water sources. Water sources can be 2-5 km away, with people carrying 5-20 litres of water per trip, and some families using 100 litres of water per day. Water-gathering is so important that it is valued higher than the cost of unskilled labor. However, the majority of water collecting is done by women or girls. Similarly, many traditional gender roles in Kenyan communities mean that changes in precipitation with climate change will disproportionately affect Kenyan women and girls.
walk

In Kenyan communities, many chores traditionally thought of as "women's tasks" are much more connected to natural resource management than are traditional "men's tasks." Traditional women's tasks include domestic chores such as water collection, as well as cooking, cleaning, health- and childcare, and often farming; about half of all farmers in Kenya are female. Conversely, men are more often involved in economic and social pursuits within their community. Because women's tasks involve water availability and sanitation, women will be disproportionately affected by changes in water access resulting from more droughts or rainfall variability under climate change.

Potential impacts of climate change on women in Kenya; from NEMA.

Provision of water resources is generally recognized as a critical way of empowering women, because it frees up women's time and energy, and also improves health, reducing the need for female-provided healthcare. In addition, women walk a long way to get water, and often suffer the threat of violence on their walks away from home. Finally, if water is difficult to get, some girls even skip school to make trips to collect water; in a study in Morocco, girls' school attendance increased when access to water improved.

Kenyan women generally have had less decision-making power than men, including decision-making power concerning water provision, in spite of their disproportionate stake in water resource management. Men have generally controlled both the social and political aspects of decision-making, with women at the grassroots level often barred from decision-making processes. This attitude in part arose because women's domestic labor is not seen as economically-valuable "real work".

Denittah Ghati, a representative in the governmental coalition
designed to decrease gender disparity in water politics,
speaking to rural farmers. From Thomson-Reuters. 

However, due in part to the the increasingly large fraction of small-scale female farmers, as well as increased representation in government bodies, these long-held ideas about gender roles in water provisioning are being challenged at both the grassroots level and at the national scale. For example, a coalition among female representatives in Kenya's government, founded on small-scale community support, has called for an increased awareness of women's role in farming and water provisioning when designing policies. This organization has worked mainly with small farmers in rural areas, striving to empower women by making them more involved in local administrative structures' policy-making.

In a similar vein, the Kenyan government has outlined goals and tactics for decreasing the gender disparity in water politics and climate change in a recent report. This report highlights three main tactics for mitigating the effects of climate change on women: first, adaptation and mitigation strategies should consider the role of gender. Second, women should be actively involved in climate change decision making and planning. Finally, because poverty often accentuates climate change impacts, especially for underprivileged groups, the government should create a fund to support the economic activities of women. While this plan has yet to be implemented on the large scale, it provides a concrete framework for addressing gender disparity issues.

Many traditional gender roles in Kenya mean that changes in water availability and rainfall with climate change will disproportionately affect Kenyan women and girls. There has already been substantial progress made on this front, at both the grassroots and national level. In subsequent posts I will discuss the effects of increased precipitation on another issue that concerns women in their role as healthcare providers, malaria transmission.

Rain-fed agriculture

Variability in the productivity of rain-fed agricultural production will increase substantially with climate change, with important implications for food security. Malnutrition, particularly in children, is a critical concern in Kenya, with high rates of wasting and undernourishment, particularly in rural areas. Effects of climate change will likely increase the frequency and severity of malnutrition, particularly in rural areas, because the vast majority of rural Kenyans obtain their food from rain-fed agriculture. In addition, already-documented increases in prices of staple foods (also grown without irrigation), will likely lead to increased urban malnourishment as well.

A water catchment system in Kenya; from
Kenya Water for Health Organization. 

