Large dams trigger climate change

Jajo Themson *

Maphou Dam, located in Mapithel Hills range, on the bank of Thoubal River in October 2016 :: Pix - Lamdamba Oinam

The earth planet we are living in, has been warped with numerous environmental infirmities that threatened pleasant living of human being today. In all, Climate Change is the scariest form of global issues which reflects almost all other key environmental problems such as Global Warming, Loss of Biodiversity, collapse of ecological balance, depletion of natural resource, public health issues, Polar Ice Caps, rise of sea level etc. Climate Change becomes the biggest challenges and a real fear factors to the world in decades.

The word climate change today refers specifically to rise in global temperature since the ending part of 20th century till date. There were times when the world faced cold climate due to blockage of sun’s rays by million tons of debris of meteorites that fall on earth which perched into the atmosphere that changed climatic conditions leading to extinction of dinosaurs because of inability to survive.

But since 1970’s, the world witnessed rapid rise of temperature in an alarming speed featuring the so called Global warming. It was recorded by researchers that the years from 2000 to 2017 saw the largest increases of greenhouse gas.

Over the decades, the world has received the threat of Global warming as a result of climate change that led to rise of temperatures of the oceans and the earth’ surface causing more often and longer natural disasters like flooding, melting of polar ice caps, rise in sea levels, hurricanes, wildfires, drought, uneven rainfall, excessive snow or desertification which are reasons to extinct living species as well as untold threat to human existence.

The world recorded rising heat due to greenhouse gases trapped more in the atmosphere. Due to rise of temperature, there is less snowpack in mountain ranges and polar areas, increasing its melting speed. Melting of all glaciers is faster and ice in the sea of Arctic Ocean around the North Pole is melting swifter. According to US Geological Survey (USGS’) in its Signs of climate change, Permafrost is melting, releasing methane, a powerful greenhouse gas into the atmosphere. Sea levels are rising, threatening coastal communities and estuarine ecosystem.

Global warming gives a big blow to sustenance of numerous living organisms and human being. As climate change, so do the habitats of living things that live in an area are threatened. Human societies depend on specific crops for food, clothing and trade. If the climate of the area changes, the people who live there may no longer be able to grow crops they have been depending for survival. Scientists are worried about causing warm and tropical diseases such as malaria, West Nile Virus and yellow fever more into temperate regions.

The issue of Climate change has broadly two key causes i,e, natural and anthropogenic causes. Climate change brought by EI Nino, fall of large meteorites on earth which brings million tons of debris causing cold climate, climate change caused by movement of tectonic plate and further it is proved that greenhouse gases like carbon dioxide trap the sun’s heat on earth’s atmosphere causing rise of temperature.

On the other hand, Anthropogenic factor is another major cause of climate change. According to the National Climate Assessment, article by Ali Alhayany, University of Diyala, human influences are the number one cause of global warming. 97 percent of climate Scientists agreed that climate warming is from human activities. Comparatively, change of climate is slow over many million years but it is rapid and largely human cause today.

One significant factor is burning fossil fuels such as coal, oil and natural gases for transportation, electricity, use of technology including agriculture technologies and factories that emit pollutants into the atmosphere. Increased amount of methane in earth’s atmosphere are usually linked to agricultural development and industrial technology. Increase of throw away waste materials; decompose of waste, release tons of methane into the atmosphere. Use of chemicals such as Chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) in refrigeration and aerosol sprays are greenhouse gases which are also contributing to climate change.

How large hydropower dam projects stimulate climate change?

Among the various anthropogenic causes of climate change, large hydropower dam projects have been playing significant roles. It’s a proven case in Europe that large hydropower dam projects are contributor to climate change. Dam protagonists considered hydropower as 70 percent source of renewable clean and green energy for countries. But the concept of dam as clean energy is repudiated by so many antagonists. Ilissa Ocko, a climate scientist said that long considered as clean energy source, hydropower is actually bad for climate. Both carbon dioxide and methane are released when vegetation decomposes under dam water.

Scientists and researchers have shown that rotting vegetation from dam reservoirs is a primary source of one of the most potent greenhouse gases such as methane. Experts say hydropower projects worsen the impact of climate-related disasters. As per the article of Samantha Stahl, the Earth Law Centre, New York City, hydropower dams worsen the climate change by releasing greenhouse gases to atmosphere from the decomposition of flooded lands and forests, destroys carbon sink in wetlands and ocean, deprived ecosystem of nutrients, destroys habitats, increase sea levels and waste water.

Claire Salisbury also remarked that decompose of forest releasing methane, a greenhouse gas into the atmosphere is 25 times more powerful than carbon dioxide. 79 percent of the greenhouse gas emissions from reservoirs are methane- a greenhouse gas with a relatively short life in the atmosphere but a very strong warming effect. A study published in BioScience, 2016 determined that dams and reservoirs contribute 25 percent of global warming.

In one vivid example, a dam in Brazil, where the flooded basin is wide and the biomass volume is high, the methane produced results in a pollution potential @ 3.5 times more than an oil-fired power plant can create. A study has indicated that global hydroelectric reservoirs may emit 104 million metric tonnes of methane gas annually which is a significant contributor to global climate change.

