David Macdonald is a
senior hydrogeologist in the Groundwater Directorate in BGS. He is currently coordinating
the BGS contribution to an exciting four-year project that is improving the
understanding of the climate in East Africa and using this to assess impacts of
climate change on urban water and sanitation, rural livelihoods and water
management.
Five years ago, the Future Climate for Africa Programme,
funded by NERC and DFID, set out to generate fundamentally new climate science
focussing on Africa, and to ensure that this science has an impact on human
development across the continent. Within the programme, the IMPALA project - led
by the Met Office - is tackling the major scientific hurdle that limits the use
of climate information: that current climate models have only a modest ability
to capture African climate systems. Four further projects are focussing on
specific regions of the continent. The project involving the British Geological
Survey is in East Africa - 'HyCRISTAL:Integrating Hydro-Climate Science Into Policy Decisions For Climate-ResilientInfrastructure And Livelihoods In East Africa', with a budget of £4M. It is
led by Leeds University and in the UK, in addition to BGS, involves the Met
Office, the Walker Institute at Reading University, the Centre for Ecology and
Hydrology, Evidence for Development and Loughborough University. In East Africa
there are many institutions and NGOs involved including Makerere University,
Maseno University, Jomo Kenyatta University, Practical Action and the national
Met Agencies. From the USA, research teams in Connecticut, Stonybrook and North
Carolina State Universities are also involved.
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| HyCRISTAL showcase event - an expert panel gives its views on the challenges facing East Africa as a result of climate change |
The first Annual Meeting was opened by the Ugandan Prime Minister four years ago, partners and
stakeholders met for the final showcase event at the Fairway Hotel in Kampala
to share some of the exciting climate science and impact studies that have
taken place during the project (although thanks to an extension until March
2020, or perhaps even longer, there is still work ongoing).
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| An automatic weather station installed at one of Kampala's water treatment works, as part of the new meteorological network |
The HyCRISTAL project has taken advantage of the new pan-Africa high-resolution (4.5 km) climate model developed
in the IMPALA project which, crucially, explicitly simulates the rainfall-generating
convection processes in the atmosphere. This has been used to show that there
is likely to be a greater and more widespread increase in extreme rainfall in
East Africa than indicated by models in the CMIP suite that feeds into the IPCC assessment reports - these take a more simplistic
approach to simulating convection. Research has also shown that in East Africa,
where there are two wet seasons, climate change may lead to later and longer Short
Rains (September to December), with a larger rainfall increase than in the Long
Rains (March to May), and with an earlier end to the Long Rains. The project
has also shown that aerosol emissions may induce climate changes not currently included
in CMIP, and that the model that generates the greatest rainfall increase for
East Africa is likely implausible due to its rainfall increase being driven by
unrealistic processes in the Southern Ocean.
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| Kampala residents gathering water from one of the springs being monitored by the HyCRISTAL project |
In terms of impact studies, the
HyCRISTAL project has examined the implications of climate change on Lake
Victoria levels and on tea production. BGS has developed river flow models for
27 catchments across East Africa and examined how flows might change by the
2050s by driving the models with rainfall and temperature outputs from the CMIP
models. The range of projected flows in each catchment is wide. In some of the
catchments there is general consensus in the direction of change of the modelled
future flows, however, across all the catchments this is neither consistently
an increase nor decrease in flow. What is consistent is that when the output
from the IMPALA high-resolution
convection-permitting climate model is used
to drive the river flow models, the flows are
higher than with the CMIP models. This shows that use of the CMIP models may
lead to underestimation of future river flows. BGS is working closely with the
Uganda Ministry of Water and Environment to assess what these model results
mean for water resource planning.
BGS is also involved in a
number of other aspects of the project. It is collaborating with flood
modellers and water and sanitation engineers to examine flood risk under future
climates, what impact this has on the low income urban population in the
region, and how infrastructure can be made more resilient. BGS is also working
with Makerere University in Kampala to better understand the resilience of
spring water supplies and has helped to set up a hydrometeorological network in the city which has provided essential data to allow high intensity
rainfall datasets to be produced to drive the flood models.
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| Impacts that may be felt in Urban East Africa under three different possible climate futures. More information here |
Informing decision makers is
a key element of the HyCRISTAL project. It is challenging for decisions to be
made given the uncertainties in the future climate, as well as other future
land use and socio-economic conditions. As a means to help decision-makers
assess the possible impacts of climate change a series of simplified urban and rural future scenarios have been
developed on the project.
The HyCRISTAL project
continues to be an excellent opportunity for interdisciplinary science and the
BGS team that also includes Matt Ascott, Vasileios Christelis and Dan Lapworth
are looking forward to working with the wider project team in the final months
ahead.
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