Author: Felicitas Röhrig

[1] World Bank, “World Bank Open Data,” 2019. Online available: https://data.worldbank.org [Accessed: 31-Jan-2020].

[2] CIA, “The World Factbook: Burkina Faso,” 2019. Online available: https://www.cia.gov/library/publications/the-worldfactbook/geos/uv.html [Accessed: 30-Aug-2019].

[3] World Bank, “World Development Indicators,” 2018. Online available: https://databank.worldbank.org/source/worlddevelopment-indicators [Accessed: 09-Apr-2020].

[4] Observatory of Economic Complexity, “Burkina Faso,” 2017. Online available: https://oec.world/en/profile/country/bfa/#Exports [Accessed: 14-Apr-2020].

[5] FAO, “Socio-Economic Context and Role of Agriculture: Burkina Faso,” Rome, Italy, 2014.

[6] FAOSTAT, “Crops in Burkina Faso (Area Harvested),” 2017. Online available: http://www.fao.org/faostat/en/#data/QC [Accessed: 06-Mar-2020].

[7] UNDESA, “Trends in International Migrant Stock: Migrants by Destination and Origin,” New York, 2019.

[8] World Bank, “Migrant Remittance Inflows (US $ Million),” Washington, D.C., 2019.

[9] CONASUR, 2020, cited in: WFP Burkina Faso, “Emergency Response Situation Report #12”, 2020. Online available: https://reliefweb.int/sites/reliefweb.int/files/resources/Sit%20Rep-%20BF%20%2311.pdf [Accessed: 28-May-2020].

[10] UNDP, “Human Development Index,” 2018. Online available: http://hdr.undp.org/en/indicators/137506 [Accessed: 08-Oct-2019].

[11] Notre Dame Global Adaptation Initiative, “Burkina Faso,” 2017. Online available: https://gain-new.crc.nd.edu/country/burkina-faso [Accessed: 24-Oct-2019].

[12] FAO, IFAD, UNICEF, WFP, and WHO, “Food Security and Nutrition in the World 2019,” Rome, Italy, 2019.

[13] S. Lange, “EartH2Observe, WFDEI and ERA-Interim Data Merged and Bias-Corrected for ISIMIP (EWEMBI).” GFZ Data Service, Potsdam, Germany, 2016.

[14] World Bank, “Local Development, Institutions and Climate Change in Burkina Faso: Situation Analysis and Operational Recommendations,” Washington, D.C., 2010.

[15] B. Ampomah-Ankrah, “The Impact of Climate Change on Water Supply in the Sahel Region: The Case of Burkina Faso,” International Water Association, 2019. Online available: https://iwa-network.org/the-impact-of-climate-change-on-water-supply-in-the-sahel-region [Accessed: 31-Oct-2019].

[16] S. Traore and T. Owiyo, “Dirty Droughts Causing Loss and Damage in Northern Burkina Faso,” Int. J. Glob. Warm., vol. 5, no. 4, pp. 498–513, 2013.

[17] M. Winsor, “Drought-Hit Burkina Faso Rations Water Supply in Ouagadougou Amid Severe Shortage,” International Business Times, 2016. Online available: https://www.ibtimes.com/droughthit-burkina-faso-rations-water-supply-ouagadougou-amid-severeshortages-2363145 [Accessed: 02-Mar-2020].

[18] B. Barbier, H. Yacouba, H. Karambiri, M. Zoromé, and B. Somé, “Human Vulnerability to Climate Variability in the Sahel: Farmers’ Adaptation Strategies in Northern Burkina Faso,” Environ. Manage., vol. 43, no. 5, pp. 790–803, 2009.

[19] B. Sarr et al., “Adapting to Climate Variability and Change in Smallholder Farming Communities: A Case Study From Burkina Faso, Chad and Niger (CVCADAPT),” J. Agric. Ext. Rural Dev., vol. 7, no. 1, pp. 16–27, 2015.

