What would life on Earth be like without the Amazon rainforest?

Fires that have been ravaging the region have prompted global concern about the impact on the planet's climate and wildlife – and raised questions about whether the world could survive with a devastated Amazon.

The Amazon rainforest is biologically the richest region on Earth, hosting about 25% of global biodiversity, and is a major contributor to the natural cycles required for the functioning of the Earth, according to the environmental group Panthera.

Animals, plants and humans would all face dire consequences if the Amazon rainforest vanished, experts say.

"The Amazon is the largest tract of continuous rainforest on the planet, and it plays a critical role in the (Earth's) climate system," said Laura Schneider, a geographer at Rutgers University.

One way it does this is by absorbing carbon dioxide, a heat-trapping gas that's a significant cause of global warming.

"With nearly 100 billion tons of carbon stored in its trees, it keeps nearly 400 billion tons of carbon dioxide out of the atmosphere," said Daniel Nepstad, director of the Earth Innovation Institute.

The world emits about 40 billion tons of carbon dioxide into the atmosphere every year. The Amazon absorbs 2 billion tons of carbon dioxide a year (or 5% of annual emissions), which makes it a vital part of preventing climate change.

Although fire activity in the Amazon varies considerably year to year and month to month, this August stands out because it has brought a noticeable increase in large, intense and persistent fires along major roads in the central Brazilian Amazon, said Douglas Morton of NASA’s Goddard Space Flight Center.

Carbon dioxide at record levels

Nearly half of the 77,000 fires across Brazil this year have been in the Amazon region. About 60% of that region is in Brazil; the vast forest also spans parts of Bolivia, Colombia, Venezuela, Ecuador, French Guiana, Guyana, Peru and Suriname.

In addition to sucking carbon dioxide out of the atmosphere, the forest acts as a giant cooling system for the planet. "All of the water evaporated from Amazon forest trees absorbs energy when it evaporates – cooling the planet just as people are chilled by evaporating water when they are wet," Nepstad said.

The Amazon is home to more than 30,000 species of plants; 2.5 million species of insects; 2,500 fish; more than 1,500 bird species; 550 reptiles; and 500 mammals, according to the Wildlife Conservation Society,

"Iconic species like the jaguar, tapir, pink river dolphin and harpy eagle are well known, but the basin contains 10-12% of all the species on the planet. It is the world’s largest freshwater system, where over 2,500 species of fish thrive," said Carlos Durigan, country director of the Wildlife Conservation Society in Brazil.

"The Amazon is home to more wild plants and animals than any other place on Earth," said Jana Gamble of the Amazon Aid Foundation. "Also, 400 to 500 indigenous tribes call the Amazon rainforest their home."

Schneider said that "in addition to potential disruptions in the climate system, the Amazon rainforest contains the highest biodiversity on Earth, and it has been the home of various indigenous communities for centuries."

She said it would be catastrophic to both biodiversity and indigenous people if the trees were to disappear, but it's very unlikely that they would.

"Rainforests are resilient ecosystems, so their disappearance is almost impossible," Schneider said. "Resilience, however, depends on the speed and extent of disturbances like land clearing, and this is the worrisome part."

The World Wildlife Fund estimates that about 17% of the Brazilian Amazon is already deforested.

Here's a stepped-back view of Rondonia:

6 charts:Why thousands of fires in the Amazon rainforest matter to the world

Is it accurate to describe the Amazon rainforest as the "lungs of the Earth" or the "Earth's air conditioner?"

No, Schneider said. "I wouldn’t use either of the metaphors, lungs or air conditioner, because the role that forests play in the climate system is not linear ... for example, cooling the Earth or absorbing carbon.

"The role of forests in the carbon and water cycles depends on several aspects of rainforest ecology, for example how fast the forest will grow back or respond to disturbances. Forest ecology is too complex to be captured in one metaphor."

Contributing: The Associated Press