Degradation of remaining Amazon forest could emit as much carbon as deforestation, if not more

The world’s largest tropical forest has already lost 30% of its carbon storage capacity owing to human activity. This and other topics were discussed at a webinar held to honor FAPESP’s 60th anniversary by the São Paulo State Academy of Sciences.

By José Tadeu Arantes  |  Agência FAPESP – Since the start of the century, the Amazon has lost some 30% of its capacity to store carbon dioxide (CO₂), one of the main greenhouse gases. Maintenance of the current policy, which favors or even promotes deforestation and degradation of the remaining areas, could reduce this capacity to zero by the end of the next decade, and the Amazon could become a carbon emitter instead of a carbon sink.

The warning came from David Montenegro Lapola, a researcher at the University of Campinas’s Center for Meteorological and Climate Research Applied to Agriculture (CEPAGRI-UNICAMP), during a webinar held on July 6 by the São Paulo State Academy of Sciences (ACIESP) to celebrate FAPESP’s sixtieth anniversary.

Besides deforestation, there is another less well-known but equally impactful factor, which is standing forest degradation. “Considering degradation by drought, fire, selective logging and the so-called edge effect, between 4% and 38% of the remaining forest is already degraded, with CO₂ emissions equivalent to or greater than those from deforested areas,” Lapola said, emphasizing the need for a new development paradigm capable of reversing the course of destruction and saving the forest.

Brazilian Environment Minister Joaquim Leite stated at the 26th United Nations Climate Change Conference (COP26), in November 2021, that the Brazilian government had decided to go beyond the existing laws and policies by undertaking to eliminate illegal deforestation in the Amazon by 2028. In first-half 2022, however, according to data published by the National Space Research Institute (INPE), 3,971 square kilometers (km²) of forest were destroyed in what is known as Legal Amazonia, an area of 5 million km² spanning nine Brazilian states and defined in federal law for the purposes of special socio-economic development and environmental protection policies.

Deforestation recorded in June 2022 was the highest for the month since INPE began monitoring the Amazon in August 2015. About 90% of the area concerned was deforested illegally.

The most consistent studies show that keeping global warming below 2 °C compared with pre-industrial levels, and preferably below 1.5 °C, is the only way to avoid a climate catastrophe. This was acknowledged by the signatories of the Paris Agreement, which came into force at the end of 2016. More than five years later, however, the statistics show that the world is heading for 3 °C, with conspicuous irresponsibility on the part of most governments and indifference among many ordinary people.

Achieving the Paris Agreement commitments depends on the fulfillment of each signatory’s nationally determined contribution (NDCs). The first version of Brazil’s NDC, in 2015, promised a 37% cut in greenhouse gas emissions by 2025 compared with the 2005 level, and a 43% reduction by 2030. The revised NDC published at end-2020 maintained these percentages but changed the basis for comparison to a year in which actual levels were higher, thus not upgrading the goals, as it should have done. Worse still, in real terms, the goals now actually allow for a rise in emissions. Leite’s promise at COP26 to achieve a 50% cut in emissions by 2030 is not being kept by any stretch of the imagination.

Greatest threat ever

Entitled “Global climate change: impacts and strategies for mitigation and adaptation”, the webinar organized by ACIESP focused on presenting and discussing the second chapter of the book FAPESP 60 Anos: A ciência no desenvolvimento nacional (“FAPESP 60 Years: Science in the Nation’s Development”).

The event was opened by Adriano Andricopulo, Executive Director of ACIESP; Luiz Eugênio Mello, FAPESP’s Scientific Director; and Paulo Artaxo, a member of the Intergovernmental Panel on Climate Change (IPCC), Vice President of ACIESP, and a member of the steering committee for the FAPESP Research Program on Global Climate Change (RPGCC). 

The other speakers besides Lapola were Gabriela Marques Di Giulio, a professor at the University of São Paulo’s School of Public Health (FSP-USP); Pedro Leite da Silva Dias, a professor at the same university’s Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG-USP); and Mercedes Bustamante, a professor at the University of Brasília’s Institute of Biological Sciences (ICB-UnB).

Di Giulio presented on the human dimension of climate change and how societies should structure public policy to respond to the social risks involved. “Change and transformation is needed in all dimensions, but above all, we urgently need to replace this predatory model of plundering nature with a model based on solidarity, respect for biological diversity and social justice,” she said, noting that almost 35 million Brazilians lack access to treated water and some 100 million lack access to sewerage systems.

“Another challenge is food security, at a time when Brazil is once again very emphatically back on the UN’s map of world hunger. Food insecurity affects over 125 million Brazilians, and more than 33 million face starvation,” she said.

Silva Dias focused on the challenges of modeling climate change in light of its complexity and the influence of human activity. “There are two main ways to understand the mechanisms responsible for climate variability and the potential role of humans: modeling of the highly complex climate system, and observational analysis of the period and of past climate estimators, or paleoclimate research. They’re complementary and should be done together,” he said, adding that it is important to choose models capable of simulating the current climate accurately.

Bustamante noted the links between two important ongoing processes, climate change and the decline of biodiversity, stressing that every fraction of a degree in global warming intensifies extreme weather events, with multiple risks, and that the impacts will be huge if the average temperature rise exceeds 1.5 °C. “Global warming is the greatest threat to biological diversity in human history,” she said.

Bustamante argued that Brazil’s exceptional environmental riches should be the basis for a new development agenda, in contrast with what is actually the case.

A recording of the complete webinar on “Global climate change: impacts and strategies for mitigation and adaptation” is at: www.youtube.com/watch?v=0XEw7wATBWs.