Climate Change-Water over Africa

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Climate Change-Water over Africa
WMO
EMA

• Dr. Ashraf Zakey
• The Egyptian Meteorological Authority

the RA I Working Group on Hydrology Meeting in
Accra, Ghana 16-21 November 2015
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Introduction

1. Africa is thought to be the region most
   vulnerable to the impacts of climate variability
   and change.
2. Changes in water demand and availability under
   climate change will significantly affect
   agricultural activities and food security,
   forestry and fisheries in the 21st century.
   Forest ecosystems, and the biodiversity
   associated with them, may be particularly at risk
   in Africa, due to a combination of socio-economic
   pressures, and land-use and climate-change
   factors.
3. Over the last few decades the northern regions of
   North Africa (north of the Atlas Mountains and
   along the Mediterranean coast of Algeria and
   Tunisia) have experienced a strong decrease in
   the amount of precipitation received in winter
   and early spring (Barkhordarian et al., 2013).
4. By 2100, negative impacts across about 25 of
   Africa (especially southern and western Africa)
   may cause a decline in both water quality and
   ecosystem goods and services.
5. In sub-Saharan Africa, 42 of the population is
   without access to improved water.
6. Areas where there are sufficient data include
   very likely decreases in annual precipitation
   over the past century over parts of the western
   and eastern Sahel region in northern Africa,
   along with very likely increases over parts of
   eastern and southern Africa (IPCC, 2015).

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Global Drivers of Change Knowledge-Scientific
Consensus Change

• The climate system is driven by solar radiation
  from the Sun
• Phenomena that affect the energy balance of the
  climate system would ultimately alter the climate

• Global warming is caused by the emission of GHG
  their increasing concentration in the atmosphere
  due to human activities
• Concentration of the major GHG has increased
  since 1750
• Carbon dioxide (CO2) increased by 32
• Methane (CH4) increased by 150
• Nitrous Oxide (N2O) increased by 17
• The increase in atmospheric CO2- fossil-fuel
  burning and land use change including
  deforestation
• The increase in CH4 N2O - emissions from
  energy use, livestock, rice agriculture, and
  landfill.

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Prospects under climate change Scientific
Consensus

• Earths climate results from interactions of many
  processes in the components of the climate
  system Anthropogenic system (human activities)
  disturb the balance
• The climate system and hydrological balance
  change as a result

• Temperature increase in Africa
• Warm atmosphere which absorb more water vapor
  and an increase in humidity,
• More water moving through the hydrological
  cycle, more extreme event

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Climate variability in Africa

• The Sahel region of West Africa experiences
  marked multidecadal variability in rainfall
  (e.g., Dai et al., 2004a), associated with
  changes in atmospheric circulation and related
  changes in tropical sea surface temperature
  patterns in the Pacific, Indian and Atlantic
  Basins (e.g., ENSO and the AMO).
• Very dry conditions were experienced from the
  1970s to the 1990s, after a wetter period in the
  1950s and 1960s. The rainfall deficit was mainly
  related to a reduction in the number of
  significant rainfall events occurring during the
  peak monsoon period (July to September) and
  during the first rainy season south of about 9N.
  
• The decreasing rainfall and devastating droughts
  in the Sahel region during the last three decades
  of the 20th century are among the largest climate
  changes anywhere.
• Sahel rainfall reached a minimum after the
  1982/83 El Niño event. Modelling studies suggest
  that Sahel rainfall has been influenced more by
  large-scale climate variations (possibly linked
  to changes in anthropogenic aerosols), than by
  local land-use change.

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African Climate Zone

• Warm Zone
• Hot and Dry Zone
• Cool and Wet Zone
• Hot and Wet Zone
• Cold and Wet Zone

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Water and Climate Change

• Climate change will lead to more precipitation -
  but also to more evaporation
• Precipitation will probably increase in some
  areas and decline in others.
• Changing precipitation patterns will affect how
  much water can be captured.
• The drier the climate, the more sensitive is the
  local hydrology.
• High-latitude regions may see more runoff due to
  greater precipitation.
• The effects on the tropics are harder to predict.
  
