Water in a Changing Climate

Water management in the western United States is rooted in an adversarial system that is highly sensitive to climate change. Reforms are needed to ensure water management is efficient, resilient and equitable moving forward.

Improved management of water has been shown to have important benefits in both climate adaptation and mitigation. Water must be explicitly considered in climate policy, on par with its energy and land siblings.

In the context of rising climate uncertainties, there is an urgent need for greater convergence between water and climate change policies. To improve adaptation outcomes, a reorientation towards justice and rights-based frameworks is required.

Man-made ice towers provide water during the growing season in the high-elevation desert in the Himalayas to buffer effects of climate change. Local and international science partnerships are now working to develop technologies to make these ice stupas more efficient.

Climate mitigation policies are enacted in the interconnected climate, land, energy and water sectors. Now, a study shows regionally different land-use change emission pricing policies can increase competition for water in African river basins.

Climate change, alongside numerous other pressures, is having unprecedented effects on water resources both globally and locally. Retailers need to implement a range of adaptation measures to ensure the sustainability of supply chains.

The high levels of water extraction from the Colorado, Murray, Orange and Yellow rivers are shown to be the main cause of reduced flows in these systems. Changes in governance are urgently required to preserve the health of these rivers, especially in light of the present and future impacts of climate change.

The growing scarcity of freshwater due to rising water demands and a changing climate is increasingly seen as a major risk for the global economy. Consumer awareness, private sector initiatives, governmental regulation and targeted investments are urgently needed to move towards sustainable water use.

Global climate change mitigation policies aim to reduce emissions, but can have unintended local consequences. Mitigation in the land sector could impact local water resources, along with food and energy in the Zambezi Watercourse and similar river basins.

Aquifer characteristics and water use data for 43 widely distributed small island states indicate that 44% are in a state of water stress. While recharge is projected to increase on 12 islands it is projected to decrease by up to 58% on the other 31.

Changes in European river flow have amplified the dry-south–wet-north contrast. Model simulations show that anthropogenic climate change accounts for this change with strong decreases in the Mediterranean and weak increases in northern Europe.

Snowmelt runoff is an important source of water for irrigating agricultural crops in high-mountain Asia, Central Asia, western Russia, western US and the southern Andes. Climate change places water resources in these basins at risk, indicating the need to adapt water management.

Mountain snowpack declines are often tracked using snow water equivalent trends sensitive to highly variable precipitation. Observational work proposes temperature-driven daily snowmelt during the accumulation season as an alternative metric, with increases that are three times more widespread.