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What The Changing Climate Means
For Water, Farms, And Human Health

Gemma Norrington-Davies, Catherine Cameron and Emma Back

Climate change is projected to bring more storms and longer droughts spread over a wider area than at any time in recorded history – effects we may already be feeling. CDKN tells us what the science says about water supplies, agriculture, and overall human health – and what we can do about it.

Climate change is projected to bring more storms and longer droughts spread over a wider area than at any time in recorded history – effects we may already be feeling. CDKN tells us what the science says about water supplies, agriculture, and overall human health – and what we can do about it.

16 October 2012| Climate change attacks water supplies and agriculture while making life easier for the kinds of opportunistic bugs and vermin that spread disease. It attacks, in other words, the very foundation of our economy, yet the cost of dealing with it, has gotten short shrift in the media – largely because the science is always complex and often impenetrable.

That’s why the Intergovernmental Panel on Climate Change (IPCC) distilled all known research on the impact of climate-change into a 600-page document called “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation” (SREX).

Published late last year, SREX grew out of a long and tedious process involving 220 authors from 62 countries and incorporating nearly 20,000 independent comments, and is designed to help policy-makers, planners and individuals whose work contributes to the water, health, agriculture and ecosystem conservation sector understand and discuss these fundamental questions:

  •  Why are extreme events a critical issue in relation to these four sectors?
  •  How are these sectors affected by the risk and impact of extreme events?
  •  What actions can be taken to manage these risks?
  •  What does SREX mean for these sectors?

To make the material more digestible, the Climate and Development Knowledge Network (CDKN) has broken the SREX down into 40-page summaries on water, agriculture, health, and ecosystems in general, as well as regionally for Asia, Africa, Latin American, and Caribbean regions. These are available at www.cdkn.org/srex and have been translated into multiple languages.

The Water Sector

The first report, Managing climate extremes and disasters in the water sector, examines the impact of heavy precipitation, intensified droughts, upward trends in extreme coastal high water levels, and changes in flood patterns on water resources.

Populations exposed to water-related hazards are already significant and are likely to increase. Water-related extreme events such as flooding, droughts and coastal inundation will have a broad range of impacts on humans and on ecosystems. These include economic losses, and pressures on particularly exposed human settlements such as coastal cities and Small Island Developing States (SIDS).

There is a high level of scientific confidence that changes in the climate could seriously affect water management systems – such as water storage and treatment plants, and supply systems. A surplus of water can affect system operation, but more typically there is a shortage of water relative to demand – a drought. Water supply shortages may be triggered by a shortage of river flows and groundwater, deterioration in water quality, or an increase in demand.

There are several approaches that planners and policy-makers can take, working with other stakeholders, to help manage the risks presented by climate extremes and disasters and their impact on water resources and water management. These include: assessing risks and maintaining information systems; developing strategies to support coping and adaptation; learning from experience in managing risk; and linking local, national and international approaches.

Examples cited in the report included Mozambique’s catastrophic flood in 2000 that led to institutional and legislative changes related to disaster risk management. New York’s holistic water management approach that will reduce water and energy costs and reduce the burden on the city’s aging sewage system through green infrastructure is also mentioned.

As extreme climate and water-related hazard events increase in coming decades, climate change adaptation and disaster risk management are likely to require not only incremental but transformational changes in processes and institutions. This will involve moving away from a focus on issues and events towards a more holistic approach – for example, integrating water management with urban planning and design, and into policies on land use.

The Agriculture Sector

The second report, Managing climate extremes and disasters in the agricultural sector, builds on the first and examines the way heatwaves, rain, droughts, and floods will impact crops, livestock and people.

One of the reasons the agricultural sector is vulnerable to climate change and weather extremes is because of its dependence on natural resources like water and ecosystem services. Water supply for agricultural production, for example, will be critical to sustain production and even more important to provide the increase in food production required to sustain the world’s growing population.

Transformational approaches are required in the management of natural resources, including new climate-smart agriculture policies, practices and tools, better use of climate science information in assessing risks and vulnerability, and increased financing for food security. Planners and policy makers have a key role to play in creating a conducive policy environment and securing financing for such transformation.

“Low regrets” adaptation options typically include improvements to coping strategies (i.e. strategies to overcome adverse conditions and restore basic functionality in the short to medium term) or reductions in exposure to known future threats, such as better forecasting and warning systems and the use of climate information to better manage agriculture in drought-prone regions. Other short-term adaptation strategies include diversifying livelihoods to spread risk, farming in different ecological niches, and risk pooling at the regional or national level to reduce financial exposure. Longer-term strategies include land rehabilitation, terracing and reforestation, measures to enhance water catchment and irrigation techniques, and the introduction of drought-resistant crop varieties.

