Key nations have announced US$ 4.8 million in funding for the delivery of early warning systems and services to reduce loss of life from severe weather events in the Pacific region. The announcement was made 10 June 2020 during the 11th Steering Committee Meeting of the Climate Risk & Early Warning Systems (CREWS) initiative by its Member States, the governments of Australia, Canada, France, Germany, Luxembourg, Netherlands, Switzerland and the United Kingdom.
The CREWS initiative was established in 2015 at the United Nations Climate Change Conference (COP21) as a financial mechanism to save lives and livelihoods through the expansion of early warning systems and services in Least Developed Countries and Small Island Developing States. Its three Implementing Partners are the World Meteorological Organization, the World Bank Group / Global Facility for Disaster Reduction and Recovery and the United Nations Office for Disaster Risk Reduction.
Filipe Lucio of WMO indicated at the meeting that the funds would allow the island countries in the region to detect, monitor and forecast severe high-impact weather events. Additional services to be developed include access to longer-term seasonal predictions and operational early warning and response plans that ensure the most vulnerable people in the communities receive warnings.
CREWS Member States also approved the allocation of funds to support countries to monitor the effectiveness of their national early warning systems. Additionally, the preparations of another US$ 4 million project, covering the South West Indian Ocean that includes the countries of Comoros, Madagascar, Mauritius, Mozambique and Seychelles was initiated for funding in the near future.
To date, the CREWS Trust Fund has delivered over US$ 43 million in project funding and mobilized an additional US$ 270 million from public funds of other development partners – realizing accelerated life-saving action and maximized finance effectiveness.
In 2019, CREWS support was scaled up to 44 least developed countries and small island developing states. Through this work, more than 10 million people in some of the world’s most vulnerable communities now have access to better early warning services.
In Afghanistan, 3D printers are being used to build automatic weather stations, bringing early warning services to rural communities.
In Burkina Faso, more than 1,100 rural farmers received 130 weather forecasts in 2019, broadcast via local radio stations.
In Fiji, nearly one million people now have advance flash flood warnings, creating increased security and saving lives.
In Niger, more than 600 women were trained in early warning services and have now created women-led WhatsApp groups to amplify advance warnings throughout their communities.
Across the Caribbean, national emergency management offices, national hydromet offices, national gender bureaux, sectorial ministries, and non-governmental groups including women organizations are now working together to bridge the gender divide in access to early warning systems.
All these far exceeded the recent Cyclone Amphan’s total of 26 deaths so far. Understanding the generally declining death toll offers lessons on how the rest of the world could prepare better for such events. Part of it is forecasting, warning, and evacuation.
But another part is local action, which we research. Much of this science is participatory, directed by the people who are vulnerable in order to balance and meld local and external ideas and approaches.
From vulnerability to resilience
Cyclone Amphan made landfall in Bangladesh on May 20 2020. It inundated over 4,000 sq km of land and destroyed homes, polders (low-lying areas of land surrounded by dikes or levees), embankments, roads, electricity poles, mobile phone towers, bridges and culverts, with the exact costs still being tallied. Many agricultural fields and fish farms were overwhelmed by the saltwater storm surge.
The low death toll can be largely attributed to Bangladesh’s long-term efforts to reduce vulnerabilities, including at the local level, which is always the key in preventing disasters. In 1970, the country had only 42 cyclone shelters, whereas now over 12,000 functionally active cyclone shelters dot the coastline, serving nearly 5 million people.
A diverse system of warning messages tailored to local needs keeps people informed about evacuation, ranging from social media to people on bicycles with megaphones. Training in school means that the announcements are trusted and the population knows how to react and why.
Bangladesh has invested in constructing numerous polders to reduce the force of storm surges, although water retention has sometimes damaged agriculture and infrastructure. Local leaders, organisations, and authorities collaborate to implement tidal river management and nature-based approaches such as mangroves. This helps to deal with storm surge and rainfall, as well as reduced freshwater due to India’s Farakka Barrage, built across the Ganges River to keep the water in India since the 1970s.
