This chapter analyzes sustainable river management in the Murray–Darling Basin, where growing salinity problems and decreasing security of supply began to cause political conflict between and within the four states that share the catchment. The Murray–Darling Basin Authority has been responsible for coordinating the management of storage reservoirs, major infrastructure, and cross-border flows since 1917. In recent years, however, water needs of different activities are mediated through the dynamics of the market rather than the decisions of government officials. In many regions in the basin, however, water management is more complex now than it was only a few decades ago. The shortage of skilled personnel to manage Australia’s highly modified hydrological systems, which is already making itself felt, could well prove the greatest risk in the medium and longer term.

The São Francisco river crosses some of the driest parts of the Brazilian Semi-arid Region and brings life to ecosystems and to millions of people. Droughts are a recurrent problem in the basin. Since the second part of the twentieth century, several dams, irrigation projects, and water and sanitation systems have been built, and these developments have impacted river conditions, such as stream flows, sedimentation, silting, and water quality. The development of the river, and its engineering solutions, have prioritized the hydroelectric and agricultural sectors. This has started to change with the new water law of 1997 and the creation of the National Water Agency (ANA) in 2000. This chapter reviews current water management and use in the basin as well as the scenarios, which indicate that, in the future, precipitation and stream flows may be reduced significantly due to climate change while water demand will increase due to population growth and development.

Currently available climate models predict the planet will be warmer at the end of this century by about 3C plus/minus 1.50C, while certain regions (the polar regions and the interiors of larger landmasses) will warm slightly more and ocean surfaces will warm at a slower pace. Climate modeling also tells us that the midlatitude storm belts will recede gradually toward their respective poles, causing the Hadley Cells to widen and expanding the arid subtropical zones. Warming in the cloud-free subtropics will lead to more warming and hence more evaporation of soil water. This chapter presents a thorough and accessible discussion of climate modeling to estimate future conditions in the Earth-hydrological system. It analyzes patterns of rainfall, potential evapotranspiration, actual evaporation, and runoff, among other factors, as well as the feedback mechanisms in the climate system that will impact water availability and use in the SERIDAS basins.

Mass extinctions decimate the planet’s biodiversity, and in doing so, they can change the composition of the planet’s biota.The biota that goes into a mass extinction is not the same as the one that emerges. The actual extinctions are over very quickly – 20,000 years in the case of the end-Permian. But the recovery takes much longer. It takes time for new species to evolve and the biosphere to recover – and the Earth System will not operate properly until both processes are complete. Detailed analysis of the fossil content of sediments deposited following the end-Cretaceous extinction event reveal a long-term ecological recovery that parallels the short-term ecological succession that follows modern environmental disasters such as fires and floods. But the succession that follows a mass extinction occurs on a global scale and over a much longer time frame – often millions of years. This new post-mass-extinction recovery phase has been dubbed the Earth System succession.

Starting in 1860, there have been many attempts to document levels of ancient biodiversity using the fossil record. I review four attempts, starting with John Phillips in 1860, followed by Jack Sepkoski’s classic study from 1984. John Alroy’s 2008 work updates Sepkoski’s work but presents problems of its own. The final review is of a study by Fan et al. (2020) who used a supercomputer to produce the most detailed analysis of ancient biodiversity so far. The four studies taken together demonstrate how palaeontologists are using increasingly sophisticated statistical techniques and an improved geological time scale to address the limitations of the fossil record. But more than that, they reveal mass extinctions as powerful agents of biotic change. These events directly influence not only the level of the planet’s biodiversity, but also the composition of its biota.

The continuation of life on Earth relies on the Earth System maintaining planetary conditions in an equilibrium suitable for its continuation. But the Earth System did not just spring into existence – it developed slowly as complex life evolved and modern-style ecosystems appeared. In this chapter I review the history of early life, beginning with the oldest Snowball Earth event (about 700 million years ago) through to the Cambrian Explosion (about 480 million years ago). A field trip down Brachina Creek in the Flinders Ranges of South Australia that start in the early Cambrian and ends at the boundary of the Cryogenian and Ediacaran Periods sets the scene for the discussion. Intimately associated with the evolution of complex organisms and the appearance of the Earth System is the story of oxygen. This history of this important gas and its role in the evolution of life is briefly reviewed.

This chapter is all about mass extinctions. I have talked about them previously but here I provide much more detail. I introduce the Gubbio section in Italy where a complete end – Cretaceous record allowed Louis and Walter Alvarez to recognised in possibility that a meteor played a significant role in triggering the end-Cretaceous mass extinction. I provide a definition of what constitutes a mass extinction, talk about how many there are in the fossil record and explain how we know how many species go extinct at each of the big five mass extinctions. Scientists have always been fascinated by the possibility of there being a cyclic pattern of mass extinctions. After reviewing the data and spending a little time the Nemesis model of cyclicity I suggest that this is not the case. Mass extinctions are associated with major shifts in the Earth System. Reflecting on this linkage, the chapter ends with what amounts to a general model for all mass extinctions.

