For most people it is hard to imagine that the Amazon, the world’s largest river basin spanning almost 7 million km2, can reach such an extreme state of dryness that it completely disrupts navigation through some of its largest rivers. In fact, in recent decades this has become quite a frequent reality throughout this immense river basin.
In the most recent case, the drought of 2023, more than half a million inhabitants of the Brazilian Amazon basin were affected by one of the most extreme droughts ever registered. The drought was accompanied by massive fish kills and the death of hundreds of river dolphin, induced by very high air and water temperatures and low water levels in some places. Tens of thousands of remote rural settlers along rivers, including the traditional “ribeirinhos”, were completely isolated from urban centres and neighbouring towns for weeks or months.
This is the “new normal” for the Amazon. For years, researchers have been calling attention to the synergistic effects of deforestation, forest degradation, and climate change, which have triggered profound hydrological changes that increase the likelihood of extreme events, such as droughts and floods.
In our recently published article “Severe droughts reduce river navigability and isolate communities in the Brazilian Amazon” we explore how past droughts have severely impacted the lives and livelihoods of the people of the Amazon, and the connections between these impacts and impaired river navigability due to low water levels.
Regional boats docked at the Manaus River port and passengers waiting for their departure. Inland water transport in the heart of the Amazon River basin is the most important form of medium to long-distance travel. The supply of goods to remote towns and villages also depends on this mode of transport. Photo Credits: Letícia Santos de Lima, 2023.
Deep connections between rivers and people
To fully grasp the profound human impacts of droughts, one must first understand the importance of river navigation for the local population. In the middle of the vast Amazon rainforest, remote communities, large urban centres, and small towns rely heavily on inland water transport for their regular access to goods and essential services, to visit family and friends, and as part of their livelihoods and culture. These beautiful connections between people and rivers have evolved over centuries as human populations gradually occupied the basin.
A typical form of regional travel in the Amazon. Mid-sized river boats carry cargo on the lower level and passengers on the upper decks. These large trips can last for hours or days, so passengers use hammocks for sitting and sleeping with their luggage nearby. Photo Credits: Letícia Santos de Lima, 2023.
Our results showed that the severe droughts of 2005, 2010, and 2015-2016 dramatically reduced water levels across substantial portions of Amazon River system. Not only that, but they also produced longer periods of low water levels that exceeded 100 days in those years across several parts of the basin. We describe how these droughts affected several services that remote rural communities depend upon, including healthcare, education, and access to food and fuel. All of these impacts were connected to the fact that droughts reduce water levels to the point that navigable stretches become narrower and shallower, sandbanks and rocks are exposed, and navigation routes become disconnected at some points. These changes in the river system impose restrictions on the load capacity per trip, lead to longer trips, and impede boats from docking in some locations. Consequently, goods become scarce and expensive, services are limited, and travelling is much harder than in normal years. Sometimes, communities become complete isolated.
Traditional floating house trapped on a large sandbank that was exposed when river levels dropped during the extreme drought of 2023 in the town of Tefé, AM. Photo Credits: João Paulo Borges @drone_da_amazonia.
Reflecting on drought policies
While my coauthors and I were writing this paper, we began reflecting on potential policy responses to extreme droughts. Although our paper does not analyse policy processes nor examine existing policies, there is evidence of a long-standing lack of coherent, well-planned, and integrated governmental response to this complex issue. What concerns us most is the strong pro-roads narrative among some local politicians, portraying the best solution to the issues communities face during droughts. However, roads are well known to be one of the most significant drivers of deforestation and forest degradation in the Amazon. Many studies have shown clear links between deforestation and changes in rainfall, forest fires, and accelerated erosion processes that lead to river siltation. All of these impair river navigation, not to mention a long list of severe threats to local populations due to land grabbing, illicit activities, and violence, which are favoured by the opening of new roads in remote areas of the Amazon. In sum, a complex issue like the impacts of droughts cannot be solved – and may even become worse – by applying a simplistic strategy focused on roadbuilding.
We are relieved, however, by the recent turn of events after President Lula da Silva took office. Under the direction of Marina Silva, Minister of Environment and Climate Change, the government has reestablished an Interministerial Committee on Climate Change. Since then, there have been intense debates and major steps are underway to develop a more comprehensive approach to tackle extreme events through long-term climate adaptation strategies.
Letícia Santos de Lima, PhD.
Twitter: @Letícia_StLima, Webpage: www.leticialima.weebly.com
Authors of the paper:
Letícia Santos de Lima, Francisco Eustáquio Silva, Paula Dorio Anastácio, Marina Marcela Kolanski, Ana Carolina Pires Pereira, Marianne Stéfanie Menezes, Evandro Paradela Cunha, Marcia Macedo