When we talk about pollution, thermal pollution rarely comes to our minds. However, with the innumerable thermal power plants and industries mushrooming everywhere, thermal pollution is a real and persistent problem of current times.

Thermal pollution in the broadest sense can be defined as the abrupt change in ambient temperature of a natural water body by any human induced processes. The increase or decrease of water temperature degrades the quality of water and makes it unfit for consumption or the life-systems of aquatic organisms. It could happen in lakes, rivers, oceans or even ponds.

What are the sources of thermal pollution?

The major sources of thermal pollution are heated waste water produced from production and manufacturing plants – coal fired thermal power plants, natural gas plants, nuclear plants, textiles, paper and pulp industries, etc. These units utilize a huge amount of water as a ‘cooling agent’ in lowering the temperature of machinery such as generators and heat engines. Thus, water acts as an efficient sink for heat waste. The heated water is then released back to the source which is either a river or an ocean in most cases causing a disturbance in the thermal equilibrium.

Removal of vegetation or deforestation is another unpopular but significant source of thermal pollution. Vegetation, particularly trees, keeps the temperature of the water cool by providing shades to ponds, lakes, and rivers etc. In the absence of trees, the water bodies are exposed to more sunlight and absorb heat, which raises the normal temperature of the water. Also, soil erosion leads to a raise in the levels of water and shallowing of lakes and rivers which could increase sunlight concentration and warming of water.

Natural processes such as volcanic eruption or geothermal activities under the ocean or land could also increase thermal pollution. The lava (molten rocks) could lead to a sharp rise in the temperature of water.

Ecological impacts of thermal pollution

Thermal pollution is still widely seen as an insignificant problem when compared to other kinds of pollutions such as carbon emissions or solid waste. Many have contested the importance of production plants and industries over the potential ecological threat posed by thermal pollution.

The most vital requirement for survival of aquatic animals is the ambient temperature. A slight deviation from this temperature could bring a detrimental effect on the living organisms and their surrounding ecology. The following are a few important ecological impacts of thermal pollution-

  • Decrease in dissolved oxygen – Oxygen, like in the air is equally essential for aquatic life. The warmer the water the lesser is the rate at which oxygen is dissolved in it. Therefore, a slight change in temperature of water could lead to an anaerobic or oxygen deficient condition thus sabotaging aquatic life. Warm water also increases the rate of organic component decomposition which is an oxygen consuming process thus contributing to depletion of dissolved oxygen.
  • Most of the aquatic organisms have evolved in such a way that the enzyme systems are functional in a very narrow range of temperature called ‘stenothermic organisms’. A small decrease or increase of temperature may bring a ‘thermal shock’ which sometimes can lead to mass killings of fishes, plants, insects etc (Pollution Issues, 2017). Organisms such as mollusc, sponges, and crustaceans are eliminated easily at temperatures above 37° C (Techgape, 2017).
  • On the other hand, there may be sudden increase in metabolism of certain species and impetuous rise in numbers. This disrupts the stability of food chains and alters the species composition in the environment. Thermal pollution is also known to have an adverse affect on the reproductive system of aquatic animals (Conserve Energy Future, 2017).
  • Abrupt mass migration of species is another severe problem associated with thermal pollution. The change in temperature may force species to migrate to another habitat creating a hollow food web.
  • Corals are highly susceptible to temperature anomaly therefore thermal pollution from run-offs and effluents causes bleaching e.i the expulsion of its symbiont algae and subsequent death of corals.

As an example, it is estimated that, about 46 million adult fish, 2.4 billion eggs, larvae and young fish are killed annually by the effluents from the First Energy Bay Shore Plant on the Maumee River shoreline near Toledo, Ohio. Also, the Monroe Power Plant in Michigan reportedly kills more than 25 million fish each year (Sourcewatch.org, 2017).

Control of Thermal Pollution

A few scientific techniques that could be employed by any industrial units for controlling thermal pollution are – creation of cooling ponds, artificial lakes, and cooling towers. Cooling ponds is one of the simplest and cheapest methods where the heated waste water is stored in a pond before releasing it into the mainstream waterways. It gives enough time to dissipate the heat into the atmosphere through the process of evaporation. Likewise, cooling towers are installed in chemical processing power plants, steel mills, and other manufacturing processes where cooling of the effluent is required before discharge. It involves upward recirculation of a cascade of heated waste water through the towers into the air by evaporative processes. However, these methods are found to be effectively operating in small scale industries limited to the developed nations. Also, change in local meteorological conditions is a concern in cooling towers as large amounts of water vapour enters the atmosphere.

The role of government in controlling thermal pollution is very crucial in developing countries such as India concerning legal and abatement policy frameworks for wastewater treatment. This could be realised through stringent regulations and constant monitoring of effluent discharges from different industrial sectors.


 

Share is Caring, Choose Your Platform!

Receive Daily Updates

Stay updated with current events, tests, material and UPSC related news

Recent Posts

  • Context:-

    At the recently concluded Leaders’ Summit on Climate in April 2021, Lowering Emissions by Accelerating Forest Finance (LEAF) Coalition, a collective of the United States, United Kingdom and Norway governments, came up with a $1 billion fund plan that shall be offered to countries committed to arrest the decline of their tropical forests by 2030.

    [wptelegram-join-channel link=”https://t.me/s/upsctree” text=”Join @upsctree on Telegram”]

    What is LEAF Coalition?

