The Congo Basin is the area where the Congo River flows. It is located in Central Africa, in a region called West Equatorial Africa. This area is sometimes called the Congo. It includes some of the world's largest tropical rainforests and provides water used for farming and energy production.

The rainforest in the Congo Basin is the largest in Africa and the second largest in the world after the Amazon rainforest. It covers 300 million hectares, while the Amazon covers 800 million hectares. The forest helps reduce climate change by absorbing carbon dioxide. However, cutting down trees and damage from climate change may harm the forest and make the water patterns in the basin less predictable. A study from 2012 found that changes in rainfall caused by climate change could harm economic activities in the region.

Eight areas in the Congo Basin are listed as World Heritage Sites. Five of these are also on the list of World Heritage Sites in Danger, and all five are in the Democratic Republic of the Congo. Fourteen percent of the humid forest is protected.

Geology

The Congo Basin is a large low area within the Congo Craton, which makes it a region of younger (Phanerozoic-aged, mostly Mesozoic and later) sedimentary rock within a much older (Archean-aged) part of Earth’s exposed continental crust. The Craton began to change shape as early as the late Cambrian or early Ordovician periods and continued to change throughout the Paleozoic era. However, these changes caused much of the Paleozoic rock to erode quickly, forming a large gap in the rock layers. Sediment began to build up in the basin during the Mesozoic (Triassic) period and has continued to the present day.

During the Jurassic period, deposits suggest the presence of a freshwater lake environment in the basin, and this continued into the Early Cretaceous. By the start of the Late Cretaceous, a connection to the Trans-Saharan seaway allowed the sea to flood into the basin (earlier evidence of a Late Jurassic marine intrusion is debated), linking the southern Atlantic Ocean and the Tethys Ocean. Many rock layers formed during these freshwater and marine environments contain rich deposits of pollen, invertebrate, and vertebrate (mostly fish) fossils. Kimberlite pipes, believed to have formed during the Cretaceous, possibly due to a sudden slowdown in seafloor spreading of the southern Mid-Atlantic Ridge, are the source of the region’s famous diamonds.

By the Cenozoic era, rising land along the edges of the Cuvette Centrale blocked further sea connections. During the Paleogene, heavy rainfall turned the basin into marshes and swamps. Drier conditions with seasonal droughts began in the Neogene. Later in the Neogene, a shift to river deposits suggests a sudden return to wetter conditions.

The following sedimentary rock layers have been deposited in the basin:

• Late Carboniferous / Permian – Lukuga Formation (part of the Lower Karoo)
• Early Triassic to Early Jurassic – Haute Lueki Formation (part of Upper Karoo)
• Late Jurassic – Stanleyville Formation
• Early Cretaceous – Loia Formation, Kamina Series
• Late Cretaceous – Bokungu Formation, Kwango Series (Nsele Group, Inzia Group)
• Paleogene – Kwango Formation, Kalahari System, Sables Bateke Series
• Neogene – Limons Series, Kalahari System, Sables Bateke Series

Description

The Congo is a traditional name for the central part of Africa near the equator, located between the Gulf of Guinea and the African Great Lakes. The basin begins in the highlands of the East African Rift system, where rivers like the Chambeshi, Uele, and Ubangi flow from the upper parts, and the Lualaba River drains wetlands in the middle parts. The young age and rising land of the East African Rift at the headwaters cause the river to carry a large amount of sediment each year. However, much of the drainage basin covers large areas that are flat or gently sloping. The basin is mostly defined by areas such as the Bie, Mayumbe, Adamlia, Nile-Congo, East African, and Zambian Swells.

The basin ends where the river flows into the Gulf of Guinea on the Atlantic Ocean. The basin covers a total area of 3.7 million square kilometers and includes some of the largest untouched tropical rainforests on Earth, as well as large wetlands.

Countries wholly or partially in the Congo region:

History

The first people who lived in the Congo Basin area were believed to be pygmies. At that time, the thick forests and wet weather made it hard for many people to live there, limiting the number of people in the region. This also made it difficult for hunter-gatherer societies to grow, though some parts of their culture still exist today. Later, Bantu people moved to the area and created the Kingdom of Kongo.

By the late 1800s, Belgium, France, and Portugal had taken control of the entire region as colonies. The General Act from the Berlin Conference in 1885 clearly defined the "conventional basin" of the Congo, which included the real basin and some other areas. This agreement required the countries involved to stay neutral within the conventional basin, but this rule was not followed during World War I.

The World Resources Institute estimated that about 80 million people live in and around the Congo Basin today.