• Reservoirs and wells would be affected.
• New patterns of runoff and evaporation will also
  affect natural ecosystems.
• Rising seas could invade coastal freshwater
  supplies.
• Reduced water supplies would place additional
  stress on people, agriculture, and the
  environment.
• Conflicts could be sparked by the additional
  pressures.
• Improved water resource management can help to
  reduce vulnerabilities.

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Drivers of change
River flows groundwater quality
Population demand for water
Wealth equity access
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The main water-related projected impacts by
regions

1. The impacts of climate change in Africa are
   likely to be greatest where they co-occur with a
   range of other stresses (population growth
   unequal access to resources inadequate access to
   water and sanitation food insecurity poor
   health systems. These stresses and climate change
   will increase the vulnerabilities of many people
   in Africa.
2. An increase of 58 (6090 million ha) of arid
   and semiarid land in Africa is projected by the
   2080s under a range of climate change scenarios.
3. Declining agricultural yields are likely due to
   drought and land degradation, especially in
   marginal areas. Mixed rainfed systems in the
   Sahel will be greatly affected by climate change.
   Mixed rain-fed and highland perennial systems in
   the Great Lakes region and in other parts of East
   Africa will also be severely affected.
4. climate change, but water governance and
   water-basin management must also be considered in
   future assessments of water stress in Africa.
   Increases in runoff in East Africa (and increased
   risk of flood events) and decreases in runoff
   (and increased risk of drought) in other areas
   (e.g., southern Africa) are projected by the
   2050s.

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Bodies Of Water

• Rivers in Africa provide
• fish for food
• water for irrigation
• transportation routes
• hydroelectric power (energy produced by moving
  water)
• source of precious metals.

Indian Ocean
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Africas Water Challenges
Safe Drinking Water

• Managing water under climate change ? complex
  problem
• Gap exists
• -Data, science base and analytical capacity,
  investment
• Adequate development gt adequately responding to
  CV and CC
• Policy and institutional instruments eg. in TB
  management

Adequate Sanitation
Manage Water Under CC
Transboundary Basin Cooperation
Meet Growing Water Demand
Water for Food Security
Develop Hydropower
Safe Drinking Water
Enhance Capacity to Meet Challenges
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Africa's Water Resources Base

• Resources summary
• Rainfall 670 mm/year providing 20,100 km3
• IRW 3,931km3 (20 of RF)
• 13 major river basins
• 63 TB, 63 land area, 93 total surface water,
  home for 77 of population
• GW is 15 of IRW
• 38 major TB aquifers

• Water development management is critical for
  resilience and growth
• Transform development management of water

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Predicted changes in water availability
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Vulnerability to climate changeThorton et. al.,
2006
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Measures of stress

• Indicators of exposure
• Numbers affected by flood / drought
• Indicators of access
• Numbers with access to safe water
• Indicators of availability
• Resources per capita

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African Climate Change and hotspot

1. Africa is especially vulnerable to climate
   change, both because of the dependence of many
   sectors on climate variability (e.g agriculture,
   water management, health) and because of the
   relatively low adaptive capacity of its
   economies.
2. Climate change may have significant impacts on
   temperature and precipitation patterns over
   Africa, which, in turn, can interact with other
   environmental stressors such as land-use change,
   desertification and aerosol emissions.
3. To date, only very few simulations based on
   regional climate downscaling (RCD) tools are
   available for Africa, so this region will benefit
   particularly from the CORDEX framework, from both
   the research and application points of view.

