The Indo-Pacific is often seen as the engine of global economic growth, given its vast human and material resources. However, climate change is setting the scene for a major transformation in the region as oceans are projected to become warmer, changing rainfall patterns induce flooding and drought in large areas, and rising seas threaten coastal ecosystems and salinisation of major agricultural areas. This will exacerbate geopolitical competition, interstate conflicts over resources and organised crime. Challenges to security in the region will adversely affect business and investments. Water scarcity and bad management of water resources will act as a major impediment to growth. Competition for water between industry and agriculture will intensify in the developing Indo-Pacific as agriculture comprises 80 per cent of current freshwater withdrawals. While water demand is expected to rise 55 per cent, twice the current amount of food will be needed to support growing populations. As a result, some 3.4 billion people in Asia could face water stress by 2050. “WaterGuide”, a report by the Australian Water Partnership and water resource advisory firm Aither, warns that urgent action could be needed as existing water infrastructure is highly unsuitable to accommodate projected growth. The region is also adversely affected by water-related disasters. Estimates suggest that, in the previous decade, the region has witnessed 700 million deaths because of climate-related disasters, whereas floods alone have inflicted a loss of US$1.4 trillion. Even though two-thirds of the population in the Indo-Pacific will be urbanised by 2050, sanitation and waste water treatment facilities will fall critically short. Urban challenges include a lack of data on unaccounted for water, theft and illegal connections. There are concerns that major cities could start running out of water soon. In most cases, water shortages are rooted in faulty municipal water management and citizen ignorance. Severe water scarcity will dampen the growth of Bangalore, which according to pre-pandemic estimates was set to grow annually at 8.5 per cent until 2035, the fastest of any city in the world. Similarly, Indonesia will have to increase its water supply by 30 to 50 per cent as its urban population is set to exceed 90 million in the next two decades. Densely populated Southeast Asian metropolises such as Jakarta, Bangkok and Ho Chi Minh City will struggle with rising sea levels . A report by the Australian Water Partnership in 2019 found that water quality was suffering in India and Southeast Asian countries such as Thailand and Vietnam because of flow alteration in Himalayan and Mekong rivers. Moreover, the warming climate will melt much of Tibet’s glaciers in the next 75 years, affecting Asia’s major rivers. Excess water is expected to run off and increase the risks of frequent flooding in thickly populated river basins, especially flood-prone Indian states such as Assam and Bihar as well as Cambodia, which has more than 80 per cent of its territory on river basins. Raghu Murtugudde, an atmospheric scientist at the University of Maryland, has said “global warming has destroyed the concept of the monsoon”. Extreme rainfall events have increased threefold in the past 70 years in parts of India while the total amount of rain has decreased. Erratic monsoons can drive India’s large agrarian populations to forced migration and substantially increase inequalities, conflict and violence. Excessive groundwater extraction is the biggest threat to sustainability in the region. India tops the list with 251 trillion litres extracted each year, followed by China with 112 trillion litres. A report by the International Institute for Applied Systems Analysis suggests China, India and Pakistan combined will be responsible for 86 per cent of groundwater extraction in the region by 2050. Timely steps are essential to combat the effects of climate change in the Indo-Pacific. Negligence and inactivity can lead to dire consequences, including drastically reduced quality of life, loss of economic opportunities and large-scale, unwanted migration. A primary focus should also be engagement of communities and ground-level stakeholders. Advanced economies in the region can be helpful in sharing expertise in water management as well as the creation of sustainable, resilient infrastructure in the Indo-Pacific. Considering that peace and security between advanced and developing economies is closely interlinked, such partnerships for the sustenance of dignified life and economic growth will benefit all parties in the region. Akash Sahu is a researcher in Indo-Pacific geopolitics, security, development and sustainability. He works as a consultant at the New Delhi-based Council for Strategic and Defence Research