Paper: General Studies Paper-I
Section: Legal and Environmental Issues
Topic: Ecological Preservation
Discuss the impact of global warming on the coral life system
Destruction of coral reef can be induced by a variety of factors, alone or in combination. However, unprecedented global warming and climate changes combined with growing local pressures have resulted in destruction of coral reefs to a large extent.
Impact of global warming on the coral life system:
- The impacts from coral bleaching are becoming global in scale, and are increasing in frequency and intensity.
- Mass coral bleaching generally happens when temperatures around coral reefs exceed 1 degree Celsius above an area’s historical norm for four or more weeks. Sea surface temperature increases have been strongly associated with El Niño weather patterns.
- However, light intensity, (during doldrums, i.e. flat calm conditions), also plays a critical role in triggering the bleaching response. If temperatures climb to more than 2 degree C for similar or longer periods, coral mortalities following bleaching increase.
Rising sea levels:
- Observations since 1961 show that the average temperature of the global ocean has increased even at depths of 3000m (IPCC report), and that the ocean has been absorbing more than 80% of the heat added to the climate system. Such warming causes sea level rise and creates problems for low lying nations and islands.
- It refers to a change in ocean chemistry in response to the uptake of carbon dioxide from the atmosphere. The amount of carbon dioxide in the atmosphere is in equilibrium with that in seawater, so when atmospheric concentrations increase so do oceanic concentrations.
- Carbon dioxide entering seawater reacts to form carbonic acid, causing an increase in acidity.
- Each year, the ocean absorbs about one-quarter of the carbon dioxide emitted from the burning of fossil fuels (oil, coal, and natural gas).
- Since the Industrial Revolution, ocean acidity has increased by about 30%, a rate that is more than 10 times what has previously occurred for millions of years.
- Further, ocean acidity levels are expected to increase by an additional 40% above present levels by the end of this century.
Coral reefs harbour the highest biodiversity of any ecosystem globally and directly support over 500 million people worldwide, mostly in poor countries. However, according to UNESCO, the coral reefs in all 29 reef-containing World Heritage sites would cease to exist by the end of this century if we continue to emit greenhouse gases. Limiting global average temperature to well below 2°C above pre-industrial levels in line with the Paris Agreement provides the only chance for the survival of coral reefs globally.
Briefly discuss the causes of depletion of mangroves.
Mangrove forests form a unique wetland ecosystem, inhabiting the edge of land and sea, thriving in seawater. Over the past four decades 35% of global mangrove forests have been destroyed. This degradation of mangrove forests has a knock-on effect on some of the world’s most endangered species which rely on them for habitat such as the proboscis monkey and the Bengal tiger.
Causes of depletion of mangroves
The natural causes:
- Cyclones, typhoons and strong wave action especially in the geographically vulnerable Andaman and Nicobar Islands;
- Browsing and trampling by wildlife (e.g. deer) and livestock (goats, buffaloes and cows), which are often left to graze freely, especially in areas close to human habitation;
- Damage by oysters to the young leaves and plumules of Rhizophora and Ceriops plants; crabs, which attack young seedlings, girdle the root collars and eat the fleshy tissues of the propagules
- insect pests such as wood borers, caterpillars (which eat the mangrove foliage and damage the wood as well) and beetles;
- Anthropogenic activities such as construction of houses and markets causing soil erosion and soil sedimentation has lead to their destruction. For example in Sunderbans collection of tiger prawn seeds for trade has greatly affected the other animals found in these forests.
- Indiscriminate tree felling and lopping, mainly for fuel wood, fodder and timber, especially in areas close to human habitation.
- Indiscriminate conversion of mangroves on public lands for aquaculture (e.g. for prawn culture at Chorao, Goa), agriculture, mining (e.g. along the Mapusa estuary in Goa), human habitation and industrial purposes.
- Encroachment on publicly owned mangrove forest lands, e.g. cultivation of paddy observed on government land, which involved uprooting of natural and planted seedlings;
- Lack of interest of private landowners (village communities and individuals) in conserving and developing the mangroves on their lands.
- Illegal large-scale collection of mangrove fruits for production of medicines, which hinders their natural regeneration.
- Discharge of industrial pollutants into creeks, rivers and estuaries, which is a major problem in some regions of the world.
Mangrove forests play a major role with more valuable ecological services. therefore conservation of the same is the need of the hour not only for the for coastal biodiversity but also for wellbeing of the mankind.