[20] J. Wanvoeke, J. P. Venot, C. De Fraiture, and M. Zwarteveen, “Smallholder Drip Irrigation in Burkina Faso: The Role of Development Brokers,” J. Dev. Stud., vol. 52, no. 7, pp. 1019–1033, 2016.

[21] R. E. Namara and H. Sally, “Proceedings of the Workshop on Irrigation in West Africa: Current Status and a View to the Future,” Colombo, Sri Lanka, 2014.

[22] USAID, “Country Profile: Property Rights and Resource Governance in Burkina Faso,” Washington, D.C., 2017.

[23] USAID, “Climate Risks in Food for Peace Geographies: Burkina Faso,” Washington, D.C., 2017.

[24] USAID, “Climate Risk in Food for Peace Geographies: Kenya,” Washington, D.C., 2019.

[25] S. Dos Santos, J. P. Peumi, and A. Soura, “Risk Factors of Becoming a Disaster Victim: The Flood of September 1st, 2009, in Ouagadougou (Burkina Faso),” Habitat Int., vol. 86, no. March, pp. 81–90, 2019.

[26] M. Dabaieh, O. Wanas, M. A. Hegazy, and E. Johansson, “Reducing Cooling Demands in a Hot Dry Climate: A Simulation Study for Non-Insulated Passive Cool Roof Thermal Performance in Residential Buildings,” Energy Build., vol. 89, pp. 142–152, 2015.

[27] T. M. Shanahan et al., “CO2 and Fire Influence Tropical Ecosystem Stability in Response to Climate Change,” Nat. Publ. Gr., no. July, pp. 1–8, 2016.

[28] IPBES, “Report of the Plenary of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on the Work of Its Seventh Session,” n.p., 2019.

[29] K. Dimobe, A. Ouédraogo, S. Soma, D. Goetze, S. Porembski, and A. Thiombiano, “Identification of Driving Factors of Land Degradation and Deforestation in the Wildlife Reserve of Bontioli (Burkina Faso, West Africa),” Glob. Ecol. Conserv., vol. 4, pp. 559–571, 2015.

[30] A. Russell et al., “Using Forests to Enhance Resilience to Climate Change: The Case of the Wood-Energy Sector in Burkina Faso,” n.p., 2013.

[31] B. Simane, H. Beyene, W. Deressa, A. Kumie, K. Berhane, and J. Samet, “Review of Climate Change and Health in Ethiopia: Status and Gap Analysis,” Ethiop. J. Heal. Dev., vol. 30, no. 1, pp. 28–41, 2016.

[32] Centers for Disease Control and Prevention, “CDC in Burkina Faso,” Atlanta, Georgia, 2011.

[33] Severe Malaria Observatory, “Burkina Faso,” 2019. Online available: https://www.severemalaria.org/countries/burkina-faso [Accessed: 31-Oct-2019].

[34] E. Diboulo et al., “Weather and Mortality: A 10 Year Retrospective Analysis of the Nouna Health and Demographic Surveillance System, Burkina Faso,” Glob. Health Action, vol. 5, no. 1, p. 19078, Dec. 2012.

[35] K. Belesova, A. Gasparrini, A. Sié, R. Sauerborn, and P. Wilkinson, “Annual Crop-Yield Variation, Child Survival and Nutrition Among Subsistence Farmers in Burkina Faso,” Am. J. Epidemiol., vol. 187, no. 2, pp. 242–250, 2018.

[36] International Committee of the Red Cross, “Burkina Faso: Increased Armed Violence Means Loss of Health Care for Half a Million People,” 2019. Online available: https://www.icrc.org/en/document/burkina-faso-increased-armed-violence-means-loss-health-care-halfmillion-people [Accessed: 31-Oct-2019].

