Deforestation
Deforestation is the large-scale removal or clearing of forests, primarily by human activities such as agricultural expansion, logging, urbanisation, and infrastructure development, resulting in the permanent conversion of forested land to non-forest use. Global forests store approximately 861 billion tonnes of carbon, and their destruction releases vast quantities of CO₂, contributing around 10–15% of annual global greenhouse gas emissions. Beyond carbon emissions, deforestation drives soil erosion, loss of biodiversity, disruption of water cycles, and the degradation of ecosystem services that support billions of people globally.
Key Formula
Carbon released = Area deforested × Above-ground biomass density × Carbon fraction
LaTeX: C_{\text{released}} = A \times B_d \times C_f
| Symbol | Meaning | Unit |
|---|---|---|
| C_{\text{released}} | Carbon dioxide equivalent released | tonnes CO₂ |
| A | Area of forest cleared | ha |
| B_d | Above-ground biomass density of forest type | tonnes dry matter/ha |
| C_f | Carbon fraction of dry biomass (typically 0.47–0.50) | dimensionless |
Worked Example
Problem
A tropical rainforest region of 500 hectares is cleared for agriculture. The above-ground biomass density is 300 tonnes dry matter per hectare, and the carbon fraction is 0.48. How many tonnes of carbon are released? Convert to tonnes of CO₂ (multiply carbon by 44/12).
Solution
Step 1: Calculate total above-ground biomass. Total biomass = 500 ha × 300 t/ha = 150,000 tonnes dry matter Step 2: Calculate carbon in biomass. Carbon = 150,000 × 0.48 = 72,000 tonnes C Step 3: Convert carbon to CO₂ equivalent. CO₂ = 72,000 × (44/12) = 72,000 × 3.667 = 264,000 tonnes CO₂
Answer
Clearing 500 hectares of tropical rainforest releases approximately 264,000 tonnes of CO₂ equivalent.
Global Deforestation Rates and Forest Loss by Region (2000–2020)
| Region | Forest Cover Lost (Mha) | Primary Driver | Notable Country |
|---|---|---|---|
| Amazon (South America) | 59 | Cattle ranching, soy | Brazil |
| Sub-Saharan Africa | 45 | Small-scale agriculture | DRC, Tanzania |
| Southeast Asia | 22 | Palm oil, logging | Indonesia, Malaysia |
| South Asia | 3 | Fuelwood, agriculture | India |
| Boreal (Russia/Canada) | 15 | Logging, fire, permafrost | Russia |
Interactive Tools
Global Forest Watch
Real-time satellite monitoring of global forest cover change and deforestation alerts
Open ToolKhan Academy – Environmental Science
Lessons on land use change, carbon cycles, and environmental impacts of deforestation
Open ToolWolfram Alpha – Carbon Calculations
Compute carbon storage, emissions, and unit conversions for biomass calculations
Open Tool
Wikimedia Commons, CC BY-SA
Related Terms
Biodiversity Loss
Biodiversity loss refers to the reduction in the variety of life on Earth at genetic, species, and ecosystem levels, currently occurring at rates estimated to be 100–1,000 times higher than natural background extinction rates due to human activities. The primary drivers include habitat destruction, overexploitation, invasive species, pollution, and climate change, collectively recognised as the "five drivers of biodiversity loss" by the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services). The current mass extinction event, sometimes called the Sixth Mass Extinction, threatens the ecological stability and services upon which all human civilisation depends.
Ecosystem Services
Ecosystem services are the direct and indirect benefits that humans derive from functioning natural ecosystems, encompassing provisioning services (food, fresh water, timber), regulating services (climate regulation, flood control, disease regulation), cultural services (recreation, spiritual value), and supporting services (nutrient cycling, soil formation). The Millennium Ecosystem Assessment (2005) estimated the total annual value of ecosystem services globally at over $33 trillion, exceeding global GDP at the time. Understanding and valuing ecosystem services is fundamental to environmental policy, conservation economics, and sustainable development planning.
Air Pollution
Air pollution is the presence of harmful substances in the atmosphere — including particulate matter (PM2.5, PM10), nitrogen oxides (NOₓ), sulfur dioxide (SO₂), carbon monoxide (CO), ozone (O₃), and volatile organic compounds (VOCs) — at concentrations that pose risks to human health, ecosystems, and climate. The World Health Organization (WHO) estimates that air pollution causes approximately 7 million premature deaths annually, making it the world's largest environmental health risk. Sources range from vehicle emissions, industrial combustion, and agricultural burning to natural events such as wildfires and volcanic eruptions.
From Latin prefix "de-" (removal, reversal) + Late Latin "forestare" (to remove from forest, from "forestis silva", forest outside the enclosure). The word entered English in the 15th century, initially in legal contexts regarding the removal of land from royal forest designation, before acquiring its modern environmental meaning.