LOSS OF TROPICAL RAINFORESTS

               Tropical forest

Tropical forests have the largest living biomass and boast some of the highest rates of terrestrial biodiversity. But rainforests are perhaps the most endangered habitat on earth and most vulnerable to deforestation. Each year, some 140,000 sq km of rainforests are destroying.

Loss of tropical forests makes climate change worse

Trees naturally suck carbon dioxide out of the air, a function that helps counteract human emissions into it each year. In fact, by some estimates, the world’s forests absorb around one-third of human-caused CO2 emissions.

An tropical trees tend to be even thirstier for CO2 than their counterparts in temperate regions, thanks at least in part to longer growing seasons.

Human activity, however, is undercutting that natural potential.

Forest loss is not exactly a new problem – more than half of the world’s tropical forests have been destroyed since the 1960s. But new information is piling-up on possible implications. Consider, for example, the recent study suggesting that deforestation, degradation, and general disturbance have already combined to make tropical forests a net carbon source rather than a sink, meaning they’re losing more carbon than they can absorb. Consider also that losses continue to pile-up despite major efforts, across many nations, to counteract them.

Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest. True rainforests are typically found between 10 degrees north and south of the equator (see map); they are a sub-set of the tropical forest biome that occurs roughly within the 28-degree latitudes (in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn). Within the World Wildlife Fund's biome classification, tropical rainforests are a type of tropical moist broadleaf forest (or tropical wet forest) that also includes the more extensive seasonal tropical forests.

More than half of Earth’s rain forests have already been lost due to the human demand for wood and arable land. Rain forests that once grew over 14 percent of the land on Earth now cover only about 6 percent. And if current deforestation rates continue, these critical habitats could disappear from the planet completely within the next hundred years.

The reasons for plundering rain forests are mainly economic. Wealthy nations drive demand for tropical timber, and cash-strapped governments often grant logging concessions at a fraction of the land’s true value. “Homesteader” policies also encourage citizens to clear-cut forests for farms. Sustainable logging and harvesting rather than clear-cutting are among the strategies key to halting rain forest loss.

Roots of problem: Social, economic, political, climatic

In the Democratic Republic of Congo (DRC), for example, the WRI report shows record high forest loss, with deforestation up 6 percent from 2016, primarily as a result of farming and artisanal logging. Considering this African nation ranks among the poorest countries globally, 176th out of 187 countries on the UN’s most recent Human Development Index, it’s understandable that people may be willing to give up some shade if they think it can help them eke out a living.

But sometimes even positive social change can feed forest loss. In Columbia, for instance, hard-won peace was recently brokered between the government and a major rebel group that had been occupying remote, forested areas. That rebel group’s presence is thought to have helped protect the land from development for years. But with that deterrent out of the way, there’s been a race to log, mine, and clear-cut for coca cultivation. The government has created new laws to protect these areas, but it’s unclear if implementation and enforcement will be effective .

Climate change is also contributing to the loss, bringing forests more severe tropical storms and perhaps also making them more frequent. In 2017, hurricanes destroyed 32 percent of Caribbean island Dominica’s forests, according to WRI. Puerto Rico offers another grim preview of what’s to come, with storms like Hurricane Maria destroying 50 percent of the canopy last year alone – compared with 1 percent in a typical year.

Tropical forest loss and climate change

When a tree falls in a tropical forest, it doesn’t matter if anyone is there to hear it; its ability to actively sequester carbon ends. These days, tropical forest loss is projected to account for about 10 percent of human-caused greenhouse gases.

Tropical forest loss is a bigger contributor to global emissions than loss of forests in temperate climes, in part because tropical trees hold more carbon in their biomass than in soil. Plus, some research has shown that – unlike in temperate forests where timber may continue to store at least some portion of carbon, as with the wooden floor of a house – most tropical forest wood is either turned into paper, used for fuel, or simply burned, none of which sequesters much, if any, carbon.

And while many tropical forests have had their fair share of extreme weather, the increasing frequency of severe storms associated with climate change could be a game-changer. Far more study is needed in this realm, but early-stage investigation points to more or more severe hurricanes translating to shorter, smaller forests, which means less carbon absorption, too.

Meanwhile in Indonesia, a 2015 fire and haze crisis across the nation’s forest and peat lands pumped more CO2 into the atmosphere than came from the entire European Union during the same time.

In a tropical forest, drought could affect which tree species prevail over time, perhaps creating more favorable conditions for trees with relatively harder wood and tougher leaves, which are less vulnerable to drought than the lusher species that contribute to canopy cover. That approach theoretically could result in less cover to store carbon and more open, hotter forests, contributing further to climate change.