Category: Climate Change Impacts

Flash flooding is a serious threat in the UK – here’s how scientists are tackling its prediction

Flash flooding is a serious threat in the UK – here’s how scientists are tackling its prediction

By Christopher J White, Laura Kelly, and Linda Speight

It’s becoming a familiar scene on the news: sodden British people wading through streets up to their knees in flood water. From Stirling to Sheffield, many parts of the UK in 2019 felt the impact of severe surface water flooding – often referred to as flash flooding – that followed torrential rain. As the climate changes and the UK experiences more intense summer storms, this is becoming an increasingly important issue.

Surface water flooding is what happens in built-up areas when heavy rainfall has nowhere to go. Unable to enter a watercourse or drainage system, the water instead flows over the ground causing flash flooding. Increased development means more areas are paved over, leaving fewer places for rainfall to drain away. And more frequent heavy rains overload the sewer and drainage network, which makes flash flooding more likely.

James Bevan, chief executive of the England and Wales Environment Agencysaid this kind of flooding “threatens more people and properties than any other form of flood risk”. In 2016, the UK government included surface water flooding on the national risk register.

Unlike river and coastal flooding, which can be widespread (as was seen in November 2019 across parts of northern England), surface water flooding presents unique challenges because it’s difficult to predict the location, timing and impact of what are typically localised events.

As the climate changes and urban populations grow, the number of people at risk of surface water flooding increases. This risk is particularly high in Scotland with over 100,000 properties identified at risk from flash floods. And for many people, even if their home or business is not at risk, there’s a good chance the roads or railway lines they use are.

Flash flood forecasting in Scotland

Although Scotland’s river and coastal flooding warning systems are well established, surface water alerting is still in its infancy. To address this gap, the Scottish Environment Protection Agency (SEPA) is continually developing its flood forecasting service with the Flood Warning Development Framework for 2017-21, which aims to explore and test innovative ways to warn people about flash floods.

Developing an effective forecasting system requires hydrological models that represent surface run-off, inundation and water movement, showing how water travels via surface and urban sewerage and drainage networks. Prediction models are also needed to quantify uncertainty in forecasting the rainfall that causes surface water flooding.

The uncertain nature of intense storms means that heavy rainfall can happen without much warning. This coupled with the pressure that excess natural run-off puts on man-made drainage networks when there are fewer places for water to go, makes surface water flooding forecasting a real challenge.

It’s a particularly acute problem in Scotland where the climate and geography contribute to the high uncertainties around predicting the location and timing of flooding. A 2016 study found the most dangerous flash floods in the UK include those that resulted from rapidly developing thunderstorm systems. Such storms can result in sudden and dangerous flooding in urban areas – yet these are the most challenging weather systems for flood forecasters to predict.

In the past five years, there has been a rapid development of thunderstorm numerical weather prediction computer models and advances in what is called probabilistic ensemble forecasting. This means instead of making a single forecast of the most likely weather, a set (or ensemble) of forecasts is produced, giving an indication of the range of possible weather ahead. Combined with an increase in computing power and skill, it is now becoming feasible to develop flash flood forecasting systems for urban areas.

Innovative solutions

Earlier this year, we were commissioned by SEPA to review the state of the science behind surface water flood forecasting in Scotland. Based on an extensive review of published research and reports, coupled with discussions with industry experts, we show that recent advances in computing, thunderstorm models, ensemble forecasting and surface water modelling mean that it is possible for SEPA to explore and build on the accumulated global knowledge about flash flood forecasting.

The risk of surface water flooding in Scotland is communicated through SEPA’s Flood Guidance Statement and Flood Alerts, where assessment is based on predetermined rainfall amount and duration thresholds and local expert knowledge. This helped to provide the UK’s first surface water flood risk forecasts for each of the big sporting events at the 2014 Commonwealth Games in Glasgow.

This information is useful to emergency services and the public, but the ability to provide detailed information on the location and timing of flash flooding remains limited. SEPA’s review highlights the growing need to provide more focused forecasts to help those concerned make the right decisions. It also identifies opportunities to learn how other countries respond to similar flooding that could be applied to Scotland.

The review provides several examples of initiatives that could improve the monitoring of flash flood impacts, including better use of crowdsourced data, as happens in the Netherlands, and better weather forecast visualisation tools (such as 3-D interactive displays and animations) as demonstrated in Spain.

The future

It may never be possible to prevent flash flooding, but reliable and early forecasting can help improve the capacity to prepare, respond and recover. The recent introduction of thunderstorm models and ensemble forecasting has resulted in significant advances in forecasting rainfall. This means it may now be possible to forecast flash flooding in urban areas, as well as make forecasts and warnings more focused and easier to understand, which in turn will help people make better, more informed decisions.

Producing flood forecasts for any particular location is likely to remain challenging beyond a few hours in advance – there will always be limits to the predictability of extreme rainfall. But our capacity to predict extreme weather is constantly improving, which SEPA may be able to apply to surface water flood forecasting.

Solutions for communicating uncertainty of heavy rainfall forecasts continue to develop. Our work means that a step-change in flash flood forecasting that builds on the experience of SEPA, the rest of the UK and other countries, is now possible. Making the best use of all available data – including social media and crowdsourced data – will increase awareness of flash flooding and help communities prepare and respond more effectively.


