Extreme droughts that used to occur once every ten or so years are now happening 70% more often, according to a report from the Intergovernmental Panel on Climate Change. Indeed, as the Intergovernmental Working Group on Drought says, drought may be attracting increasing attention but its “management has not evolved in scope and activity commensurate to other disasters.”.

In a report called The Blue Paper: Drought Risks, Resilience and Restoration, the working group states that:

  • Drought is underestimated and has deep, widespread impacts on societies, ecosystems, and economics, with only a portion of actual losses accounted for.
  • There is evidence that human-induced climate change has led to an increased risk of drought.
  • An estimated 55 million people globally are directly affected by drought every year, making it the most serious hazard to livestock and crops in nearly every part of the world.
  • From 1970-2019 drought was one of the hazards that led to the largest human losses of approximately 650,000 deaths.
  • By 2040 it is estimated that one in four children will be living in areas with extreme water shortages.
  • Limiting global warming to 1.5 degrees Celsius is expected to substantially reduce the probability of extreme drought.


Contrary to popular belief, as Victoria Cardenas from the International Hydropower Association says: “Climate volatility will mean the need for more hydropower, not less”.

Cardenas gives the example of Sichuan in southwest China, where hydropower provides 77% of power generation. After experiencing high temperatures and droughts in July and August 2022, Sichuan experienced its first power shortage in more than three decades.

He Shengming from Yalong Hydro says that the region needs to optimise its power structure and will address the problem by “vigorously developing” new energy, hydropower and pumped storage hydro. Last year the company began construction of a 258MW wind farm, a 1GW solar plant that will be the world’s largest hydro-solar hybrid station, plus the 1.2GW Lianghekou pumped storage plant.  In the long run, Shengming says that hydro, pumped storage, wind and solar power all need to work together.

Arizona initiative

In the US, Arizona State University (ASU) has announced that it will lead a multi-year Arizona Water Innovation Initiative to provide immediate, actionable, and evidence-based solutions to ensure that Arizona will continue to thrive with a secure future water supply.

The university will work with industrial, municipal, agricultural, tribal, and international partners to rapidly accelerate and deploy new approaches and technology for water conversation, augmentation, desalination, efficiency, infrastructure, and reuse. The state of Arizona will make a $40 million investment in ASU for the initiative, which will build upon the university’s successful programmes in water science, technology, management, and law.

The initiative will also focus on an advanced water observatory and real-time decision support to revolutionise water measurement, modelling and prediction and provide data necessary to identify critical risks, vulnerabilities and capabilities.

The observatory will deploy state-of-the-art technology to fully map, monitor and model all of Arizona’s water supplies. This will enable ASU to partner with federal and state agencies, local water management agencies, research institutions, and the private sector to enhance water security and reduce risks of future water shortages.

“This is an economic and social opportunity for Arizona to emerge as a national and global leader in water innovation, creating entirely new industries and technologies,” ASU President Michael Crow said. “The status quo will not solve the problem. This is a critical moment for our institution and for the state, and we have the tools, ideas, and systems to be of service.”

Meanwhile, in the UK, the National Drought Group said at the end of last year that significant risks remain for water supplies and impacted sectors, despite an improving water resources situation in some parts of the country.

Recent above-average rainfall in October and November 2022 was described as being beneficial in wetting up soils, improving river flows, and recharging groundwater and refilling reservoirs across the country. As a result, reservoir stocks across England were back up to around 68% capacity which led to some water companies revoking drought permit applications and removing restrictions such as temporary use bans on hosepipes.

Although improved reservoir and river levels led to the West Midlands region moving from drought status to recovery, and Greater Manchester, Merseyside and Cheshire from prolonged dry weather to normal status, some reservoirs remain well below the levels expected at this time of year. These include:

  • Colliford Reservoir in Cornwall (24% of capacity)
  • Roadford Reservoir in Devon (43% of capacity)
  • Grafham Water in Cambridgeshire (63% of capacity)


If rainfall levels through the winter are 80% or less of the long-term average, National Drought Group projections show that currently depleted reservoirs and groundwater aquifers are unlikely to fully recover, and farmers would be concerned their water supply storage reservoirs may not fully refill. Large parts of the country could be at risk of drought continuing into the summer of 2023 – most notably in parts of the South West, South East, East Anglia, Yorkshire and East Midlands. In more severe rainfall scenarios, the projections suggest drought conditions would be widespread, covering most of the country.

“We cannot rely on the weather alone,” Environment Agency Executive Director and Chair of the National Drought Group, John Leyland, said. “If we are to avoid a worse drought next year, it will require action by us all. Early and precautionary planning must start now to manage the risks that this would bring.”

