Okay, in UPSC syllabus we have three sections. The first is about the physical feature, the second regarding the natural resources and the third in the third section tsunami volcano after that there is a critical changes in geographical features and its effect on the flora and fauna of the particular region our topic will be that okay today before going to the critical changes in geographical feature let us first see what is geographical feature all about what is geographical feature all about geographical features are man-made or naturally created features on earth that is a geographical feature geographical feature can be a lake an ocean a mountain system island anything can be a geographical feature on the other hand that is a natural geographical feature on the other hand we will have geographical feature on the other hand we will have non-geographical, man-made geographical features. That may be a dam, construction of a huge dam, changes the entire ecology, ecosystem of that region. So that is a man-made geographical feature. And for example, we have a huge track of wetland.
Suppose tomorrow some government came into power and they wanted to reclaim that particular piece of wetland. it will destroy the complete wetland ecology and you know how sensitive a wetland ecology can be because there are many other factors but see migration of birds takes place and many other related economic and other activities so there are natural as well as man-made geographical features natural I've already explained So look, those are the geographical features and now we are concerned with critical changes that is taking place in these geographical features. This kind of question has been asked in the UPSC in last two years. And there is a probability of asking this, there is a high probability in fact, because these are the new areas, these are the new areas and many changes are going on in these areas.
Okay. So if we go for geographical features, what can be more important than a river system? River system itself is a geographical feature. Okay. Thank you.
There is a significant amount of changes that is taking place in a river. And why river is important? Because river is linked not only for human civilization, but many other flora and fauna related to it.
The earliest civilization on this planet earth, be it the Harappan civilization or Indus civilization or the Mesopotamian civilization that is the present era, happens in the valley of a river. So river is the lifeline. not only for human beings but for related flora and fauna.
So river importance of river cannot be overstated. It is very important and today if we look in India or across the world yesterday also we have discussed about how importance of oil will come down but the importance of water will go up and that scenario you can imagine the dynamics that is going on in the construction of dams by the Chinese on the northern side of Himalaya. That is very important.
Now, so let us see the changes, especially we will go for Indian rivers only, you can extend this to other important rivers across the globe, okay. Before going into what is dying river in India, we will have to understand what is healthy river. Only then you will appreciate, okay, this is dying. Otherwise, if you don't know what is dying, if you don't know what is what is healthy then how can you say this dying okay so let us see what is healthy okay please follow me an entity which performs all the evolutionary geomorphological means what erosion and deposition see geography it is very important to understand the terms and if you can write at least one two terms in your answer pepper it will really enhance the quality okay and the mark that you will fetch will be very rewarding. It is an evolutionary geomorphological, means erosion and deposition.
Ecological means what? Ecological because... It brings sediments, it transports many other chemical particles, which is helpful for the flora and fauna of the particular region. Okay? Dependent on this river, that is ecological.
Social, why? Civilization happened in the river valley only. Social, cultural, economical. Because?
Transportation system, water transportation system, all functions of a river, giving life not only to a selected class of people, selected class of society. Why selected? See, there is an equality aspect also.
It is very important. Equality aspect also. A rich guy can drink a bottle of water directly from Himalaya, but a poor person in a slum area cannot even afford a pouch. okay so that is a difference in India and that is the reality and as an aspirant for administrative job it is very important to know and to appreciate the different colors and the different shades of our own society so equality factors play very prominently especially in India so see not only to a selected class of society but the living world at large can be called as a living river now do you understand what is healthy river all about it is ecological very simple evolutionary ecological social cultural economies at the same time bring the equality factor that is complete okay river natural ecosystem processes are maintained these are important major natural habitats feature are represented and are maintained over time native river banks vegetation is sustained along the majority of the river line please interrupt me if you don't understand than any term.
These are easy terms that's why I'm just reading through. Native fish and other animals can move and migrate up and down the river. Linkages between river and floodplain and associated wetland maintain ecological processes.
Because wetland floodplain is very important. We will see when we in the coming slides about how wetland is important. Natural linkages with the sea or terminal lakes are maintained. Associated estuaries and terminal lake system are productive ecosystem.