This article was originally published on the Conversation.
Cover photo by Rainbow International on Flickr.
Climate change, pandemics, biodiversity loss: no country is sufficiently prepared

Climate change, pandemics, biodiversity loss: no country is sufficiently prepared

By Gabriel Recchia & Haydn Belfield

There’s little that the left and the right agree on these days. But surely one thing is beyond question: that national governments must protect citizens from the gravest threats and risks they face. Although our government, wherever we are in the world, may not be able to save everyone from a pandemic or protect people and infrastructure from a devastating cyberattack, surely they have thought through these risks in advance and have well-funded, adequately practiced plans?

Unfortunately, the answer to this question is an emphatic no.

Not all policy areas are subject to this challenge. National defence establishments, for example, often have the frameworks and processes that facilitate policy decisions for extreme risks. But more often than not, and on more issues than not, governments fail to imagine how worst-case scenarios can come about – much less plan for them. Governments have never been able to divert significant attention from the here and happening to the future and uncertain.

recent report published by Cambridge University’s Centre for the Study of Existential Risk argues that this needs to change. If even only one catastrophic risk manifests – whether through nature, accident or intention – it would harm human security, prosperity and potential on a scale never before seen in human history. There are concrete steps governments can take to address this, but they are currently being neglected.

The risks that we face today are many and varied. They include:

The ‘Baker’ Explosion, part of Operation Crossroads, a US Army nuclear test at Bikini Atoll, Micronesia, on July 25, 1946. Wikimedia Commons

Each of these global catastrophic risks could cause unprecedented harm. A pandemic, for example, could speed around our hyper-connected world, threatening hundreds of millions – potentially billions – of people. In this globalised world of just-in-time delivery and global supply chains, we are more vulnerable to disruption than ever before. And the secondary effects of instability, mass migration and unrest may be comparably destructive. If any of these events occurred, we would pass on a diminished, fearful and wounded world to our descendants.

So how did we come to be so woefully unprepared, and what, if anything, can our governments do to make us safer?

A modern problem

Dealing with catastrophic risks on a global scale is a particularly modern problem. The risks themselves are a result of modern trends in population, information, politics, warfare, technology, climate and environmental damage.

These risks are a problem for governments that are set up around traditional threats. Defence forces were built to protect from external menaces, mostly foreign invading forces. Domestic security agencies became increasingly significant in the 20th century, as threats to sovereignty and security – such as organised crime, domestic terrorism, extreme political ideologies and sophisticated espionage – increasingly came from inside national borders.

Unfortunately, these traditional threats are no longer the greatest concern today. Risks arising from the domains of technology, environment, biology and warfare don’t fall neatly into government’s view of the world. Instead, they are varied, global, complex and catastrophic.

Global and local. Maksim Shutov/UnsplashFAL

As a result, these risks are currently not a priority for governments. Individually, they are quite unlikely. And such low-probability high-impact events are difficult to mobilise a response to. In addition, their unprecedented nature means we haven’t yet been taught a sharp lesson in the need to prepare for them. Many of the risks could take decades to arise, which conflicts with typical political time scales.

Governments, and the bureaucracies that support them, are not positioned to handle what’s coming. They don’t have the right incentives or skill sets to manage extreme risks, at least beyond natural disasters and military attacks. They are often stuck on old problems, and struggle to be agile to what’s new or emerging. Risk management as a practice is not a government’s strength. And technical expertise, especially on these challenging problem sets, tends to reside outside government.

Perhaps most troubling is the fact that any attempt to tackle these risks is not nationally confined: it would benefit everyone in the world – and indeed future generations. When the benefits are dispersed and the costs immediate, it is tempting to coast and hope others will pick up the slack.

Time to act

Despite these daunting challenges, governments have the capability and responsibility to increase national readiness for extreme events.

The first step is for governments to improve their own understanding of the risks. Developing a better understanding of extreme risks is not as simple as conducting better analysis or more research. It requires a whole-of-government framework with explicit strategies for understanding the types of risks we face, as well as their causes, impacts, probabilities and time scales.

With this plan, governments can chart more secure and prosperous futures for their citizens, even if the most catastrophic possibilities never come to pass.

Governments need to look further into potential futures. FotoKina/Shutterstock.com

Governments around the world are already working towards improving their understanding of risk. For example, the United Kingdom is a world leader in applying an all-hazard national risk assessment process. This assessment ensures governments understand all the hazards – natural disasters, pandemics, cyber attacks, space weather, infrastructure collapse – that their country faces. It helps local first responders to prepare for the most damaging scenarios.

Finland’s Committee for the Future, meanwhile, is an example of a parliamentary select committee that injects a dose of much-needed long-term thinking into domestic policy. It acts as a think tank for futures, science and technology policy and provides advice on legislation coming forward that has an impact on Finland’s long-range future.

And Singapore’s Centre for Strategic Futures is leading in “horizon scanning”, a set of methods that helps people think about the future and potential scenarios. This is not prediction. It’s thinking about what might be coming around the corner, and using that knowledge to inform policy.

But these actions are few and far between.