Climate

The Congo Basin is an important climate area with yearly rainfall between 1,500 and 2,000 mm. It is one of three major areas in the tropics where strong thunderstorms, called deep convection, frequently occur. The other two areas are the Maritime continent and the Amazon. Together, these three regions help control the weather patterns in the tropics and other parts of the world. The Congo Basin experiences the highest number of lightning strikes anywhere on Earth. The heavy rainfall supports the second largest rainforest on Earth. This rainforest is a globally important carbon sink and plays a key role in the global carbon cycle.

Across the entire basin, there are two main rainy seasons: March to May and September to November. In both hemispheres, rainfall is highest between September and November, with more than 210 mm of rain each month. During northern hemisphere winter, rainfall is lower north of the equator (less than 80 mm per month). During southern hemisphere winter, rainfall is lower south of the equator (less than 80 mm per month). The seasonal changes in wind patterns that carry water vapor explain the rainfall patterns. Much of the rainfall comes from large weather systems called Mesoscale convective systems. These systems typically last over 11 hours and can cover more than 500 km in some areas of the Congo Basin.

Temperatures in the Congo Basin are usually between 20 and 30 degrees Celsius. These temperatures are cooler than those in the Sahara Desert to the north and the Kalahari Desert to the south. The temperature differences between the deserts and the Congo Basin help create wind systems called African easterly jets. These wind systems influence weather and climate in the Sahel and Southern Africa.

Future climate predictions show the region will become hotter due to global climate change. Scientists are less certain about how average rainfall might change in the region, as different climate models from the Intergovernmental Panel on Climate Change (IPCC) give conflicting results about rainfall patterns. While average rainfall changes are uncertain, it is likely that extreme rainfall events will become more intense because the atmosphere will hold more water vapor.

Because the Congo Basin is so important for global climate, scientists have suggested that major changes in rainfall or climate in the Congo Rainforest could act as a "tipping point." Such changes might have wide-reaching effects on the Earth's systems.

Flora and fauna

The Congo forest is home to many animals, including the okapi, African forest elephant, pygmy hippopotamus, bongo (a type of antelope), chimpanzee, bonobo, and Congo peafowl. The top predator in this area is the leopard. These leopards are larger than those in the savannah because there are fewer large predators to compete with. The Congo Basin is also home to the endangered western lowland gorilla. In 2010, the United Nations Environment Programme warned that gorillas might disappear from the greater Congo Basin within 15 years.

• Western lowland gorilla
• African forest elephant

The Congo Basin is the largest forest in Africa. Over 10,000 plant species live in and around the forest. The humid forests cover 1.6 million square kilometers. The Congo Basin is an important source of African teak, a type of wood used to make furniture and flooring. About 40 million people rely on these forests for their traditional ways of living.

Ecology and protection

Congo's forests are often called the planet's second lung because they help absorb carbon dioxide from the air, just like the Amazon rainforest. These forests are a major "carbon sink," meaning they trap carbon that would otherwise become harmful carbon dioxide. The Congo Basin holds about 8% of the world's forest-based carbon. However, it receives much less scientific study than the Amazon or other tropical forests in Southeast Asia. If these forests are destroyed, the stored carbon would be released into the atmosphere. Scientists predict that by 2050, deforestation in the Democratic Republic of the Congo (DRC) could release as much carbon dioxide as the United Kingdom has emitted over the past 60 years. A 2013 study found that deforestation in the Congo Basin was slowing. In 2017, researchers discovered that peatlands in the Cuvette Centrale, covering 145,500 square kilometers, store 30 billion tonnes of carbon—equal to 20 years of U.S. fossil fuel emissions. However, by 2021, the deforestation rate in the Congolese rainforest had increased by 5%.

The Global Forest Atlas estimates that logging industries use between 44 and 66 million hectares of forest. A 2019 study in Nature Sustainability found that 54,000 miles of roads were built for logging concessions between 2003 and 2018, totaling 143,500 miles. In 2002, the World Bank and the DRC agreed to a moratorium on logging, which banned new logging permits and the renewal of existing ones in exchange for $90 million in development aid.

The DRC government has created a new forestry code that requires logging companies to invest in local development and follow a 25-year plan for sustainable logging. Companies must sign agreements with local leaders and hereditary landowners, who grant permission to log in return for development benefits. Companies are required to pay nearly $18 million annually in rent for logging rights, with 40% of that money going to provincial governments for local development.

The current Kyoto Protocol does not provide financial rewards for "avoided deforestation," which refers to efforts to protect forests from being cut down. However, many scientists and policymakers hope future climate agreements will include such incentives. In the Lualaba River near Kisangani, an island called L’Île Mbiye is part of a project by Stellenbosch University to conserve forest ecosystems. The DRC also aims to expand protected forest areas and seek financial support through new markets for forest carbon. The main environmental group working to protect Congo's forests is an NGO called OCEAN, which connects international organizations like Greenpeace with local communities in logging areas.