As Water Minister Rebecca Pow added: “The recent rainfall will be a relief for many, but we should approach the improving drought situation with cautious optimism. I urge water companies to continue to plan their water resources and take precautionary steps to ensure water resilience. This includes emphasising to the public that water shouldn’t be taken for granted.”

The Environment Agency says that recent heavy rain and flooding, whilst most of England remains in drought, highlights how climate change is happening now. The country is seeing more extreme weather – in 2022 alone there were three named storms in a week, record-breaking temperatures and the joint hottest summer on record leading to a widespread drought. It warns that flooding and drought can occur at the same time, and it is essential to plan and prepare for increasingly extreme events.

Indeed the Environment Agency’s Chief Executive, Sir James Bevan, has set out how natural flood management must be a core part of the nation’s defence against flooding and climate change, and needs to be seen standing shoulder to shoulder with its programme of crucial bricks and mortar hard defences.

“The warning signs of the climate crisis are stark – and sadly devastating flooding is likely to become a more familiar sight over the next century,” he said. “As we prepare for more extreme weather events, we must use every weapon in our armoury and natural flood management will play an essential role in this. By harnessing the power of nature alongside our traditional flood defences, we can not only help keep communities safer, but also create wildlife havens and tackle the climate emergency.”

Natural flood management measures include planting trees and hedges to absorb more water, creating leaky barriers to slow water flow in streams and ditches and restoring salt marshes, mudflats, and peat bogs. In Cumbria, a project trailed a variety of measures across different landscapes aiming to slow or store 10,000 cubic metres of water per square kilometre. The team worked with a range of landowners and the Forestry Commission to change overland flow routes, build earth dams and leaky barriers, plant 8000 trees and create offline flood storage ponds.

Meanwhile, the community-led Shipston Area Flood Action Group used measures across the River Stour in Warwickshire to create 700 leaky barriers and ponds to slow the flow of water during heavy rainfall, reducing the flood risk to people and businesses in 17 villages and towns.

The Rivers Trusts says natural flood management has a really important role to play in protecting communities from the misery of flooding, while at the same time making a contribution to nature recovery, pollution prevention, soil protection, drought resilience, amenity value and carbon sequestration.

“Our country faces several major environmental threats, and we cannot solve them one at a time,” Mark Lloyd, CEO of Rivers Trusts said. “Managing landscapes to store more water provides multiple benefits to society, and can therefore attract multiple sources of funding.  This pilot programme needs to become business as usual urgently and we need to break down the barriers to delivery at scale.”

The government has a target of doubling the number of natural flood management projects over the next five years and is investing £5.2 billion in flood and coastal defences to ensure more communities are better prepared – and nature-based solutions are a key component of this.

Mega flood

Back in the US, with drought and wildfire becoming increasingly more prevalent and receiving more attention throughout California, there is a fear that Californians may now underappreciate the risk the region faces from severe but infrequent flooding.

According to a new paper from Xingying Huang and Daniel Swain in Science Advances, climate change is increasing the risk of a Californian mega flood.

“California is a region more accustomed to water scarcity than overabundance in the modern era. Between 2012 and 2021, California experienced two historically severe droughts—at least one of which was likely the most intense in the past millennium — resulting in widespread agricultural, ecological, and wildfire-related impacts and ongoing drought-focused public policy conversations,” the authors state.

Huang and Swain go on to discuss The Great Flood of 1861–1862 where weeks of winter storm events produced widespread catastrophic flooding across virtually all of California’s lowlands. A temporary but vast inland sea of floodwaters was up to 480km long and 96km across. Back then the population was approximately 500,000 but today it is nearer to 40 million.

A growing body of research now suggests that climate change has already increased the risk of another megaflood scenario in California and that “future climate warming will likely bring about even sharper risk increases”. The authors say that runoff in a future extreme storm scenario is 200-400% greater than in historical values in the Sierra Nevada, due to increased precipitation rates and decreased snow fraction.

Estimates suggest that a modern-day megaflood would be a US1 trillion-dollar disaster, larger than any in world history. Every major population centre in California would get hit at once, along with other adjacent states. Relief efforts would be complicated as major roads could be shut down for weeks, or even months, while there would be global impacts on economic and supply chains. It would also be practically impossible to evacuate up to ten million people who could be displaced by the flood waters, even with weeks of notice from meteorologists and climatologists.

Further inter-agency collaboration and research is planned to try to map out where flooding could be worst and to help inform state-wide mitigation plans, such as drawing down reservoirs in preparation or inundating dedicated flood plains.

This article first appeared in International Water Power magazine.