We assessed one local programme funded and supported by the British and Swedish Red Cross for implementation by the Bangladesh Red Crescent. This “Vulnerability to Resilience” programme ran between 2013 and 2016 in the coastal villages of Pashurbunia and Nowapara in Kalapara Upazila in Patuakhali district.
This was the first time that people there had been involved in such resilience-building work. They installed flood-resistant tubewells, raised latrines above expected flood levels, trained for improved hygiene and first aid, distributed safety equipment, improved local early warning and evacuation systems, and were trained as local volunteers to continue these activities.
Diverse and alternative livelihood opportunities were also promoted. Household-level businesses and shops were encouraged, alongside local markets for the products.
This included people growing and selling garden vegetables and rice, producing crafts through quilting and sewing, rearing cattle for milk and beef, and investing in ducks, chickens, and aquaculture for fish. If any one of these livelihoods is interrupted or ruined, then people would still have options for earning income.
These initiatives are clearly not about cyclones only and move far beyond forecasting, warning, and evacuation. They improve livelihoods, living conditions, community interaction, health, and safety irrespective of a storm. Our calculations immediately after the programme demonstrated that every dollar invested in the programme produced a quick payback of almost five times that amount through enhanced income and local activities.
The real test, though, remains what happens during a hazard. Three weeks after the programme ended, Cyclone Roanu ripped through the south coast of Bangladesh on May 21, 2016. Pashurbunia and Nowapara reported successful warning and evacuation, no casualties, livelihoods with limited interruption, and a water supply and latrines that functioned afterwards.
Similar success is now repeated with Amphan. Despite the cyclone’s devastation, the people are alive and are returning home to rebuild. In Pashurbunia and Nowapara, seven kilometres of polder length were destroyed while the villages and agricultural lands were inundated.
The local population is repairing the damaged polders, houses, and latrines while restoring the drinking water supply and resuming their livelihoods. This is mainly through self-help, without much external assistance so far. It is not easy, but much better than before.
The UK government currently spends £2.6 billion on flood defences in England, and that amount is set to double by 2026. Flooding in February 2020 showed how that’s likely to be a good investment, as climate change drives warmer and wetter weather each winter. But when it comes to managing rivers to prevent flooding in towns and cities downstream, we’re often our own worst enemy.
After the second world war, Britain embarked on a mission to reconstruct its rivers. Workers cut ditches to drain moorland, making it suitable for livestock farming. Looping rivers which once wound lazily through floodplains – flooding these areas once every two years or so – were straightened into rigid channels. River beds were dredged to deepen them and banks excavated to make them steeper, an unnatural situation that takes routine management to maintain.
The idea behind all of this was to reduce flooding by increasing the speed at which water moves downstream. But this also increased the power of rivers to move sediment. Gravels and cobbles dash along these modified and heavily managed rivers, accumulating where the water slows down, as it moves through towns and cities. Here, the river bed swells as sediment piles up, increasing local flood risk.
Over 60% of the UK’s watercourses have been transformed in this way, changing the fundamental character of many British rivers – and the natural processes that would usually govern them – over just a few generations. In a new study, we found that doing nothing is often a better course of action for reducing flooding than these heavy handed attempts to mechanically alter rivers.
Going with the flow
We studied the River Caldew in Cumbria, which has caused three major floods in nearby Carlisle since 2010. Satellite data showed that straightening, deepening and embanking was common along the river between 2005 and 2016. Very little sediment was spotted in the river and across the floodplain, suggesting that almost all of it was being funnelled downstream towards Carlisle.
During this time, the channel through the city was widened in the hope that this would cause flood water to spread out and lose energy. But this only increased the problem of sediment building up within the river, creating a shallower channel through Carlisle that’s prone to overflowing.
Outside of the city, in parts where maintenance has been relaxed, the river has begun to return to a more natural state. Multiple “wandering” channels can now be seen alongside wide areas of deposited gravel. This is encouraging, as it suggests that the main river and its floodplain are reconnecting, allowing the sediment it transports to fall out of the channel and collect upstream.