Okay, all those are attributes of healthy river. See, let me just concentrate here. Estuaries.
Why it is important? Because estuaries are one of the most unique ecosystem. Because what is estuary?
It is a melting, say for example this is ocean, this is mountain region, here is a river, here is a river. This is saline river, saline water, this is fresh water. This will come and heat here, there will be some churning that will take place, some mixing, this is called story.
This ecology is completely different from this ecology. This ecology is completely different from this because it is a little bit saline. little bit of fresh and in a natural scale see at home in your kitchen you can create such kind of atmosphere little bit saline little bit fresh weather but in natural scale such kind of environment is very difficult to find and in this particular environment there are flora and fauna which is again very important for transportation and ecological functions that it performs and once this environment is destroyed if you destroy this, the dependent flora and fauna will disappear because it cannot survive neither here or neither here. And this again becomes very important because these estuaries are not large. Say for example this is ocean.
Ocean is very big so they can move from one location to the other. Even the river is very long but this estuary, if you look in a global scale, it is very small. That is the important.
of history okay and suppose if you destroy this river or you let this to die this environment will completely vanish that is the importance of a healthy river Now, I have selected two, three important rivers. Let us run through that. But mind you, while you read newspapers or while you read anything, if you find any important rivers, please follow the same exercise. Okay?
Now, River Ganga. What are the challenges? Let us see.
This is River Ganga. Starts from here, travels, follow the pointer please. This is Bangladesh, it comes to Bukli, Bukli Basin. It will be around 2-3,000 km.
It's a plain region, heavily populated. Heavily populated, very important, heavily populated, okay? And second thing, it is coming from this.
There are mountain ranges here. There are mountain ranges. How it is travelling? It is first travelling through mountain ranges. Gradually it bounces in the plane, follows this path.
makes a delta out here. Okay, now let us see what are the challenges in the river Ganga. During the past few decades, ecologically unplanned urbanization and fast industrialization has degraded.
the entire Ganga ecosystem. You agree or not? Yes.
Discharge of sewage, industrial effluent, see these terms are very important. The only purpose of this, see the purpose of these classes are not for PhD degree or M.Sc. in geography. It is for clearing UPSC exam. So in that particular three hours time frame you sit in the exam you are under tremendous pressure.
Everybody knows that. in that particular confined time limit, it is very important to produce such kind of terms. It doesn't kick much in the exam. You need to practice again and again, only then you can be able to go and reproduce. Because in exam nothing generates.
In exam no time for creativity. It's all about what you produce. And if nothing is here, what you will produce? So you need to give some input, only then there will be some output. So, repeated practice is the only answer.
Discharge of sewage. You will say like, oh I understand what is Ganga all about. But in exam you say Ganga is very holy to India.
Then only holiness can save you. See discharge of sewage, industrial effluent, cremation of dead body, agricultural runoff, disposal of solid and biomedical waste, relief of procedures, waste material, etc. From here, even if you can remember three terms, that is enough. Three, four terms is enough.
I've elaborated this. Extraction of huge quantity of water through leaf canals. Construction of dam.
See, it is flowing through a mountain region. So there is a construction of dam on these regions. Okay.
That's why I say it is flowing through this mountain region, plain region, formation of dalda. Population. Then you can remember all those terms, population, it's a memory aid actually. So see, deforestation of Himalayan region, these are the challenges, okay? See, one of the most important thing, what do you think?
And it is rightly said so. There is a healing power in the waters of Ganga. And especially for the people, like for the religious purpose.
Many people take pilgrimage to Ganga and it is considered like a cleansing agent or there is a healing power in the waters of Ganga. And it has been rightly so. And as a geography student, you should know that You should be very proud because we can be able to explain that scientifically. How it can be explained scientifically?
Let me tell you. During runoff from East Kashmir area are consisting of different quality of rocks. It contains lots of chemical substances.
