Environmental research on the Amazon should be integrated with socioeconomic studies

At a workshop in Washington, scientists presented the results of advances in research on the region and stressed the need to investigate the social impact of climate change as a contribution to public policy.

By Maria Fernanda Ziegler in Washington | Agência FAPESP – Amazonia is in transition. The seasonal alternations of floods and droughts that are characteristic of the region are less balanced; additionally, the annual dry period is lengthening by an estimated 6.5 days each decade, which causes an extra month of drought every 40 years. However, the hydrological cycle is intensifying, as evidenced by measurements showing that the mean water flows in the Amazon River at the Óbidos gauging station in Pará have risen 30% in the last 25 years. Amazonia is also much warmer. The mean air temperature has increased 0.9°C, which is large enough to change the behavior of plants, animals and humans.

Scientific studies have observed shifts in the region’s energy balance and hydrological cycle, and these shifts have significant effects on biodiversity, soil composition and everyday life. However, the integration of environmental science with socioeconomic studies is crucial for the purposes of designing public policy to drive sustainable development in the region.

These points were stressed by participants in a workshop on the Scientific, Social and Economic Dimensions of Development in the Amazon held in Washington DC (USA) on September 24, 2018. The event was a continuation of a workshop held in August in Manaus, Amazonas (Brazil). Both were organized by FAPESP in partnership with Brazil’s National Institute for Research on Amazonia (INPA) and the Washington-based Wilson Center’s Brazil Institute.

The workshop opened with a video message from Professor Thomas E. Lovejoy of George Mason University (USA), who said the Amazon’s hydrological cycle and rainfall patterns are currently being affected by deforestation, excessive use of fire and climate change. There is a risk of reaching a tipping point if deforestation surpasses a certain threshold, beyond which the region’s tropical rainforest would undergo irreversible changes.

In February, Lovejoy and Carlos Nobre, chair of Brazil’s National Institute of Science and Technology (INCT) for Climate Change – one of the INCTs supported by FAPESP in São Paulo State in partnership with the National Council for Scientific and Technological Development (CNPq) – published a warning on the subject in Science Advances (read more at agencia.fapesp.br/27378).

“Changes in the energy balance and hydrological cycle have already been observed from research conducted in Amazonia. We’re discovering and monitoring these changes. However, if public policy is to be designed specifically for the region, we must integrate the science with socioeconomic dimensions of critical importance to its sustainability,” said Paulo Artaxo, Full Professor at the University of São Paulo’s Physics Institute (IF-USP) in Brazil and a member of the steering committee for the FAPESP Research Program on Global Climate Change (RPGCC).

Changes in the drought-flood cycle affect biodiversity and day-to-day life in the region. “Not all plants are adapted to longer dry periods,” Artaxo said. “As a result, the composition of biodiversity changes and tree mortality rises, for example, potentially altering carbon storage.”

Given the sheer size of the Amazon Rainforest, it stores a massive amount of carbon from the atmosphere and, therefore, plays a key role in the unfolding of climate change.

“The Amazon stores between 100 billion and 200 billion metric tons of carbon in its biomass. However, with the rising pace of tree loss due to drought, flooding and deforestation in recent years, there will be a massive change in atmospheric CO₂ if even a small fraction of this stored carbon returns to the atmosphere,” Artaxo stressed.

Extreme weather

This transition in the biome is confirmed by historical records showing that both the amount of rainfall and the drought-flood cycle have become more intense. “There have been three very intense droughts, one after the other, in less than 20 years. That’s an alarming trend. The data show something important is happening,” said José Marengo, Head of Research & Development at Brazil’s Natural Disaster Surveillance and Early Warning Center (CEMADEN), adding that extreme weather events also heighten the risk of forest fires.

“Not all droughts are caused by El Niño [periodic natural warming of the eastern Pacific Ocean]. Some are, but others have to do with warmer sea surface temperatures in the tropical North Atlantic, as we saw in 2005 and 2010,” Marengo explained. “In some cases, the key factor is El Niño; in others it’s the Atlantic. Sometimes it’s both together, as in 1983 and 1998.”

This is the natural part and does not include the influence of human activities. “If we add to El Niño and the Atlantic other conditions such as increasing deforestation, we can see the situation becomes far more serious,” he said.

The consequences of the drought-flood cycle intensification are also felt outside Amazonia. For example, scientists estimate that 70% of water resources in the Rio de la Plata basin in southern South America depend on evaporation over Amazonia. The region’s transition and its impact on the hydrological cycle could therefore have important consequences for agriculture in the south, southeast and center-west regions of Brazil as well as in Argentina.

Marengo also advocated more integrated research, as exemplified by Project Metropolis, an international study he led to develop strategies for adapting to climate change in three coastal locations, including Santos, a major port city in São Paulo State. The study estimated economic losses and health impacts based on modeling extreme weather events (read more at agencia.fapesp.br/26110).

“We could do something like that for Amazonia. The frequency of extreme weather events is forecast to increase significantly in the region in the coming decades,” Marengo said.

Another participant in the workshop was Rita Mesquita, a researcher at INPA. Mesquita agreed that more integration is needed. “Studies must be interdisciplinary,” she said. “Social, economic and environmental models don’t always have the same interests. We’ll make progress on sustainability issues only when we analyze all these dimensions together.”

Estimating the impact of human activities

When asked by the audience to estimate the human contribution to Amazon forest fires, Artaxo replied: “One hundred percent. Even during the dry season, it’s a rainforest and very moist, so starting and maintaining a fire is difficult.”

Destruction of the forest by fire has proved to be far greater than destruction by illegal logging. “Fire is the most efficient way to clear tropical forest,” said Douglas Morton, an earth scientist at NASA’s Goddard Space Flight Center, in a presentation during the workshop.

“Brazil has been a world leader in deforestation monitoring. Systems like PRODES and DETER run by INPE, the National Space Research Institute, have created a database with historical data, but we need to go further and invest more.”

A forest degradation measurement project led by Morton includes flyovers of the Amazon to produce images of deforestation in three tiers. In addition, NASA operates 20 remote sensing satellites that produce publicly available data and can be used for monitoring. “The satellites provide patterns for what’s happening. We have forecasting models that can help design public policy,” he said.

At the event in Washington, researchers presented other results of projects supported by FAPESP to an audience of scientists, environmental NGOs and US government agencies. The aim was to exchange experiences for future international collaboration in research on the Amazon.

More information: www.fapesp.br/eventos/amazon-workshop.