We found that rivers which are allowed to behave more naturally are better at locking up sediment upstream, rather than letting it accumulate in unnaturally high quantities in flood-prone towns and cities. If more rivers are allowed to behave naturally and develop this way, it could help reduce future flooding.
This hands-off approach to managing rivers is also much cheaper than hard engineering and brings a wealth of environmental benefits with it. The wandering channel system that’s evolving on the River Caldew has the greatest variety of features and habitats across the entire watercourse.
There are gravel bars, deep pools, floodplain wetlands, ponds and river cliffs. This diversity provides greater spawning habitat for fish, and cooler refuges for their fry. The open water habitats benefit amphibians, the trees and shrubs help kingfisher hunt and sand martins can nest in the river cliffs. Beetles and spiders scurry in the shingle, earning this wilder stretch of the Caldew a designation as a site of special scientific interest.
The last 75 years have seen many UK rivers change beyond recognition. The way we manage them in future must look very different. Relaxing our iron grip and allowing natural processes to flourish on rivers once more could be our best hope for reducing flooding, while reviving lost ecosystems rich in native wildlife.
A fresh-off-the-press IDB technical guidance document will help LAC-based project developers prepare bankable Nature-based Solutions (NbS) projects that provide a substitute, compliment or safeguard to conventional ‘gray’ infrastructure projects.
Nature based Solutions (NbS) can play a central role in meeting the
rising demand for infrastructure, and strengthening the resilience of
infrastructure assets. They offer a cost-effective approach to enhance
resilience, while providing a range of social and environmental benefits (e.g.
recreational opportunities, habitat for biodiversity). In this context, NbS
refer to activities associated with the protection, management, enhancement,
and restoration of nature and implemented to deliver climate resilient
infrastructure. This could refer to re-forestation activities for erosion
control, coral reef restoration for coastal protection, and green space
creation for stormwater runoff control in densely populated urban areas.
There is a high awareness of the benefits and services that NbS can
provide, yet significantly less implementation within the Latin American and
Caribbean (LAC) context. Their potential remains largely untapped due to a
number of barriers that prevent mainstreaming NbS into project development.
Some of these barriers are upstream, for example, the lack of NbS incorporation
into infrastructure policy and planning documents, or a lack of financial
instruments to finance NbS. Other barriers are further downstream: these
include, the challenges of defining the business case and accessing finance and
funding, and the lack of adequate data, methods, and tools to incorporate NbS
into project development.
In tackling some of these downstream challenges, the IDB, in collaboration with Acclimatise, have released a 12-step technical guidance document to integrate NbS into project development. The Guidance is targeted to planners, engineers, architects, contractors and operators interested in preparing bankable climate resilient projects that incorporate NbS either as a substitute, complement or safeguard to conventional infrastructure projects.
How was the guidance developed?
In September 2019, the IDB convened a workshop with a range of LAC-based
project developers and international experts with experience in NbS
implementation (e.g. Deltares, World Bank, World Resources Institute, U.S. Army
Corps of Engineers). As LAC as a whole is early stages of NbS implementation,
the IDB considered it opportune to leverage lessons learned from other parts of
the world where NbS is more mainstream in project development, for example the
Netherlands. At the workshop, the NbS experts iterated a preliminary technical
guidance document that was drafted based on a review of LAC and international
literature. The experts iterated the early stage draft and helped answer
important questions such as ‘is this how it works in practice?’ ‘what
steps or processes still need to be incorporated in this document?’, ‘what are
the important LAC-specific elements that must be included?’.
The NbS experts shared their experiences and insights which were
incorporated in the document, both at the workshop and throughout an extensive
review in the months after. The end
product is the result of a participatory process incorporating multiple
iterations with field experts, and should be considered a reference (or
“go-to”) document for project developers interested in developing NbS projects
in LAC, and globally.
The Techincal Guidance Document is available in English and in Spanish and can be accessed here*
Climate change, it’s fair to say, is complicated. And it’s big. One of the main challenges of responding effectively is simply getting your head around the scale of the problem.