We need all governments to put more energy towards understanding the risks, and acting on that knowledge. Some countries may even need grand changes to their political and economic systems, a level of change that typically only occurs after a catastrophe. We cannot – and do not have to – wait for these structural changes or for a global crisis. Forward-leaning leaders must act now to better understand the risks that their countries face.


This article was originally posted on The Conversation.
Cover photo by aladdin hammami on Unsplash.
Climate crisis could reverse progress in achieving gender equality

Climate crisis could reverse progress in achieving gender equality

By Nitya Rao, University of East Anglia

People who directly depend on the natural world for their livelihoods, like farmers and fishers, will be among the greatest victims of the climate crisis. In vulnerable hotspots, such as the arid lands of Kenya and Ethiopia, farming communities are already struggling with droughts and water scarcity that kill their cattle and threaten their very survival. The glacial-fed river basins of the Himalayan mountains, or the deltas of Bangladesh, India and Ghana, are increasingly prone to floods, landslides and powerful cyclones.

As a result, men are often migrating further to keep their families going, looking for casual work in neighbouring towns or villages for a few days or weeks at a time, or to cities further away. Many try to return home when they can, with whatever they have earned. But during their absence, the entire burden of maintaining the family is on women.

Researchers are in a race against time to predict how climate change will affect these communities and help them adapt, with drought and flood resistant crops and cattle breeds for example. But it’s often overlooked that climate change will affect one half of humanity significantly more than the other. Longstanding gender inequality means that within regions of the world that are particularly vulnerable to climate change, women are likely to suffer more than men.

A woman leads goats to grazing and water in the Moyar Bhavani Basin, India. Prathigna Poonacha, Author provided

Isolated and overburdened

In a recent study, we found that extreme weather and unpredictable seasons disproportionately weaken the agency of women to find well paid work and rise above rigid gender roles, even when these appear to be bending after decades of reform and activism. Without support in the form of assured drinking water, energy, childcare or credit, women end up working harder and in poorer conditions for lower wages.

Women already in poverty are increasingly finding themselves in a vicious cycle of low productivity, indebtedness and food insecurity as crops and livestock fail, as we found particularly in semi-arid parts of Africa and India. Women in northern Kenya complained that they could no longer afford meat, so ate rice and potatoes instead, even when this wasn’t enough to satisfy their hunger.

As environmental stresses accumulate, community support networks break down. When people are displaced and have to settle elsewhere, men search for work and women are left behind at home, often in unfamiliar surroundings and lacking support from friends and relatives. But even if they do know people, with all the challenges of running the household in a strange environment, there is little time to help others.

As men migrate to find work, women have to shoulder the burden of housework, farming and childcare. Prathigna Poonacha, Author provided

With full responsibility for household chores, farming and caring for the children and elderly, women have less time to socialise or take part in community events, including meetings of the elected village government. If the state or charities can help, there’s often competition for securing those benefits. In Namibia, people tend to stick with their ethnic groups to guarantee access through collective effort, but this means that ethnic minorities in the region are often excluded.

In Mali, heavier burdens are placed on women who are young and less educated. In India or Pakistan, women belonging to a lower social class or marginal caste suffer the most. Gender relations differ in each place and according to each situation – they’re often too variable to emerge in broad national and global assessments. We tried to find a way to generalise our findings across 25 very diverse locations, in Asia and Africa, without losing the nuance of each woman’s experiences.

The bare necessities

If much of the problem is structural, then short-term solutions like cyclone shelters or drought relief won’t address the underlying causes of poverty and precariousness. Social safety nets that can ensure the basic necessities of food and shelter are needed, like the public distribution system for cereals in India, or the pensions and social grants available in Namibia.

To ensure that the health of people in these places doesn’t irreversibly decline, women need to be supported with child and healthcare services, but also drinking water and cooking fuel. The role of community support is crucial during crises, but there’s little that women can do to help themselves without resources and skills.

A woman collects drinking water from a well in Bangalore, India. Prathigna Poonacha, Author provided

Competitive labour markets are also undervaluing the labour of poor women. Ensuring minimum wages and fair working conditions would help, but these are hard to implement across borders. As climate change causes traditional livelihoods to collapse, migrant men are similarly exploited by new employers. Deprived of adequate food and rest, many end up sick and spend their earnings on medical treatment.

Tackling the climate emergency and making sure these women and men live meaningful lives will take more than overcoming gender stereotypes. If given support, they can find creative solutions to the disruption that climate change has brought. But this support must mean the guarantee of universal access to food, shelter and basic services. At COP25 in Madrid, world leaders should help vulnerable communities to adapt to climate change with resources and solidarity, not warm words and rhetoric.


This article was originally posted on The Conversation.
Cover photo by Asantha Abeysooriya on Unsplash
Arctic’s oldest ice shows signs of change

Arctic’s oldest ice shows signs of change

By Tim Radford

Stretches of the Arctic’s oldest ice, and its thickest – the last refuge ice that should survive even when the Arctic Ocean technically becomes ice-free in summers later this century – are now disappearing twice as fast as the rest of the Arctic icecap.

Although the north polar ice is vulnerable to global heating, and has been thinning and retreating at an accelerating rate for the last 40 summers, researchers have always expected some winter ice to survive: they define an “ice-free Arctic Ocean” as one with less than 1 million square kilometres of surviving ice pack.