Up until this chapter, I have avoided discussion of what causes a mass extinction. Rather than a run-through of each mass extinction, I concentrate on two; the largest, the end-Permian; and the most controversial, the end-Cretaceous. Many (most) mass extinctions are linked to the environmental damage that results from the eruption of a Large Igneous Province (LIP) – that is certainly the case with both the end-Permian and end-Cretaceous. At the end of the Permian, the eruption of the Siberian Traps resulted in global warming and caused ocean waters to become both anoxic and acidic, resulting in the largest mass extinction seen on the planet.The situation of the end-Cretaceous is more complex. The eruption of the Deccan Traps placed significant environmental stress on the planet’s ecosystem which is recorded as shifts in the composition of the biota prior to the event. But the impact of a meteor is also involved in this extinction event, and it may have delivered the coup de grace.

The book sets today's defaunation event into its historical setting. The best source of information available to do that is the fossil record. Unfortunately, the fossil record has some inbuilt limitations that affect any analysis that uses it. This chapter starts by outlining these limitations and what we can do limit them. I then look at how the extinction and origination (evolutionary appearance) of species are recorded in the fossil record. This is important as the pattern of extinction and origination of species over deep time forms the basis of the geological time scale that is used throughout the book. Finally, I examine the beginnings of modern extinction studies and the recognition of the Big Five mass extinctions.

The Colorado is a river in transition – a newly “closed” basin where demands have exhausted reliable supplies. Decades of often short-sighted management decisions have contributed to the crisis environment that currently surrounds the Colorado River. Over the past fifteen years, however, stakeholders and managers have enacted significant changes to the rules and regulations governing the Colorado, and additional reforms remain close to enactment. Unlike the deal-making that characterized negotiations in the twentieth century, recent efforts focus primarily on strategies to promote coordinated management, reduce consumption, and restore a more holistic watershed perspective to a river that was legally apportioned long ago among a highly complex amalgam of jurisdictions and water users. In many respects, the river management system is a successful example of adaptation to changing social and hydrological conditions. Yet, it remains an open question whether the pace and scale of reform is sufficient to deal with the basin’s future.

The Yellow River is by its nature not sustainable since it carried the world’s heaviest silt load for a long time. Yet, this silt load (loess plateau) has fallen considerably in recent years, but at the cost of other forms of sustainability, such as streamflow. The reasons for this dramatic decline in runoff are complex. In addition to reducing silt load, terraces and vegetation have led to the marked reduction in runoff. The fall in natural runoff can also be attributed to groundwater and mining extractions, as well as reservoir filling. Population per se is not a major driver of water demand compared to irrigated agriculture and other sectors, notably mining and industry. While China is not a federal system, it is organized in a complex hierarchical system where provinces play an important role and are capable of serving their own interests in negotiating usages and allocations of the river. The chapter analyzes peculiar physical conditions and water management institutions in the Yellow River Basin.

On top of dealing with climate change impacts on rainfall and temperature, and rising populations and development, the Euphrates–Tigris basin also faces conflict and instability. The Syrian Civil War, the presence of many nonstate armed groups, and the lack of coordination between Turkey, Syria, and Iraq to manage the water resources can lead to continued political confrontation and economic disintegration. This complicates the existent issue of nexus in the Euphrates–Tigris basin. The conflicting needs of energy, water, and food require more coordination not just between countries but between sectors within the countries. Each sector must be allocated a certain amount of water based on the needs it fulfills for the country. If violence continues and instability in the region is not resolved, these demands may increase and further pressure the basin.

This chapter reviews the role of irrigation districts, city water utilities, and environmental groups in basin management. Examples from two river basins – Rio Grande and Euphrates–Tigris – illustrate vast differences in stakeholder participation. The authors recommend that all SERIDAS rivers pay increased attention to this option for better management. The four options for creating sub-basin water councils recommended for the Rio Grande provide useful guidance. Other models, reflecting different basin conditions, may emerge. Whatever model is selected, stakeholders should always organize to address the water agenda of their sub-basin. Doing so directly contributes to reaching and maintaining sustainability of the river as a whole.

We are probably living in the newest period of geological time, the Anthropocene. This interval of time is in the process of being formally established by the geological community to reflect the extraordinary impact that humans have had on the planet. Future geologists will examine rocks of Anthropocene age and, preserved in them, will recognise the massive changes to the planet’s ecosystem brought about by human activity. They will find the remains of huge mega-cities and the debris of manufacturing. The sediments will clearly show immense changes in land use, with forests and grasslands abruptly giving way to the intensive agriculture needed to feed an exploding population. Their sophisticated geochemical analyses will show how the planet underwent rapid warming, the result of humans injecting excess carbon dioxide into the atmosphere. Future palaeontologists will note a significant shift in the fossil record. In older sediments deposited prior to the Anthropocene, they will recover fossils reflecting a diverse mammal fauna. But that will change as we enter the Anthropocene. Here, the rocks will yield a mammal fauna much less diverse than the one that preceded it. Not only that, but the fauna will be dominated by fossils of domesticated stock – sheep, pigs, and cattle. And this loss of diversity won’t be confined to mammals. The record will show a massive loss of biodiversity across all biotic groups in response to deteriorating environmental conditions.