Featured Collection Introduction: Climate Change Solutions

Climate change is one of the complex issues facing humanity today. While people may debate the causes of climate change, there is incontrovertible evidence carbon dioxide levels in the atmosphere have continued to increase over much of the last century resulting in the trapping of heat in the atmosphere. The shifts in atmospheric thermal regimes have also had a profound influence on the hydrology of the earth. There is growing evidence changes in climate have intensified hydrologic extremes (Mao et al., 2015; Trenberth et al., 2018). In addition to floods and droughts, climate change also has contributed to sea level rise, desertification, harmful changes to water quality, and accelerated snowpack melting — factors that have threatened the resilience of our water infrastructure and called for paradigm shifts in how we plan for and manage this already scarce resource. The stresses posed by changes in climate often act in unison with pressures created by a growing population, aging infrastructure, and technological barriers that limit our ability to manage water resources effectively and efficiently. Nonetheless, it is important we tackle these stresses and pressures head on and ensure high-quality water resources are available to future generations as they are to us today (intergenerational equity). Also, climate change stresses and socioeconomic pressures manifest differently in different parts of the world. The spatial variability in the impacts and the associated intra-generational equity must also be borne in mind as we grapple with the wicked problem of sustaining our water resources for the future. Throughout its existence, humankind has ingeniously solved many challenges and continues to strive to make this world a better place to live in. We are once again at a crossroads where we know hard decisions and innovative solutions are needed to sustain our water resources. However, the path forward is fraught with uncertainty. To quote John F. Kennedy, “There are risks and costs to action. But they are far less than the long range risks of comfortable inaction.” The time for action and innovations to deal with climate change is now!! The solutions to climate change must be multifaceted and there is no silver bullet. Both policy innovations and technological advances are necessary to improve our water planning and management practices. These solutions must be based on sound science and incorporate the variability in hydro-climatic factors that fundamentally affect the hydrology and water footprint in a region. Understanding what we know and do not know and developing rational and structured approaches to guide our future decision making are essential elements of solutions aimed at mitigating the impacts of climate change. This featured collection, Climate Change Solutions, brings together a multidisciplinary group of papers highlighting the various facets of climate change. The focus here is not just analyzing how climate will likely change, but also how we should adapt and what solutions are likely to work. Two papers in the collection focus on evaluating the impacts of climate change in two very different geographies with widely varying data availability and resources. Sridhar et al. (2019) use a suite of observed (gaging station) and reconstructed datasets from Multivariate Adaptive Constructed Analogsbased downscaled daily extreme precipitation of 15