Research Memo: Predicted Effects of Deforestation on Rondônia's Regional Climate

By Cassie Sevigny and Fernando de Sales

The Connections between Water and Rural Production project (CAP) investigates whether and which farmers adapt their production systems when they experience water variability, what adaptations they make, and whether these adaptations reduce income losses when droughts occur. Improved understanding of these feedbacks will inform efforts by government agencies and civil society to help farmers respond to water scarcity. This research memo describes how different deforestation scenarios would affect rainfall patterns and temperatures in Rondonia.

Figure 2: (a) Land cover distribution in the domain nested grid as of 2015 from MapBiomas data. (b) Forest protection in Rondônia: high (dark blue), moderate (green), and low (gray) protection. Low‐protection areas include private properties and undesignated public land. Filled triangles in (a) indicate the location of major urban centers. From north to south: Porto Velho, Ariquemes, Jaru, Ouro Preto do Oeste, Ji‐Parana, Cacoal, Rolim de Moura, and Vilhena.

Research Question: What are the effects of deforestation on Rondonia's water cycle and climate?

A recent paper by Fernando de Sales, Thais Santiago, Trent Biggs, Katrina Mullan, Erin Sills, and Corrie Monteverde explores the effects of deforestation on the climate patterns of Rondonia. The researchers use observations and remote sensing data to inform climate simulations based on various deforestation scenarios. This study differs from previous studies to the extent that it uses realistic vegetation distribution and deforestation rates based on up-to-date satellite data. Understanding the effects of land-atmosphere interactions can help policy makers and farmers anticipate negative impacts of land degradations and climate change and help prepare mitigation strategies to limit these impacts.

De Sales et al. hypothesize that land degradation through deforestation, combined with global warming, will decrease rainfall and increase temperatures. The simulated scenarios show that the clearing of protected forested areas would have several effects. In general, there would be more rain in newly deforested areas during the dry season, but the ground would be warmer and drier in the afternoons. The decreased afternoon moisture could stress the remaining natural vegetation. Outside the deforested areas, which is mostly urban and agricultural land, afternoon rainfall could decrease as much as 30% during the dry season. These climatic changes have the potential to negatively impact agricultural productivity. This finding corroborates existing research which shows changes in wind and rainfall patterns following deforestation. It also reinforces the beneficial role of protected forest areas in maintaining the state's climate and water resources. Studies like this can help inform policy to prevent further deforestation of these areas.

Learn more about Fernando de Sales’ research at fdesales.sdsu.edu.

De Sales, Fernando, Thais Santiago, Trent W. Biggs, Katrina Mullan, Erin O. Sills, and Corrie Monteverde (2020). Impacts of protected area deforestation on dry‐season regional climate in the Brazilian Amazon. Journal of Geophysical Research: Atmospheres, 125, e2020JD033048. https://doi.org/10.1029/2020JD033048