Key Facts and Statistics about the Tropical Zone of Earth

What are Tropics?

The Tropics are a region of the Earth surrounding the Equator, roughly defined as the area between the Tropic of Cancer in the Northern Hemisphere at 23.43663°N and the tropic of Capricorn in the Southern Hemisphere at 23.43663° S.

According to the State of the Tropics 2014 Report, the tropical region accounts for 40 per cent of the Earth’s total surface area and are host to approximately 80 per cent of the world’s biodiversity and much of its language and cultural diversity.

Features of the Tropics

In the tropical region where sunlight is usually intense, climate variation is not significant. Tropical locations are typically hot and experience little seasonal change in day-to-day temperature. Tropical climates are featured by monthly average temperatures of 18 ℃ (64.4 ℉) or higher year-round.

Another important feature of the Tropics is the prevalence of rain in the moist inner regions near the equator, and that the seasonality of rainfall increases with the distance from the equator. Annual precipitation is often abundant in tropical climates and show a seasonal rhythm to varying degrees.

Challenges Faced by the Tropics

With modernization and industrialization driven by population growth in recent decades, the tropical region is facing several challenges such as climate change, deforestation, logging, urbanization, and demographic changes. Some of these challenges are greater in the Tropics than in the rest of the world.

Key Facts and Statistics about the Tropics

To better understand the challenges faced by the Tropics, key facts and statistics about the tropical region, extracted from relevant reports, are compiled at the following:

The social system

1. The Tropics is home to over 40 per cent of the world’s population. Around 55 per cent of the world’s children live in the Tropics. By 2050, the tropical region will host more than half of the world’s population and two-thirds of its children.
2. Between 1980 and 2018, the proportion of people living in tropical cities increased from 30% to 47%, whereas the world’s urbanization rate increased from 39% to 55%. In the Tropics, more people live in rural areas than in urban centers,
3. By 2018, there were more than 1.5 billion people living in tropical urban areas. The proportion of the urban population living in slum conditions is higher in the Tropics than in the rest of the World.
4. Globally, 40 million people were considered displaced in their own countries in 2018, compared with just under 6 million in 2000—an almost 600% increase. Of these 40 million, refugees in tropical countries accounted for 28 million (68%).
5. The vast majority of the extreme poor live in tropical countries (85%). It is estimated that around 670 million people living in extreme poverty in the Tropics remained in extreme poverty in 2018.
6. Five tropical countries (Nigeria, the Democratic Republic of Congo, Ethiopia, India and Bangladesh) are collectively home to 50% of the world’s extreme poor.
7. Consistent with the higher levels of poverty, more people experience undernourishment in the Tropics than in the rest of the world.
8. The number of people aged 15 – 49 living with HIV in the Tropics is much higher than in the rest of the world. In 2018, an estimated 16.8 million 15–49-year-olds in the Tropics were living with HIV, compared to 7.3 million in the rest of the world.
9. Globally, the number of malaria cases reduced from an estimated 241 million to 223 million between 2000 and 2017. An estimated 97% of malaria cases occurred in the Tropics in 2017. Unfortunately, in some regions, improvement has stagnated.
10. An estimated 62% of all new TB cases in 2018 (more than 6 million) occurred in the Tropics, and the incidence of TB in the Tropics is more than double that for the rest of the world.
11. In the Tropics, access to an improved water source increased from 71% in 2000 to 82% in 2017, whereas the change outside the Tropics was from 87% to 93.5%.
12. In the Tropics, more than 40% of the region’s population still did not have adequate access to improved sanitation facilities in 2017.
13. Over 20% of the population in the Tropics did not have access to electricity in 2017. In the rest of the world, only 3.5% of people did not have access.
14. The existing gap in GDP per capita between the Tropics and the rest of world has grown larger, indicating that economic growth in the Tropics is not keeping pace with global growth.

The ecosystem

15. The Tropics host nearly 95% of the world’s mangrove forests by area and 99% of mangrove species.
16. The Tropics have more than half of the world’s renewable water resources (54%), yet almost half their population is considered vulnerable to water stress.
17. Biodiversity is greater in the Tropics – however, loss of biodiversity is also greater in the Tropics than in the rest of the world.
18. Wild marine fish capture has continued to grow at a higher rate in the Tropics than in the rest of the world.
19. It is estimated that 33% of coral species are threatened and at greater risk of extinction compared to most other groups.
20. CO₂ emissions have climbed at a greater rate in the Tropics compared to in the rest of the world, although the Tropics continues to be a much lower emitter of CO₂ (20%) both in total and per capita emissions.

Key references:

• State of the Tropics (2020). State of the Tropics 2020 Report. James Cook University, Townsville, Australia.
• State of the Tropics (2014). State of the Tropics 2014 Report. James Cook University, Townsville, Australia.

Relevant Post:

     International Day of the Tropics 2022