Small- scale agriculture is an important part of Kenya's economy, as well as an important source of sustenance for the rural poor. Agriculture comprises 26% of Kenya's GDP and 75% of the country's employment, primarily on small-scale farms. About 75% of total agricultural output is produced on 0.2-0.3 hectare farms. Such farms produce both marketable produce, as well as comprise the most important source of staple food production for the rural poor. Projections suggest that such small-scale farms will remain the most important source of food for most poor rural Kenyans, and thus should remain a critical component of any development plan.

These farms are primarily rain-fed, which increases Kenya's vulnerability to increased precipitation variability under climate change. Irrigated agriculture comprises only 1.7% of total agricultural land under production. This reliance on rain-fed, rather than irrigated, agriculture means Kenya is highly vulnerable to changes in precipitation patterns. Irrigated agriculture is, at least in the short-term, less volatile with respect to changing precipitation patterns than is rain-fed agriculture. Recognizing this risk, a recent report recommends an increase in irrigated agriculture from140,000 hectares to 1 million hectares to increase economic and food security in this region. The Kenyan government has invested a substantial amount of money into this operation, recently developing an initiative to bring 1 million hectares under irrigation over 5 years. Greenhouse farming, another form of irrigated agriculture, has also gained traction in recent years.

Women working in a Kenyan greenhouse; from Thomson Reuters. 

In spite of these steps towards irrigation, the potential for irrigated agriculture is limited, both logisticadlly and politically. Logistically, this increase in irrigation is close to the limit of the water resources available to Kenya. While the country has an estimated irrigation potential of ~1.3 million hectares, only about 30% of this water production is possible with available water resources; the remainder will require water harvesting and storage. Water harvesting in Kenya is currently fairly uncommon, but is becoming more widespread in rural communitites through grassroots rural initiatives. In spite of these successes, governmental support of water harvesting is critical to the success of this technique for expanding irrigated agriculture. While Kenyan policies have historically not been supportive of water harvesting for agriculture, as-yet-unimplemented new policies are paving the way for large-scale water harvesting.

Projections of rainfed maize yield with climate change; from Odera et al. 2013.

While Kenya's expansion into irrigated agriculture is critical for mitigating increased variability under climate change, there are some positive outcomes of changes in precipitation patterns with climate change. All of the leading climate models suggest that rainfall patterns over some arid- and semi-arid regions in northern Kenya will become more suitable for growing maize, Kenya's staple crop. Increases in productivity in these regions could help mitigate some of the productivity lost in other regions, but these effects are complicated by historical land-use patterns. Efforts to encourage maize cultivation in these areas have not yet begun, but must consider land tenure and migration issues.

The reliance on rainfed agriculture makes Kenya highly vulnerable to the impacts of increased variability with climate change; increased variability in rainfed agricultural production under climate change may lead to increases in malnutrition issues in both rural and urban areas.

precipitation and hydroelectric power

Gibe III; from peak water.

Construction on the Gibe III Dam in Ethiopia, the fourth largest dam in the world, began in 2006 and is a highly controversial hydroelectric project. Ethiopia should earn over $400 million annually from power exports, much of which will be exported to Kenya. Environmentalists claim that construction of the dam will further reduce human-available water supply in the already drought-stricken Gibe III region, which spans Ethiopia and parts of Kenya, as well as drastically reduce water levels in Lake Turkana in Northern Kenya. Dam-induced water shortages will be exacerbated by the erratic rainfall patterns predicted by climate change. Widespread protests over dam construction reflect disenchantment with both dams and hydroelectric power generation across Kenya, in part due to increasingly variable rainfall under climate change.

A child fishing on Lake Turkana, in Northern Kenya. Fishing
is an important source of income in this region and will likely
be hurt by the construction of Gibe III. 

Movement away from hydroelectric power coincides with increased power needs in Kenya due to  booming populations and higher per capita demand for electricity. Currently, less than 20% of Kenyans (and only 5% of rural Kenyans) have access to electricity, and frequent rolling blackouts due to electricity shortages are common throughout the country. Many businesspeople say that blackouts are one of the key barriers to economic growth.