Climate change threatens the health and sanitation sector through more frequent incidences of heatwaves, floods, droughts and storms [31]. Among the key health challenges in Burkina Faso are morbidity and mortality through temperature extremes, vector-borne diseases, such as malaria, waterborne diseases related to extreme weather events (e.g. flooding), such as diarrhoea, and respiratory diseases, which are the number one cause of death [32]. According to the Severe Malaria Observatory, malaria is responsible for 61.5 % of hospitalisations in Burkina Faso and the largest contributor to mortality for children under five years of age [33]. Furthermore, extreme weather events as well as climate impacts on food and water supply are likely to increase the risk of malnutrition, hunger and death by famine. Scientific investigations found a strong link between extreme weather events and mortality patterns in Burkina Faso [34]. Additionally, climate-induced variations in crop yields were negatively associated with children’s nutritional status and child survival in rural areas [35]. Despite increased government funding and expansion of health interventions, access to health care in Burkina Faso remains limited and is becoming increasingly difficult: According to the International Committee of the Red Cross (ICRC), more than 500 000 people in Burkina Faso have no access to health care because many health and humanitarian organisations have limited or even closed down their operations due to armed conflicts [36].

Exposure to heatwaves

Rising temperatures will result in more frequent heatwaves in Burkina Faso, leading to increased heat-related mortality. Under RCP6.0, the population affected by at least one heatwave per year is projected to increase from 1.7 % in 2000 to 10 % in 2080 (Figure 17).

Heat-related mortality

Furthermore, heat-related mortality will likely increase from approximately 2 to about 10 deaths per 100 000 people per year, which translates to an increase by a factor of five towards the end of the century compared to year 2000 levels, provided that no adaptation to hotter conditions will take place (Figure 18). Under RCP2.6, heat-related mortality is projected to increase to about 5 deaths per 100 000 people per year in 2080.

References

[31] B. Simane, H. Beyene, W. Deressa, A. Kumie, K. Berhane, and J. Samet, “Review of Climate Change and Health in Ethiopia: Status and Gap Analysis,” Ethiop. J. Heal. Dev., vol. 30, no. 1, pp. 28–41, 2016.
[32] Centers for Disease Control and Prevention, “CDC in Burkina Faso,” Atlanta, Georgia, 2011.
[33] Severe Malaria Observatory, “Burkina Faso,” 2019. Online available: https://www.severemalaria.org/countries/burkina-faso [Accessed: 31-Oct-2019].
[34] E. Diboulo et al., “Weather and Mortality: A 10 Year Retrospective Analysis of the Nouna Health and Demographic Surveillance System, Burkina Faso,” Glob. Health Action, vol. 5, no. 1, p. 19078, Dec. 2012.
[35] K. Belesova, A. Gasparrini, A. Sié, R. Sauerborn, and P. Wilkinson, “Annual Crop-Yield Variation, Child Survival and Nutrition Among Subsistence Farmers in Burkina Faso,” Am. J. Epidemiol., vol. 187, no. 2, pp. 242–250, 2018.
[36] International Committee of the Red Cross, “Burkina Faso: Increased Armed Violence Means Loss of Health Care for Half a Million People,” 2019. Online available: https://www.icrc.org/en/document/burkina-faso-increased-armed-violence-means-loss-health-care-halfmillion-people [Accessed: 31-Oct-2019].

Climate change is expected to have a significant influence on the ecology and distribution of tropical ecosystems, though the magnitude, rate and direction of these changes are uncertain [27]. With rising temperatures and increased frequency and intensity of droughts, wetlands and riverine systems are increasingly at risk of being converted to other ecosystems, with plants being succeeded and animals losing habitats. Increased temperatures and droughts can also influence succession in forest systems while concurrently increasing the risk of invasive species, all of which affect ecosystems.

Species richness

Model projections of species richness (including amphibians, birds and mammals) and tree cover for Burkina Faso are shown in Figure 15 and 16, respectively. The models applied for this analysis show clear patterns of change in species richness across both RCPs: In most regions, the number of species is projected to decrease in response to climate change (Figure 15). In 2080, under RCP6.0, this decrease will reach almost 10 % compared to the year 2000. An increase of species richness is only projected for the south-west of Burkina Faso.