This is not unique in the study of the physical world, of course. Scientists and economists spend a lot of time simplifying the complex real world into simpler, smaller parts, to find out how it all works. It’s one of the reasons we create “models” – mini versions of reality in which we can play, change variables, and see what happens.
We love it when we can find something out about the real world and present it in a form that is understood by other people. In environmental research, this sometimes comes in the form of the cost-benefit analysis that is understood by politicians and money-managers everywhere: spend this much cash now to make (or save) more money later.
A new study by European Commission scientists, now published in the journal Nature Communications, is a classic of this type. It looks at the costs of protecting coastal communities from climate change. The authors underline that our coasts will suffer from sea levels that are predicted to rise as much as one metre by the end of the century, as well as from more intense storms.
Of all the many varied impacts in a warming planet, sea level rise is one of the most straightforward to predict, although it will not affect everywhere the same and so some communities will be more at risk than others. We can be quite confident that the sea level is rising due to climate change, because sea water expands as it warms and because extra water is flowing from melting glaciers and ice sheets.
As the oceans warm, the sea levels rise bit by bit – and if ice sheets on Antarctica or Greenland collapse and water currently locked up is released, then sea levels will rise very suddenly, and by a lot. It will be expensive to deal with these impacts, and this new research shows by quite how much in Europe. Given the costs of flooded coastal cities, the European Commission scientists suggest that it would save money in the long run to build improved sea defences around 70% of the continent’s coastline.
There are other options
Do we really want to live in a world in which we all live behind huge walls? Is this the only way to adapt? Many of us have trapped ourselves in places that will no longer be safe, and in some places building large defences is the only option. Certainly London will not survive without the next-generation Thames barrier.
But there are other options in other places, and we can “defend” in different ways. Nature-based solutions such as recreating dunes or marshland or retreating from coastal zones are possibilities that we should consider wherever we can.
These solutions work with natural processes and have loads of other benefits for wildlife and humans, as well as removing some of the worst issues of “hard” coastal defences such as the way concrete walls can simply displace erosion further along the coast to places which are not defended. But it would be unrealistic to think that these are options everywhere.
There may even be other more cost-effective ways to reduce the risk. This is certainly the case for river flooding, where, by using our best weather and river models, we can now predict in advance when and where they will flood and take early action to avoid damage.
But we’re still working hard at making these forecasts better and it remains very difficult to forecast floods. We have a long way to go until we’ve mastered the science, but it is only through combining methods – forecasting, natural-solutions, some hard defences and so on – that we will survive the watery future that awaits.
The cost of climate change even in this one small part of the world and for this one impact area is eyewatering. We have a choice. The first option would be to accept business as usual and pay to treat the symptoms. This will mean building enormous sea walls to deal with increased floods, and paying for disaster recovery operations.
The preferable alternative is to take a more nuanced approach. We know the climate is changing, and we will need a combination of more concrete, clever natural solutions, and better flood forecasts to prepare for what’s ahead. But by showing the sheer scale of the “hard” defences that would be needed on their own to keep Europeans safe, this new paper represents more scientific evidence that cutting emissions now, and mitigating the worst impacts, is the best future we can hope for.
The UK Government’s independent advisors on climate change have written to the Prime Minster and First Ministers in Scotland, Wales and Northern Ireland, to encourage them to put climate change at the heart of post-COVID-19 recovery efforts. Published last week, the Committee on Climate Change’s (CCC) letters set out six key principles to rebuild the nation following the COVID-19 pandemic whilst delivering a stronger, cleaner and more resilient economy.
The Committee calls for immediate action to support
reskilling, retraining and research to ensure that the UK can recover from the
economic shock of COVID-19 and the lockdown measures that accompany it. Reducing
greenhouse gas emissions and adapting to climate change must be integral to the
UK’s recovery package, the Committee says.
“The COVID-19 crisis has shown the importance of planning
well for the risks the country faces. Recovery means investing in new jobs,
cleaner air and improved health. The actions needed to tackle climate change
are central to rebuilding our economy.” Said CCC Chairman, Lord Deben. “The
Government must prioritise actions that reduce climate risks and avoid measures
that lock-in higher emissions.”
