Chapter 3 of the UN 2020 Water and Climate
change report dives deeply into water availability, infrastructure, and
ecosystems. Climate change impacts many elements of water management, including
water storage, supply, and sanitation.
Impacts
on water resources and infrastructure
It is important to consider how climate change
will affect water scarcity ,
ecosystem degradation, and water pollution. Water scarcity can be categorized
into economic water scarcity and physical scarcity. Economic water scarcity is
caused by a lack of water infrastructure, which is typically seen in Africa and
South Asia. The only way to alleviate economic water scarcity
is to build water climate-resilient infrastructure that provides water to
people. Physical scarcity, on the other hand, is caused by excessive water
withdrawals for developed infrastructure causes. Physical scarcity can be seen
in places including but not limited to North Africa, Southern Africa, the
Middle East, Northern China, Australia. These places with depleted water
sources are at risk of seeing major biodiversity loss and ecosystem
degradation, which reduces the ecosystem's resilience and makes communities
more vulnerable to climate change. Other factors can add to water
infrastructure’s vulnerability to climate change, including the
infrastructure’s age, quality, and location relative to flood-prone low-lying
cities.
Two major water infrastructures that need to
be assessed are dams and sanitation and hygiene infrastructure. Dams are
costly, can have negative environmental and social impacts, and can be
destroyed or weakened by the effects of climate change. Many existing dams in
places like the United States are decommissioned, so it is vital that future
dams like those being built in Morocco are climate-resilient. Sanitation, and
hygiene infrastructure are at risk of facing increased damage from climate
change. Flooding sewer pumping stations, for example, can spread faces and
associated viruses, causing severe health-hazards for the population. Although
this is not
a pretty example,
it is emblematic of the need for climate-resilient infrastructure.
Options
to enhance water security under a changing climate
In order to secure our water in a changing
climate, we need to innovate conventional water infrastructure so that it
factors in drought resistance, flood control, regional development and other
needs conjunctively and yet provide public goods (navigation, river basin
management, maintaining ‘ecological’ river flows, etc.), and recognizes the cross-sectoral
and multi-purpose nature of water.
The report highly recommends blending
nature-based solutions with conventional infrastructure, and strengthening
existing water, sanitation, and hygiene infrastructure. Water, sanitation, and
hygiene infrastructure development should focus on six categories: technologies
and infrastructure, financing, policy and governance, workforce, information
systems, and service delivery. The report also stresses the development of
groundwater collection infrastructure and the need to reassess the capacity of
aquifers.
The report also states that it is increasingly
necessary to consider unconventional water sources to ensure accessibility to water. All strategies must be evaluated for their environmental
impacts and associated human health risks.
Safe water reuse/reclaimed water: Treating
used water for new use is a way to save water. This is mostly done in arid and
semi-arid regions that use treated wastewater for irrigation. In Namibia, the
city of Windhoek has used this strategy for over 50 years. There is growing
potential for safe water reuse in Europe, particularly in Portugal and Spain.
Sea water and brackish water desalination:
Desalination turns saltwater into freshwater and is mostly present in the Middle
East and North Africa. Although the source of seawater is unlimited and
renewable energy sources are becoming cheaper, the desalination process does
consume a lot of energy.
Atmospheric moisture harvesting: Cloud seeding
or fog water collection like Dar Si Hmad’s works in areas where fog is
abundant. Because of the limited reach of fog, this works best at the local
level and is a low-cost and low-maintenance approach.
Offshore aquifers: According to the report,
0.5 million km3 of fresh/brackish water exists in offshore aquifers located
below shallow (<500 m) ocean water within 100 km of the shoreline. The
report spends little time talking about offshore aquifers because it points out
that offshore groundwater is not the solution to water scarcity, although it
can be weighed with alternatives.
Physical transportation of freshwater by the
sea: This strategy involves shipping freshwater from places like the Amazon, or
icebergs or ‘shaved ice’ from icebergs, around the world to places in need.
This was considered for Cape Town South Africa in 2017-2018, when the city
almost ran out of water in a severe drought. This strategy only exists as a
concept, however, because it is costly, requires a large fleet, and has large
potential losses.
Mitigation
options for water resources management
Mitigation measures should also be implemented because water management produces 3-7%
of the world’s greenhouse gasses, especially from energy used to power systems
and the biochemical processes involved in water and wastewater treatment.
80-90% of wastewater in developing countries, however, is not collected.
Collecting wastewater may be a positive step in decreasing greenhouse gas
emissions from water management.
Electricity use is another big greenhouse gas
emitter for water management systems. One way to make energy use more efficient
is to convert the organic matter from wastewater into energy for the water
management system.
Finally, wetlands and peatlands can be
conserved and sustained because they accommodate the largest carbon stocks and
store twice as much carbon as forests. Unfortunately, many wetlands and
peatlands are poorly managed and drained for agricultural purposes, which
releases more carbon dioxide and other greenhouse gases into the air.
Written by: Gari DeRamos, Dar Si Hmad former intern
