Freshwater can make or break our ability to successfully implement many climate change mitigation solutions. Our upcoming report, launched in the autumn 2022, will present why, where, and how freshwater should be integrated into climate change mitigation plans and activities, to enable effective transition to net-zero greenhouse gas emissions.

This Executive Summary, published ahead of the report, details the main areas of the research undertaken, and highlights the key messages which have come out of that.

The essential drop to reach net-zero

In its Sixth Assessment Report on Mitigation of Climate Change, the International Panel on Climate Change (IPCC) has identified numerous climate mitigation measures that can provide a pathway to achieve rapid transition to net-zero emissions. Many of these measures have a direct link to freshwater.

In this report, we explain how the journey towards climate security requires massive, cross-sectoral efforts in improved management of water.

It focuses on:

  1. climate mitigation measures that require or modify freshwater sources or freshwater-dependent social-ecological systems
  2. climate mitigation options within the water and sanitation sector with upscaling potential

The report addresses the multiple freshwater-related synergies and trade-offs that exist between climate mitigation and adaptation measures. It highlights the benefits of water-wise mitigation actions working with nature, such as enhanced system resilience, functioning ecosystems and enhanced biodiversity, contributing to sustainable development.

The findings attest to the urgent need to improve the understanding of the links between the different climate mitigation measures, freshwater availability, and water management. It identifies high-potential water-related mitigation opportunities across the sectors and biomes where water management and nature-based solutions can contribute to reduce greenhouse gas (GHG) emissions and thus global warming. It further points out water-related risks to be avoided in mitigation planning to prevent uninformed and therefore unsustainable GHG mitigation planning from negatively impacting water resources.

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Water is the foundation of successful mitigation action: Earth's climate system and water cycle are deeply intertwined.

wetlands at sunrise in Thalaynoi, Thailand

Part I. Setting the Scene on Freshwater’s Role in Mitigation: A Physical Science and Governance Background

The report starts with providing a background and context by introducing the biophysical interdependencies of freshwater’s role for climate mitigation, and the governance context of climate mitigation measures.

Read more about Part I

Chapter 2. Freshwater’s role for climate mitigation – the physical science basis

Chapter 2 focuses on the intricate relationship between climate and water in the larger context of the Earth system. It explains how climate mitigation measures fundamentally depend on, and impact, freshwater resources and the water cycle and why a functioning freshwater cycle is crucial for climate mitigation measures to reach their full potential.

Read more about Chapter 2

Chapter 3. Governance context of mitigation measures

Chapter 3 provides an overview of the global governance frameworks and national instruments relating to climate change, biodiversity, land, water, and sustainable development. It also covers various financing mechanisms and instruments available to realise the goals outlined in these frameworks. The review points out the existing barriers to achieve climate mitigation as leverage points are not capitalised on, and risks are not accounted for. It also highlights that integrated approaches are needed to overcome these barriers.

Read more about Chapter 3

Sewage plan at sun set

Part II: Water-related mitigation opportunities across biomes and sectors

The second part provides an analysis of climate mitigation measures, keying in on their use of, and impacts on, freshwater and freshwater-dependent systems.

Read more about Part II

Chapter 4. Mitigation measures in drinking-water and sanitation services

Chapter 4 examines the mitigation potential and risks in drinking water and wastewater management. It includes abstraction, treatment, distribution and discharge, and accounting for both direct and indirect GHG emissions including the electricity consumption associated with indirect carbon emissions. Lowering the release of these GHGs presents major opportunities for climate change mitigation.

Read more about Chapter 4

Chapter 5. Mitigation measures in freshwater ecosystems

Chapter 5 examines mitigation potential and risks in freshwater ecosystems. Aquatic environments, such as freshwater peatlands, marshes, swamps, lakes, streams, rivers, and tidal wetlands, can function as either GHG sources or sinks, depending on their use and the climate. To account for the emission reduction services from freshwater systems, it is necessary to include them as part of a portfolio of measures to reduce GHG emissions.