The COVID-19 crisis demonstrates clearly, the significant
threats posed by global-scale systemic risks. Climate change increases the
likelihood that the world will face similar whole-system risks in the future. The
CCC explicitly points out that building resilience to climate change is needed
when considering how to rebuild the economy and society in the wake of
Chair of the CCC’s Adaptation Committee, Baroness Brown of
Cambridge, said that the pandemic demonstrates the need of global co-operation
to tackle systemic risk. “As President of next year’s pivotal COP26 climate
summit, the UK now finds itself in a unique position to ramp-up climate action
at home and supercharge the international response to climate change
abroad.” She said. “The risks we face as a globalised society are now in sharp focus
– for their part, UK leaders must act decisively on a climate resilient
recovery, and do so together.”
The letter encourages governments in all UK nations should
prioritise actions to recover from the pandemic based on six resilience
principles. These are:
Use climate investments to support economic recovery and jobs. The CCC has previously identified a detailed set of investments to reduce emissions and manage the social, environmental and economic impacts of climate change. Many are labour-intensive, spread across the UK and ready to roll out as part of a targeted and timely stimulus package.
Lead a shift towards positive, long-term behaviours. The Government can lead the way to new social norms that benefit wellbeing, improve productivity and reduce emissions. This includes actions to support home-working, remote medical consultations and improve safety for cyclists.
Tackle the wider ‘resilience deficit’ on climate change. Strong policies are needed to reduce the UK’s vulnerability to the destructive risks of climate change and to avoid a disorderly transition to Net Zero. They must be implemented alongside the response to COVID-19 and will bring benefits to health, well-being and national security.
Embed fairness as a core principle. The benefits of acting on climate change must be shared widely, and the costs must not burden those who are least able to pay, or whose livelihoods are most at risk as the economy changes. Lost or threatened jobs of today should be replaced by those created by the new, resilient economy.
Ensure the recovery does not lock-in greenhouse gas emissions or increased risk. As it kick-starts the economy, the Government should avoid locking-in higher emissions or increased vulnerability to climate change in the longer-term. Support for carbon-intensive sectors should be contingent on them taking real and lasting action on climate change, and all new investments need to be resilient to future climate risks.
Strengthen incentives to reduce emissions when considering tax changes. Revenue could be raised by setting or raising carbon prices for sectors of the economy which do not bear the full costs of emitting greenhouse gases. Low global oil prices provide an opportunity to increase carbon taxes without hurting consumers.
The Committee’s letter details the steps that Governments can take as a priority, emerging from these six overarching principles.
As we celebrate the 50th anniversary of Earth Day, the coronavirus pandemic puts a spotlight on climate change and health. Temperatures are already rising to 40°C (104°F) while the countries’ 1.3 billion people remain on lockdown. Government officials and health care professionals in India are actively diligently working to contain the spread of COVID-19 while also initiating efforts to protect communities from imminent heat waves through Heat Action Plans and Cool Roofs. NRDC and partners that are leading this work have recently been selected as finalists for the prestigious 2020 Ashden Awards, which recognize pioneering sustainability solutions.
India’s 2020 Heat Season
Brutally hot weather is a major health threat in India and many other parts of the world. Climate change is fueling more frequent, intense, and longer heat waves. The COVID-19 emergency worsens the response to heat-related illness since hospitals and urban health centers are already stressed. In response to this mounting threat, cities and regions across India are taking concrete actions to build resilience and better prepare and protect communities.
Heat is not merely an inconvenience; it kills. Symptoms of heat-related illness include vomiting, headaches, dehydration, and diarrhea. Staff in hospitals, businesses, and municipal buildings often struggle to keep communities cool and healthy. The number of high-temperature days in India has increased over the past fifty years, and especially since the 1990s, in highly-populated cities, such as Mumbai and New Delhi.