But this supposedly ancient remnant of the polar winters, concentrated north of Greenland and the Canadian polar archipelago, is showing signs of change.

Researchers do not explicitly finger climate change driven by ever-greater human use of fossil fuels as the direct agent of this change: this is an area of polar ice difficult to observe and explore, is little known, and may always have been subject to change.

“This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning”

But scientists know why it is important. From submarine algae to polar bears, an entire Arctic ecosystem is dependent on the ice sheet. As the ice disappears, so will the seals, and their predators too.

Conservation-minded governments that want to establish protected areas need to know where protection will work best. “Eventually, the Last Ice Area will be the region that will repopulate the Arctic with wildlife,” said Kent Moore of the University of Toronto in Canada. “This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning.”

Dr Moore and his colleagues report in the journal Geophysical Research Letters that they used computer models and satellite observation data to build up a picture of what they call “spatiotemporal variability” in their Last Ice Area.

They found two distinct places where ice thickness fluctuated by up to 1.2 metres from year to year. In some patches, the ice was thinning by the decade: a loss of 1.5 metres since the late 1970s.

No monolith

Most north polar ice is youthful: seldom more than four years old. The Last Ice Area is certainly more than five years old, and has been measured at a thickness of four metres. It is not a static region: ice moves with the ocean beneath it.

And even the levels of melting are affected by natural cyclic ocean shifts as well as higher temperatures fuelled by greenhouse gas build-up in the atmosphere.

The race is on to understand the forces at work in what might be – one day – the only surviving ice in the polar summer.

“We can’t treat the Last Ice Area as a monolithic area of ice which is going to last a long time,” said Dr Moore. “There’s actually lots of regional variability.”


This article was originally posted on The Climate News Network.
Cover photo by Annie Spratt on Unsplash
The flooding emergency in Northern England is a policy failure not a freak of nature

The flooding emergency in Northern England is a policy failure not a freak of nature

By Will Bugler

Last week the government declared a national emergency as devastating floods affected parts of Northern England. Communities living on the River Don were particularly badly affected. The speed of the river’s response to a period of very intense rainfall seemingly caught authorities off guard. People were forced to evacuate their homes, businesses were forced to close their doors, and one person lost their life. The tragedy of these floods is compounded by the fact that they were both predicted and preventable. Their impacts represent a failure of policy.

Residents living in the flood affected areas have been in this position before. The River Don has burst its banks on several occasions, causing devastating flooding in 2007, then again in 2012

The previous severe floods provided ample warning of the vulnerability of communities to flood risk. This was reinforced by the UK Government’s own Climate Change Risk Assessments in 2012 and 2017. In 2012, Acclimatise led the work for part of the Risk Assessment, the document explicitly warns that “we currently expect a shift towards generally wetter winters, and a greater proportion of precipitation to fall as heavy events.” Flooding was also identified as a top risk for each of the sectors analysed in the report. Five years later in 2017, the UK Climate Change Risk Assessment Evidence Report presented “compelling evidence that climate change may lead to increases in heavy rainfall and significantly increased risks from fluvial and surface flooding”.

Image 1: The Adaptation Sub-Committee’s assessment of the top six areas of inter-related climate change risks for the UK. Source: Committee on Climate Change (2016) UK Climate Change Risk Assessment 2017 Synthesis Report, www.theccc.org.uk/uk-climate-change-risk-assessment-2017/synthesis-report/

One of the businesses flooded this year was the Meadowhall Shopping Centre in Sheffield. The Centre was featured in a 2007 Acclimatise report on climate risks to commercial property after it was badly flooded that year. The risks that flooding poses are not just foreseeable, they are foreseen and even experienced.

Image 2: An excerpt from Acclimatise’s report Understanding the investment implications of adapting to climate change (2007) which featured the Meadowhall Shopping Centre as a case study. http://www.acclimatise.uk.com/wp-content/uploads/2018/01/Acclimatise_USS_Commercial_Property_Final_Report_Oct09.pdf

Data from the UK Met Office shows the amount of rain from extremely wet days has increased by 17%, when comparing 2008-17 records with those from 1961-90. They calculate that an extended period of extreme winter rainfall in the UK is now about seven times more likely because of climate change.

A lack of action

Despite these repeated warnings, government action on flooding has been piecemeal. According to the government’s official advisers, the Committee on Climate Change there were no areas where the government was preparing properly for climate impacts. This is evident from the reduction in staff numbers working in key departments. In 2013 the number of staff working directly on climate adaptation at Defra was counted in dozens, by 2018 only around five remained. Government support for important services including the UK Climate Impacts Programme, the Environment Agency’s Climate Ready programme and the Regional Climate Change Partnerships was also cut, and reporting on adaptation, mandatory in 2011, has since been made voluntary.

This year’s Committee on Climate Change’s progress report on the government’s record on flooding was damning. It found that “vulnerability and exposure to climate change are increasing across a range of priority areas; including terrestrial and freshwater habitats; development in flood risk areas; risks to health from heat and cold; and risks to health from changes in air quality. Urban greenspace, which has a host of benefits for reducing flood and heat risks, continues to decline, from 63% of urban area in 2001 to 55% in 2018. The proportion of impermeable surfacing in towns and cities, which increases flood risk, has risen by 22% since 2001.”

