Fluid connections | Nature Climate Change

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Many of the impacts of climate change will be felt first through the presence — or absence — of water and access to water resources. To mitigate these impacts, water must be included in climate policy and adaptation planning.

Water seeps into the Earth’s surface, just as rain does after a storm. It touches and connects processes and impacts all over the globe, just like rain seeps into ground. The tangible effects of climate change are also reflected in this connecting flow of water. Climate change can have many effects on the water cycle. Rising temperatures have a significant impact on atmospheric moisture, circulation, and precipitation patterns. This in turn affects the distribution of water around the globe. Some regions become wetter and experience flooding, while others become drier and experience drought. Changes in the flow and timing of meltwater from snow or glaciers can also have an impact on areas that depend on them.

Owing to its fundamental importance for life and deep interconnectedness with Earth’s physical and ecological systems, water is likely to be the primary mechanism through which the impacts of climate change are felt. It is important to understand these impacts and how to manage water resources sustainably and fairly in a changing climate. This issue of Nature Climate ChangeAssoc. FocusWe feature pieces that connect climate and water resource impacts as well as suggestions for ways forward.

Climate change has direct effects on the water cycle. Adaptation and mitigation strategies could also have an impact on water demand. Climate policy has historically been focused on energy and land use measures to reduce emissions. These policies assume that water is available and not limited. Nature-based Solutions, such as planting trees or biofuels, may require irrigation water. This can cause conflicts with other water uses like agriculture or household use. Writing in a Comment in this issue, Fernando Miralles-Wilhelm argues for stronger inclusion of water constraints and water resource management in climate policy due to water’s critical role in mitigation strategies and vulnerability to human activity. Matteo Giuliani, along with co-authors, illustrate these points in their ArticleGlobal climate mitigation policies designed to reduce emissions from land use can have unintentional impacts on local water allocation. Their case study on the Zambezi Watercourse shows that these mitigation policies could create more risks to water resources than climate change.

Water scarcity is leading to concerns about rights, justice, and access for all. Around two billion people worldwide are unable to access safe drinking water.https://go.nature.com/3sbj0Pp) and current policies often disadvantage marginalized and vulnerable communities. They are able to use their Comment, Shilpi Srivastava and colleagues outline the importance of water for adaptation to climate change, as well as the need to address the underlying inequities in water access that impact peoples’ ability to adapt. In another instance, CommentDylan Hedden–Nicely proposes reforms to the western United States’ current water allocation system. This system, which has its roots and is based on the exploitation of the west, fosters conflict and exclusion, especially for Indigenous communities. A system that is more resilient against climate change would be built in cooperation and include better infrastructure and more efficient laws for management. Equity should also be considered.

However, resource management demands that the resource be available to manage. Water storage in extremely dry areas is a challenge. Climate change is changing the timing of meltwater and affecting mountain communities that have depended on streams for water supply. Communities are now looking at ways to control the unpredictability of water access. This includes the construction of ice stupas, towers made of ice that store meltwater for longer periods of times. A FeatureThis issue describes the need to build such structures in Ladakh’s Himalayan region, as well the engineering and practical challenges.

Water is critical for human survival — and indeed for that of all life. Given changing precipitation patterns, increasing demand from different sectors, it will be difficult to manage the scarce freshwater resources available over the next decades and ensure equitable access. A recent report (https://go.nature.com/3rVvLNwThe World Meteorological Organization warns about a possible water crisis and calls for improvements in water management, monitoring, and early warning systems. Many regions are already feeling the effects of climate change through water. Water resource management and research should play a central role in adaptation and policy.