Tree cover

The opposite gradient is found in tree cover projections, with increases projected for the north-east and decreases projected for the south-west (Figure 16). Under RCP6.0, the increase in tree cover in the northeast amounts to about 5 % compared to the year 2000. This can be explained by the increasing precipitation levels in this region.

Although these results paint an overall positive picture for climate change impacts on tree cover, it is important to keep in mind that the model projections exclude any impacts on biodiversity loss from human activities such as land use, which have been responsible for significant losses of global biodiversity in the past, and are expected to remain its main driver in the future [28]. In Burkina Faso, the need for new settlements, land for cultivation and for fuel wood threatens tree cover and biodiversity [29]. Fuel wood covers 85 % of household energy needs in Burkina Faso, resulting in ongoing deforestation [30]. These pressures are likely to intensify due to low agricultural production and population growth, resulting in even higher rates of deforestation, land degradation and forest fires, all of which will impact animal and plant biodiversity.

References

[27] T. M. Shanahan et al., “CO2 and Fire Influence Tropical Ecosystem Stability in Response to Climate Change,” Nat. Publ. Gr., no. July, pp. 1–8, 2016.
[28] IPBES, “Report of the Plenary of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on the Work of Its Seventh Session,” n.p., 2019.
[29] K. Dimobe, A. Ouédraogo, S. Soma, D. Goetze, S. Porembski, and A. Thiombiano, “Identification of Driving Factors of Land Degradation and Deforestation in the Wildlife Reserve of Bontioli (Burkina Faso, West Africa),” Glob. Ecol. Conserv., vol. 4, pp. 559–571, 2015.
[30] A. Russell et al., “Using Forests to Enhance Resilience to Climate Change: The Case of the Wood-Energy Sector in Burkina Faso,” n.p., 2013.

Climate change is expected to significantly affect Burkina Faso’s infrastructure sector through extreme weather events, such as flooding and droughts. High precipitation amounts can lead to flooding of transport infrastructure including roads and railroads, while high temperatures can cause roads, bridges and protective structures to develop cracks and degrade more quickly. Transport infrastructure is very vulnerable to extreme weather events, yet essential for social, economic and agricultural livelihoods. Roads serve communities to trade their goods and access healthcare, education, credit as well as other services, especially in rural and remote areas.

Extreme weather events will also have devastating effects on human settlements and economic production sites, especially in urban areas with high population densities like Ouagadougou or Bobo-Dioulasso. Informal settlements are particularly vulnerable to extreme weather events: Makeshift homes are often built in unstable geographical locations including river banks, where flooding can lead to loss of housing, contamination of water, injury or death. Dwellers usually have low adaptive capacity to respond to such events due to high levels of poverty and a lack of risk-reducing infrastructures. These challenges are particularly salient in Ouagadougou, where urban flooding is a major problem during the rainy season. For example, in 2009, the city experienced torrential precipitation leading to water runoffs and flooding, affecting more than 180 000 people. 41 people died and 33 172 houses were completely destroyed [25].

Despite the risk of infrastructure damage being likely to increase due to climate change, precise predictions of the location and the extent of exposure are difficult to make. For example, projections of river flood events are subject to substantial modelling uncertainty, largely due to the uncertainty of future projections of precipitation amounts and their spatial distribution, affecting flood occurrence (see also Figure 4 in the Climate section). In the case of Burkina Faso, projections for both RCP2.6 and RCP6.0 show almost no change in the exposure of major roads to river floods. In the year 2000, 0.13 % of major roads were exposed to river floods at least once a year, while by 2080, this value is projected to change to 0.14 % under RCP2.6 and to 0.12 % under RCP6.0. In a similar way, exposure of urban land area to floods is projected not to change under either RCP (Figure 13).

