Tagged / Henry Bang

Conversation article: Cameroon’s exploding lakes – deadly gas release could lead to another tragedy

BU research, Featured, Research communication, the conversation

Dr Henry Ngenyam Bang writes for The Conversation about the potential dangers associated with crater lakes located in a region of volcanic activity in Cameroon…

Cameroon’s ‘exploding’ lakes: disaster expert warns deadly gas release could cause another tragedy

The waters of Lake Nyos, Cameroon, turn a murky brown following a deadly release of toxic gas.
Photo by Thierry Orban/Sygma via Getty Images

Henry Ngenyam Bang, Bournemouth University

A sudden change on 29 August 2022 in the colour and smell of Lake Kuk, in north-west Cameroon, has caused anxiety and panic among the local residents. Fears are driven by an incident that happened 36 years ago at Lake Nyos, just 10km away.

On 21 August 1986, Lake Nyos emitted lethal gases (mainly carbon dioxide) that suffocated 1,746 people and around 8,300 livestock. It wasn’t the first incident like this. Two years earlier, Lake Monoum, about 100km south-west of Lake Nyos, killed 37 people.

Desolation around Lake Nyos on 1 August 1986.
Photo by Eric Bouvet via Getty Images

Research into the cause of the Lake Nyos disaster concluded that carbon dioxide gas – released from the Earth’s mantle – had been accumulating at the bottom of the lake for centuries. A sudden disturbance of the lake’s waters due to a landslide resulted in a sudden release of around 1.24 million tonnes of carbon dioxide gas.

Survivors briefly heard a rumbling sound from Lake Nyos before an invisible gas cloud emerged from its depths. It killed people, animals, insects and birds along its path in the valley before dispersing into the atmosphere where it became harmless.

Both Kuk and Nyos are crater lakes located in a region of volcanic activity known as the Cameroon Volcanic Line. And there are 43 other crater lakes in the region that could contain lethal amounts of gases. Other lakes around the world that pose a similar threat include Lake Kivu at the border of Rwanda and the Democratic Republic of Congo, Lake Ngozi in Tanzania and Lake Monticchio in Italy.

After Lake Nyos erupted, its water turned a deep red colour and survivors reported the smell of rotten eggs. These are the same characteristics to have recently manifested at Lake Kuk. The change in colour of Lake Nyos was only noticed after the gas burst.

In an official press release, heavy rainfall was linked to the odour and change in colour of Lake Kuk. The tens of thousands of people living around the lake were urged to “remain calm while being vigilant to continuously inform the administration of any other incident noted”.

As a geologist and disaster management expert, I believe that not enough is being done to address and manage the potential danger from crater lakes in the region.

Through my experience and research I’ve identified several key steps that policymakers must take to prevent another tragedy from happening.

Preventing disaster

To start with, it’s important to know which lakes are at risk of “exploding”.

Initial checks in some of the lakes were done more than 30 years ago and not thoroughly – it was just one team and on one occasion. Further investigations and regular monitoring are required.

Currently it’s believed that, of the 43 crater lakes on Cameroon’s Volcanic Line, 13 are deep and large enough to contain lethal quantities of gases. Although 11 are considered to be relatively safe, two (Lakes Enep and Oku) are dangerous.

Map showing the Cameroon Volcanic Line and other hazards in Cameroon.

Research has revealed that the thermal profile (how temperature changes with depth), quantity of dissolved gases, surface area or water volume and depth are key indicators of the potential for crater lakes to store large quantities of dangerous gases.

The factors that lead to the greatest risk include: high quantities of dissolved gases, held under high pressures, at great depths, in lakes with large volumes of water. They are at an even greater risk of explosion when the lakes sit in wide or large craters where there are disturbances.

The two lakes that caused fatalities (Nyos and Monoum) are deep and have thermal profiles that increase with depth. Other lakes are too shallow (less than 40 metres) and have uniform thermal profiles, indicating they do not contain large amounts of gases.