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• Africa is one of the most vulnerable continents
  to climate variability and change because of
  multiple existing stresses and low adaptive
  capacity.
• Water Disaster Risk is projected to severely
  compromise agricultural production, including
  access to food, in many African countries and
  regions.
• By 2050, between 350 million and 600 million
  people are projected to experience increased
  water stress due to climate change

Fig. Africas climate zones by Raúl Iván
Alfaro-Pelico, 2010
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Effects of CC on Water Resources in Africa

• Global models
• Agree in predicting warming of surface
  temperature over this region.
• The same models disagree on even the sign of the
  predicted changes in rainfall and hence river
  flow.

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1. CRCM5 CORDEX-Africa simulation domain, including
   the semi-Lagrangian halo and Davies sponge zone
   only every 5th grid box is displayed
2. The different regions within the African domain

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Future Projected precipitation In JFM

1. In JFM projected changes of rainfall are overall
   small and there is little consensus between
   models.
2. CanESM2 gives an increase in precipitation in the
   East Africa region that intensifies towards the
   end of the century, which is not the case for MPI
   or CanESM2-driven CRCM5 simulations.
3. CanESM2-driven CRCM5 simulation projects drying
   in the Congo basin while CanESM2 projects no
   change in the region.
4. MPI and MPI-drivenCRCM5 simulations project
   little change in precipitation over land.
5. Otherwise over the ocean there is an increase in
   precipitation over the equatorial Atlantic Ocean
   growing toward the end of the century in MPI,
   which is not reproduced in the MPI-driven CRCM5
   simulation.

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Laprise et al., 2013
Projected changes in seasonal-mean precipitation
for a JFM from CRCM5 driven by CanESM2 (line 1)
and by MPI (line 3), as well as from the
corresponding driving models
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Future Projected precipitation In JAS

1. The common feature of the projected precipitation
   changes in JAS is a narrowing of the tropical
   rain-belt and intensification of its maximum,
   although the details of projected changes differ
   among the models.
2. There is a decrease in precipitation over the
   equatorial Atlantic Ocean and the Gulf of Guinea
   in CanESM2, particularly intense in the second
   half of the twenty-first century, and it goes
   inland over central Africa to the east and over
   southern Mali and Senegal to the north.
3. At the same time there is an intensification of
   the precipitation over land in a band south of
   15N. Drying is also projected but of lesser
   extent by MPI over the ocean to the north and to
   the south of the tropical rain-belt for which
   there is a projected increase of intensity.

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Laprise et al., 2013
Projected changes in seasonal-mean precipitation
for JAS from CRCM5 driven by CanESM2 (line 1)
and by MPI (line 3), as well as from the
corresponding driving models
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Laprise et al., 2013
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The hotspot shows the ensemble mean of RCCI over
Africa based on the three scenarios A1B, A2, and
B1 for the periods 2081-2100, i.e. the period
when the climate change signal is maximum, with
respect to 1961-1980. The RCCI shows pronounced
spatial variability over this region, varying
from values less than 8 to greater than 16. SMED
and SAH have the largest RCCI value, where the
contribution comes from decrease in mean
precipitation in the two seasons, and small
increase in the RWAF in MAMJJA and the increase
in precipitation interannual variability in
MAMJJA and SONDJF seasons. WAF, EAF, EQF have
similar RCCI values and the contributions come
from the increase in mean precipitation in the
SONDJF season.
Hotspots over Africa during the period 2081-2100,
A1B, A2 and B1 Scenario Ensemble
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SAF RCCI value is relatively large and the
contributions come from the decrease in the mean
precipitation in the MAMJJA season, and small
increase in the precipitation variability in the
two seasons. The contribution of precipitation
generally shows complex patterns and substantial
variability, especially for the interannual
variability. For mean precipitation we can see
symmetrical patterns around the equator which is
consistent with the symmetry in the climatic
zones in the northern and southern hemispheres in
Africa. Over EQF, there is a small increase in
the precipitation in MAMJJA and a large increase
in SONDJF. Over WAF there is a small increase in
precipitation in the SONDJF case. A large
increase in precipitation is found over the EAF
in the SONDJF season.
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• Here we could see the contribution of the changes
  in interannual variability shows complex patterns
  and marked geographical variations .
• The results indicated that are is an increase in
  the precipitation interannual variability, with
  noticeable exceptions occurring over parts
• in Mali and Niger in the WAF,
• North West of Sudan in EAF, and
• over Uganda in the EQF.
• The increase in variability is especially
  pronounced over SMED and SAH in the two seasons,
  while in SQF and SAF we find small increase in
  the precipitation variability. The marked spatial
  variability of the change in variability further
  highlights the need of a fine scale analysis of
  climate change variables.