Now what will happen is Ganga emerges from the Himalayan region. While flowing through the Himalayan region, it encounters many different types of rocks. And you know... rocks are very rich in minerals there are many minerals zinc or this or any other okay there are many minerals so what will happen it will due to erosion due to cutting it will collect all the minerals and it used to supply into the ganga river and now some so it has like a disinfectant it acts like anti-oxid many other things okay which is helpful to us which is helpful for our skin which is helpful while drinking in a pure state okay now the more it gets deteriorated day by day that cleansing power is also completely destroyed and it cannot be man-made we cannot reproduce by Human action again. So that is one of the most important aspects, one of the most important aspects, aesthetic aspect in fact.
Consequences for that kind of deterioration are very simple. The river is now leading cause to infant and child mortality, skin problems many other because see can you at least appreciate and correlate Encephalitis, Japanese encephalitis or other infection, diarrhea, any other infection, disease because it is highly populated and how it is related? It is related with the river because water is again very important. Okay?
And the degradation of Ganga can be linked up directly to the help or the IMR. Ganga, the quality of a Ganga, the river quality of a Ganga can be related to IMR. And in the exam, if you can bring that correlation, that is very good.
Another of the main issue of Ganga River pollution is the vast irrigation network which have brought up to fed India's ever-expanding population. This vast network of channels and ditches slowly but surely filled up the water. Ganges and its subsidiary causing an alarming drop of water level especially in the tri-season.
Another set side story of the destruction of Ganges is the downfall of native river Ganges River, Lordfield. So it is affecting the Dependent community, you can say, the dependent community on the well-being of the Ganga. Okay.
What are the recommendations? Before going into recommendations, please see this. This is a river Ganga. And this is how untreated water are discharged.
Just see, this is the state of Ganga. Recommendations are very simple. Must not allow development activities to deprive the masses of the vast invaluable services they have been getting freely from the natural ecology of Ganga and of the Himalaya for ages.
Okay, clear enough? You just go through this because river Ganga and Yamuna meets together and Aditya flow together so the issues problems recommendation are almost the same. Okay Let us go into Eastern rivers that is river Brahmaputra.
Brahmaputra is one of the maximum most load carrying water means maximum sediments. It carries the world's highest sediments. Okay this river it flows from this region takes a 90 degree turn the bounces on the Assam okay now the river Brahmaputra has been the lifeline of north-eastern state India since ages this mighty river runs for this kilometer through India China Bangladesh any alluvial river of such magnitude has problems sediment erosion deposition attached with it.
Brahmabhutra is no exception. The challenges are the problems of flood, erosion and drainage congestion in the Brahmabhutra basins are gigantic. that you can realize by looking at the frequent flood in the Assam region. The Brahmaputra river is characterized by its exceedingly large flow, enormous volume of sediment lot. In fact, it is one of the world's most highest sediment lot.
Continuous changes in channel morphology. What do you mean by continuous change in channel morphology? It means you know a term known as prated channel. the shape of the course that has been created by the river during its journey is known as its morphology or you can say. Now for example, when a river flows initially it will be somewhere like this straight.
Gradually it will become sinusoidal. And gradually once, what happens with a river, especially like Brahmaputra, it is carrying a huge amount of sediments. When you carry a sediment, the speed will become lower down because of the amount of work it needs to do. It reduces the speed. Once it reduces the speed, The speed, it has a tendency of depositing the load that has been carried by the river.
So what we'll do is, suppose a river is running through like this. There is a huge sediment. speed will get lost and after that deposition will take place. While deposition takes place, this deposition again will obstruct the flow and after that this flow will bifurcate into different regions.
Means there will be a deposition here, there will be a deposition... So the river will flow in three four different direction and this kind of channel is known as preta channel and that is how there is a change of channel morphology in the Brahmaputra basin and that is the reason why many agricultural land has been occupied by the river Brahmaputra in the Assam plain. There is a erosion continuous erosion the position takes place spread at the same time but at the same time inundation of the higher level also and destroying the agricultural field near the river course okay Changes in channel morphology, rapid bed aggradation and bank line recession and erosion. The river has spread a channel in most of its course in the alluvial plain of Assam. The lateral changes in channel cause severe erosion along the banks, leading to a considerable loss of good fertile land each year.
