Geology for Global Development

Disaster Management

Rainfall related geohazards: floods, landslides and mudslides in Rio – A dangerous combination of nature and human-related factors

Rainfall related geohazards: floods, landslides and mudslides in Rio – A dangerous combination of nature and human-related factors

Rainfall-related geohazards in Brazil’s poorer, mountainous city margins could be mitigated using better urban planning and communication. Our own Brazilian blogger Bárbara Zambelli Azevedo explores the problem and possible solutions.

I come from Brazil, a country well-known for its beautiful landscapes, football and carnival. Ok, some stereotypes are true, indeed.

Situated in the middle of the South American tectonic plate and away from geohazards such as earthquakes, volcanoes and tsunamis, this tropical country may seem like paradise to some. However, we are not completely safe from geohazards.

Every year during the summer, which is a heavy rain season, many lives are lost, and people are displaced by floods, landslides and mudslides all over the country. I want to give a particular focus on the state of Rio de Janeiro, where a summer storm killed at least 6 people on the 6th of February this year. I should mention that it was not an isolated event at all.

The situation of the state of Rio de Janeiro is complicated, and its analysis should take into consideration the geomorphology of the area, its climate and – importantly – urban planning.

According to the Brazilian Geological Survey, the bedrock in the area is composed mainly of igneous and metamorphic rocks, and the relief is characterised by steep mountain slopes over 2,000 m, alternated with sedimentary basins.

In 2011 floods, landslides and mudlslides resulted in 903 deaths and over 2,900 people had their homes destroyed

These mountains are a part of a major structure named Serra do Mar (Sea Ridge), a 1,500 km long system of mountain ranges and escarpments parallel to the Atlantic Ocean, running from Rio de Janeiro State until Santa Catarina, in the south of Brazil. Geomorphological features seen today started to form during the opening of the Atlantic Ocean during the Cretaceous, were consolidated throughout the Tertiary and still are modified by erosional and sedimentary events.

The climate is described as tropical in coastal areas such as Rio de Janeiro City and Angra dos Reis. It is warm and humid all year round, with a mean temperature around 23°C and an average annual precipitation of 1,300 mm. The rain season occurs in the summer (Dec-Mar) when 45% of precipitation falls.

In mountainous areas such as Nova Friburgo and Teresópolis, the climate is characterised as temperate. Temperatures are milder at an annual mean of 18°C and the average annual rainfall is 1700 mm, with 59% falling in the summer months of December to March. Therefore, extreme rainfall events are not rare, and they are usually associated with floods and landslides.

The worst weather-related natural hazard-induced disaster in Brazil happened in January 2011, when it rained 166 mm in a 24 hour period in the Serra dos Órgãos region, which is a local denomination of Serra do Mar. Six cities were affected by floods, landslides and mudslides: Teresópolis, Petrópolis, Nova Friburgo, Bom Jardim, Sumidouro and São José do Vale do Rio Preto. These flows resulted in 903 deaths and over 2,900 people had their homes destroyed.

A year earlier the state of Rio had been the scene of another tragedy. It was New Year’s Eve and the city of Angra dos Reis was full of tourists. After intense rainfall, many mudslides were triggered and left at least 44 people dead. Such events repeat themselves every year.

Satellite imagery of the 2011 mudslides in Nova Friburgo - before and after. Via Google Earth, collected in 2019.

Satellite imagery of the 2011 mudslides in Nova Friburgo – before and after. Via Google Earth, collected in 2019.

Just like Rio, most Brazilian cities lack urban planning and settlements are segregated socio-economically. Usually an impoverished population is pushed to marginalised areas of cities, which are usually steep and mountainous areas where the risk of landslides is higher.

In this article geologist and former president of the Institute of Technological Research of São Paulo Álvaro Santos states that only few Brazilian geohazards are triggered exclusively by nature.

In fact, most of our geological and hydrological issues are, somehow, led by poor land-use management, both in cities and in the countryside. Santos also explains that tragedies related to rainfall are usually caused by a lack of land-use planning and housing, and inefficient government communication.

We must learn from our own history and examples from other places like Indian Chennai and Tamil Nadu to tackle the challenge elevated hazard risk in city margins. A good starting point is raising the awareness of the population living in high-risk areas by using geoscience education and science communication.

Geoprevention aims to raise the awareness of the local community about geotechnical and environmental risks such as floods, landslides, infiltration, river erosion and sedimentation and waste disposal

We have a good example from the city of Curitiba, where students from the Federal University of Paraná developed a project titled GeoPrevention. This project aims to raise the awareness of the local community about geotechnical and environmental risks such as floods, landslides, infiltration, river erosion and sedimentation and waste disposal. The students use didactic material like folders, manuals, booklets and provide mini-courses and lectures about these topics with a playful character that is easily understood.