Building flood resilience

As implied by the Committee on Climate Change’s report, dealing with flood risk requires a systemic approach in order to be truly effective. After severe flood events in the UK, there are a lot of calls for measures such as flood walls and levees to be constructed and for rivers to be dredged. Treating the symptoms of flooding in this way is unlikely to be effective in the face of climate change.

In a 2014 report on dredging as an approach for flood management, the Chartered Institute of Water and Environmental Management (CIWEM) said that “claims that the widespread use of dredging can act as a flood prevention measure are not only unsupported by both science and evidence, they are a cruel offer of false hope to those living in flood prone communities.”

Dredging targets just one small part of the hydrological system (the river), temporarily increases capacity and the speed of flow of the water. This can have serious unintended consequences for towns as flood waters move faster through them.

Only a small proportion of water in a river basin is held in the river itself. An effective flood prevention strategy should take a whole systems approach, implementing measures that slow the flow of water as it moves through the catchment. These might include tree planting in upland areas, more green spaces in cities, more water stores and floodable areas outside of towns, and improved farming practices to prevent runoff.

The floods on the River Don this year were made a lot worse by poor land management in the Peak District and the upland areas in the Pennines. Over the past decades the areas have seen huge amounts of peat cutting, drainage and heather burning. With nothing to stop it the water now runs very quickly from the hills into stream and river channels. Flooding remains one of the most significant climate risks to the UK. Without significant investment in systemic flood resilience building, events like those experienced by the residents living along the River Don will continue.


Cover photo of The River Don, in Attercliffe Sheffield. Photo from Dan Cook Archived on Flickr
New-borns face multiple climate health risks

New-borns face multiple climate health risks

By Tim Radford

Today’s world is not a welcoming place for babies, who – across the globe – face multiple climate health risks.

On present trends, any new-born today is likely to live in a world 4°C hotter than it has been all through human history.

On present trends, climate change will affect infant health by reducing the yield and nutritional value of maize, wheat, soybean and rice, to stunt growth and weaken immune systems.

Older children will be at increasing risk from climate-related diseases such as cholera and dengue fever, and adolescents will be at increasing risk from toxic air, driven by fossil fuel combustion and ever-higher temperatures.

And then throughout their lives, today’s newly-borns will be at hazard from increasingly severe floods, prolonged droughts and wildfires.

“This year, the accelerating impacts of climate change have become clearer than ever,” said Hugh Montgomery, who directs the Institute for Human Health and Performance at University College London.

“The world has yet to see a response from governments that matches the unprecedented scale of the challenge facing the next generation”

“The highest recorded temperatures in Western Europe and wildfires in Siberia, Queensland and California triggered asthma, respiratory infections and heat stroke. Sea levels are now rising at an ever-concerning rate. Our children recognise this climate emergency and demand action to protect them. We must listen, and respond.”

Professor Montgomery is a co-chair of the Lancet Countdown, which has assessed research from 120 experts in 35 global institutions on health damage from climate change and the lifelong health consequences of rising temperatures.

The Lancet is one of the world’s oldest and most distinguished medical journals and has already published three important studies of the  challenge of climate change in terms of nutritiondiet and the effect of extreme temperatures on human health.

The latest study compares a world in which governments everywhere fulfil a promise made in Paris in 2015 and contain global heating by the century’s end to a rise of “well below” 2°C, or follow the notorious “business as usual” scenario in which developing economies burn ever more fossil fuels and ratchet up global temperatures to potentially catastrophic levels.

The new study looks at the available indicators and warns that climate change driven by global heating is already damaging the health of the world’s children and will shape the wellbeing of an entire generation unless the Paris targets are met.

Targets receding

Right now, average planetary temperatures have already risen by 1°C in the last century and the latest analysis of national plans to reduce fossil fuel use suggest that the Paris targets will not be met.

And climate change has begun to take its toll. In the last 30 years the average global yield potential of maize has shrunk by 4%, of winter wheat by 6%, of soybean by 3% and rice by 4%: this alone makes more infants vulnerable to malnutrition and rising food prices.

Eight of the ten hottest years ever recorded have happened in the last decade, and this heating has been driven by fossil fuel use: every second the world burns 171,000 kg of coal, 186,000 litres of oil and 11,600,000 litres of gas.

Nine of the 10 most suitable years for the transmission of dengue fever – carried by the mosquito – have happened since the turn of the century. Last year was the second most suitable year on record for the spread of the bacteria that cause diarrhoeal disease and wound infection.

In 2016, deaths from outdoor air pollution were set at around 2.9 million; of these, 440,000 were from coal alone. The share of global energy from coal actually rose by 1.7% between 2016 and 2018.

Better future possible

And the journal also records a rise in extreme weather events: out of 196 countries, 152 experienced an increase in citizens exposed to wildfires since the first four years of the century; and a record 220 million more citizens over the age of 65 were exposed to heatwaves in 2018, compared with 2000. This is an increase of 63m just on 2017.

