Climate change and water crises, which have featured prominently in the Global Risks Landscape over the last five years, are joined this year by large-scale involuntary migration. The links among these risks appear clearly in the Global Risks Interconnections Map 2016 (Figure 2), and the intertwined challenges are unfolding against a background of many socio-economic pressures. 

As illustrated by the Global Risks Interconnections Map, climate change and water risks are intricately linked to food security concerns – a subject explored further in Part 3 of this Report. About 70% of the world’s current freshwater withdrawals are used for agriculture, rising to over 90% in most of the world’s least-developed countries.⁴ Carbon dioxide also causes ocean acidification, which makes it harder for small shellfish to form the calcium carbonite shells they need to grow – with implications rising up the food chain, threatening the availability of food from the seas as well.⁵

Challenges around water management are already immense. On the one hand, over a billion people lack access to improved water. Some 2.7 billion – or 40% of the world’s population – suffer water shortages for at least a month each year.⁶ The Organisation for Economic Co-operation and Development (OECD) estimates that 4 billion people could be living in water-scarce areas by 2050. According to the World Water Council, 80% to 90% of the scarce water in many of the world’s arid and semi-arid river basins is already being used, and over 70% of the world’s major rivers no longer reach the sea.⁷ On the other hand, inadequate sanitation exposes 2.4 billion people to many diseases, such as diarrhoeal disease, which is the third leading cause of death among children under five.⁸

Governance – at global, regional and national levels – lies at the heart of water management. Even many developed countries are failing to proactively address water vulnerabilities, instead reacting only after extreme weather events. In developing countries, the political challenges inherent in water infrastructure and conservation projects are exacerbated by greater financing challenges.

Brazil exemplifies the challenge of managing water even within a single country: it has 12% of the planet’s freshwater reserves, mostly in the Amazon region, but much of this water does not reach its urban population. Sao Paulo, which contributes a third of Brazil’s GDP, has a lower water-per-capita availability than even the historically drought-prone north-eastern region of the country. With hydropower constituting approximately 64% of the electricity power load, there are conflicts caused by unclear rules about water governance at federal, state and basin levels.⁹

Water management is further complicated around the world by economic pressures – developing an economy can be a thirsty business, based on unsustainable use of water. As countries industrialize, more fresh water is needed for energy production – the United States allocates about 40% of its fresh water to energy, Europe over 30% – and the demand for water for energy and industry is forecast to increase by 70% by 2030 across Asia.¹⁰ Globally, based on current trends, water demand is projected to exceed sustainable supply by 40% in 2030.¹¹ Adding to the pressures, agricultural production will have to increase in the coming decades to feed a growing population and a rising demand for meat.¹²

Unless current water management practices change significantly, many parts of the world will therefore face growing competition for water between agriculture, energy, industry, and cities. Tensions are likely to grow within countries, especially between rural and urban areas and between poorer and richer areas, and also potentially between jurisdictions. More than 60% of the world’s transboundary water basins lack any type of cooperative management framework. Even where such frameworks do exist, they often do not cover all states that use the basin.¹³ Interstate tensions over water access are already apparent in some parts of South Asia, and could impact the evolution of the international security landscape, as discussed in Part 2.

Climate change will only exacerbate these challenges. The latest Intergovernmental Panel on Climate Change (IPCC) report, in November 2014, reaffirmed that this warming in the climate system is “unequivocal” and that human influence is “extremely likely” to be the dominant cause. Atmospheric concentrations of three major greenhouse gases (carbon dioxide, methane and nitrous oxide) are at their highest level in 800,000 years, with CO₂ concentration up 13% since 1990. The world today is estimated to be about 1°C warmer, on average, than it was in the 1950s, and the effects are being felt. Regional analysis of the Global Risks Perception Survey shows that declining water availability features as the most likely risk in the Middle East and North Africa and South Asia, and the likelihood of extreme weather events is considered especially high in North America, South Asia and East Asia and the Pacific (see Figure 3).

Scientists caution that a total warming of 2°C implies a high risk of catastrophic climate change that could damage human well-being on a global scale. Yet even if each country meets its Intended Nationally Determined Contributions plans, submitted to the United Nations Framework Convention on Climate Change (UNFCCC) and agreed at the Paris Climate Conference in December 2015 (Box 1.2), warming is projected to reach 2.7°C by 2100.

Given these developments, it will, therefore, be impossible to live without adaptation – but adaptation planning is complicated by the difficulty of predicting not only the expected degree of warming but also the expected pace. One source of uncertainty is the Arctic feedback loop – will ice sheets collapse slowly or rapidly? The average sea level is already rising by 3 millimetres per year, faster than any other time in the last two millennia; many of the world’s cities lie on the coast or on river banks, with poor neighbourhoods most likely to be in low-lying areas vulnerable to flooding.¹⁴ Another source of uncertainty is the “Amazon Dieback” scenario: recent oscillation between unusually dry years and heavy flooding could be an early indicator of irreversible system phase change.¹⁵ If the Amazon stops absorbing carbon and starts releasing the estimated 120 billion tonnes of carbon it holds – equivalent to 15 years’ worth of 100% fossil fuel emissions – the impact will be global.

Failure to address climate change and water crises will forcibly displace more people – the IPCC warns that droughts and coastal floods could cause “large-scale demographic responses – for example, through migration”. Forced displacement is already at an unprecedented level, causing severe humanitarian challenges, as explored in the following section.