While all models project an increase in the exposure of the GDP to heatwaves, the magnitude of the increase is subject to high modelling uncertainty with two models projecting strong and two models projecting weak increases. Median model projections for RCP2.6 show an increase from 2.0 % in 2000 to 7.0 % by 2080. Under RCP6.0, exposure is projected to increase to 10.5 % over the same time period. It is recommended that policy planners start identifying heat-sensitive economic production sites and activities, and integrating climate adaptation strategies, such as improved, solar-powered cooling systems, “cool roof” isolation materials or switching the operating hours from day to night [26].

References

[25] S. Dos Santos, J. P. Peumi, and A. Soura, “Risk Factors of Becoming a Disaster Victim: The Flood of September 1st, 2009, in Ouagadougou (Burkina Faso),” Habitat Int., vol. 86, no. March, pp. 81–90, 2019.
[26] M. Dabaieh, O. Wanas, M. A. Hegazy, and E. Johansson, “Reducing Cooling Demands in a Hot Dry Climate: A Simulation Study for Non-Insulated Passive Cool Roof Thermal Performance in Residential Buildings,” Energy Build., vol. 89, pp. 142–152, 2015.

Smallholder farmers in Burkina Faso are increasingly challenged by the uncertainty and variability of weather that climate change causes [18], [19]. Since crops are predominantly rainfed, they depend on water availability from precipitation and are prone to drought. However, the length and intensity of the rainy season is becoming increasingly unpredictable and the use of irrigation facilities remains limited due to high costs of initial investment, problems regarding the maintenance of the equipment and harsh environmental conditions [20]. Currently, only 0.5 % of the total national crop land and 27 % of the estimated irrigation potential of 233 500 ha are irrigated [21], [22]. Especially in northern Burkina Faso, soils are poor in nutrients, sandy and shallow, which makes them vulnerable to drying, erosion and flooding [23]. 

Crop land exposure to drought

Currently, the high uncertainty of projections regarding water availability (Figure 9) translates into high uncertainty of drought projections (Figure 10). According to the median over all models employed for this analysis, the national crop land area exposed to at least one drought per year will hardly change in response to global warming. However, there are models that project a strong increase in drought exposure. Under RCP6.0, the likely range of drought exposure of the national crop land area per year widens from 0.07–3.8 % in 2000 to 0.04–16.0 % in 2080. The very likely range widens from 0.01–12.0 % in 2000 to 0.01–29.0 % in 2080. This means that some models project up to a fourfold increase in drought exposure over this time period, while others project no change.

Crop yield projections

Climate change will have a negative impact on yields of maize, millet and sorghum (Figure 11). While maize is sensitive to hot temperatures above 35 °C, millet and sorghum tolerate hot temperatures and dry periods better [24]. Still, model results indicate a negative yield trend for all three crops under both RCPs with a stronger decrease under RCP6.0. Compared to the year 2000, amounts are projected to decline by 12.0 % for maize and 7.5 % for millet and sorghum by 2080 under RCP6.0. Under RCP2.6, yields of maize are projected to decline by 8.4 % and yields of millet and sorghum by 5.2 %, whereas yields of cow peas and rice are projected to gain from climate change. Under RCP6.0, projections show an increase in yield by 16.2 % for cow peas and 27.0 % for rice by 2080 relative to the year 2000. An explanation for the positive results under RCP6.0 is that cow peas and rice are so-called C3 plants, which follow a different metabolic pathway than maize, millet and sorghum (C4 plants), and benefit more from the CO2 fertilisation effect under higher concentration pathways. Yields of groundnuts are projected to decrease under RCP2.6 and slightly increase under RCP6.0. The decrease under RCP2.6 can be explained by non-temperature related parameters such as changes in precipitation, while the increase under RCP6.0 can be explained by the CO2 fertilisation effect.