In the face of the country's desperate need for energy, however, the source of this energy is in flux. Historically, most power production in Kenya has been hydroelectric, with dam-generated power supplying over 80% of the country's electricity at its peak. The largest power producer in Kenya, Kenya Electricity Generating Company, is curtailing its output from hydropower, choosing instead to rely more on other sources of renewable energy such as solar and geothermal. The company indicated that this shift will reduce their dependency on often erratic weather for power generation. With precipitation slated to become even more erratic, it is essential to diversify modes of power generation in Kenya in order to keep up with rising demand.

Climate change projections for the region suggest increased mean rainfall and increased variability in rainfall. While increased rainfall in the region could lead to increased capacity for hydroelectric power, due to the increasingly erratic rainfall patterns, higher electricity generation is likely unfeasible for most large dams. One approach to generate hydroelectric power from increased rainfall would be to increase storage capacity in existing dams, but this is an expensive endeavor. Some dams have successfully modified timing of discharge to accommodate increased variability in rainfall, but these approaches require substantial data on in-stream flow rates. Coupled with uncertainty in the predictions of rainfall amounts and variability, this approach seems too data-intensive for the majority of dams in Kenya.

A small hydroelectric dam in Kenya, from treehugger.com

While large-scale power generation on the Gibe III scale may be a thing of the past in Kenya, small power generation (~500 KW generation) can be used to help the government's efforts to increase rural access to electricity, and excess energy can often be given back to the National Grid. While these projects have a high installation cost, and often suffer from inadequate data on water flow in rivers, they can help increase electricity generation in rural areas that have not historically had energy. In addition, these efforts can help provide a source of water during dry seasons, mitigating the agricultural effects of increased variability in precipitation.

As Kenya moves away from large-scale power generation via hydroelectric power, toward energy production that is less dependent on erratic rainfall patterns, large dams may become less and less common. Given high variability in rainfall that has led to closing of hydroelectric dams due to low water availability, these changes will likely lead to a more consistent electricity supply, increasing Kenya's economic prosperity. In my next post, I will discuss how Kenyans are coping with changes in precipitation patterns in the context of another important component of Kenya's economic prosperity, rainfed agriculture.

current and future floods in Kenya

Recent flooding in Kenya in April 2013 led to 62 deaths and almost 90,000 displaced people.  Heavy rains during the March rainy season resulted in many riparian flooding events, washing away villages and agriculture along many of Kenya's waterways. These events have led to substantial pressure on the Kenyan government to improve its response to such flooding events and flood control.

Disaster aid during the April 2013 floods, from the
Facebook page of the Kenya Red Cross Society.

These most recent floods are part of a string of large floods in the past 20 years. The 1997/1998 floods affected almost 1 million people, with economic costs of $0.8 to 1.2 billion. Another 2006 event affected over 723,000 Kenyans. In a recent survey on flooding events in Kenya, 96% of respondents said that floods have become more frequent or intense over the past 20 years. Flash floods occur in both rural and urban areas, most commonly in river valleys, marshes, lakeshores, and along the coasts, during either the short and long rains. High vulnerability to floods can be exacerbated by high poverty, poor land use patterns (such as deforestation, agriculture, and settling along river banks), low education and literacy, and low levels of infrastructure. 

In addition to land-use practices, climate change has likely contributed to this increase in flood frequency and severity, and flood risk will only increase in the future. Many models indicate an intensification of heavy rainfall in the wet season; this intensification will lead to greater flood risk, with more significant floods occurring more frequently

Floods can devastate both local and national economies. Even in the absence of climate change, population and economic growth (particularly in riparian areas) will increase the costs of flooding events by a factor of 5 by 2030. Climate change will only compound these costs: because flood damage costs rise very sharply with flood depth and strength, a higher frequency and intensity of flooding events with climate change will drastically increase these costs. Costs include mortality, damage to infrastructure (roads, buildings, and communications), public health, loss of crops, as well as undocumented effects on rural populations and the non-formal economy. Costs can also include ecological damage: coral reefs in Mombasa, a popular coastal tourist destination, were highly damaged by the 1997/1998 floods, with 50% of coral reefs in nearby Malindi killed by light limitation arising from sediment deposition, hurting the tourism in this region. 