In 2018, compared with 2000, heat extremes cost the world’s economies a potential 45 billion hours of additional work: in the hottest month, outdoor agricultural workers and construction teams lost as much as 20% of potential daylight working hours.

But, the Lancet Countdown experts say, if the world did fulfil its Paris Agreement promise, then any child born today would grow up on a planet that had reached net zero carbon emissions by their 31st birthday: there would be a healthier future for coming generations.

“The climate crisis is one of the greatest threats to the health of humanity today, but the world has yet to see a response from governments that matches the unprecedented scale of the challenge facing the next generation,” said Richard Horton, editor-in-chief of the Lancet.

“With the full force of the Paris Agreement due to be implemented, we can’t afford this level of disengagement. The clinical, global health and research community needs to come together now and challenge our leaders.”


This article was originally published on the Climate News Network.
Cover photo by Khoa Pham on Unsplash
River deltas are ‘drowning’, threatening hundreds of millions of people

River deltas are ‘drowning’, threatening hundreds of millions of people

By Frances Eleanor Dunn and Stephen Darby

The world’s river deltas take up less than 0.5% of the global land area, but they are home to hundreds of millions of people. Many live in major fast-growing cities such as Kolkata in the Ganges delta, Bangkok in the Chao Phraya delta, or Shanghai, one of dozens of large cities in the Yangtze delta region.

With fertile soils and easy access to the coast, deltas are critical hotspots of food production. Vietnam’s Mekong delta alone supplies almost 20% of the world’s rice. They also host unique ecosystems such as the Sundarbans in Bangladesh and India, the largest mangrove forest in the world.

But many of the world’s deltas are now facing an existential crisis. Sea levels are rising as a result of climate change, while deltas are themselves sinking, and together this means the relative sea level is rising extra fast.

Deltas are built from sediments that are carried downstream by rivers and eventually deposited where the river meets the sea. As these sediments compact under their own weight, deltas naturally sink. Where left undisturbed, the supply of new river sediment can compensate for the subsidence and help to maintain the delta surface above sea level.

But deltas are now subsiding much faster than they would do naturally. That’s thanks to groundwater being pumped (or “mined”) from aquifers underneath them and used to irrigate crops and provide water for rapidly growing cities.

In these circumstances, only the continued deposition of sediment on deltas can keep them from “drowning”. We therefore wanted to find out whether supplies of river sediments would be affected by future environmental changes.

To address this question, we used a computer model to project changes in the flows of sediment to almost 50 major deltas worldwide. We used the model to explore the impact of various environmental changes, including climate change, population growth, increases in wealth and the construction of dams. Our results are published in the journal Environmental Research Letters.

Rice farmers in the Mekong Delta, Vietnam. Phuong D. Nguyen / shutterstock

We found that most of the world’s major deltas will receive less river sediment by the end of the century, regardless of the environmental change scenario. On average, we projected a 38% decrease. Our results suggest that many deltas – already significantly stressed – will become sediment starved, further compounding the risks of rising relative sea levels.

Some of the most severe reductions will be found in major Asian deltas such as the Ganges (81% less sediment) and the Mekong (77%). This is particularly concerning because these deltas are among the largest and most densely populated in the world.

We found that climate change will generally drive a small increase in the flows of sediments as, among other factors, warmer temperatures lead to increased precipitation and more soil is washed into rivers. But in many deltas this modest uptick will be more than offset by dams (which trap river sediments) and improved soil conservation practices as societies become wealthier. The Aswan Dam on the River Nile in Egypt or the Hoover Dam on the Colorado River in the US are among the dams that have already starved their downstream deltas of sediment.

Bad news for a river delta. Tupungato / shutterstock

Better management of river sediment is vital to improve the outlook for the world’s deltas. International cooperation will be essential in deltas such as the Mekong and Ganges which are supplied by large rivers that drain many countries. For dams specifically, comprehensive environmental risk assessments that fully cost the consequences for downstream regions are required so that plans can be changed or scrapped. For those dams that are to be built in the coming decades, their design must accommodate transport of sediment downstream.

For authorities within deltas, faced with managing a dwindling supply of river sediment, new approaches are needed to better manage this precious declining resource. Flood embankments prevent sediment reaching delta plains and may need to be breached, as is being explored in the Ganges delta. Additionally, the removal of sand from rivers for construction materials, which is pervasive in many deltas around the world, must be better managed.

Ultimately, difficult decisions need to be made about development priorities between countries upstream of deltas and those including the deltas themselves, and there will be trade-offs to be made between hydropower, agricultural practices and delta sustainability.


This article was originally published on The Conversation.
Photo by Drew Coffman on Unsplash.
Rising heat drives hungry people to hospital

Rising heat drives hungry people to hospital

By Tim Radford

Australian and Chinese scientists have identified a new hazard in the summer heat waves – more undernourished and hungry people are driven into hospitals.

They combed the records of Brazil’s hospitals, matched them against temperature readings and found that for every 1°C increase in temperature, there was a 2.5% increase in hospital admissions for undernutrition.

Undernutrition is defined as “inadequate intake of energy and nutrients to meet an individual’s needs to maintain good health.” That is: with extremes of heat come the ravages of hunger. The researchers also found that the very young and the very old were the most vulnerable.