    • Lowering Emissions by Accelerating Forest Finance (LEAF) Coalition, a collective of the United States, United Kingdom and Norway governments, came up with a $1 billion fund.
    • LEAF is supported by transnational corporations (TNCs) like Unilever plc, Amazon.com, Inc, Nestle, Airbnb, Inc as well as Emergent, a US-based non-profit.

    Why LEAF Coalition?

    • The world lost more than 10 million hectares of primary tropical forest cover last year, an area roughly the size of Switzerland.
    • Ending tropical and subtropical forest loss by 2030 is a crucial part of meeting global climate, biodiversity and sustainable development goals. Protecting tropical forests offers one of the biggest opportunities for climate action in the coming decade.
    • Tropical forests are massive carbon sinks and by investing in their protection, public and private players are likely to stock up on their carbon credits.
    • The LEAF coalition initiative is a step towards concretising the aims and objectives of the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism.
    • REDD+ was created by the United Nations Framework Convention on Climate Change (UNFCCC). It monetised the value of carbon locked up in the tropical forests of most developing countries, thereby propelling these countries to help mitigate climate change.
    • It is a unique initiative as it seeks to help developing countries in battling the double-edged sword of development versus ecological commitment. 
    • The initiative comes at a crucial time. The tropics have lost close to 12.2 million hectares (mha) of tree cover last year according to global estimates released by Global Forest Watch.
    • Of this, a loss of 4.2 mha occurred within humid tropical primary forests alone. It should come as no surprise that most of these lost forests were located in the developing countries of Latin America, Africa and South Asia.
    • Brazil has fared dismally on the parameter of ‘annual primary forest loss’ among all countries. It has lost 1.7 mha of primary forests that are rich storehouse of carbon. India’s estimated loss in 2020 stands at 20.8 kilo hectares.

    Brazil & India 

    • Between 2002-2020, Brazil’s total area of humid primary forest reduced by 7.7 per cent while India’s reduced by 3.4 per cent.
    • Although the loss in India is not as drastic as in Brazil, its position is nevertheless precarious. For India, this loss is equivalent to 951 metric tonnes worth carbon dioxide emissions released in the atmosphere.
    • It is important to draw comparisons between Brazil and India as both countries have adopted a rather lackadaisical attitude towards deforestation-induced climate change. The Brazilian government hardly did anything to control the massive fires that gutted the Amazon rainforest in 2019.
    • It is mostly around May that forest fires peak in India. However, this year India, witnessed massive forest fires in early March in states like Odisha, Uttarakhand, Madhya Pradesh and Mizoram among others.
    • The European Union’s Copernicus Atmospheric Monitoring Service claimed that 0.2 metric tonnes of carbon was emitted in the Uttarakhand forest fires.

    According to the UN-REDD programme, after the energy sector, deforestation accounts for massive carbon emissions — close to 11 per cent — in the atmosphere. Rapid urbanisation and commercialisation of forest produce are the main causes behind rampant deforestation across tropical forests.

    Tribes, Forests and Government

    Disregarding climate change as a valid excuse for the fires, Indian government officials were quick to lay the blame for deforestation on activities of forest dwellers and even labelled them “mischievous elements” and “unwanted elements”.

    Policy makers around the world have emphasised the role of indigenous tribes and local communities in checking deforestation. These communities depend on forests for their survival as well as livelihood. Hence, they understand the need to protect forests. However, by posing legitimate environmental concerns as obstacles to real development, governments of developing countries swiftly avoid protection of forests and rights of forest dwellers.

    For instance, the Government of India has not been forthcoming in recognising the socio-economic, civil, political or even cultural rights of forest dwellers. According to data from the Union Ministry of Tribal Affairs in December, 2020 over 55 per cent of this population has still not been granted either individual or community ownership of their lands.  

    To make matters worse, the government has undertaken systematic and sustained measures to render the landmark Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006 ineffective in its implementation. The Act had sought to legitimise claims of forest dwellers on occupied forest land.

    Various government decisions have seriously undermined the position of indigenous people within India. These include proposing amendments to the obsolete Indian Forest Act, 1927 that give forest officials the power to take away forest dwellers’ rights and to even use firearms with impunity.

    There is also the Supreme Court’s order of February, 2019 directing state governments to evict illegal encroachers of forest land or millions of forest dwellers inhabiting forests since generations as a measure to conserve wildlife. Finally, there is the lack of data on novel coronavirus disease (COVID-19) deaths among the forest dwelling population;

    Tardy administration, insufficient supervision, apathetic attitude and a lack of political intent defeat the cause of forest dwelling populations in India, thereby directly affecting efforts at arresting deforestation.

    Way Forward

    • Implementation of the LEAF Coalition plan will help pump in fresh rigour among developing countries like India, that are reluctant to recognise the contributions of their forest dwelling populations in mitigating climate change.
    • With the deadline for proposal submission fast approaching, India needs to act swiftly on a revised strategy.
    • Although India has pledged to carry out its REDD+ commitments, it is impossible to do so without seeking knowledge from its forest dwelling population.

    Tuntiak Katan, a global indigenous leader from Ecuador and general coordinator of the Global Alliance of Territorial Communities, aptly indicated the next steps at the Climate Summit:

    “The first step is recognition of land rights. The second step is the recognition of the contributions of local communities and indigenous communities, meaning the contributions of indigenous peoples.We also need recognition of traditional knowledge practices in order to fight climate change”

    Perhaps India can begin by taking the first step.