Climate Change Impacts on Water Resources: Integrated Water Resources Management (IWRM) as an Adaptation Tool

Climate change is currently the planet’s most important environmental issue. The increase in global surface temperature over the last decade has been around 1.1 °C. Human influence is likely to have contributed to the observed pattern of precipitation changes since the mid-twentieth century. Water resources, one of the most significant economic sectors, would be significantly impacted by climate change. Numerous effects, such as extremes, quantity, and quality, will be felt as a result. Future climate change will result in more hydrologic extremes, including compound ones, a decrease in the amount of available water, and a reduction in the quality of the water. It is anticipated that hundreds of millions of people in both developing and developed nations will experience water stress. Water managers currently react to changing circumstances, many of which are comparable to future climate change, and have developed a variety of adaptive options. Although demand side management is increasingly important, most water managers are more familiar with supply-side decisions. Water management is constantly evolving, and this change will affect how climate change manifests itself in daily life. Current water management systems are expected to be stressed by climate change, especially in nations with insufficient experience incorporating uncertainty into water planning. How to incorporate climate change into the different types of uncertainty that have historically been dealt with in water planning is the main challenge. Integrated water resources management (IWRM) is increasingly regarded as the most effective approach to managing water resources in a changing world with conflicting demands. We conducted a few IWRM case studies from the Canadian context where water resources are highly vulnerable to future climate change. In Canada, the rate of change in mean temperature is higher than that of the global rate. Annual mean temperature over northern Canada increased by 2.3 °C, roughly three times the global mean. Climate models project further precipitation increases, with annual mean precipitation projected to increase a range of 7–24% with significant regional variations. The study locations were the watersheds of Okanagan Basin, British Columbia, Grand River in Ontario, and Yamaska in Quebec. Bottom-up water demand estimates, the augmentation of low flows to dilute wastewater, the monitoring and modeling of water quality, awareness creation to increase water efficiency, the estimation of adaptation costs for the present and the future, and strong policy for involving stakeholders are just a few of the IWRM actions that were carried out in these locations. The stakeholders and ecosystems in these catchments benefited from the application of IWRM principles. IWRM-based solutions for sustainable water resource management and human well-being could be implemented jointly by co-basin countries and developing nations using the lessons learned from the Canadian context. However, not all risks and effects may be completely mitigated by IWRM. Possibilities of vulnerability remain.