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the RCCI values averaged over each of the 7
regions of Africa calculated for 5 successive
20-year periods (2001-2020, 2021-2040, 2041-2060,
2061-2080, 2081-2100) with respect to 1961-1980
and for the mid-range A1B scenario, high-range A2
scenario, low-range B1scenario, and their average.
In general, we find increasing values of RCCI
with time, and thus with GHG forcing. we define
an RCCI threshold of 10 to identify a hot-spot,
the first to appear in 2021-2040 is SAH for A2,
and having only a slightly smaller value for A1B
and smaller in B1 scenario. The RCCI for the
SMED, SAH, and SAF regions increases almost
linearly with time in the full ensemble average.
However we also notice a decrease towards the end
of the century for the SMED region in the B1
scenario, a decrease towards the end of the
century for the SAH region in the A2 scenario,
and a decrease towards the end of the century for
the SMED and SAH regions in the A1B scenario.
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Effects of Climate Water and None Water Disasters

• At a global scale, water disasters are increasing
  under climate change
• The frequency of heavy precipitation events has
  increased over most land areas.

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The annual total and cumulative number of natural
disaster events recorded globally between 1900
and 2006
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Effects of Climate Africas risks
Drought Exposure
Flood Exposure
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Impact of climate change snow melt- Climate
change is already heating Africa

• The ice-cap on Kilimanjaro disappearing
• Reduction of the ice-cap by 82 since 1912
• It may disappear within 15 years
• Drying out of several rivers

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1. Angola High Plateau (AHP) plays an important role
   in partitioning water resources from
   precipitation among key major basins in the
   Southern Africa, and is a critical recharge area
   for the Northern Kalahari Aquifer (NKA) system.
2. shows the large major aquifer systems in Africa.
   The NKA is between the rich Congo Intracratonic
   Basin and the deep Southeast Kalahari Aquifer
   system.
3. illustrates the location of the Upper Zambezi
   River Basin (UZRB) while displaying the major
   river basins in Southern Africa.
4. shows the digital elevation model(DEM) of the
   UZRB, also displaying the river systems of the
   area.

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Niger Basin river network of hydrometric stations
(Note flow data are shown in billion m3/year)
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Shrinking of Lake Chad
Driven by climate change or land use change?
Lake Chad in a 2001 satellite image, with the
actual lake in blue, and vegetation on top of the
old lake bed in green. Above that, the changes
from 1973 to 1997 are shown.
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Impact of climate change sea level rise

• gt 25 of Africas population lives within 100km
  of the coast
• 30 percent of Africas coastal countries is at
  risk of inundation
• Impacts of sea level rise
• Reduced productivity of coastal fisheries
• Migration and health issues
• negative impacts on tourism

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Impacts agriculture and economy

• Climate is already changing and Africa already
  impacted
• Ethiopia Extreme variability affecting GDP as
  agriculture is affected
• Burkina Faso Variability linked to cereal
  productivity
• Kenya30-50 around the mean- drought flood

Loss in production, infrastructure, and increased
poverty
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CC Impacts production, livelihood, settlement

• Impacts on Production System
• Flood Impacts on Shelter with displacement
  migration from one area to another
• Drought influence infectious diseases such
  meningitis,
• Deplete food cash savings

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CC Impacts production, livelihood, settlement

• The weak Infrastructures in Africa
• National Security
• Impact on the drinkable water and water
  sanitation
• River Basin

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Conclusion get on board (the bit has left the
station)
Any Questions
Thank You