Deforestation for the expansion of agribusiness, together with climate change, has induced the worsening of severe drought conditions in the last decade in the transition zone between the eastern Amazon and the cerrado.
This combination of trends can jeopardize the stability of biomes and, consequently, food production in the region where Matopiba is located — an area considered the new Brazilian agricultural frontier, comprising portions of the states of Maranhão, Tocantins, Piauà and Bahia, and responsible for almost 12% of Brazilian soy production.
The alert was made by a group of scientists linked to research institutions in Brazil and abroad in an article published in the journal Scientific Reports.
The study, conducted by researchers from the National Center for Monitoring and Alerts for Natural Disasters (Cemaden), was supported by Fapesp through a Thematic Project and the National Institute of Science and Technology for Climate Change (INCT-MC) — one of the INCTs funded by Fapesp in partnership with the National Council for Scientific and Technological Development (CNPq) in the state of São Paulo.
“Current conditions already show that this transition region between the Amazon and the cerrado is suffering the impacts of land use for the expansion of agribusiness and also of climate change”, José Marengo, general coordinator of research at Cemaden, tells Agência Fapesp. and first author of the study.
“These processes could become more intense in the future and impact both biomes and agricultural production in the Matopiba region, particularly soybeans”, estimates Marengo, who also coordinates the INCT on Climate Change.
The researchers used a combination of meteorological and satellite data to analyze changes in hydrological and climatic variables in tropical South America over the past four decades.
The regions that suffered long-term warming or showed a tendency towards drought in the period from 1981 to 2020 were identified through the analysis of spatial patterns for different radiative, atmospheric and hydrological variables.
The results of the analyzes indicated that the greatest warming and drought trends in South America in this 40-year period were observed precisely in the transition region between eastern Amazonia and the cerrado.
Over the last four decades, the region has experienced a broad and significant warming trend during the dry to wet transition season, which occurs between the months of July and October.
These warming trends have delayed the rainy season and worsened severe drought conditions over the past decade.
“The results show an increase in temperature, a deficit in vapor pressure, frequency of dry days and a decrease in precipitation, humidity and evaporation”, says Marengo.
“They also point to a delay in the beginning of the rainy season, which increases the risk of fire during the dry to wet transition season”, he explains.
Despite the warming in the last four decades, the agricultural area in the region more than doubled in the period between 2003 and 2013, jumping from 1.2 million to 2.5 million hectares.
Approximately 74% of the new agricultural land in the region is in savannah areas, until then intact.
“These findings provide observational evidence of increasing climate pressure in this area, which is sensitive for global food security, and the need to reconcile agricultural expansion and the protection of natural tropical biomes,” says Marengo.
Adaptation plan
According to the researcher, droughts in the Amazon and in the region adjacent to the Cerrado are usually related to events such as El Niño and/or to the surface temperatures of the North Atlantic.
These ocean temperature increases favor the occurrence of anomalous regional water deficits, warmer temperatures and intense fire seasons, which can be limiting factors for the development, harvest and production of soybeans in Matopiba.
During the 2015-2016 El Niño, a reduction in soybean productivity was recorded – which between 2014 and 2015 was just over 96 million tons and, in the period of the climatic phenomenon, it dropped to 95.4 million tons.
“In the future, events such as the 2015-2016 El Niño may be more intense. Therefore, it is necessary to start implementing adaptation measures to mitigate the impacts of climate change in that region, such as reducing deforestation in the Amazon and changes in land use. in Matopiba”, points out Marengo.
“If nothing is done, agricultural production will fall because it is heavily dependent on the climate,” he says.
The work had the participation of researchers from Inpe (National Institute for Space Research) and from the universities of Valencia, Spain, and Grenoble, France.
The article Incresed climate pressure on the agricultural frontier in the Eastern Amazonia-Cerrado transition zone (DOI: 10.1038/s41598-021-04241-4), by José A. Marengo, Juan C. Jimenez, Jhan-Carlo Espinoza, Ana Paula Cunha and Luiz EO Aragão, can be read online.
Source: Folha
