Climate Change is a phenomenon and situation that has to be dealt with by all governments and nations. The change in climate, though a natural process is being rapidly sped up due to human activity and development. As such, we are facing extreme weather and persistent droughts and floods, which affect us in a number of ways. The most pressing matter for the small state of Mizoram on this matter is the situation of the River Tlawng, an important source of water, going dry in summer and flooding in monsoon season. Thus, it has become imperative that the situation must be monitored closely and that steps must be taken quickly to ensure the survival and replenishment of this river. ‘Climate Change in Mizoram, A Case Study of River Tlawng’ has been prepared by the Author, David Lalmuankima, an Asst. Professor in the Geography Department and Vanlalnguri Khiangte Assistant Professor Dept. of Sociology of the Government Lawngtlai College, Mizoram with a view to enlighten and inform not only the academic circle, but with the vision that further change may come into action when the general public can understand fully and grasp the gravity of the consequences that may happen if climate change is not curbed. This paper thus points out certain facts and experiences from a ground level, thanks to the helpful and informative data provided by various NGOs such as ‘Save Tlawng Project’ and with the help of government agencies such as Mizoram State Climate Change Cell.
Climate Change and its Effects on Tlawng
It has become common knowledge that every day, the Earth is heading down a path of destruction, due to the actions of its inhabitants. One of many such consequences is the phenomena known as Climate change and it can be observed that climate change has an effect on the Earth’s ecological, biological and geological resources. The Framework Convention on Climate Change (UNFCCC) has defined climate change as ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’ in Article 1 of the UNFCCC [1].
According to the data provided by the Department of Environment, Forests and Climate Change and Government of Mizoram in the study of ‘Climate change and its adaptation’, Mizoram has been experiencing 0.33 mm/yr increase in annual rainfall. However, the distribution is quite uneven, with summer rainfall and monsoon rainfall increasing by 2.80 mm/yr and 7.71 mm/yr respectively [2]. On the other hand, post monsoon rainfall and winter rainfall are following a decreasing trend. In the years 2007-2017, annual rainfall showed a deviation of 1185.1 mm according to the data provided by the Mizoram State Climate Change Cell, highlighting the impact of climate change. For context, the years 1986-1996 showed a deviation of 793 mm [3].
The impact of climate change can be felt across the entire ecosystem. In the small state of Mizoram, a majority of the population still depend on natural resources for their livelihood, be it agriculture, horticulture, fishing etc. Thus the change in climate affects not only the ecological aspect, but also the economy of Mizoram, further highlighting the need for action to be taken [4].
Climate Change
Climate is defined by many as the average weather conditions of a particular area, over a long period of time. For example, the climate of Mizoram can be described as wet and mild. But nowadays, the climate of many places have begun to change, formerly rainy places are receiving less rainfall, the average temperature of many places are going up, polar caps are melting etc. All these indicators point to climate change which is also the benefactor of extreme weather [5].
Globally, the body with duties to assess and monitor the extent of climate change is known as the IPCC. The Inter-Governmental Panel on Climate Change is a body established by the United Nations, in 1988, to monitor and report the Climate change conditions on a global scale. The IPCC has three working groups supplemented by task forces and provides reports which are considered to be the most reliable when it comes to climate change. This report helps several governments to make its policies on climate [6].
It is important to note however, that climate change at a very slow and steady rate is quite a natural process. It is not solely due to the actions of human population that such a phenomenon is occurring. But due to the change happening at an immensely fast rate, we can understand that the activities of human population has had an adverse effect on the ecosystem of the Earth.
Causes of Climate Change
The cooling/heating system of the planet can be oversimplified by stating that, the energy provided by the Sun controls the climate of the Earth. When the Sun’s energy (rays) are reflected back by the clouds and ice, off the earth and back into space, the planet cools down. This is also the case when the planet releases energy: it cools down. On the other hand, when the Earth absorbs the energy of the Sun, or when the atmospheric gases namely Greenhouse gases trap the Sun rays from leaving the atmosphere into space, the Earth warms up [7].
Climate change is not a new phenomenon and has occurred several times in the past. Long before humans inhabited the Earth, Ice Age and evidences of other such extreme climate like Volcanic Eruptions could be seen. However, the rate at which climate is currently changing is too rapid for these factors to be considered, according to NASA. Thus it has to be said that the main cause is human activity. Nonetheless, it is quite useful to understand the natural causes of change.
Continental drift is the first important natural cause. Scientists and researchers, based off of evidence found in certain areas like Antarctica, believe that the entire land mass of the Earth might have been joined together at some point. However, as land mass began to drift away, the physical features of the surface of Earth changed greatly, which led to the change in climate of that place. For example, the Himalayan peaks are rising today at a rate of 1 mm per year. It also changed the position of many places in relevance to water bodies. These places acquired more moderate climate. Moreover, the continental drift changed the courses of ocean currents, which in turn changed the direction of winds. This had the greatest impact on the climate at the time.