Investigating all the crater lakes in Cameroon would be a logistical challenge. It would require significant funding, a diverse scientific team, technical resources and transportation to the lakes. Since most of the crater lakes are in remote areas with poor communication network (no roads, rail or airports), it would take a couple of years for the work to be completed.

Since Cameroon has many potentially dangerous crater lakes, it is unsatisfactory that 36 years after the Lake Nyos disaster, not much has been done to mitigate the risks in other gas-charged hazardous lakes.

Managing dangerous lakes

Lake Kuk was checked shortly after the 1986 Lake Nyos disaster and found not to contain excess carbon dioxide. Its relatively shallow depth and surface area means the risk of gas being trapped in large quantities is low.

Nevertheless, authorities should have immediately restricted access to Lake Kuk pending a thorough onsite investigation. The official press release urging calm was sent just one day after the incident was reported. It’s not possible that a scientist could have carried out a physical examination of the lake. The release said that rainfall was responsible for the changes, but this will be based on assumptions.

Lake Kuk might be considered safe, but due to the dynamic and active nature of the Cameroon Volcanic Line, there is a possibility that volcanic gases can seep into the lake at any moment.

An onsite scientific investigation would determine with certainty the abnormal behaviour of Lake Kuk. Keeping people away from the lake until a swift and credible investigation had been done would be the most rational decision.

An additional step would be for a carbon dioxide detector to be installed near Lake Kuk and other potentially dangerous crater lakes. This would serve as an early warning system for lethal gas releases.

A carbon dioxide early warning system is designed to detect high concentrations of gases in the atmosphere and to produce a warning sound. Upon hearing the sound, people are expected to run away from the lake and onto higher ground. After the Lake Nyos disaster, carbon dioxide detectors and warning systems were installed near Lakes Nyos and Monoum. Nevertheless, no simulation has been conducted to determine their effectiveness.

The Directorate of Civil Protection is the designated agency responsible for coordinating disaster risk management in Cameroon. The agency should liaise with other stakeholders in the government and private sector to ensure the safety of Cameroon’s dangerous lakes. If the authorities are not proactive, the Lake Nyos disaster scenario may repeat where thousands of people and livestock are suddenly killed.The Conversation

Henry Ngenyam Bang, Disaster Management Scholar, Researcher and Educator, Bournemouth University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Conversation article: The environment is the silent casualty in the Cameroon Anglophone crisis

BU research, Featured, Research communication, the conversation

Dr Henry Ngenyam Bang writes for The Conversation about his research into the environmental consequences of the Anglophone crisis in Cameroon…

The environment is the silent casualty in the Cameroon Anglophone crisis

Women displaced from rural villages in the Anglophone region gather to wash clothes in a stream.
Photo by Giles Clarke/UNOCHA via Getty Images

Dr Henry Ngenyam Bang, Bournemouth University

Most analysis of Cameroon’s Anglophone crisis has been skewed towards the socioeconomic, cultural and political ramifications of the conflict.

But, based on my work on natural, environmental hazards and disaster management in Cameroon over the past two decades, I would argue that the environment in the Anglophone region is a silent casualty of the conflict. And it has largely been ignored.

Our recently published research on the crisis showed that over 900,000 people had been internally displaced. Eighty percent of the inhabitants of villages that were conflict hot spots had fled into adjacent forests. The research investigated the consequences of the Cameroon Anglophone crisis and determined it to be an acute complex emergency.

These developments are leaving huge environmental footprints and causing serious damage. This will get worse if the armed conflict escalates into a “complex disaster emergency”.

I have identified six environmental consequences of the Cameroon Anglophone crisis. These range from failures in environmental governance to increases in deforestation, unmet measures in Cameroon’s climate action plan, poor municipal waste management, the effects of scorched earth tactics and the impact of improvised explosive devices.

There is a need to address these environmental oversights and build them into resolving the crisis. This would prevent the environmental legacies of the armed conflict from haunting the region’s population after the crisis has ended.

