2019 UPSC Main GS 1 Examination Answers to Questions on Environment and Ecology

General Studies Paper 1

Q.No.4. Assess the impact of global warming on coral life system with examples. (150 words; 10 Marks).                    

Coral reefs, mostly found in the shallow coastal zones, are hard, intricate, and colourful three-dimensional structures. They are the nurseries and habitats for thousands of species of marine animals. Corals are built by very large colonies of tiny organisms called polyps.

Coral reefs protect marine biodiversity, provide many ecosystem services, and protect the coast against tsunamis and cyclones. Coral reefs are very vulnerable to damage because they grow very slowly, get disrupted easily, and are very sensitive to variations in temperature and salinity.

Global warming has led to the following negative impacts on corals:

·      Coral bleaching: When global warming increases the ocean temperature, coral reefs become stressed, eject the zooxanthellae, and thus lose their food and die. This is called bleaching, because they turn white.

·      Sea-level rise: Global warming leads to sea-level rise and the vertical growth rate of coral is likely to be slower than the rate of sea-level rise. Consequently, corals will be deeper, receive less sunlight, and grow more slowly.

·      Ocean acidification: The ocean absorbs about 25% of the carbon we deposit in the atmosphere through our emissions. Since we have been rapidly increasing our emissions, more carbon enters the ocean, making it more acidic. This in turn makes it difficult for polyps to create their reefs. With greater acidification, corals may also form weaker reefs, making them more vulnerable to storm damage, careless tourists, and destructive fishing practices.

·      Storms: More frequent storms that are expected due to climate change may also damage reef structure more significantly, and the corals’ regrowth may not be able to keep pace. Healthy reefs also reduce the impact of storms.

(While the topic of coral reefs is discussed in Chapter 6 of my book, global warming is covered in Chapter 15.)

Q.No.5. Discuss the causes of depletion of mangroves and explain their importance in maintaining coastal ecology. (150 words; 10 Marks)

Mangroves are salt-tolerant trees that grow in the coastal intertidal zone. Like coral reefs, mangroves are also among the most productive and biologically complex ecosystems on earth.

Mangroves are vital for coastal ecology due to the following reasons:

·      Mangroves offer protection against the rising seas and cyclones. They are buffers between the land and the sea.

·      Mangroves help in reclaiming land from seas.

• Mangroves provide nutrients to other ecosystems such as coral reefs and sea grass beds.

·      Mangrove forests are the nurseries and habitats for a large number of marine organisms including shrimps, crabs, and fish species.

·      Mangrove trees are used as timber for house building, furniture, boat building, etc. 

·      Poor people use mangroves as fuelwood and also as a substitute for fodder.

·      Tannin from the bark of some mangrove species is used by fishermen to dye their fishing nets.

·      Honey is collected from some mangrove species.

• Mangroves absorb carbon from the atmosphere.

Mangroves are depleted due to the following reasons:

·      As the coastal zone faces population and developmental pressures, mangroves are cut down to make way for salt pans, aquaculture ponds, human settlements, roads, port facilities, resorts, golf courses, and farms.

·      Mangroves also die from oil spills, chemical pollution, sediment overload, and disruption of their sensitive water and salinity balance.

(The topic of mangroves is discussed in Chapter 6 of my book.)

Q.No.14. What is water stress? How and why does it differ regionally in India? (250 words; 15 Marks)

The minimum per capita requirement of water is about 1700 cu. m per year. This includes the amounts required for home, agriculture, and industry (including energy production). Once the water availability drops below this level, the country becomes water-stressed.

According to a 2019 Report from the World Resources Institute, among the 17 extremely highly water-stressed countries, India ranks 13th. At the same time, India has more than three times the combined population of the other 16 highly stressed countries.

In addition to rivers, lakes and streams, India’s groundwater resources are severely overdrawn, largely to provide water for irrigation. Groundwater tables in some northern aquifers declined at a rate of more than 8 cm per year between 1990 and 2014.

The Union Territory of Chandigarh has the highest water stress, followed by Haryana, Rajasthan, Uttar Pradesh, Punjab, Gujarat, Uttarakhand, Madhya Pradesh, and Jammu and Kashmir. The states of Punjab and Haryana alone produce 50% of the national government’s rice supply and 85% of its wheat stocks. Both crops are highly water intensive.