The India Meteorological Department (IMD) and National Disaster Management Authority (NDMA) are already working to prepare and respond to anticipated heatwaves. NDMA is also charged as the central agency responsible for COVID-19 response, making the burden of this season even heavier. For the 2020 heat season, IMD’s seasonal forecast shows the heat wave conditions are likely to be severe. NDMA has already activated the network of state disaster response agencies and city leaders to prepare for the soaring temperatures, including an updated list of Do’s and Don’t’s.
Heat Action Plans and Cool Roof Program
NRDC and a broad set of partners, including the Public Health Foundation of India – Indian Institute of Public Health-Gandhinagar (PHFI-IIPH-G) work with government leaders and key experts across India and internationally to develop, launch, and implement heat action plans. Heat action plans are a comprehensive plans for building climate resilience to extreme heat events through public awareness and community outreach; early warning system and interagency coordination; capacity building among health care professionals; and reducing heat exposure and promoting adaptive measures.
A peer-reviewed and published study found that Ahmedabad, one of India’s largest cities, avoided an estimated 1,190 deaths each year after implementing the country’s first Heat Action Plan. The Ahmedabad Heat Action Plan was originally released in 2013 and developed by NRDC, IIPH-G and partners. Heat Action Plans have since expanded to over 23 states and over 100 cities and districts through the leadership of NDMA.
An important component of heat action plans includes cool roofs. Cool roofs reflect sunlight and absorb less heat. Depending on the setting, cool roofs can help keep indoor temperatures lower by 2 to 5°C (3.6 – 9°F) as compared to traditional roofs. They are cost effective solutions that work to protect vulnerable groups and slum communities.
Cities, states and the national government are taking steps to protect communities and save energy costs, through cool roof programs. For example, Ahmedabad has started a cool roofs program for over 15,000 buildings as part of its heat action plan this year, focusing on slum households and city-owned buildings. Building on its initial pilot program two year ago, Hyderabad now has a draft statewide policy as part of its building efficiency program. The national government is working towards sustainable cooling for all with the India Cooling Action Plan, which includes promotion of passive cooling techniques such as cool roofs and energy efficiency programs for buildings, air conditioners and fans.
Ashden Cool Cities Award Finalist
The Ahmedabad Heat Action Plan, along with its cool roofs program, is among the two finalists up for the award in the Cool Cities category, as highlighted in the Ashden blog earlier this month. We are honored to share the nomination with a women-led architecture firm ECOnsult, keeping farm workers in the Egyptian desert cool.
The Ashden Cool Cities Award, sponsored by K-CEP and Climateworks, emphasized the link between the COVID-19 pandemic and the climate crisis because “those already disadvantaged are most at risk”. That is why the Ashden finalists include organizations helping the most vulnerable. Ashen also highlights another link between the two emergencies and theme for the finalist: “How all of us, whatever our wealth or status, can come together to create change that benefits everyone.”
NRDC is deeply humbled to share the Ashden nomination with the many partners who contribute to effective Heat Action Plans and Cool Roofs Programs. We congratulate all of our partners and their unique roles.
As climate change continues to fuel brutal heat waves worldwide, effective public health response strategies are more important than ever before. Drawing on the strengths of government leadership, efficient interagency coordination, scientific expertise, robust communication programs, effective community engagement, strong action on heat preparedness can deliver lifesaving benefits. In discussing the commonality between the coronavirus emergency and climate crisis, Shloka Nath with TataTrusts recently reminded us, “The only boat that is going to save us, is the boat we build together.”
A US-government study has found that the country could save $1 trillion dollars by removing around a million homes from flood-prone areas. The report indicates that government schemes to buy and demolish homes at high risk of repeated flooding, moving residents to higher ground, should be expanded. The report notes that climate change will drive flood risk to real estate even higher in the coming decades and warns that without action financial losses will climb substantially.
The report says that buyout programmes are essential to
minimise exposure to flood risk. However, existing schemes operated by the
Federal Emergency Management Agency (FEMA) are hampered due to funding
shortages and the reluctance of homeowners to move.