This initiative is important because it provides an interdisciplinary dialogue between a university and civil society, in particular, the population affected by those geohazards, to recognise and avoid them at the individual level.

At a higher level, we need governments and policy-makers to take action on effective urban planning and risk management, and invest more in the prevention of rainfall-related geohazards than on their remediation.

In addition, the active participation of civil society and the private sector is crucial to building resilient societies. Technological innovations such as the internet of things and dashboards should also be used to improve disaster prediction and population warning.

The city of Rio de Janeiro has two big data operation centres, the Operation Centre and Integrated Centre of Command and Control, both launched before World Cup which granted Rio the title of “World Smart City” in 2013.

The centres improved disaster management by mapping areas with high risk of flood-related landslides and implementing a critical early warning and evacuation system for Rio’s favelas. However, according to this article, they have failed at “go[ing] beyond high-tech marketing rhetoric and help[ing] real people living in the city”.

Even though it is very complicated and takes time to solve the problem of rainfall-related hazard risk in city margins, it must start sometime: why not now?!

The ethical questions behind the school climate strike. Do we have a place in earth’s ecosystems? Jesse Zondervan’s February 2019 #GfGDpicks #SciComm

The ethical questions behind the school climate strike. Do we have a place in earth’s ecosystems? Jesse Zondervan’s February 2019 #GfGDpicks #SciComm

Each month, Jesse Zondervan picks his favourite posts from geoscience and development blogs/news which cover the geology for global development interest. This month’s picks include: The ethical questions behind the school climate strike; Military worries about the fight against sea-level rise – how will you help? Do we have a place in earth’s ecosystems?

School climate strikes

As school climate strikes inspired by Greta Thunberg spread across the world in the past month, adults are starting to ask ethical questions.

If one would prefer climate activism to focus on conventional electoral politics, rather than civil disobedience, Rupert Read argues one should question the premise that our societies are fully democratic. If adults have failed, how can we support and listen to our children rather than telling them what to do?

The idea that young people are the key to making positive change to the way we live in our environment is not a new one, but did you ever wonder why? Steve Cohen at Columbia University’s Earth Institute considers how the experiences of the next generation support a survivalist ethic and a change in environmental politics.

The fight against sea-level rise

If the urgency displayed by our children leaves you hungry to roll up your own sleeves, paradoxically it may appear you could help by joining the army to help fight sea-level rise. At a conference on climate change and security at The Hague defence leaders from around the world expressed worry not only for a risk for conflict risks but also of stress on military capacity in all countries with a coastline, not just the poorer nations.

Alternatively, if you have a more entrepreneurial spirit, I would recommend looking at entrepreneurial opportunities for addressing climate change in the developing world.

Sea-level rise and it’s cost is a hot topic this month, with climatologist Radley Horton testifying on capitol hill about sea level rise.

“There has been a lot of focus on whether worst-case scenario for 2100 is 4.3 feet, six feet, or even eight feet of sea level rise,” he said. “Even the most optimistic scenario imaginable—of one foot of sea level rise by 2100—would have direct and profound impacts.”

Indeed, the house market has already responded and cost US coastal home owners nearly 16 billion in property value. Buyout programs in flood-prone areas are becoming more common, even as they come with their own shortcomings.

The insurance industry recognises that investors, lenders, insurers and policymakers undertake significant risk management efforts to minimise rising losses from climate-related hazards. Might more geoscientists be needed here?

As usual, I have many more interesting topics on offer for you, such as: humans have been present in ecosystems for a long stretch of time, so is there a place for us? Check out all stories below!

School climate strikes – an ethical debate

School climate strikes: why adults no longer have the right to object to their children taking radical action by Rupert Read at The Conversation

Youth Strike for Climate and the Ethics of Climate Policy by Steve Cohen at State of the Planet

Climate Adaptation

How Entrepreneurs Can Help Developing Countries Hard Hit by Climate Change by Georgina Campbell Flatter at Entrepeneur

Prepare now for accelerating climate threats, military officials warn by Laura Goering at Thomson Reuters Foundation

There’s a place for us: New research reveals humanity’s roles in ecosystems from the Santa Fe Institute at ScienceDaily

Sand from glacial melt could be Greenland’s economic salvation from University of Colorado Boulder at ScienceDaily

Climate Change Is Having a Major Impact on Global Health by Tanya Lewis at Scientific American

How pollution and greenhouse gases affect the climate in the Sahel by Alessandra Giannini at The Conversation

Investors and lenders need better tools to manage climate risk to homes, mortgages and assets, finds new research at the Cambridge Institute for Sustainability Leadership