NITI Aayog has developed a Composite Water Management Index (CWMI) for every state based on groundwater restoration, irrigation management, on-farm water use, rural and urban drinking water supply, water policy frameworks, etc. CWMI is expressed as a score out of 100.

CWMI scores for 2016-17 show that Gujarat is the highest performer, closely followed by Madhya Pradesh and Andhra Pradesh. Meghalaya is the worst performer. Of the 24 states assessed, 14 are low performers, concentrated across the populous agricultural belts of North and East India, and among the North-Eastern and Himalayan states.

The high water-stress in the North is due to:

·      Water- and chemical-intensive agriculture requiring heavy withdrawal of ground water.

·      Availability of free power leading to excessive pumping of water.

Other factors include pollution of water sources and arsenic contamination of tubewells.

(The topic of water resources is discussed in Chapter 7 of my book.)

Q.No.15. How can the mountain ecosystem be restored from the negative impact of development initiatives and tourism? (250 words; 15 Marks)

Mountain ecosystems perform many ecological services for us. The majority of the world’s forests are in the mountains. Apart from being home to endemic species of plants and animals, they are also sanctuaries for animals driven away from the lowland by human activities.

Mountains also play a vital role in the water cycle. They absorb precipitation in the soil and vegetation and slowly release the water through small streams. These streams often join together and become rivers. Thus the mountains act as reservoirs, storing water in the monsoon and releasing it slowly during the dry season.

Human beings have interfered in many mountain ecosystems: We have cleared the forests, laid roads, dammed rivers, mined minerals, built towns, and so on. Tourism has increased the floating population to unsustainable levels. Tourists also dump large quantities of waste on mountain ranges.

Due to deforestation the mountains cannot hold the soil and the water. The slopes become barren there are floods during monsoon and drought during the summer. The biodiversity is also lost.

The following measures should be taken to restore the ecology of mountain ranges:

• Forests should be protected by setting up reserves, national parks or biosphere reserves, as appropriate.
• The existing laws such as the Indian Forest Act 1927, Wildlife (Protection) Act 1972, Forest Conservation Act 1980, and the Environment (Protection) Act 1986 should be strictly enforced.
• Instead of planning big dams, sustainable alternatives such as micro-hydel systems and other alternative energy sources should be examined.
• Strict regulations should be enforced on mountaineering and trekking expeditions.
• Practical steps should include the banning of plastic, conservation of lakes, better town planning, regulation of tourism, rejuvenation of springs and catchments, promoting alternative cooking fuels, involvement of communities, creation of environmental awareness, empowerment of women, etc.

(The topic of mountain ecosystem is discussed in Chapter 2 of my book.)

IPCC Special Report on the Ocean and Cryosphere in a Changing Climate

The Intergovernmental Panel on Climate Change (IPCC) released the Special Report on the Ocean and Cryosphere in a Changing Climate at its 51st Session held in September 2019. The Report highlights the urgency of prioritizing timely, ambitious and coordinated action to address unprecedented and enduring changes in the ocean and cryosphere.

The Key Messages of the Report

The ocean and the cryosphere – the frozen parts of the planet – play a critical role for life on Earth. A total of 670 million people in high mountain regions and 680 million people in low-lying coastal zones depend directly on these systems. Four million people live permanently in the Arctic region, and small island developing states are home to 65 million people.

Global warming has already reached 1°C above the pre-industrial level, due to past and current greenhouse gas emissions. There is overwhelming evidence that this is resulting in profound consequences for ecosystems and people. The ocean is warmer, more acidic and less productive. Melting glaciers and ice sheets are causing sea level rise, and coastal extreme events are becoming more severe.

Urgently reducing greenhouse gas emissions limits the scale of ocean and cryosphere changes. Ecosystems and the livelihoods that depend on them can be preserved.

The world’s ocean and cryosphere have been ‘taking the heat’ from climate change for decades, and consequences for nature and humanity are sweeping and severe. The rapid changes to the ocean and the frozen parts of our planet are forcing people from coastal cities to remote Arctic communities to fundamentally alter their ways of life.  

