Scorched Earth:

Figure 1: Charred areas of the Amazon in Brazil, August 27, 2019, captured by João Laet of Getty Images

The increasing frequency and intensity of forest fires in the Amazon are the direct result of man-made climate change and deforestation. Climate change, deforestation, and fires are changing the landscape of the Amazon Basin. The process is called savannization.

Savannization refers to the gradual transition of the tropical rainforest into savanna. The Amazon is currently a tropical rainforest, with a dense canopy and vegetation, high precipitation, and high biodiversity.

A tropical or subtropical savanna, most commonly found in Africa and southern Brazil, is a biome characterized by grasslands with scattered vegetation, as well as a long dry season and short wet season. 

Researchers (Nobre et al., 2016; Marengo et al., 2018) theorize that savannization will occur if global temperature increases by 4° C or 40% of the forest being degraded or deforested.

To date, the Amazon is 20% deforested and the global temperatures already increased 1-1.5° C in the Amazon (Nobre et al., 2016). Global temperature increase is expected to reach 4.1° C by 2100. Meanwhile, Amazon deforestation rates increase. 

Savannization will happen in the Amazon rainforest for two main reasons: deforestation and climate change (Nobre et al., 2016).

One of the main greenhouse gases that causes climate change is carbon dioxide. Vegetation absorbs CO2 and is one of the most powerful regions to capture carbon and remove it from the atmosphere, also known as a carbon sink. The Amazon has experienced deforestation rates of 20% to date, meaning roughly a fifth of the forest’s ability to capture carbon is gone (Nobre et al., 2016).

Over the last 60 years, temperatures in the Amazon rose by 1-1.5°C (Nobre et al., 2016). Temperature rise increases the length and intensity of both the dry and fire seasons in the Amazon. Higher temperatures increase evapotranspiration, or the ability of forest to cycle water, leading to a reduction in rainfall of 15-40% reduction in rainfall over the next 60 years (Marengo et al., 2018).

When forest canopy is destroyed, more sunlight penetrates the forest and dries out the forest, contributing to a longer dry season and higher overall temperatures. A longer dry season also means a longer fire season, increased deforestation, higher emissions of greenhouse gases, the spread of invasive grasses (Nobre et al., 2016).

Climate change threatens indigenous people of the Amazon (Brugnach, Craps, & Dewulf, 2017). There are around 400 Indigenous tribes living in the Amazon currently.

This map, created by Raisg, shows the indigenous groups living in the amazon. Blue represents indigenous territories and the pin points shows indigenous communities without designated territory.

Climate change threatens indigenous people of the Amazon as landscapes change and resources to disappear (Brugnach, Craps, & Dewulf, 2017). Without a forest, they could become climate refugees, if savannization causes landscapes change and resources disappear from fires, drought, and soil degradation. A migration of Indigenous Amazonians will put strain on local cities and towns who will also have issues due to drought and lack of food due to soil degradation. 

Drought is one of the largest threats of savannization. Increased temperatures and canopy loss will reduce moisture for the entire region and increase evaporation from reservoirs and lakes will affect irrigation and soil moisture (Marengo, Torres, & Alves, 2017). The moisture cycle in the Amazon affects climate all over the region, meaning that a drying rainforest will lead to a dryer, warmer climate throughout the continent. This will affect transportation, food security, and health within South American cities and communities (Lapola et al., 2018). These effects will in turn cause higher rates of crime, poverty, and overall instability in the region due to limited resources. 

Climate variability and soil degradation from savannization and the excess of carbon dioxide decreases the success of agriculture (Nobre et al., 2016). The loss of tree cover and higher temperatures means less rainfall and unpredictable growing seasons, as well as high temperature swings which can damage crop productivity. Researchers (Lawrence & Vandecar, 2014) predict a drop in productivity in agriculture and cattle pastures. The failures of agriculture and livestock sectors will hurt national economies and cause unemployment and starvation, creating social and economic crisis.

A longer fire season threatens small communities such as indigenous tribes in the Amazon and also worsens air pollution for the region, leading to more respiratory illnesses and worsening climate change.

The loss of ecosystem services from the Amazon is costly. Ecosystem services are process that the environment goes through that allow for the existence of life. The services the Amazon currently provides include water cycling rainfall, stabilizing regional and continental climate, regulating air quality, mitigating extreme climate events, high biodiversity, preventing soil erosion, and carbon storage. One study (Lapola et al. (2018) estimates that losing these services due to savannization will cost the region between hundreds and thousands of billions of dollars in a 30 year period after savannization. These factors are often not assessed when people price out the costs of deforestation in relation to the perceived profits.

Biodiversity is the amount of species that live in a designated area. The Amazon is one of the most biodiverse regions in the world and its home to a tenth of the planet’s species (Nobre et al., 2016). Species loss may be one of the largest effects of savannization on the region as few animal and insect species will be able to adapt quick enough to survive new, limited conditions of the landscape (Ribeiro, Sales, & Loyola, 2018).

While deforestation is on the rise and climate change increasing will rising global temperatures, there is still hope for the Amazon. Savannization will only occur if deforestation continues at high rates and no action is taken on climate change. The forest has a high capacity to absorb carbon dioxide, which will help mitigate global temperature increase, and many countries in the Amazon are beginning to regulate deforestation more closely and follow global agreements such as REDD+.

REDD+ stands for reducing emissions, deforestation, and forest degradation and is global plan to help developing nations limit carbon emissions and forest destruction (Angelsen et al., 2018). Adhering to plans such as this will help with deforestation and degradation, as will finding new ways to utilize existing deforested land without removing more vegetation (Nobre et al., 2016).

Other plans such as the UN led Paris Agreements that set goals for each nation in order to prevent global temperature increase from reaching 4.1°C by 2100 will also help limit the spread of savannization. Emissions are global entities, so the decrease of carbon dioxide emitted in China and the United States will help the amazon as much as Brazil decreasing emissions. Savannization is a global and local problem and will only be prevented by global and local action.

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