The fight against sea-level rise

Lamont Climatologist Testifies on Capitol Hill About Sea Level Rise by Marie Denoia Aronsohn at State of the Planet

Rising Seas Soaked Home Owners for $16 Billion over 12 Years by Thomas Frank at E&E News

Leave No House Behind in Flood Buyout Programs, Group Says by Daniel Cusick at E&E News

What rising seas mean for local economies from Stanford University at ScienceDaily

Predicting impacts of climate change

The Ocean Is Running Out of Breath, Scientists Warn by Laura Poppick at Scientific American

Disaster Risk

Large-scale hazard indication mapping for avalanches at the Institute for Snow and Avalanche Research SLF

Norway’s Arctic islands at risk of ‘devastating’ warming: report by Alister Doyle at Thomson Reuters

Observing Volcanoes from Space by Emily Underwood at EOS Earth and Space Science News

The U.S. May Finally Get an Early Warning System For Volcanoes by Robin George Andrews at Earther

Deep sea mining

Deep sea mining threatens indigenous culture in Papua New Guinea by John Childs at The Conversation

 

Check back next month for more picks!

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What is happening after the Fuego eruption in Guatemala? Is climate migration a bad thing? This and more in Jesse Zondervan’s June 2018 #GfGDpicks #SciComm

What is happening after the Fuego eruption in Guatemala? Is climate migration a bad thing? This and more in Jesse Zondervan’s June 2018 #GfGDpicks #SciComm

Each month, Jesse Zondervan picks his favourite posts from geoscience and development blogs/news which cover the geology for global development interest. Here’s a round-up of Jesse’s selections for the last month:

Everything about the Fuego eruption

At the start of this month, Guatemala’s Fuego volcano erupted explosively, costing many lives and destroying properties and infrastructure.

Professor Handley from Macquarie University explains why the eruption was so disastrous, while Professor Little notes the recovery efforts Guatemalans make on their own, without much government input. Sophie Brockmann delves into history and recovers the cultural significance and political intricacies of Guatemalan dealings with volcanoes.

Climate migration: is it a bad thing?

While the world wakes up to the magnitude of climate migration, a key question we will need to ask is: does climate migration pose a problem or an opportunity to climate adaptation? As always, knowledge is power: a team of New York scientists has modelled future migration due to sea level rise in Bangladesh.

Drought: South Africa out, India in

Drought seems to be a trendy topic this month. South Africa has moved out of the national state of drought disaster and is moving on to resilience. At the same time, India is approaching a long term water crisis and a map of desertification by the EU Joint Research Centre shows building pressures on the world’s resources.

Somewhat reassuring is the opportunity for mitigation that MIT researchers give us. They conclude that climate action can limit Asia’s growing water shortages.

This month a lot was written on climate change adaptation, but as well as disaster risk reduction and sustainability. I would like to highlight this one question: What’s the right goal – resilience, well-being or transformation?

Go ahead and explore:

The Fuego Volcano Eruption and Adaptation

Fuego volcano: the deadly pyroclastic flows that have killed dozens in Guatemala at The Conversation

How Guatemala has dealt with volcanoes over the centuries by Sophie Brockmann at The Conversation

From Kilauea to Fuego: three things you should know about volcano risk by Heather Handley at The Conversation

After volcano eruption, Guatemalans lead their own disaster recovery by Walter E. Little at The Conversation

Migration due to Climate Change and Natural Hazards

Problem to opportunity: migration in times of climate change by Arthur Wyns at The Ecologist

World wakes up to climate migration by Harjeet Singh at India Climate Dialogue

Universal migration predicts human movements under climate change by Simon Davies at Physics World

How Will People Move as Climate Changes? At State of the Planet

Droughts

India faces worst long term water crisis in its history -government think tank at Thomson Reuters Foundation

National state of the drought disaster expires at South Africa news

Is Australia’s current drought caused by climate change? It’s complicated at The Conversation

New World Atlas of Desertification shows unprecedented pressure on planet’s resources at the European Commission Joint Research Centre

Climate action can limit Asia’s growing water shortages at ScienceDaily

Sustainability

Science migrations hold the stage at èStoria, Gorizia at The World Academy of Sciences

What’s the right goal – resilience, well-being or transformation? By Laurie Goering at Thomson Reuters Foundation

Climate Change Adaptation

Alien apocalypse: Can any civilization make it through climate change? At ScienceDaily

Economic models significantly underestimate climate change risks at the London School of Economics and Political Science

Better be safe than sorry: Economic optimization risks tipping of Earth system elements at ScienceDaily

 

Follow Jesse Zondervan @JesseZondervan. Follow us @Geo_Dev& Facebook.