Volcanic eruptions also play a part in climate change. When a volcano erupts, it emits a huge amount of Sulphur Dioxide (SO2), dust, ash and water vapour from the Earth’s crust to the atmosphere. Although eruptions last for only a few days, its consequences can be felt for long periods of time. After a big volcanic eruption, the Sulphur dioxide gas can reach the upper level of the atmosphere. It combines with water, forming tiny little droplets of sulphuric acid which can remain afloat for long periods of time. These little droplets, combined with dust are efficient blockers of sunlight and can prevent the warmth of the Sunrays from entering the atmosphere, thus causing the area to cool down. As these aerosols are quite tiny, they are light and winds in the upper level of the atmosphere can carry them away to different areas, spreading the affected region. An example of this can be seen in 1816, known as “the year without summer”, which was attributed to a major volcanic eruption in Tambora, Indonesia in 1815.
Tilt in the Earth’s orbit also plays a natural part in this aspect. The earth is titled at an angle of about 23.5° to its perpendicular axis. More tilt means more extreme weather i.e., colder winters and warmer summers; less tilt means milder weather. However, the climate change brought about by the tilt of the Earth is very slow and it can be observed only by taking tens of thousands of years into consideration.
The major component in global climate change, however, is human activity. The aforementioned factors are, natural and slow actions only noticeable after tens of thousands of years. According to the European Commission on Energy and Climate change (E.C), natural factors are estimated to have contributed to less than plus or minus 0.1°C to the total warming between 1860-2010. The rapid change in weather is more attributed to human development and activity within the last century.
The Main Driver in this Regard, is the Aptly Named Greenhouse Effect
Certain gases, namely carbon dioxide, Methane, nitrous oxide and fluorinated gases trap the energy of the sun much like the glass of a greenhouse. These gases prevent the heat of the sun from leaving the atmosphere, thus denying the climate system a chance to cool down. Emission of these gases, particularly Carbon dioxide, has gone up by at least 48% as compared to the emission before 1750 (pre-industrial age) (E.C).
Emission of greenhouse gases has gone up in recent years, due to human activities like burning of fossil fuels for energy and automobiles, deforestation which results in less regulation of carbon dioxide by trees, fluorinated gases which are used in spray canister like deodorants and increased livestock farming which increase methane production.
River Tlawng-Case Study
The Tlawng River can be described as the single most important river flowing in Mizoram. It flows through 5 districts, namely Aizawl, Lunglei, Serchhip, Mamit and Kolasib and there are more than 90 rural settlements on its banks repportedly. According to Engineer H. Duhkima, in his lecture, stated that most of these settlements use the river and its richness for their main source of living, that is fishing, farming on sedimentary soil etc.
River Tlawng is the main water source for the two biggest districts in Mizoram, namely Aizawl and Lunglei. In fact, as of 2021 it remains the only water source for Lunglei district. Therefore, it is an extremely important river body for the state of Mizoram.
Unfortunately, the Tlawng River is running dry. According to data provided by Engineer H. Duhkima. The State Co-ordinator in Mizoram government Public Health Engineering department (PHE), the amount of water obtained from the river has gone down by 87% as compared to 2015. The PHE Lunglei department had acquired approximately 24,00,000 liters of water from River Tlawng in 2015, whereas in 2021, only 11,50,000 liters of water could be pumped. This highlights the general decline of water resource, which indicate that major steps must be taken in order so that the future generation should get sufficient water supply from the resources readily available.
The three main reasons for the depletion of fresh water resource, according to the Public Health Engineering department are:
Decrease in rainfall
Deforestation which leads to surface runoff
Unsanitary practices of the general public
The decrease in rainfall is following a trend observed across the world, due to the impacts of climate change. Moreover, the rainfall is quite irregular, with heavy rainfalls arriving in monsoon leaving the summer periods quite dry. Here we can see the regression in rainfall of Mizoram annually (Figure 1 and 2).
Figure 1: Rainfall Regression of Mizoram by Year
Source: Data and table provided by Mizoram State Climate Change Council
Figure 2: Trend of Total Annual Rainfall of Lunglei (in mm) 1986-2017
The total amount of rainfall is increasing at the rate of 8.53 mm per year. During a period of 32 years, total annual rainfall was at its highest in 2000 (5554 mm) and on its lowest in 2008 (1742.5 mm). The average annual rainfall received every year is approximately 3204.7 mm (Figure 3).