A coral reef on the Kenyan coast. Image from the
Smooth Guide to the Kenya Coast.

The Kenyan government's response to flooding events has focused on post-flooding relief, as well as prevention of future flood damage. Post- flooding relief has been the government's main focus, but such relief efforts have been poorly coordinated and unnecessarily expensive, likely due to the lack of a disaster management policy, as well as the government's lack of response to early warnings. Governmental post-flood efforts have focused on distributing food, but other critical components of the response, such as healthcare, have been neglected due to lack of funds, lack of roads, and absence of infrastructure in rural areas. Governmental efforts to prevent and control flooding via dam construction have also suffered from inadequacies. A recent United Nations Report highlighted that poorly-designed dams in some regions of Kenya have led to seepage and backflows of water. Many of these dams are more than 20 years old and must be repaired or replaced soon.

In an effort to address shortcomings with preventing, controlling, and responding to flooding, in April 2013, the Kenyan government announced the establishment of a national disaster management authority. This program will help coordinate multiple institutions' disaster prevention and response, hopefully leading to a more efficient, effective, and integrated disaster management system. In addition, this program will develop a five-year plan to build dykes and dams to curb flooding. In addition to flood relief and prevention, this group will likely focus on improving both forecasting of flood events, as well as improving warning systems for communities in flood areas.  

Flooding in Bunyala after a dam failed; many of the dams in
this region are quite old, some up to 40 years. Image from IRIN.

In addition to a national response, work on improving flood resiliency at the local level has also helped mitigate flood damage. Local communities in some areas are working together to raise the level of dykes in order to hold the increased precipitation coming from climate change. Additionally, farmers in many areas have also been working to diversify the livestock they keep in an effort to minimize flood damage. Finally, some riparian communities have been trying to change infrastructure, such an putting houses on higher ground, in an effort to withstand floods.  

While floods in Kenya are a substantial problem, and will likely only increase in frequency, intensity, and cost in the future, both governmental and local efforts to mitigate and prevent future damage will likely help improve flood control and response. While this post has outlined how floods can be a disastrous problem in Kenya, my next post will discuss how increased river flow can also be beneficial: I will discuss how increased river flow arising from increased precipitation might help Kenya's energy sector. 

future changes in rainfall

Endangered black rhinos using a
water hole in Kenya; from KWS website.

In a partnership with UNESCO and financial backing from Japan, Kenya very recently discovered large aquifers in its arid Northern Turkana region, a place plagued by droughts and suffering from severe water scarcity. The discovery, hailed as a "scientific triumph" that will improve access to drinking water as well as improve agriculture for "generations of people", illustrates the desperate need for water in this arid region, and its reliance on consistent sources of drinking and irrigation water. A UNESCO statement highlighted the importance of such a discovery in the face of Kenya's water vulnerability, emphasizing that Kenya's water scarcity will likely increase precipitation with climate change.  

Children gathering water in Kenya;
such water sources will likely decrease
in frequency in the future.

Such examples highlight how critical water is in East Africa in general and Kenya specifically, particularly given future changes in water availability with climate change. These changes in precipitation patterns will likely have strong ecological and economic effects. Such effects include accelerated water cycling, increased drought, and the cascading effects on both wild plants and animals, as well as crops and livestock. These changes are of paramount importance not only because they will have strong effects on the ecology, farming, and livestock of the region, but because dryland tropical economies are strongly driven by rainfall. Subsequent posts to this blog will explore specific aspects of how and why future changes in precipitation will (or will not) affect economics and livelihoods in the the arid tropics, using Kenya as an example, but first it is essential to understand the predictions for the region.