Overall, adaptation strategies such as switching to improved varieties in climate change sensitive crops should be considered, yet carefully weighed against adverse outcomes, such as a resulting decline of agro-biodiversity and loss of local crop types.

References

[18] B. Barbier, H. Yacouba, H. Karambiri, M. Zoromé, and B. Somé, “Human Vulnerability to Climate Variability in the Sahel: Farmers’ Adaptation Strategies in Northern Burkina Faso,” Environ. Manage., vol. 43, no. 5, pp. 790–803, 2009.
[19] B. Sarr et al., “Adapting to Climate Variability and Change in Smallholder Farming Communities: A Case Study From Burkina Faso, Chad and Niger (CVCADAPT),” J. Agric. Ext. Rural Dev., vol. 7, no. 1, pp. 16–27, 2015.
[20] J. Wanvoeke, J. P. Venot, C. De Fraiture, and M. Zwarteveen, “Smallholder Drip Irrigation in Burkina Faso: The Role of Development Brokers,” J. Dev. Stud., vol. 52, no. 7, pp. 1019–1033, 2016.
[21] R. E. Namara and H. Sally, “Proceedings of the Workshop on Irrigation in West Africa: Current Status and a View to the Future,” Colombo, Sri Lanka, 2014.
[22] USAID, “Country Profile: Property Rights and Resource Governance in Burkina Faso,” Washington, D.C., 2017.
[23] USAID, “Climate Risks in Food for Peace Geographies: Burkina Faso,” Washington, D.C., 2017.
[24] USAID, “Climate Risk in Food for Peace Geographies: Kenya,” Washington, D.C., 2019.

Over the last decades, Burkina Faso has experienced strong seasonal and annual variations in precipitation, which present a major constraint to agricultural production. According to the International Water Association, drought has affected a cumulative number of about 12.4 million people between 1969 and 2014 in Burkina Faso [15]. While transhumance used to be an effective way to deal with variations in precipitation and droughts in Burkina Faso, people’s reliance on this type of pastoralism has been challenged by increasingly unpredictable precipitation patterns and, consequently, a lack of good pastures and water, leading to increasing competition for limited natural resources. Other factors include population growth, conflicts between farmers and herders and terrorist activities in the region, making this mode of living less profitable and sometimes even dangerous [16]. Extreme droughts tend to have a cascading effect for farmers: First, lack of water reduces crop yields, which increases the risk of food insecurity for people and their livestock, which in turn limits their capacity to cope with future droughts [16]. Not only rural but also urban areas experience the consequences of droughts: Especially Ouagadougou suffers from recurring water shortages, intensified by rapid urban growth and poor infrastructure. During a severe drought in 2016, the local government had to ration the city’s water supply to 12 hours a day, affecting more than two million people [17].

Per capita water availability

Current projections of water availability in Burkina Faso display high uncertainty under both GHG emissions scenarios. Assuming a constant population level, multi-model median projections suggest only a minor decrease in per capita water availability over Burkina Faso by the end of the century under RCP2.6 and a decrease of 20 % under RCP6.0 (Figure 8A). Yet, when accounting for population growth according to SSP2 projections5, per capita water availability for Burkina Faso is projected to decline by 80 % by 2080 relative to the year 2000 under both scenarios (Figure 8B). While this decline is driven primarily by population growth rather than climate change, it highlights the urgency to invest in water saving measures and technologies for future water consumption.

Spatial distribution of water availability

Projections of future water availability from precipitation vary depending on the region and scenario (Figure 9). However, common to all regions is the high modelling uncertainty of the projected changes. This modelling uncertainty, along with the high natural variability of precipitation, in particular in the north of the country, contribute to uncertain regional future precipitation trends all over Burkina Faso.