Undernutrition is a global public health concern, especially in the low- and middle-income nations. In 2016, around 420 million adults of 20 years and more, and 192 million children and adolescents between 5 and 19, were underweight.

Of children under 5 years of age, 150 million were stunted, and 52 million were wasted. Around 45% of deaths of children under 5 were associated with undernutrition.

“The malnourished are more often from the poorest communities: they cannot stay indoors with the air-conditioning switched on”

And now the climate emergency, which brings with it ever greater extremes of heat, could make a global problem even worse.

Quite how dangerous heat and dangerous hunger are linked is uncertain, but the researchers report in the Public Library of Science journal PLOS Medicine that they have confirmed that the link is a real one.

Yuming Guo of Monash University in Australia and colleagues gathered data from the 5,570 cities in Brazil’s unified health system from January 2000 to December 2015. However, they included data only from the 1,814 cities – with more than 78% of Brazil’s population, in five regions – that could produce 16 complete years of records.

They had already established that hospital admissions rose with the thermometer. This time they established that one in six of the hospitalisations for undernutrition – that is, 37,129 cases – could be attributed to heat exposure. This proportion had risen from 14% in 2000 to 17.5% in 2015, during which time average temperatures rose by 1.1°C.

Spreading heat extremes

The links between heat and health have been repeatedly confirmed. Heat extremes, driven by global average temperature rises, in turn powered by profligate fossil fuel use, are on the increase: by the end of the century, they will be more intense, more frequent and more prolonged. And by the end of the century, three-fourths of the world could be at potentially lethal risk from the baking days and sweltering nights.

Researchers have repeatedly established that extremes of heat can affect harvest yields, and that high growing season temperatures, driven by ever higher levels of atmospheric carbon dioxide, can reduce protein and vital nutrient levels in crops, to amplify global hunger and malnourishment. One research group even catalogued 27 ways in which heat extremes could kill.

These are long-term consequences. What the latest study does is put a measure to the short-term effect of heat upon illness linked to undernourishment. How the connection works is – the scientists concede – “not well understood.”

They suggest that high temperatures could reduce appetites, provoke more alcohol consumption, or reduce motivation to shop and cook, which would make any existing under-nutrition even worse. They also think that the sweltering heat could worsen already-impaired digestion and increase the frequencies of gastroenteritis.

Less healthy targeted

And, of course, those already undernourished are less healthy and less able to naturally regulate their own body temperatures. Finally, the malnourished are more often from the poorest communities: they cannot stay indoors with the air-conditioning switched on.

There could be many factors. But one thing is clear: heatwaves most harm those already less healthy because of undernutrition. By 2050, climate change could reduce global food supplies by more than 3% and cause around 30,000 underweight-related deaths.

But, the researchers warn, this now looks like an under-estimate, because it does not take into account the short-term and direct effects of temperature rise on future undernutrition-related morbidity and mortality.

“This direct, short-term effect will be increasingly important with global warning,” the scientists warn. 


This article was originally published on the Climate News Network.
Cover photo by Russel Watkins on Wikimedia Commons.
Acclimatise contributes to Risk Magazine on the pressures facing energy firms, driven by physical climate change

Acclimatise contributes to Risk Magazine on the pressures facing energy firms, driven by physical climate change

By Anna Haworth

Acclimatise’s Anna Haworth recently contributed to an article for Risk Magazine focused on the increasing pressure energy firms are facing to assess physical climate risks. In the article, Anna shares a number of insights, developed through our long-standing experience of helping corporate clients, particularly in the oil, gas and extractives sector, position themselves to effectively manage physical climate risks.

In the article, Anna highlights that climate change doesn’t necessarily create new risks, but instead acts to change existing risk profiles – by altering their frequency, severity and spatial distribution. She reflects that the energy sector, and others with large, fixed assets and complex supply chains (e.g. mining and metals), are very experienced and well-equipped to identify and manage risks. Future climate-related risks have been on companies’ radars for a long-time, particularly from an operational, business continuity and supply chain management perspective. “What they are struggling with a bit more is bringing in the longer-term dimension and understanding how those risks might change over time, driven by changes in the climate and evolving stakeholder expectations” reflects Anna.

Anna describes the step-changes in the last few years in the positions of many key stakeholder groups around the imperative to understand and manage physical climate risks, with associated calls for disclosure. Arguably the most significant recent development is the publication of the Financial Stability Board’s Task Force on Climate-related Financial Disclosures (TCFD) recommendations, in 2017. The TCFD set out a framework for the voluntary disclosure of climate-related risk and opportunities (governance, strategy, risk management, metrics and targets). The TCFD identifies physical risk as one of two categories of climate-related risk, alongside transition risk to a lower-carbon economy.

Anna reflects that corporates are encouragingly viewing the TCFD’s recommendations as being more than just disclosure: meeting the recommendations is also changing corporate behaviour and driving action. “The TCFD’s recommendations have really created an impetus for companies to progress their climate risk and opportunity assessment and management,” says Anna. “Oil and gas companies are increasingly aligning their climate change activities with these recommendations,” such as improving governance, strategic planning, risk management and reporting on targets, including progress in meeting these. We are also witnesses a flow-through of this information into companies Integrated Annual Reports or the development of stand-alone TCFD-style climate reports.

