Tropical Climates

Tropical Climates Definition

Most tropical climates are found in and around the Equator between the Tropic of Cancer (23°27'N) and the Tropic of Capricorn (23°27'S), a region of the world known as the tropics. On average, the tropics receive more solar energy than anywhere else on Earth.

In other words—tropical climates are hot and rainy!

Fig. 1 - Tropical climates are generally found between the Tropic of Cancer and the Tropic of Capricorn

While associating tropical climates with the tropics is a good general rule of thumb, it is important to note that not all climates in the tropics are tropical climates, and not all tropical climates are found in the tropics.

For example, southern Florida (including the city of Miami) has a tropical climate but is not located in the tropics, while Somalia—located entirely within the tropics—has a mix of dry desert and steppe climates.

Tropical Climate Characteristics

Tropical climates are caused by the uneven distribution of solar energy. As our planet rotates around the sun, the Equator receives more direct sunlight than other areas. This abundance of solar energy is essentially the driving force behind tropical climates:

1. The heat causes more frequent evaporation in tropical bodies of water, leading to greater humidity and more rain;

2. The greater availability of water and the higher concentration of solar energy makes it easier for plant life to proliferate, which, in turn, supports other forms of life.

Speaking of humidity and rain, tropical climates are typically characterized by two overarching seasons: the wet season and the dry season. These two seasons roughly correspond to winter and summer in other climates, though the main factor here is precipitation rather than temperature; it rains more in the wet season and less in the dry season, though in some cases, the dry season may not be all that dry relative to other climates!

Temperature changes have more to do with elevation than they do seasonality. As with anywhere else in the world, the higher up you go, the colder things tend to get. Many tropical highlands and mountains experience relatively cool temperatures year-round. However, frost, ice, and snow are exceedingly rare in the tropics in all but the highest of high elevations; tropical mountains are still warm compared to mountains found in polar or temperate regions.

Types of Tropical Climates

German-Russian climatologist Wladimir Köppen described three different types of tropical climates: tropical rainforest climates, tropical monsoon climates, and tropical savanna climates. He further subdivided tropical savannas into those that experience dry summers/wet winters and those that experience wet summers/dry winters—making for four different major types of tropical climates total.

Fig. 2 - According to Köppen, the three main types of tropical climates are tropical rainforest (Af), tropical monsoon climate (Am), and tropical savanna (Aw)

In the Köppen climate classification system, which Köppen created in 1884 to try and describe all of the world's different climates, tropical climates are designated with the letter "A." Take a look at the chart below.

Tropical Climate Examples

When you think of tropical destinations, you probably think of sunny island beaches and dense, thick jungles. Fair enough—much of the time, you're not wrong!

Fig. 3 - Pristine beaches, like this one in the Maldives, are amongst the most iconic features of tropical climates

Tropical climates are found in the Caribbean, Mexico and Central America, northern and central South America, Southeast Asia, South Asia, central Africa, and Oceania. The entire island of Cuba, for example, has a tropical climate.

Tropical Climates and Agriculture

As with most people in temperate zones, the main way humans feed themselves in the tropics is through agriculture.

Tropical agriculture includes subsistence farming and cash crop farming. Subsistence farming is agriculture that is practiced only to meet the food needs of a family or local community. Cash crop farming is a form of commercial farming in which a relatively valuable crop is grown for export to the international marketplace.

Advantages of Tropical Climate Agriculture

As we mentioned earlier, the combined forces of sun and water make the tropics an absolute hotbed for the proliferation of plants. This, in turn, creates more habitats for animals, leading to a veritable abundance of life. Tropical rainforests in particular are the most biodiverse areas in the world, both in terms of density and variety of life.

These conditions can be a boon for farmers as well. Solar energy and an abundance of water make farming more feasible than in many other climates. Additionally, some of the world's most profitable cash crops, such as bananas, cocoa, coffee, coconuts, and tea, go hand-in-hand with tropical climates. Rubber trees and oil palm trees are also native to tropical climates and thrive in tropical conditions. The abundance of water makes traditional rice farming, which requires flooding to create rice paddies, more feasible.

The Negative Impacts of the Physical Environment

The heat and humidity of the tropics cause rapid decomposition of dead plants, leaf litter, and animals. You might imagine that all this decomposition infuses tropical soil with rich organic nutrients. You would be wrong! Many nutrients are quickly reabsorbed by plants and fungi, so are not stored in the soil. Excessive rain removes most of whatever nutrients are left through a process called leaching. Overabundant sunlight dries out any exposed soil quickly, even at higher, cooler elevations. In other words, tropical soils are surprisingly nutrient-deficient.

This difference in soil quality is one of the main reasons that tropical agriculture is less productive than agriculture practiced in temperate regions. Another major factor? Pests. Temperate farmers rely on winter temperature drops to kill off most pests; tropical farmers are afforded no such luxury and have to deal with pests year-round.

Slash-and-Burn, Deforestation, and Climate Change

Slash-and-burn agriculture is practiced in and around forests worldwide but is particularly ubiquitous in tropical forests. It is a solution to tropical soil nutrient deficiency and one of the most straightforward ways to keep families fed in tropical regions. Slash-and-burn agriculture involves cutting down and burning a section of a forest; letting the soil absorb the nutrients from the burnt plant matter; then planting crops over the fresh, nutrient-rich soil. Once crops are harvested and the soil is exhausted, the plot is allowed to "re-wild" and farmers move on to another patch of forest to slash and burn (check out our explanation on Slash and Burn Agriculture for more information!).

Fig. 4 - Farmers in Thailand clear a plot of land via slash and burn

The human population is increasing, and with it, the demand for food. In tropical climates today, slash-and-burn agriculture is being practiced alongside agriculture that requires permanent land conversion. The combined effect of these practices is causing forests to be depleted before they have a chance to regenerate, leading to widespread deforestation. Any carbon dioxide that these trees were sequestering is released into the atmosphere, enhancing the greenhouse gas effect and contributing to climate change. Rising temperatures will challenge the resiliency of tropical crops, posing a threat to the livelihoods of tropical farmers.

Sustainable Agriculture in Tropical Climates

So we have bad soil, a bunch of pests, and unsustainable deforestation. Are there any solutions to these issues? Yes—and in fact, most tropical farmers apply one or more of the following practices.

One alternative to slash-and-burn agriculture is slash-and-mulch agriculture. After the trees are cut down, the soil is treated with commercial fertilizer, which allows the plot to be used for a much longer period of time.

Terracing involves cutting a staircase-like pattern into a slope and growing crops on the steps. This pattern reduces soil erosion and leaching, as it decreases the momentum that rainwater would normally gain from gushing down a hill.

Many species of pests prefer only one or two types of plants. An entire farm of the same plant, season after season, year after year, can essentially be an endless buffet for a pest. Similarly, weeds can flourish in plots that are left empty or sparse. Both of these issues can be mitigated through crop rotation, cover cropping, and mixed cropping.

Crop rotation involves keeping a plot of land continuously occupied with different species of plants. For example, after harvesting a field of corn, you would then immediately plant soy in the same plot. Pests and weeds that rely on corn are suddenly robbed of an easy meal and free home.

Cover cropping involves planting extra crops on a farm purely for the purpose of covering all bare soil. In tropical climates, this can help prevent leaching. It also makes it harder for weeds to find ground to take root.

Mixed cropping involves planting more than one type of crop on the same plot of land simultaneously. The diversity of species helps prevent pests from overwhelming a farm.