References

[15] B. Ampomah-Ankrah, “The Impact of Climate Change on Water Supply in the Sahel Region: The Case of Burkina Faso,” International Water Association, 2019. Online available: https://iwa-network.org/the-impact-of-climate-change-on-water-supply-in-the-sahel-region [Accessed: 31-Oct-2019].
[16] S. Traore and T. Owiyo, “Dirty Droughts Causing Loss and Damage in Northern Burkina Faso,” Int. J. Glob. Warm., vol. 5, no. 4, pp. 498–513, 2013.
[17] M. Winsor, “Drought-Hit Burkina Faso Rations Water Supply in Ouagadougou Amid Severe Shortage,” International Business Times, 2016. Online available: https://www.ibtimes.com/droughthit-burkina-faso-rations-water-supply-ouagadougou-amid-severeshortages-2363145 [Accessed: 02-Mar-2020].

Temperature

In response to increasing greenhouse gas (GHG) concentrations, air temperature over Burkina Faso is projected to rise by 1.9 to 4.2 °C (very likely range) by 2080 relative to the year 1876, depending on the future GHG emissions scenario (Figure 2). Compared to pre-industrial levels, median climate model temperature increases over Burkina Faso amount to approximately 2.0 °C in 2030, 2.3 °C in 2050 and 2.4 °C in 2080 under the low emissions scenario RCP2.6. Under the medium / high emissions scenario RCP6.0, median climate model temperature increases amount to 2.0 °C in 2030, 2.6 °C in 2050 and 3.6 °C in 2080.

Very hot days

In line with rising mean annual temperatures, the annual number of very hot days (days with daily maximum temperature above 35 °C) is projected to rise dramatically and with high certainty all over Burkina Faso (Figure 3). Under the medium / high emissions scenario RCP6.0, the multi-model median, averaged over the whole country, projects 32 more very hot days per year in 2030 than in 2000, 52 more in 2050 and 88 more in 2080. In some parts, especially in south-western Burkina Faso, this amounts to about 250 days per year by 2080.

Precipitation

Future projections of precipitation are less certain than projections of temperature change due to high natural year-to-year variability (Figure 4). Out of the four climate models underlying this analysis, two models project a decreasing trend in mean annual precipitation over Burkina Faso, while the other two models project an increase. Median model projections show strong interannual variability but no clear trend in mean annual precipitation until 2080 under either RCP.

Heavy precipitation events

In response to global warming, heavy precipitation events are expected to become more intense in many parts of the world due to the increased water vapour holding capacity of a warmer atmosphere. At the same time, the number of days with heavy precipitation events is expected to increase. However, this tendency can only be found in half of the climate projections for Burkina Faso. Median climate model projections show no change in the number of days with heavy precipitation under either RCP (Figure 5). The year 2080 is projected to receive 8 days of heavy precipitation, which is equal to the year 2000.

Soil moisture

Soil moisture is an important indicator for drought conditions. In addition to soil parameters and management, it depends on both precipitation and evapotranspiration and therefore also on temperature, as higher temperatures translate to higher potential evapotranspiration. Annual mean top 1-m soil moisture projections for Burkina Faso show a decrease of 2.5 % for both RCP2.6 and RCP6.0 by 2080 compared to the year 2000 (Figure 6). However, there is considerable modelling uncertainty as different hydrological models project different directions of change, which makes it difficult to identify a clear trend.

Potential evapotranspiration

Potential evapotranspiration is the amount of water that would be evaporated and transpired if sufficient water was available at and below the land surface. Since warmer air can hold more water vapour, it is expected that global warming will increase potential evapotranspiration in most regions of the world. In line with this expectation, hydrological projections for Burkina Faso indicate a stronger rise of potential evapotranspiration under RCP6.0 than under RCP2.6 (Figure 7). Under RCP6.0, potential evapotranspiration is projected to increase by 2.7 % in 2030, 3.8 % in 2050 and 6.8 % in 2080 compared to year 2000 levels.

4 Changes are expressed relative to year 1876 temperature levels using the multi-model median temperature change from 1876 to 2000 as a proxy for the observed historical warming over that time period.