New mining frontiers: Digging into the unknown

New mining frontiers: Digging into the unknown

While climate change occupies the headlines as our biggest long-term concern for sustainability,  there may well be further anthropogenic challenges that arise in the next century as we disrupt the delicate interplay of natural ecological and geological cycles to satisfy the need for resources of our ever-growing population. The mining industry makes for a pertinent example: it sits on the verge of new key locations for digging – from the deep ocean to deep space – the consequences of which may not be fully explored.

The shift to a low-carbon economy is likely to entail an increase in demand for a wide variety of minerals. A 2017 report from the World Bank highlights the growth in demand for Lithium, Platinum and Lead, for new battery technology and rare earth element demand for solar and wind technology is also likely to increase.

As demand for these metals and resources rises, the cost and difficulty of extracting them rises too. Millennia of mining have exhausted the easy-to-access deposits for most metals, and the ratio of exploration sites that turn into actual mines is in the order of 1 in 1000. Combined with a decline in the overall quality of ore that is mined, it’s not hard to see why mining industry strategists are looking to previously unusable locations for their new mining ventures.

Geologists have known for a long time that the sea floor contains extensive mineral deposits of a wide variety of types; from ferro-manganese nodules to ores linked to submarine volcanism, economic minerals are spread across the global ocean floor. Until recently, the economics of dredging these sea beds for minerals have not been favourable, and technology has been too rudimentary to make an effective industry out of this approach. Now, however, prices and demand for these minerals are high enough that seafloor mining is beginning to take place in a few locations around the world.

Extraction like this could, of course, have major consequences. Biodiversity in the deep ocean is, even today, poorly understood, so strip mining these systems before we explore them fully could cause untold damage. At a small scale, this kind of mining might only have more limited, local impacts, but for the first time in the history of human society we have the capability to affect biological systems and geological cycles at a global scale, to a degree that might have significant and deleterious effects.

For example, mining waste on land can lead to contamination of local water supplies with acidic runoff. Deep sea mining could similarly lead to acidification of sea water, which could have far reaching consequences. Marine creatures living in the ocean are often very finely tuned to the chemistry of the water they’re bathed in; even small changes in acidity have been linked to increased coral bleaching and death. The risk of heavy metal pollution has also been pointed out from sand and mud kicked up by mining activity as it disturbs the sea bed; these toxic metals could cause problems both the sea life and to humans, as the fishery stocks would become increasingly exposed to heavy metals. The global extent of ocean currents mean that these effects wouldn’t be limited to the vicinity of the mining, as chemicals would be mixed into the whole ocean over time.

Unlike mining on the surface, the spread of this kind of pollution could be truly global; ocean currents could eventually spread the pollutants, and the mining itself would hardly be limited to a specific locality. Humans are poorly positioned to deal with this kind of crisis; a negative impact on the ocean – a global resource, not owned by any individual nation state – is a classic ‘tragedy of the commons’, much like carbon dioxide accumulation in the atmosphere. Given the lack of ownership of the oceans, individual states or mining companies lack strong incentives to regulate the exploitation of such sea-floor resources. Moreover, the globalised nature of the extractive industry means this could be a truly significant impact; the combined revenue of the top 40 surface mining companies is approximately half a trillion dollars, dwarfing all but the largest national economies, affording such corporations major financial clout to explore and develop mining on the sea floor.

At the dawn of the fossil fuel era in the Industrial revolution, the risks of burning coal, and later oil and gas, were poorly understood in comparison to today. Some authors suggest that since we are now much more aware of environmental issues, we are better placed to assess the future risks and rewards of deep sea mining than the earlier resources for which we mined and drilled.

It is perhaps worth pointing out, though, that with the range out impacts still poorly constrained even as dredging begins, it is incumbent upon geologists to explore and quantify the potential risks; academic research must keep pace with the growth of industry.

Even if deep sea mining does not have major, long-lasting impacts, there is one other mining frontier for which the risks are nearly totally unconstrained: asteroids.

It may sound like science fiction, but serious consideration is being given to mineral resources on near Earth asteroids. Given their potential value (some estimates – of the asteroid Psyche suggest mineral resources worth a quintillion dollars – an amount of money that’s basically inconceivable), it’s not surprising that enterprising drillers are looking up, as well as to the sea floor. Again, though, research into the potential geological hazards needs to be undertaken well before such ventures are carried out.

Our ever increasing environmental footprint has the potential to spread to new and poorly studied horizons, and we should endeavour not to make the same mistakes as we did with fossil fuels.

Robert Emberson is a science writer, currently based in Vancouver, Canada. He can be contacted via Twitter (@RobertEmberson) or via his website (www.robertemberson.com).

**This article expresses the personal opinion of the author. These opinions may not reflect official policy positions of Geology for Global Development.**