A rainforest is a forest ecosystem characterized by a dense, continuous tree canopy and high annual rainfall. These conditions create a highly humid environment that supports an extraordinary concentration of plant and animal life. Tropical rainforests, found near the equator, maintain warm temperatures year-round and receive substantial precipitation, often exceeding 1,800 millimeters annually. While many such forests exist, the most famous rainforest in the world is the Amazon Rainforest of South America.
Defining Global Fame: Why the Amazon is Number One
The primary factor establishing the Amazon’s global reputation is its overwhelming size, being the largest contiguous tropical forest on Earth. Its vast expanse covers approximately 5.5 million square kilometers, making it larger than the next two biggest rainforests combined. This colossal scale has cemented its status in the public imagination as the archetypal jungle environment.
The Amazon’s profile is amplified by its immense influence on global climate, earning it the nickname “the lungs of the Earth.” The forest acts as a massive carbon sink, absorbing an estimated two billion tons of carbon dioxide annually and storing between 150 to 200 billion tons of carbon in its biomass. This capacity for carbon sequestration directly impacts the regulation of global temperatures, making the Amazon a subject of constant international conservation attention.
It also plays a fundamental part in continental weather patterns, generating much of its own rainfall through evapotranspiration. Water vapor released by the forest forms “flying rivers,” which carry moisture across South America, influencing rainfall as far away as Argentina and the southern United States. This environmental significance elevates the Amazon to a planet-wide concern, which further fuels its fame and political relevance.
Geographic Scope and Political Boundaries
The Amazon Rainforest is situated within the Amazon River Basin, a colossal drainage area roughly the size of the contiguous United States. The forest’s geography is inextricably linked to the Amazon River, which is the largest river in the world by volume, carrying more water than the next seven largest rivers combined. The river and its tributaries act as the lifeblood and primary defining feature of the entire ecosystem.
The Amazon Basin spans across nine South American nations. About 60% of the rainforest is contained within Brazil’s borders. Significant portions are also found in Peru and Colombia, with smaller amounts extending into Bolivia, Ecuador, Venezuela, Guyana, Suriname, and French Guiana. This political fragmentation means that conservation efforts are subject to the governance and policies of multiple sovereign states.
Biodiversity: The Scale of Life in the Amazon
The Amazon’s fame is also deeply rooted in its unparalleled biological richness, housing at least 10% of the world’s known species. This species density is so high that a single hectare of forest can contain more tree species than are native to the entire continent of Europe. This makes it arguably the most critical biodiversity hotspot on the planet.
Current estimates suggest the Amazon is home to approximately 40,000 plant species, including around 16,000 different tree species. The animal life is similarly varied, with over 2.5 million insect species estimated to live within the forest. Scientists have formally cataloged thousands of vertebrate species, including:
- Roughly 1,300 species of birds
- More than 430 mammals
- Approximately 3,000 freshwater fish species that inhabit the river system
The forest is also a stronghold for endemic life, meaning many species are found nowhere else on Earth. This isolation contributes to the Amazon’s status as a living repository of genetic material. The sheer scale of its biological inventory, with countless species yet to be formally described, ensures its continued prominence in scientific and public discourse.
Notable Contenders for the Title
While the Amazon holds the title of most famous, other rainforests are globally significant and warrant recognition. The Congo Rainforest in Central Africa is the world’s second-largest, spanning six countries and serving as a major carbon sink for the African continent. It is notably the habitat for endangered species like forest elephants and lowland gorillas.
The Daintree Rainforest in Queensland, Australia, is recognized as the world’s oldest continuously surviving tropical rainforest, with an estimated age of 180 million years. Its ancient lineage makes it a unique living museum for studying evolutionary history.
The rainforests of Southeast Asia, particularly those on the island of Borneo, are also significant biodiversity hotspots. Borneo’s forests are home to iconic species such as the Bornean orangutan and are divided among three nations: Indonesia, Malaysia, and Brunei. While these magnificent forests are defined by unique features, none rival the Amazon’s combination of colossal size, planetary climate impact, and overwhelming species count.