Photo from ILRI website

Climate change will affect two important aspects of future precipitation: total amount of rainfall and variability in rainfall (or, when rainfall falls during the year, including time between rainfall events and rainfall per event). While we have a poor understanding of how total rainfall will change, most models predict an increase in the variability of rainfall over the tropics. An increase in variability means that rainfall events will likely occur less frequently, but more rainfall will fall per event. 

Total annual rainfall in the tropics will likely decrease in dry areas and increase in wet areas (see the figure below, with lower precipitation over the African Sahara but higher precipitation over the South American wet tropics), meaning that dry areas will get drier and wet areas will get wetter; trends since 1980 and from as early as 1930 show that this has already begun to happen. This pattern (dry-gets-drier and wet-gets-wetter) likely arises because of changes in temperature; tropical regions that get warmer should get wetter, and those that cool should get drier. Tropical regions differ substantially in how much they will warm: regions may differ by 1.5 degrees C. These differences in amount of warming will lead to large differences among tropical regions in the amount of rainfall that falls. It is particularly challenging to predict changes in total precipitation over the ocean, but it is relatively easy to predict changes over land.

Predictions of changes in precipitation from ©2007 IPCC WG1 AR-4. 

The vast majority of climate change models predict a substantial increase in precipitation variability (again, increased time between rainfall events but more rainfall per event). Increased variability in precipitation is largely a product of increased evaporation, due to an accelerated water cycle. Variability will increase even in regions that get drier; in regions that get wetter, variability in precipitation will increase even more. 

Though we know that the variability of precipitation will increase, the frequency of precipitation extremes (events that are are very extreme and very rare, in the highest 99.9%), is difficult to predict for tropical regions, with predictions varying widely across models. Discrepancies among model predictions likely arise because these models are very sensitive to how they incorporate air circulation. More specifically, these models are sensitive to how they incorporate vertical air motion. We have a poor sense of how air moves vertically in nature (because it requires detailed and expensive-to-obtain satellite data), and thus, different models of climate dynamics treat vertical air motion differently.

These models try to predict global-scale changes in precipitation patterns, and do a fairly good job, but predictions for specific regions are more difficult to make.

Kenya generally has two rainy seasons, with long rains occurring in March to June and short rains from September to December. Even without climate change, Kenya's rainfall is quite variable, both in time and space. Years differ greatly in the duration and timing of the rainy seasons and the amount of rain that falls. Rainfall also varies dramatically over small regions; for example, annual rainfall can vary by as much as 600-1600 mm annually within one rainfall basin.

Different models of climate change predict either increases or decreases in total annual rainfall in Kenya, but most models predict increased variability in precipitation. While a recent IPCC report predicts increases in rainfall in East Africa generally and Kenya specifically, other reports incorporating more data suggest that rainfall will actually decrease over much of East Africa, including Kenya, likely due to warming over the Indian Ocean. Drying has already been observed in Ethoipia, with drying usually occuring during the long rains season, rather than the short rain season.

Climate models predict that variability in precipitation will increase in Kenya, meaning that rainfall events will become more intense and less frequent in Kenya. This has already been happening over much of Kenya; see the figure below, where total rainfall has not changed over time, but the rainfall per storm has increased, and rain events have become less frequent. 

Graph from Franz et al. 2010, showing no significant change in total rainfall (top row), but higher variability (increased rain per storm, second row, and longer time between storms, third row). 

While changes in mean annual precipitation and precipitation variability may be mitigated by discoveries of water or other scientific advances, Kenya cannot count on such advances in its preparation for the future. In a region characterized by water scarcity, whose economies and ecology are driven by erratic variation in rainfall, it is important to understand precipitation's effects on the ecology, economics, and livelihoods in the region. Subsequent posts will illustrate specific examples of the putative effects of changes in future precipitation on economic and ecological phenomena.