Drought, Dams, Mangroves and the Amazon


Ghillean Prance at CoventryGhillean Prance reports on progress and challenges from the Amazon rainforest.

Ghillean is a patron of Green Christian and wrote this article for Green Christian Magazine (Spring 2017). He is a former director of Kew Botanic Gardens and has helped set up the Eden Centre.


In August last year, I visited Brazil to do some research on mangroves. I came back with both good news and bad.

Amazonia is really a battlefield between those that want to destroy and develop at all costs and those who want to conserve and sustainably-use the forest. My visit was to the state of Pará, the state with the highest rate of rainforest destruction at present. Flying over this eastern part of Amazonia reveals the extent of deforestation there.


Deforestation in eastern Amazonia, that receives its rainfall coming off the Atlantic Ocean, is interrupting the circulation of water westwards over the region. This is causing the droughts further south in Brazil and Argentina because of the absence of the “flying rivers” that send rain-laden clouds down to the south of Brazil. Massive volumes of vapour rise from the evapo­transpiration of the Amazon trees and it flows gradually west until blocked by the Andes and is then diverted towards the southern agricultural areas. Drought is becoming a serious problem in Brazil.

The good news is that the overall rate of deforestation has slowed down dramatically and in 2015 was about 75% below the average for 1996 to 2005. This is the reason that Brazil has been able to greatly reduce its net greenhouse gas emissions in accordance with pledges towards an 80% reduction by 2020. Deforestation has been reduced through good satellite surveillance, better control of the illegal actions of farmers and land speculators, and the establishment of more protected areas, but it is still a concern especially during the current political uncertainty in Brazil.

In contradiction to the overall trend, data from IMAZON  (Instituto do Meio Ambiente e Homem da Amazonia) show that deforestation in June 2016 was the highest in any month since November 2007, being an area of 972 km2 (240,000 acres) which is double that of June 2015. (More figures) This is alarming as 2016 has been a dry year which encourages more deforestation and burning; . It to be hoped that this increase is not a permanent trend. While in Brazil I was watching photos on the TV of the city of Rio Branco, the capital of Acre State, completely shrouded in smoke from the burning forest and with the inhabitants on the streets using face masks for protection.

Another area of particular concern is  the Amazon part of Peru which is a rich hotspot for biodiversity of plants and animals. Recent reports from there have shown the impact of oil mining and the frequent spills from the pipeline across the Andes from the Amazon region to the Pacific coast. The latest threat there is the expansion of oil palm growing in lowland rainforest areas, something that has already destroyed much of the rainforest areas of western Ecuador. Peru is rapidly becoming the place of concern for those monitoring rainforest destruction: forest loss in 2014 in Peru was 1775 km2, and in 2015 over 1586 km2 (392,050 acres). Peru is rapidly becoming the place of concern for those monitoring rainforest destruction.


Dead flooded trees - Balbina Dam, Amazon

Dead Trees – Balbina Dam, Brazil

Deforestation has drawn much attention from the media over the years, but one of the greatest threats in Amazonia is the number of hydroelectric dams that are being built. There are 191 existing dams in Amazonia and the total planned at present is 246. Hydroelectric is good clean energy that does not use fossil fuels, but better consideration is needed of where to locate dams. The environmental impact studies for the location of some Amazon dams is minimal. Over the past 40 years considerable progress has been made in Brazil with the licensing system to evaluate and mitigate the impacts of development projects. However, the most recent threat is a proposed one-sentence constitutional amendment that would revoke this, allowing the mere submission of an environmental impact assessment to permit any project to go forward unchecked – a frightening prospect for the Amazon ecosystem.

The dams that flood rainforest are not as green as claimed because the reservoirs flood the forest and submerge the trees and soil; this causes the release of huge quantities of the greenhouse gas methane, and furthermore can kill the trees. I have observed masses of dead trees standing in areas flooded by the Balbina Dam, north of Manaus in central Amazonia.

Much of the energy produced by the Amazon dams is to power the international mining industry rather than the domestic market. However, while I was in Brazil some good news was announced: the suspension of the São Luiz Dam in the mighty Tapajós River. This was largely due to the actions of the Munduruku peoples whose territory would have been most affected by the dam.

This was to be the second largest Amazonian dam after the controversial Belo Monte dam on the Xingú River which was built despite the objections of several tribes that are affected.

Dams are a particular threat to river dolphins, turtles, giant otters and fish as well as to the indigenous peoples. They also damage floodplain vegetation that is controlled by the annual flood pulse system and block the important flow of nutrients from the Andes to the lowlands. There is no doubt that dams are putting some of the region’s biodiversity at risk.


I was in Pará to look at mangrove forest as part of my research on the plant family Rhizophoraceae.


Mangrove roots

This group includes including the red mangrove with its arching mass of prop roots that anchor the trees to the soil against the pressures of the rising and falling tides and stormy seas. Mangroves, which naturally occur around tropical coastlines, contribute an important environmental service, preventing erosion of the coastline and protecting against storms. The effects of many typhoons and tsunamis would have been far less in tropical Asia if they had not cut down their mangrove forests.

Mangroves are full of crabs and fish and so provide food and income for many people. I visited some intact mangroves that were teaming with small crabs, but nearby locals were complaining because much had also been felled to provide firewood and fuel to a factory and replaced by rice plantations.

One of the striking things I noticed in the towns and villages of Brazil on this trip was the enormous growth of the Pentecostal Church. Membership is increasing and some huge and extravagant church buildings are springing up. They are enthusiastic about conversion, but many of them preach a prosperity gospel message, rather than the true gospel of love and care for Creation. A challenge for the Church of today is to work with these people to convert their enthusiasm into care for Creation and each other, rather the desire for wealth.

Amazonia and weather regulation

Brazil is a country of contrasts. On the one hand protected areas have been expanded and deforestation reduced. On the other hand this progress is being compromised by development pressures and shifts in legislation, such as recent changes to the Forest Code. The last decade has seen great progress in curbing deforestation in Brazil, but the tendency of the current government has been to encourage investments in ports, mining and hydroelectric dams. Even if this is better controlled the impact of worldwide climate change is a threat to the Amazon forest. I go to Amazonia to study and conserve the plants and vegetation, but probably the most important current concern is the role of the Amazon forest in its ability to regulate weather systems, and today climate scientists such  Antonio Nobre, a well known Brazilian climate expert, are warning that the “vegetation-climate equilibrium is teetering on the brink of the abyss.” Part of this change is caused locally by deforestation, but it also associated with how the whole world acts and so we, as stewards of creation, should be seeking to curb climate change wherever we are.





Author: | Date: 8 August, 2017 | Category: Biodiversity Climate Change Uncategorized | Comments: 0

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