Other Major Environmental Issues

5.1 Deforestation

Global status:

• World's forests cover ~31% of land area (4.06 billion hectares)
• Net forest loss: ~4.7 million hectares/year (2015–2020) — reduced from 12 million ha/year in 1990s due to reforestation efforts (Brazil, China)
• Tropical deforestation is worst — Amazon, Congo, SE Asia (Indonesia, Malaysia)

Amazon Crisis:

• Amazon houses ~10% of all species on Earth and stores 150–200 billion tonnes of carbon
• Deforestation: 18–20% of original cover lost since 1970 (~750,000 km²)
• Critical tipping point: Scientists warn at ~25% deforestation the Amazon may "dieback" — shift from rainforest to dry savanna — a catastrophic, potentially irreversible change
• 2019 Brazil: Bolsonaro administration → deforestation surged; 2023: Lula reversal — Amazon deforestation fell 50%

India's forest status:

• Forest cover: 21.71% of land area (India State of Forest Report 2021) vs 33% national target
• Dense forest: 3.04% (Crown density >70%); Moderate: 9.34% (40–70%); Open: 9.33% (10–40%)
• Northeast India and Andaman islands have highest forest cover but most threatened

5.2 Desertification and Land Degradation

Desertification: Loss of dryland productivity due to human land-use practices and climate variability/change.

• Scale: ~40% of Earth's land is drylands; 2 billion people live in drylands; 1.5 billion people depend on degraded lands for food
• Annual cost: Loss of $490 billion in ecosystem services annually
• Causes: Overgrazing, deforestation, over-irrigation (salinisation), climate change

Land Degradation Neutrality (LDN): Target under UNCCD — no net loss of productive land by 2030; India committed to restore 26 million hectares by 2030.

Rajasthan context:

• Western Rajasthan (Thar Desert fringe): Desertification most severe — dunes advancing eastward
• Indira Gandhi Canal partially reversed desertification in Bikaner, Jaisalmer (irrigated agriculture, windbreaks)
• Sand dune stabilisation through afforestation with drought-tolerant species (Prosopis juliflora, Ziziphus)

5.3 Plastic Pollution

Key facts:

• ~8,300 million tonnes of plastic produced since 1950; ~9% recycled, ~12% incinerated, ~79% in landfills or environment
• Annual production: ~400 million tonnes (2023)
• Ocean plastic: ~8 million tonnes enter oceans/year; Great Pacific Garbage Patch (North Pacific subtropical gyre) — estimated 80,000 tonnes of plastic, area 1.6 million km² (twice France's area)
• Microplastics (<5 mm): Found in Mariana Trench (deepest ocean, 11,000 m), Arctic sea ice, Antarctic snow, human blood, placenta, breast milk, and lungs

UN Global Plastics Treaty: Negotiations in progress (2022–2024) for legally binding treaty to end plastic pollution by addressing full lifecycle — production to disposal.

India's action:

• Single-Use Plastics (SUP) ban: 19 specific single-use plastic items banned from 1 July 2022 (plates, cups, straws, sachets, etc.)
• Extended Producer Responsibility (EPR) — manufacturers responsible for plastic waste collection and recycling

5.4 Ocean Acidification and Coral Bleaching

Ocean acidification mechanism:

• Oceans absorb ~30% of CO₂ emitted by human activities annually (~10 billion tonnes CO₂/year)
• CO₂ + H₂O → H₂CO₃ (carbonic acid) → H⁺ + HCO₃⁻
• Ocean pH: From 8.2 (pre-industrial) to 8.1 (current) = 26% more acidic (logarithmic scale)
• Aragonite saturation: Decreasing — affects ability of marine organisms to build calcium carbonate shells and skeletons

Impacts:

• Coral reefs: Corals need CaCO₃ saturation >1 to build skeletons; acidification weakens and dissolves existing structures
• Molluscs: Oysters, mussels, clams — shell formation disrupted
• Pteropods (sea butterflies): Key food for salmon, cod — shells dissolving in Southern Ocean already
• Threat to 25%+ of marine species dependent on coral reef ecosystems

Coral Bleaching:

• Coral bleaching = when corals expel their symbiotic algae (zooxanthellae) under thermal stress → turn white → starvation → death if prolonged
• Threshold: 1°C above normal max temperature for 4 weeks causes bleaching
• 2024: 4th Global Mass Coral Bleaching Event — affecting Great Barrier Reef, Caribbean, Indian Ocean simultaneously — worst on record; 54% of reef area bleached

---