International Day of the Tropics: How climate change is affecting the hottest region on Earth

Maldives, Indonesia, Thailand, or Barbados are usually seen as holiday paradises, but the reality there is far from carefree. Celebrated on June 29, the International Day of the Tropics is meant to draw attention to the challenges faced by a region that is home to 3 billion people and harbors 80 percent of the world’s biodiversity.

From tropic to tropic

Geographically, the tropics are defined as the zone stretching from the Tropic of Cancer (23.4°N) to the Tropic of Capricorn (23.4°S), covering about 40 percent of Earth’s surface. Average temperatures here range from 25 to 28°C throughout the year, and annual precipitation can reach as much as 1800–2500 mm. It’s hot, rainy, and often stormy.

These unique conditions have allowed for the development of some of the most fascinating ecosystems on Earth—from rainforests and wetlands to savannas and coral reefs. The tropics are home to 95 percent of the world’s mangrove forests and more than half of the planet’s renewable freshwater resources. Unfortunately, the rate of biodiversity loss here is also the highest in the world.

International Day of the Tropics reminds us of an ecological crisis

Climate change is leaving its mark on the tropical zone, showing that it can always get even hotter. According to the Intergovernmental Panel on Climate Change (IPCC), depending on the level of greenhouse gas emissions, the average temperature in this part of the globe could rise by 1.6 to 3.3°C by the end of the century. In Darwin, northern Australia, the number of days with temperatures above 35°C could increase from 11 in 2015 to as many as 111 in 2090.

Strengthening cyclones are toppling forests, causing destructive floods, and leading to massive land erosion. According to American scientists, this has catastrophic effects on coral reefs, salt marshes, and underwater seagrass meadows. Entire ecosystems are suffering.

Paradoxically, climate change is partly driven by human-induced phenomena. The destruction of rainforests not only reduces their potential to absorb CO₂, but also generates additional emissions. Similar consequences come from the degradation of marine ecosystems, which act as natural blue carbon reservoirs.

And while the polar bear has become the symbol of dramatic climate change impacts, the tropics are home to the most threatened species: mammals, birds, reptiles, amphibians, and trees. Corals are bleaching and dying, overexploited fisheries can’t recover, and green turtles are losing their ability to reproduce.

Let’s not forget the people

About 40 percent of the global population lives in the tropics. This is where the fastest-growing economies are located and where population growth is most intense. No wonder these regions are often seen as the future of the world—by 2050, they will be home to two-thirds of all children on Earth.

Unfortunately, the International Day of the Tropics also reminds us of poverty, hunger, and outbreaks of infectious diseases, which are more widespread here than anywhere else. Rising temperatures alone will have tragic consequences—in Jakarta, heat-related deaths are projected to rise from 1,800 in 2010 to 27,000 in 2050. Meanwhile, the well-being of local communities is closely tied to natural resources, which are their main sources of water, food, and livelihoods.