Figure 3: Trend of Total Annual Rainfall of Aizawl (in mm) 1986-2017
The total amount of rainfall is decreasing at the rate of 3.99 mm per year. During a period of 32 years, total annual rainfall was at its highest in 2017 (2905.3 mm) and on its lowest in 2008 (1569.5 mm). The average rainfall received each year is around 2395 mm.
The second major cause of freshwater depletion is deforestation. As Mizoram is a hilly area, the water table is uneven and quite unpredictable. Water also tends to roll off slopes, as compared to plains where it may form marshes and puddles and stay in a particular area for a long time. In hilly areas however, trees and its roots act as underground reservoirs for water, holding it in place and storing the water for long periods of time.
The source of the river, rumoured to be somewhere in Zobawk village, is also a victim of this phenomenon. When the underground water gets depleted due to surface runoff, the numerous sources of the river get dried up, which contribute to the river having less and less of water, apart from the direct participation of rainfall in this process. Deforestation and urban development on forest areas will lead to groundwater discharge reduction, surface flow increase and annual runoff increase.
Peak discharge of the watershed, which is the highest flow of the river will increase due to rainwater collection caused by surface runoff and the time taken between the beginning of rainfall and the start of groundwater runoff, known as lag time will also decrease.
Owing to all these consequences we can see how deforestation is quite detrimental to the collection of water resource for use by the general public. However, as more and more rural areas are getting developed to accommodate the growing population, deforestation is becoming a larger and larger problem. Here, with data provided by the Mizoram State Council on Climate Change, we can see the change in surface runoff (Figure 4)
Figure 4: Projected Change in Surface Runoff (%) Across Mizoram Districts from Baseline (1979-2014) to Mid-Century (2041–2050) under RCP 4.5 Scenario.
The third reason for reduced usage of the water of River Tlawng is mismanagement of waste. The rural areas are quite accustomed to disposing of garbage in and around the river banks. In the monsoon season, due to overflowing of the river and soil erosion, the waste gets collected in the river. At this time, as the current is quite strong, the garbage is carried away by the water. However as the season gets drier and the current of the river weakens, the garbage becomes heavy and stagnates in the river. This makes the water polluted and unfit for use and according to the Public Health Engineering department, Mizoram this is one of the main cause of damage to the water pumps.
Aside from this, mass deforestation in and around the river area had led to loose land patterns, causing more soil erosion. In the same way as garbage stagnates, when the soil stagnates in water, the water becomes muddy and ha to be left for sedimentation for longer periods of time. This increases the gap between water collection and distribution to the public for usage.
Action Plan-What Next?
As stated before, Tlawng River remains the most important river for the state of Mizoram. It is the main source of water for Aizawl district and the only water source for Lunglei. As such, the government is taking steps to ensure its restoration and make it a reliable source for a long time. The challenge remains in eradicating the highly destructive method of farming, namely slash and burn type of farming from the minds of the farmers. As this type of farming was practiced by the forefathers, it remains a somewhat cultural object for the farmers.
Education about waste management is also being carried out by the government. Proper garbage disposal systems are being created at the local level and this has created several agreeable results in recent years. However, it is quite a challenge to reach everyone and there remains a long way to go in this aspect. In the modern age, people are also becoming more and more aware of the situation and have started to take the matter into their own hands. There are several NGOs committed to the preservation of natural resources. Out of these, the notable one is the ‘Save Tlawng’ project, whose sole aim is the regeneration and well-being of the River Tlawng. Noteworthy activities include plantation drives, education of the matter to the public, cleaning drives etc.
Afforestation remains the most sustainable and practical remedy to the problem at hand. According to the latest research provided by the IPCC, a single tree is able to absorb up to 48 pounds of carbon annually. The global Carbon emission may also be reduced by 1.1 to 1.6 GT per year. Trees also preserve surface run off and keep the water table high to replenish the river water in dry months.
Initiative at the government level would also provide definitive help in this regard, particularly when it comes to increasing reserved forest areas especially near water sources. According to data provided by Forest Survey of India 2009, out of a total of 16,717 km2 forest area in Mizoram, 47.31% is reserved forest area. Steps taken to further reserve forest areas and better protection and administration of the reserved forest area may be the next steps in the plan for the battle against climate change in Mizoram.
The actions of human population around the globe has led to climate change around the world. The rapid change and unpredictable nature of the climate is having direct impacts on the planet and its inhabitants. Although change of climate in itself is a natural process, development and mismanagement is driving the entire climate system towards the wrong direction.
In the case of the River Tlawng, although there are no steps that can be taken which result directly in the generation of more rainfall, a lot can be done to help the river to reach its full potential and maintain its flow throughout the year. Steps taken by the government and the NGOs are taking this towards the right direction and restoration of the river will carry on as long as these steps are continued.
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