Major changes in high mountains affecting downstream communities

People in mountain regions are increasingly exposed to hazards and changes in water availability. Glaciers, snow, ice and permafrost are declining and will continue to do so. This is projected to increase hazards for people, for example through landslides, avalanches, rockfalls and floods.

As mountain glaciers retreat, they are also altering water availability and quality downstream, with implications for many sectors such as agriculture and hydropower.

Melting ice, rising seas

Glaciers and ice sheets in polar and mountain regions are losing mass, contributing to an increasing rate of sea level rise, together with expansion of the warmer ocean. While sea level has risen globally by around 15 cm during the 20th century, it is currently rising more than twice as fast – 3.6 mm per year – and accelerating.

Sea level will continue to rise for centuries. It could reach around 30-60 cm by 2100 even if greenhouse gas emissions are sharply reduced and global warming is limited to well below 2°C, but around 60-110 cm if greenhouse gas emissions continue to increase strongly.

More frequent extreme sea level events

Sea level rise will increase the frequency of extreme sea level events, which occur for example during high tides and intense storms. Indications are that with any degree of additional warming, events that occurred once per century in the past will occur every year by mid-century in many regions, increasing risks for many low-lying coastal cities and small islands.

Without major investments in adaptation, they would be exposed to escalating flood risks. Some island nations are likely to become uninhabitable due to climate-related ocean and cryosphere change, but habitability thresholds remain extremely difficult to assess.

Increases in tropical cyclone winds and rainfall are exacerbating extreme sea level events and coastal hazards. Hazards will be further be intensified by an increase in the average intensity, magnitude of storm surge and precipitation rates of tropical cyclones, especially if greenhouse gas emissions remain high.

Changing ocean ecosystems

Warming and changes in ocean chemistry are already disrupting species throughout the ocean food web, with impacts on marine ecosystems and people that depend on them.

To date, the ocean has taken up more than 90% of the excess heat in the climate system. By 2100, the ocean will take up 2 to 4 times more heat than between 1970 and the present if global warming is limited to 2°C, and up to 5 to 7 times more at higher emissions. Ocean warming reduces mixing between water layers and, as a consequence, the supply of oxygen and nutrients for marine life.

The ocean has taken up between 20 to 30% of human-induced carbon dioxide emissions since the 1980s, causing ocean acidification. Continued carbon uptake by the ocean by 2100 will exacerbate ocean acidification.

Ocean warming and acidification, loss of oxygen and changes in nutrient supplies, are already affecting the distribution and abundance of marine life in coastal areas, in the open ocean and at the sea floor.

Shifts in the distribution of fish populations have reduced the global catch potential. In the future, some regions, notably tropical oceans, will see further decreases, but there will be increases in others, such as the Arctic. Communities that depend highly on seafood may face risks to nutritional health and food security.

Declining Arctic sea ice, thawing permafrost

The extent of Arctic sea ice is declining in every month of the year, and it is getting thinner. If global warming is stabilized at 1.5°C above pre-industrial levels, the Arctic ocean would only be ice-free in September – the month with the least ice – once in every hundred years. For global warming of 2°C, this would occur up to one year in three.

Some people living in the Arctic, especially indigenous peoples, have already adjusted their traveling and hunting activities to the seasonality and safety of land, ice and snow conditions, and some coastal communities have planned for relocation. Their success in adapting depends on funding, capacities, and institutional support.

Permafrost ground that has been frozen for many years is warming and thawing and widespread permafrost thaw is projected to occur in the 21st century. Even if global warming is limited to well below 2°C, around 25% of the near-surface (3-4 metre depth) permafrost will thaw by 2100. If greenhouse gas emissions continue to increase strongly, there is a potential that around 70% near-surface permafrost could be lost.

Arctic and boreal permafrost hold large amounts of organic carbon, almost twice the carbon in the atmosphere, and have the potential to significantly increase the concentration of greenhouse gases in the atmosphere if they thaw. Wildfires are disturbing ecosystems in most tundra and boreal as well as mountain regions.

Knowledge for urgent action

Strongly reducing greenhouse gas emissions, protecting and restoring ecosystems, and carefully managing the use of natural resources would make it possible to preserve the ocean and cryosphere as a source of opportunities that support adaptation to future changes, limit risks to livelihoods and offer multiple additional societal benefits.