Tropical forests play an important role in helping to counteract climate change. They currently absorb nearly a fifth of the world’s man-made CO2 emissions every year. We hear a lot of talk about the need to reduce fossil fuel use to combat climate change but 15-20% of man made carbon emissions are from deforestation and degradation. We must find ways to live with less fossil fuels, but reducing deforestation, especially in the tropics, is also vital. It is not a case of either/or – we need to do both.
Tropical rainforests are especially important habitats, and not just for those living there – they play a vital role for everyone on the planet. A square metre of rainforest can support up to 80kg of living biomass, and can produce up to 3.5kg of biomass every year. A single hectare of rainforest may contain 200 species of tree, some over 60m tall, and over 40,000 species of insect. They play a crucial role in storing water, regulating rainfall, and preventing floods, droughts and erosion. In addition they produce much of the world’s oxygen which all animals breathe.
‘Rainforests’ are so named because they have a high annual rainfall of between 1.5 and 10 metres which is evenly distributed through the year. It is this lack of seasonal variation in rainfall, along with a steady temperature of between 20 and 28 degrees Celsius, which are important in distinguishing them from other forest types.
Tropical forests have come under severe attack by deforestation in recent years. Globally, there was twice as much tropical forest a century ago as there is today. The rate of deforestation in Africa is of particular concern, with around four million hectares of forest being destroyed each year. An incredible 45 per cent of its original forest cover has now disappeared.
As human populations have expanded, they required more space for housing and agriculture. Coupled with a lucrative international trade in timber, this has meant an ever increasing rate of deforestation. Forests are being cleared for commercial logging, agriculture, roads and railways, mining, fuel and housing. The extent and speed with which such activities are carried out, means that soils are not given enough time to recover and they are now becoming severely depleted.
The world’s population is likely to increase from 6 billion to 9 billion over the next 40 years. This population growth, combined with rising incomes, will lead to a continual increasing demand for food, animal feed and fuel. This, in turn, will lead to a greater risk of more rainforest destruction, with potentially devastating effects for everyone.
Tropical forests are predominantly found within a narrow band around the earth that extends 4 degrees either side of the Equator. These forests are called ‘tropical’ because they exist between the Tropic of Cancer and the Tropic of Capricorn.
Most of Africa’s rainforest is concentrated in the centre of the continent. The Democratic Republic of Congo, Gabon, Cameroon and the Central African Republic all have substantial areas of rainforest, but smaller rainforests are also found in Ghana, Nigeria, Cote D’Ivoire and Togo. Although less than 7 per cent of Africa’s surface area is covered by tropical rainforest, they contain more than half of the continent’s animal and plant species.
There are also other tropical forests in Africa, these include drier forests such as the miombo woodland found in East Africa including Tanzania; thorn forests which grow in Somalia and Ethiopia, montane forests in the upland areas of Uganda. These Eastern forests support very different wildlife from the rainforests of West and Central Africa but are also vital both to local people and wildlife and globally in terms of our climate.