Amazon rainforest

The Amazon rainforest is a massive, moist broadleaf tropical ecosystem. It covers most of the Amazon basin in South America. This basin spans 7 million square kilometers. About 6 million square kilometers of that area are covered by the rainforest.

It is the largest and most biodiverse tropical rainforest on Earth. The forest contains an estimated 390 billion individual trees. These trees represent about 16,000 different species. This vast region is shared by nine different nations.

It represents over half of all remaining rainforests on the planet.

The forest stays healthy through a unique connection to the Sahara desert. The Amazon soil loses nutrients like phosphorus due to heavy rain and floods. To replace these nutrients, wind carries dust from the Bodélé depression in Northern Chad.

This dust contains phosphorus, which is vital for plant growth. NASA's CALIPSO satellite tracks this process using a laser range finder. Each year, about 182 million tons of dust blow out of the Sahara. About 15% of that dust, or 22 million tons, falls over the Amazon basin. This windblown dust provides the essential minerals the forest needs to thrive.

The geography of the Amazon is divided among several countries. Brazil contains the majority of the forest at 60%. Peru holds 13%, and Colombia holds 10%.

Other nations with parts of the forest include Bolivia, Ecuador, French Guiana, Guyana, Suriname, and Venezuela. France manages a protected area called the Guiana Amazonian Park. The forest likely formed during the Eocene era, roughly 56 million years ago. It appeared as the Atlantic Ocean widened and created a warm, moist climate.

Over millions of years, the forest expanded and retracted due to climate changes and ice ages.

Human history in the Amazon is much older and more complex than once believed. Archaeological evidence from Caverna da Pedra Pintada shows humans settled there at least 11,200 years ago.

For a long time, scientists thought the soil was too poor to support large populations. Archaeologist Betty Meggers argued that hunting could only sustain 0.2 people per square kilometer. However, recent findings show the region was actually densely populated. In AD 1500, as many as 5 million people may have lived there. Some estimates suggest over 8 million people lived in the basin in 1492.

Indigenous people have actively shaped the forest for millennia. They developed terra preta, which is a type of fertile, human-managed soil. This soil allowed for advanced agriculture and silviculture in the rainforest.

Recent discoveries have found evidence of large settlements with roads, bridges, and plazas. In the 1970s, researchers discovered geoglyphs, which are large earthworks, dating between AD 1 and AD 1250.

These findings prove the Amazon was not a pristine wilderness, but a managed landscape. Today, more than 30 million people from 350 ethnic groups live in the region. Indigenous groups make up 9% of this population.

History also records periods of conflict and change. The name "Amazon" comes from Francisco de Orellana's 1542 travels. He named the area after the female warriors of Greek mythology after fighting the Tapuya tribes. In the early 20th century, the explorer Percy Fawcett searched for a lost civilization he called the "City of Z."

The region also saw the impact of the rubber boom. During this time, diseases like typhus and malaria killed an estimated 40,000 native people. In the 1960s, activists like the Villas-Bôas brothers helped establish the first Brazilian National Park for indigenous people along the Xingu River.

Today, the Amazon faces serious threats from large-scale deforestation. This loss of trees has severe economic and environmental consequences. In Brazil, economic losses from deforestation could be seven times higher than the value of the commodities produced.

Deforestation can damage agriculture so badly that it leads to "agro-suicide." To address this, the World Bank proposed a new economic program in 2023. This program aims to create a way to grow the economy without destroying the forest. Protecting this massive system is essential for the planet's biodiversity and climate.