The fallout for the environment

One of the effects of the fighting since 2016 was that it brought conservation activities to a halt in the country’s biodiversity hot spots in the Anglophone regions. Cameroon has around 14 national parks, 18 wildlife reserves, 12 forest reserves and three wildlife sanctuaries hosting rare and threatened species.

Before the crisis, many of these protected areas were still in a pristine condition because Cameroon had less tourism than other regions of Africa.

But the crisis has stalled several environmental projects.

For example, violence forced environmentalists and NGOS operating in the Tofala Hill Wildlife Sanctuary in Lebialem to flee. The Tofala Hill Wildlife Sanctuary is home to the critically endangered Cross River gorillas and other endangered wildlife like the African chimpanzee and elephant.

These gorillas are also under increased threat from militias such as the “Red Dragons” which have set up camps within the sanctuary (see Figure 1).

Likewise, efforts to protect the Mount Cameroon National Park, which hosts endangered primates, have been hampered. This poses a threat to the Nigerian-Cameroon chimpanzee, which already faces extinction.

A map
Figure 1: Landscape of the Lebialem Highlands hosting the Tofala Hill Wildlife Sanctuary.
GSAC (2022)

Insecurity in areas hosting wildlife has led to a rise in uncontrolled illegal hunting. Poaching of endangered chimpanzees (see Figure 2) and elephants increased in the Tofala Hill Wildlife Sanctuary and the Takamanda and Korup National Parks after state rangers and eco-guards fled.

An ape sitting on a tree.
Figure 2: Endangered ape species in Cameroon’s protected reserves.
Photo by Julie Langford courtesy of the Limbe Wildlife Centre.

The rise in the number of internally displaced people has had a number of consequences.

Deforestation has risen as relocated communities have cut down trees to provide shelter and firewood.

They are also putting pressure on access to water. Toilet facilitates are inadequate in areas hosting large numbers of people. Drilling of wells, sometimes in unhygienic surroundings, and defecation in streams are also responsible for the poor water quality in the region.

The southwest region has recently experienced a cholera epidemic.

Thirdly, measures in Cameroon’s climate action plan have been halted by the crisis. The measures include providing fertilisers and improved seeds to farmers; installing renewable energy in rural areas; and restoring mangrove forests along the Limbe coast.

Fourthly, the crisis has worsened the problem of municipal waste management.

Separatists have threatened to burn the garbage collection company, HYSACAM. Some of its workers have been attacked. This has affected the collection of municipal waste in Bamenda and Buea, capitals of the Anglophone northwest and southwest regions.

Fifth, military forces are using scorched earth tactics that could create serious environmental harm. The military has destroyed houses, crops and livestock in several villages perceived to be strongholds of militia groups.

Likewise, militias have destroyed property owned by the state and that of civilians suspected to be colluding with security forces.

Satellite images from February and March 2021 confirm the destruction of multiple villages in the northwest region.

Lastly, the use of improvised explosive devices by militia groups against Cameroon’s military vehicles has been increasing and getting more sophisticated.

Explosive remnants and munitions can make the land uninhabitable, severely harm wildlife, and contaminate the soil and watercourses. Clearance of devices can also cause localised pollution, soil degradation and negative land use consequences.

A destroyed military vehicle.
Figure 5: Military vehicle destroyed by IED.
Photo courtesy of SBBC (2022).

Next steps

Contingency plans being put in place by the Cameroon government for a potential complex disaster emergency should consider the environmental aspects of the conflict.

First it’s necessary to empirically diagnose the environmental ramifications and how they can be resolved.

When seeking political solutions to the crisis, stakeholders should also incorporate measures to mitigate the environmental consequences.The Conversation

Dr Henry Ngenyam Bang, Disaster Management Scholar, Researcher and Educator, Bournemouth University

This article is republished from The Conversation under a Creative Commons license. Read the original article.