“Flooding is the country’s biggest risk, and we just have all of these homes
in the floodplain that keep getting repetitive losses,” said Keith Porter, one
of the study’s authors and a structural engineering researcher at the
University of Colorado. “We never should have been building in the floodplain
in the first place. It’s time to solve that problem.”
According to the report, while a nationwide buyout programme
would cost around $180 billion, it could save around nine times that amount –
$1.6 trillion – over a 100-year period. Savings would accrue thanks to reduced
costs to public disaster programmes and avoiding property damage reducing
pay-outs through federally subsidised flood insurance schemes.
The report found that moving properties out of the flood
zone through a buyout scheme was by far the most cost-effective way to reduce
risk, saving $6.50 for every $1 spent. Other flood related protection measures
such as levees and home adaptations still represented value, but were much more
costly, saving $2 for every $1 spent.
The findings are important, as federal agencies consider the
best course of action to reduce climate risks, faced with mounting costs from
properties that are flooded repeatedly. FEMA’s National Flood Insurance Program
ensures that homeowners that would otherwise be refused flood insurance can
continue to insure their properties. However, “repetitive-loss properties”
(those that flood repeatedly, year after year) are becoming increasingly
burdensome to the programme. The government has resisted cutting funding for
the flood insurance programme, as that would increase premium pay-outs
considerably, or leave homes uninsurable.
And by 2100, the kind of extreme high tides that now happen once in a lifetime could wash over the streets and gardens of 93% of these communities, almost every day.
The message, from researchers led by the US Geological Survey, is that sea levels will go on rising steadily by millimetres every year, but the number of extreme flooding events could double every five years.
Researchers outline their argument in the journal Scientific Reports. They looked at the data routinely collected from 202 tide gauges distributed around the US coasts and then extended the tidal levels forward in time in line with predictions based on global sea level rise that will inevitably accompany ever-increasing global average temperatures, driven by greenhouse gas emissions from fossil fuel use.
“The impact of this finding bears repeating: sea level rise will likely cause ‘once-in-a-lifetime’ coastal flooding events to occur nearly every day before 2100”
But researchers based in Chicago, Santa Cruz and Hawaii wanted more than that: they wanted to know what sea level rise will do, as the waters lap ever higher, from year to year.
“Sea level rise is slow, yet consequential and accelerating,” they point out. “Upper end sea level rise scenarios could displace hundreds of millions of people by the end of the 21st century. However, even small amounts of sea level rise can disproportionately increase coastal flood frequency.”
The researchers selected 202 sites, most of them in sheltered harbours or bays, for their tide data: that way their record reflected the highest tides and storm surges, but not the haphazard readings of waves.
They concentrated on what they called “extreme water-level events” of the kind that happened once every 50 years, because most US coastal engineering work is based on that kind of hazard frequency. And then they started doing the calculations.
Exponential hazard growth
For nine out of 10 locations, the difference between the kind of flood that happened every 50 years and the sort that occurred maybe once a year was about half a metre. For 73% of their chosen tide gauges, the difference between the daily highest tide and the once-every-50-years event was less than a metre. Most projections for sea level rise worldwide by the end of the century are higher than a metre.
Once the researchers had set their algorithms to work, they found that even in median sea-level rise scenarios, the hazards grew exponentially. They found that all tidal stations would by 2050 be recording what remain for the moment 50-year events, every year. When they set the timetable to 2100, 93% of their locations would be recording a once-in-50-years flood every day.
“The impact of this finding bears repeating: sea level rise will likely cause ‘once-in-a-lifetime’ coastal flooding events to occur nearly every day before 2100,” they warn.
A new study has provided clear economic evidence of the benefits of mangrove forests for coastal storm protection. The research, published last month in the journal Scientific Reports, finds that without mangroves, flood damage costs would increase by more than US$ 65 billion a year, and 15 million more people would be flooded.
provide incredibly effective natural defences, reducing flood risk and damages,”
said Pelayo Menéndez, a postdoctoral fellow in the Institute of Marine Sciences
at UC Santa Cruz
and lead author of the paper.
the study, the researchers provide high-resolution estimates of the economic
value of mangrove forests for flood risk reduction across more than 700,000
kilometres of coastlines worldwide. They combined engineering and economic
models to provide the best analyses of coastal flood risk and mangrove
benefits. Their results show when, where, and how mangroves reduce flooding,
and they identified innovative ways to fund mangrove protection using economic
incentives, insurance, and climate risk financing.