The Health Sector

The third report, Managing climate extremes and disasters in the health sector, examines the number of deaths, injuries and disability that may directly result from extreme events, but also takes stock of the impact that infectious diseases (such as cholera) and malnutrition due to crop damage and disruption of food supply will have on people. Other health impacts of extreme events may be indirect, but long lasting, and are often associated with mental health impacts such as stress, anxiety and depression.

Extreme climate and weather events can also negatively impact the critical infrastructure needed to protect human health. There is high confidence that changes in the climate could seriously affect water management systems, which will affect sanitation and health. Extreme events may cause failures in hospital or health centre building structures, and can also prevent people accessing health services, for example during a storm or flood.

Those most likely to experience difficulty accessing health services during or after an extreme event are individuals already considered vulnerable with respect to their health – such as children, the elderly, pregnant women, and those who may need additional response assistance including people with disabilities. In addition, as those with the least resources often have low health status and the least ability to adapt, the poor and disenfranchised are also the most vulnerable to climate-related health impacts. Extreme events can therefore exacerbate health inequalities.

Importantly, there are several approaches that planners and policy-makers can take, working with other stakeholders, to help manage the risks presented by climate extremes and disasters and their impact on health infrastructure, services, outcomes and inequalities. These include:

  • assessing risks and maintaining information systems, particularly public health surveillance systems
  • developing strategies to support coping and adaptation, including building the capacity of communities to prevent, prepare, respond to and recover from extreme events
  • learning from experience in managing risk
  • linking local, national and international approaches

The Ecosystem Sector

Finally, Managing climate extremes and disasters for ecosystems examines the impact of climate change on the planet’s living ecosystems.

Healthy ecosystems, whether natural or modified, have a critical role to play through adaptation by reducing the risk of impacts from climate extremes and disasters on human society. Investment in sustainable ecosystem management has the potential to provide improved livelihoods and well-being. For example conservation of water resources and wetlands that provide hydrological sustainability can further aid adaptation by reducing the pressures and impacts on human water supply. Forests have also been used in the Alps and elsewhere as effective risk reducing measures against avalanches, rock falls and landslides since the 1900s, and mangrove replanting has been used as a buffer against cyclones and storm surges, with reports of 70-90% reduction in energy from wind generated waves in coastal areas and reduction in the number of deaths from cyclones, depending on the health and extent of the mangroves.

The benefits of healthy ecosystems should place ecosystem services management at the heart of key policy decisions associated with climate change. Some countries have begun to explicitly consider ecosystem-based solutions for climate change mitigation, adaptation, and responses to weather and climatic extremes as an integral element of national and sectoral development planning. These include Brazil, the Caribbean Islands, Tajikistan and Vietnam. However, in choosing an ecosystem-based adaptation option, decision makers may need to make tradeoffs between particular climatic risk reduction services and other ecosystem services also valued by humans.

Investment in sustainable ecosystems and environmental management has the potential to provide improved livelihoods. There is consensus on the important role of ecosystems in risk reduction and well-being, which should make the value of ecosystem services an integral part of key policy decisions associated with adaptation. Ecosystem-based adaptation integrates the sound management of biodiversity and ecosystem services into an overall adaptation strategy, and can provide cost effective risk reduction.

Increasing and restoring the biological diversity of ecosystems allows a greater range of ecosystem responses to hazards, thus increasing the resilience of the entire system. With a changing climate there is a likelihood of pest, diseases and non-native species expansion. This can adversely affect species distribution and dominance in a given ecosystem and therefore affect the system’s overall resilience. Reducing non-climate stresses on ecosystems can also enhance their resilience to climate change and weather extremes. For example, coral reef ecosystems are damaged by overfishing, damage and extraction of corals and shells for sale.

Ecosystem management can play an important part in the global endeavour to mitigate greenhouse gas emissions and therefore avoid the worst climate extremes and their associated impacts. For example, supporting forest ecosystems can deliver both adaptation and mitigation benefits, providing a ‘win-win’ response. Forest conservation can reduce carbon emissions and, where timber extraction is carefully managed at renewable rates to provide sustainable biomass for heat and power, can contribute to human development. Forest conservation can create or maintain large contiguous areas of wildlife habitat that increase species’ resilience to weather and climate extremes.


Catherine Cameron is the Director of Agulhas. Emma Back is the Principle of Agulhas and Gemma Norrington-Davies is a consultant for Agulhas.
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