After Fires, Amazon Rainforest May Now Get Drought, And Humans Must Be Held Responsible For It

There have been rising reports of the threats of global warming and climate change as well as the implications that they may have on human life. However, in most instances we see that such trends are a direct result of human activities.

A new NASA study has now shown that over the last 20 years, the atmosphere above the Amazon rainforest has been drying out. This is increasing the demand for water, thus leaving ecosystems vulnerable to fires and drought. It also shows that this increase in dryness is primarily the result of human activities.

Marcio Isensee e Sa / Adobe Stock. VIA NASA

Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, analyzed decades of ground and satellite data over the Amazon rainforest to track both how much moisture was in the atmosphere and how much moisture was needed to maintain the rainforest system.

"We observed that in the last two decades, there has been a significant increase in dryness in the atmosphere as well as in the atmospheric demand for water above the rainforest," said JPL's Armineh Barkhordarian, lead author of the study. "In comparing this trend to data from models that estimate climate variability over thousands of years, we determined that the change in atmospheric aridity is well beyond what would be expected from natural climate variability."

The atmosphere over the Amazon rainforest is drying out. According to decades of ground & @NASAEarth satellite data, the largest rainforest on Earth is now more vulnerable to drought due to human activities such as burning to clear land for agriculture: https://t.co/yCOZarkpNM pic.twitter.com/BKuZOT3e6Y

¡ª NASA (@NASA) November 7, 2019

So if it's not natural, what's causing it?

Barkhordarian was quoted on NASA website as saying that elevated greenhouse gas levels are responsible for approximately half of the increased aridity. The rest is the result of ongoing human activity, most significantly, the burning of forests to clear land for agriculture and grazing. The combination of these activities is causing Amazon's climate to warm.

The image shows the decline of moisture in the air over the Amazon rainforest. NASA GRAPHIC

When a forest burns, it releases particles called aerosols into the atmosphere ¡ª among them, black carbon, commonly referred to as soot. While bright-colored or translucent aerosols reflect radiation, darker aerosols absorb it. When the black carbon absorbs heat from the sun, it causes the atmosphere to warm; it can also interfere with cloud formation and, consequently, rainfall.

This becomes significant because Amazon is the largest rainforest on Earth. When healthy, it absorbs billions of tons of carbon dioxide (CO2) a year through photosynthesis ¡ª the process plants use to convert CO2, energy and water into food. By removing CO2 from the atmosphere, the Amazon helps to keep temperatures down and regulate climate.

But it's a delicate system that's highly sensitive to drying and warming trends.