Read more about Chapter 5

Chapter 6. Mitigation measures in land systems

Chapter 6 examines mitigation potential and risks in land systems. Mitigation measures in land systems can have notable synergies but also trade-offs with local-to-regional water sustainability goals. Land system mitigation measures have the potential to decrease soil erosion, increase groundwater recharge, and increase water vapour exchange with the atmosphere, thereby enhancing local cooling and regional rainfall. Misguided implementation of land system mitigation measures can, on the other hand, cause local water shortage, biodiversity loss, and harm to local communities.

Read more about Chapter 6

Chapter 7. Mitigation measures in energy system

Chapter 7 examines the water-related climate mitigation potential and risks of low-emission energy transition plans. To enable the transition to renewable energies, strategies are also needed to mitigate potential water risks for energy storage solutions, including pumped hydropower, as well as mining for minerals. Low emission energy scenarios often lack quantification of impacts on water quality and ecosystems, which must be incorporated in national, local and regional planning.

Read more about Chapter 7

Wetlands and ecopark with bright blue sky

Part III: Integrating freshwater into climate change mitigation planning and action

The third part draws cross-sectoral conclusions building on the findings in Part II, identifying priority risks and opportunities for water-wise climate planning, including ‘win-wins’.

Read more about Part III

Chapter 8. Water-mitigation leverage points and risk hotspots globally

Chapter 8 presents priority water risks that need to be evaluated in climate mitigation plans. Building on Part II, this chapter outlines opportunities to effectively mitigate emissions through measures taken in water and sanitation services and the protection, restoration and management of ecosystems. The chapter also touches upon key issues for climate mitigation that are beyond the scope of this report, including industrial processes and design, transport, solid waste management, as well as issues related to diet, sustainable consumption and behavioural change.

Read more about Chapter 8 

Chapter 9. Achieving climate mitigation through integrated and cross-sectoral approaches

Chapter 9 demonstrates the need for integrated approaches to achieve water-wise climate mitigation. This chapter provides an overview of some of these approaches, including Integrated Water Resources Management (IWRM), the Water-Energy-Food Nexus approach, Source-to-Sea (S2S), the Landscape approach, and Integrated Urban Management, each exemplified through case studies.

Read more about Chapter 9

For our governance systems and national implementation plans to succeed we need to place water in its rightful place: at the heart of all efforts to adapt to, as well as to mitigate climate change.

Key Messages: Unpacking Freshwater’s Role in Climate Change Mitigation

  • Climate mitigation measures depend on freshwater resources. Present and future freshwater availability needs to be accounted for in climate mitigation planning and action.
  • Climate mitigation measures impact freshwater. Freshwater impacts – both positive and negative – need to be evaluated and included in climate mitigation planning and action.
  • Water and sanitation management can reduce greenhouse gas emissions. Climate mitigation planning and action should include the substantial emission reduction potential in drinking water and sanitation services and through the management and protection of freshwater resources.
  • Nature-based solutions to mitigate climate change can deliver multiple benefits for people and the environment. Priority should be given to measures that can safeguard freshwater resources, protect biodiversity, and ensure sustainable and resilient livelihoods.
  • Joint water and climate governance need to be coordinated and strengthened. Mainstreaming freshwater in all climate mitigation planning and action requires polycentric and inclusive governance arrangements that can facilitate integrated approaches.

Explore the key messages

Pre-launch at the Bonn Climate Change Conference

The Executive Summary was initially presented at the Unpacking freshwater’s role in climate change mitigation Side Event at the SB56 UN Climate Change Conference in Bonn, Germany, on June 13 2022.

Watch the recording of the Side Event:

We need to act now!

Limiting global warming to 1.5 degree is still narrowly within reach, and water across terrestrial, aquatic, and technological systems plays a critical role for the necessary transformation towards net-zero.

Read the full Executive Summary
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This report has been made possible thanks to the collaboration of our partners
United Nations Development Programme (UNDP)
United Nations Development Programme (UNDP)
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German Corporation for International Cooperation (GIZ)
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Stockholm Resilience Centre (SRC)
logo of the Potsdam Institute for Climate Impact Research (PIK)
The Potsdam Institute for Climate Impact Research (PIK)
This report is funded by
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UNDP-SIWI Water Governance Facility
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Federal Ministry of Economic Cooperation and Development of Germany