Anna, and others in the Acclimatise team, are at the forefront of developing methodologies and metrics that help corporates to identify, quantify, and disclose physical climate risks and opportunities. Anna has been instrumental in the development of our bespoke TCFD benchmarking and audit toolkit, which we have successfully deployed for several of our FTSE100 and major corporate clients. If you would like to discuss your needs, Anna Haworth would be delighted to hear from you.

The full Risk Magazine article published on 10 October 2019 is available here


Photo by Raghu Nayyar on Unsplash
Climate change is forcing butterflies and moths to adapt – but some species can’t

Climate change is forcing butterflies and moths to adapt – but some species can’t

By Callum Macgregor

Butterflies are rather like Goldilocks, preferring conditions to be neither too hot nor too cold, but “just right”. Under climate change, the temperature at any given time of summer is, on average, getting warmer, leaving butterflies (and their nocturnal cousins, the moths) with the challenge of how to remain in their optimal temperature window.

One of the main ways in which species are achieving this is by changing the time of year at which they are active. Scientists refer to the timing of such lifecycle events as “phenology”, so when an animal or plant starts to do things earlier in the year it is said to be “advancing its phenology”.

These advances have been observed already in a wide range of butterflies and moths – indeed, most species are advancing their phenology to some extent. In Britain, as the average spring temperature has increased by roughly 0.5°C over the past 20 years, species have advanced by between three days and a week on average, to keep track of cooler temperatures.

Is this a sign that butterflies and moths are well equipped to cope with climate change, and readily adjust to new temperatures? Or are these populations under stress, being dragged along unwillingly by unnaturally fast changes?

In a new study published in Nature Communications, colleagues and I sought to answer this question. We first pulled together data from millions of records submitted by butterfly and moth enthusiasts to one of four recording schemes run by charities or research institutes. This gave us information on 130 species of butterflies and moths in Great Britain every year for a 20-year period between 1995 and 2014. We could then estimate the abundance and distribution of each species across this time, along with how far north they had moved. The data also, crucially, allowed us to estimate subtle changes in what time of the year each species was emerging from the chrysalis as a fully-grown butterfly.

It pays to reproduce quickly

Analysing the trends in each variable, we discovered that species with more flexible lifecycles were more likely to be able to benefit from an earlier emergence driven by climate change. Some species are able to go from caterpillar to butterfly twice or more per year, so that the individual butterflies you see flying in the spring are the grandchildren or great-grandchildren of the individuals seen a year previously.

Among these species, we observed that those which have been advancing their phenology the most over the 20-year study period also had the most positive trends in abundance, distribution and northwards extent. For these species – such as Britain’s tiniest butterfly, the dainty small blue – emerging early in spring gives more time for their later-summer generations to complete their reproductive cycles before the arrival of autumn, allowing more population growth to occur.

Small blue: Britain’s tiniest butterfly. Callum Macgregor, Author provided

Other species, however, are less flexible and restricted to a single reproductive cycle per year. For these species, we found no evidence of any benefit to emerging earlier. Indeed, worryingly, we found that the species in this group that specialise in one very specific habitat type (often related to the caterpillar’s preferred diet) actually tended to most harmed by advancing phenology.

The beautiful high brown fritillary, often described as Britain’s most endangered butterfly, fits this category perfectly. It is found only alongside the dog-violets that its caterpillar eats, in coppiced woodland and limestone pavement habitats. It’s also a single-generation butterfly that has advanced its phenology. This suggests that climate change, while undoubtedly not the sole cause, might have played a part in the downfall of this species.

The high brown fritillary was once widespread, but is now found in just a few sites in Lancashire and the south-west. Callum Macgregor, Author provided

All is not lost, however. Many of Britain’s single-generation species show the capacity, in continental Europe, to add a second generation in years that are sufficiently warm. Therefore, as the climate continues to warm, species like the silver-studded blue might be able to switch to multiple generations in the UK as well, and thereby begin to extract benefits from the additional warmth, potentially leading to population increases.

Specialists are at risk

More immediately, we can arm ourselves with this knowledge to spot the warning signs of species that may be most at risk. Clearly the single-generation habitat specialists are of particular concern, as many are already endangered or vulnerable – not just the high brown fritillary and silver-studded blue, but also species such as pearl-bordered fritillary, grizzled skipper and the particularly sought-after white admiral of southern England. Multi-generation species that are failing to advance their phenology might also be threatened: into this category falls another of Britain’s most sharply-declining butterflies: the wall brown.

Using this knowledge to help protect moths and butterflies from climate change is not simply important for the sake of the butterflies and moths themselves – these species also play a number of important roles in our ecosystems. Their caterpillars consume vast quantities of plant material, and in turn act as prey for birds, bats, and other small mammals, while moths even act as pollinators of a surprisingly wide range of plant species, possibly including some important crops.

According to Butterfly Conservation, around two-thirds of butterfly species have declined in the UK over the past 40 years. If this trend continues, it might have unpredictable knock-on effects for other species in the ecosystem. Only by arming ourselves with an understanding of why butterfly numbers are down can we hope to halt or reverse the decline.


This article was originally posted on The Conversation
Photo by Ana Martinuzzi on Unsplash