Mangroves show wide ranging benefits across geographies
geographical analysis of the benefits of Mangroves, shows that the flood
protection benefits are widely distributed across countries with exposed
coastlines. However, the type of benefits varies significantly according to the
flood characteristics, mangroves extents and the degree of exposure.
the research found that mangroves provide the greatest benefits in the Western
Pacific and Caribbean islands. This is in part due to the amount of benefit
mangroves provide in comparison to a country’s GDP. For example, in Belize,
Suriname and Mozambique, the flood protection benefits from mangroves were
found to account for over 15% of the national GDP.
The study also found that mangroves provide critical flood protection benefits in countries with lower GDPs with coastlines that were highly exposed to climate hazards; for example, Mozambique and Bangladesh. The study found that these countries receive over $US 1 billion in benefits per year.
absolute terms, the countries that receive the greatest annual economic
benefits from mangroves were found to be richer nations, benefiting from
protection to high-value coastal assets and real estate. The United States,
China and Taiwan reap most rewards in these terms. On the other hand, Vietnam,
India and Bangladesh were found to benefit the most from mangroves in terms of
number of people protected, due to the high density of coastal populations in
the study also found that the benefits of mangroves do not accrue only to those
countries that experience extreme coastal storms such as hurricanes and
cyclones. While Mexico, India and Vietnam, do benefit from this protection, the
research also finds that countries, where cyclones are not as common such Japan
and China, mangroves still provide significant benefits from common high waves
Analysis provides vital evidence to inform adaptation
analysis is vitally important for climate adaptation decision making as it
provides clear evidence that Mangrove conservation provides significant
economic gains, and mangrove restoration essentially pays for itself in most
that we can value these flood protection benefits, it opens all kinds of new
opportunities to fund mangrove conservation and restoration with savings for
insurance premiums, storm rebuilding, climate adaptation, and community
development,” said co-author Michael Beck, research professor in the
Institute of Marine Sciences at UC Santa Cruz.
The study valued the social and economic coastal protection benefits provided by mangroves globally. Many 20-kilometer coastal stretches, particularly those near cities, receive more than $250 million annually in flood protection benefits from mangroves.
Despite their numerous
benefits, almost 10,000 km2 of mangroves were lost since between 1996
and 2016 and a further 1,400 km2 of mangroves have substantially
degraded over the same period. The Middle East, South East Asia and Central
America and the Caribbean have suffered the worst losses, primarily due to
deforestation for aquaculture, and coastal development, including the
construction of public infrastructure such as ports and airports.
As well as coastal flood
protection, losing mangroves also undermines livelihoods, food security, valuable
timber production, and one of the most efficient and important carbon stores on
High restoration potential
The good news is that
Mangroves remain relatively well distributed geographically, being found in
over 100 countries globally. As an ecosystem, mangroves are relatively
resilient and, with careful management can be restored successfully. The
researchers note that projects in Vietnam, Philippines, and Guyana have
restored 100,000 hectares of mangroves in recent years. “Mangroves are
resilient and can grow like weeds, even around cities, if we give them half a
chance,” Beck said.
To ensure the study’s
findings have a bearing on policy and conservation work, the researchers are
now working with insurance companies, the World Bank, and conservation groups
to use these results for risk reduction and conservation.
One of the greatest
challenges for ecosystem-based adaptation measures is convincing policy makers,
engineers and urban planners of their value, using hard evidence. This is why
the researchers used the “expected damage function” approach,
commonly used in engineering and insurance sectors to assess flooding.
Hydrodynamic models were used to calculate the flooding that occurs globally
under current and no-mangrove scenarios. In this way the study is able to show the
places where mangroves provide the greatest flood reduction benefits, this
study informs policies for adaptation, sustainable development, and