Pollution, Ecosystems and Biodiversity

Four types of pollution, and how it’s regulated

Pollution is any harmful change introduced into the environment. It has four major forms, each with its own sources, causes, and fix.

• Air pollution — mainly from vehicle emissions and industrial smoke.
• Water pollution — mainly from industrial effluents and farm runoff.
• Soil pollution — from pesticides, heavy metals, and dumped waste.
• Noise pollution — from traffic, construction, and industry.

Left unchecked, pollution damages public health, farm yields, and water security together.

Ecosystem, habitat, and niche

An ecosystem is a community of living organisms interacting with their physical surroundings. Energy and matter move through it constantly.

A habitat is simply the physical place where an organism lives — a forest, a pond, a burrow. A niche is different. It is the specific role that organism plays in its ecosystem: what it eats, what eats it, how it affects its neighbours.

What biodiversity is, and its three roles

Biodiversity means the variety of life in a given area, counted at three levels. A region can be rich at one level and poor at another.

• Genetic — variation within one species.
• Species — the number of different species.
• Ecosystem — the range of habitats and processes present.

Today’s biodiversity is the product of 2.5 to 3.5 billion years of evolution. Global species estimates range from 2 million to 100 million, with 10 million as the best guess. Biodiversity is consistently richer near the equator — moving toward the poles, species counts drop while each surviving species grows more numerous.

Biodiversity plays three roles:

• Ecological — species capture energy, cycle water and nutrients, and regulate climate; a more diverse ecosystem survives shocks better.
• Economic — biodiversity supplies food crops, livestock, timber, fish, and medicines (crop diversity is called agro-biodiversity).
• Scientific — every species offers clues about how life evolved and ecosystems function.

Losing biodiversity: the main causes

• Overexploitation — tropical regions hold about a quarter of the world’s land but three-quarters of its population, driving heavy deforestation and resource overuse.
• Natural calamities — earthquakes, floods, volcanic eruptions, and forest fires all directly damage flora and fauna.
• Pollutants and exotic species — pesticides and toxic heavy metals kill off weak, sensitive species; species introduced from elsewhere can badly damage a local ecosystem’s balance.
• Poaching — tigers, elephants, rhinoceroses, and crocodiles have all been hunted heavily for horns, tusks, and hides, pushing several into the endangered category.

Rio, India’s law, and the habitat-loss link

• Rio Earth Summit, June 1992 — India and 155 other nations signed the Convention on Biological Diversity.
• Wildlife (Protection) Act, 1972 — India’s own law protecting species; national parks, sanctuaries, and biosphere reserves were established under it.

Biodiversity loss and habitat destruction move together. As a habitat shrinks or degrades, the species that depend on it decline too. Conservation is not only an ecological concern — it also protects food and water security, and public health from pollution-linked disease. That is why India’s conservation laws treat habitat protection and pollution control as one connected problem, not two separate ones.

TEEB, mega-diversity countries, and hotspots

The Economics of Ecosystems and Biodiversity (TEEB) is a global initiative that puts an economic value on the benefits ecosystems provide. TEEB is hosted by UNEP alone — not jointly run by UNEP, the IMF, and the World Economic Forum, a mix-up exam questions sometimes test. It helps governments recognise, demonstrate, and actually capture the real economic value of nature in policy decisions. See EnvEco0084 for the full treatment.

A country only earns “mega-diverse” status by meeting a specific bar, not just by having a lot of wildlife:

• Conservation International defined the criteria in 1998: a country needs at least 5,000 endemic plant species, and it must border a marine ecosystem.
• Just 17 countries meet this bar, yet together they hold over 70% of the world’s species.
• India is one of the 17, holding this status despite covering only about 2.4% of the world’s land area.

The full list of 17 megadiverse countries:

• Brazil, Colombia, Ecuador, Peru, Mexico, Venezuela, United States.
• DR Congo, Madagascar, South Africa.
• China, India, Indonesia, Malaysia, Philippines, Papua New Guinea, Australia.

The IUCN identifies biodiversity hotspots by vegetation, since plants set an ecosystem’s primary productivity. Most hotspots also supply local food, firewood, and timber income.

• Madagascar — about 85% of its plants and animals exist nowhere else on Earth.
• Hawaii — its unique species face pressure from introduced species and land development.