Bruce Forsberg and Alexandre Kemenes have demonstrated that the Balbina Dam in Brazil emits 39,000 tonnes of methane each year. Another researcher also confirmed in November 2017 that dams and reservoirs are a major source of greenhouse gas emissions substantiating climate change that about 20 percent of all man-made methane emissions came from the surface of reservoirs. Damming rivers creates the perfect conditions for microorganisms to generate greenhouse gases which bubble up to the surface of the reservoir and are released into the atmosphere.

As per publication by Science Alert, if we’ve deliberately flooded areas of land to generate energy, irrigate our crops, or perform flood control, we’re contributing to the accelerated warming of the planet. According to Philippe Van Cappellen, co-author of a 2017 Canadian study on the impacts of reservoirs on the world’s carbon cycle and climate system, “Dams don’t just have local environmental impacts but they play a key role in the global carbon cycle and therefore the earth’s climate.

Loss of forest on dam building is a big agent to climate change

Dams are development activities which usually encompass large scale submergence of land and forest. It has been normally associated with loss of forest globally due to dilution by water reservoir, road constructions and compulsive aggression on forest by affected people. Greenhouse gases are emitted during decomposition of plant materials and soil carbon at one side while depletion of forest trees due to dam building implicates loss of natural sinks of carbon dioxide as well as reduced regulation of temperature and rainfall, killing the stable space for living species.

So it is confirmed that deforestation because of dam building constitutes a significant reason in triggering climate change. It is alarming that only Amazon area have to loss over 10 million hectares of forest due to dam construction. It was recorded that 32 Sq. Km of forest are lost to construction of dam in Narmada in India. About 800 hectares of forest was lost due to construction of Mapithel dam in Manipur. An annual loss of 591-660 sq km of forest caused due to construction of Tucurui dam in Brazil as per 2016 record.

The proposed Tipaimukh Dam envisaged submerging 27,000 hectares of forest land. The proposed construction of another 30 dams in Manipur will entail massive impacts on people, environment and climate. Therefore extensive annual loss of forest trees due to dam construction is jeopardizing environment which substantiates activating climate change.

Conclusion

It is quite irrelevant that the North Eastern states of India are placed under pressure of building numerous large hydropower dam projects while blames are put on such projects as a big factor to climate change globally. The NE India accounted to about 40 percent of the total hydropower potential of the country. In 2003, the Ministry of Power launched a hydro initiative of 50,000 MW, with a major focus on the NE states.

The National Hydro Power Corporation (NHPC) and Sikkim govt. inked an agreement on 13 January 2021 for takeover of 120 MW Rangit-IV hydropower project, 500 MW Teesta VI is yet another undergoing dam in Sikkim and Teesta IV HEP has been pursued aggressively despite protest from Lepcha people. In Arunachal Pradesh, state-owned hydropower giant NHPC Ltd is building India’s largest Dibang hydroelectric project. The Cabinet Committee on Economic Affairs, Govt of India approved the expenditure on pre-investment activities and various clearances for the Project with an amount of Rs 1600 crore in July 2019.

Assam, one of the major NE states recently awarded construction of 2000 MW Subansiri hydropower project to NHPC Ltd. The Asian Development Bank (ADB) also approved funding for 120 MW Lower Kopili dam in Assam in 2020. India is considering a plan to build a 10 Giga Watt (GW) hydropower project over the River Brahmaputra, carried by the Economic Times in December, 2020. State Govt. of Manipur in 2010, 2011 and 2014 signed several MoUs with construction companies envisaged generating more than 2,000 MW of Hydropower by building about 32 dams. Besides, large dam projects continue to be pursued in the entire states of NE India.

Almost all the key agents of climate change such as deforestation, depletion of natural resources and degrading biodiversity are compulsively taking place in the NE when multiple large dams are built. Several dams in the region will be a good manufacturer of the dangerous methane and carbon dioxide, a greenhouse gas, aggrandizing the global climate issue that is at the verge of collapse at any time. Taking such significant impacts of large hydropower dam projects on climate into account, it is imperative to challenge that Environmental stability is much worthier than making little profit and safe and pleasant living of human being and biodiversity over greed and selfish meagre gain.

On comparative analysis on the above two major causes of climate change, anthropogenic or human cause is by far ahead of the natural cause. It’s time to realise the result of selfish acts of human race that caused such a degree of climate change menace today. The world is becoming a planet which is unfit for survival of human and other aquatic and terrestrial living species.

Deeper look into the so called development interventions by all countries across the continents is compelling especially on dam building. It is inevitable the world need to learn lesson of the past and present scenario to take right strategic action steps so as to save the earth planet from the threat of climate change before it is too late. The world is running out its time to regain the lost balance.

Therefore, it is the time countries all over the world review all large hydropower dam projects and take necessary steps to dismantle them in order to reduce the fast trend of global warming. We need to stop all proposed large dam projects because they are triggering environmental problems and threat of climate change. Considering unsustainability and being a big threat of climate change, discouragement of large dam projects in India in general and North East in particular, will be one of the best solutions to counter the issue of global warming due to climate change.

Reduction of 25% carbon and methane from dam projects would be a remarkable achievement in curbing the rise of temperature. Instead of building many more large dams, venturing out alternative energy sources such as small hydropower plants, wind mills, solar power plants, Geo thermal power and Bio-mass energies are much more viable environmentally and for sustainability. The world needs to remember that teasing the change of climate is amounting to catastrophic consequences. Any action of negligence and repetition of the same mistakes today will definitely lead to irreversible and irreparable dimensions at last.