Just go through this. See, climate change and this, how it can be related? With climate change, there is a rapid melting of iron glacier. The melting of iron glacier, where does melted water go? Into the river.
And once that goes into the river, the volume of that river increases. And by increasing that volume, it will create a flood-like situation in the downstream. Okay? What are the recommendations?
See, these are the pressure channels. This is a satellite image, so it's not so clear. OK?
See, these are the, see, river comes down here. Deposit the sediments. Deposit the lot, because it reduces its speed.
And after that, by deposit. By proceeding this, this has obstructed this flow and bifurcated into two directions. Gradually such process happens n number of times and what you find in the final analysis is known as braided channel.
Flood management and not just flood mitigation. Why this one? Because see, in such kind of river, carrying such kind of sediment lot, having passing through such a plain.
Flood situation is not exception. It's a regular phenomenon. We all know.
We know this area is a flood prone area. But we occupied and stayed there. So it is, nature is nothing wrong. It is we...
who have decided to stay there so it is well known Assam plain is a flood prone area so every year there is going to be a flood in Assam so the process is not just mitigation not by constructing certain thing but flood management because we already occupied Assam plain and there is going to be a flood in that region so flood management is important means what what do you mean by flood management early broadcasting settlement of population or the high higher levels and you all know all those point those are very simple point just go okay integrated in their institutional R&D support need of renewed policy of integrated water resource management okay see please concentrate in this term in the exam instead of writing three four line if you can give some keywords that is enough and there will be a constraint of time in the examination please remember those words These are some of the unique feature. Majority of the issue that happens in one river will happen in the other river but there are certain specific issues regarding rivers in different region. Accordingly I have arranged these slides.
Okay now let us go for Western God the main challenges are and robotic trade like deforestation of catchment area for what sand mining and dam construction do you agree you have a sand mining in all those Western flowing rivers the second thing is diversion of water for irrigation release of untreated pollutants in the river because these Western regions are very highly developed region especially suppose if you go to Kanata our monastery Jim and industry will One of the five products of industry is waste water, means untreated water, and that has been discharged and leads to a pollution of the river. Viable solution may be linkages of catchment area, river and sea in river basin planning. This again is entirely a different topic altogether.
But just remember this, river basin planning. Rivers of Gujarat. Challenges are excessive groundwater use leading to increasing salinity, increase in this coastal area. You know, I hope you all know why the lowering of the water table causes the saline water to transgress or increase inside the landmass.
See, I'll tell you. This is a landmass, or means this is a land. This is ocean.
Now what will happen is this is the level of ocean. Say for example water level is this. Now this is above the sea level. But what will happen?
Because of repeat... or continuous exploration of this water, the surface, the groundwater, this water level will come down. It will come down to such an extent, at some point because of the basic principle of gravity, this sea water will seepage into this area and that is how it will become saline. The same case with the sand mining also, which we will discuss further. Poor management of existing large dams, interlinking of river proposals and river pollutions.
Rivers of Tamil Nadu and Kerala, new water supplies leading to competition for scarce resources, water pollution, excessive ground... for agricultural use catchment deforestation habitat fragmentation dams and diversion sand mining incorrect land use and encroachment how sand mining is important for this sand mining is also the same for example this is a coastal region you go for a sand mining and for example the person water devil is this present water table is this this is the sea level now what will happen is there will be a sand mining gradually gradually what will happen you will remove all this you are mining the sand you will remove all this gradually it will touch the water table again gradually what will happen it will go beneath this so now what will happen all the water will come here, water table has lowered down so this water will also come here and it will make the entire region saline. Understood?
That is how sand mining is causing salinity of the water table in that particular region. Recommendation just go through okay. That is one of the geographical features that we have discussed. That is what?
The river. The river is a geographical feature and in the UPSC... levels there is a point regarding critical changes that is taking place in important geographical features.
And can you correlate, at least now can you correlate how changes that is taking place in the geographical feature. When I talk about geographical feature that is the river in this particular case. The second important geographical features are the river. mangrove because mangrove and today I'll be taking this Sunderbann okay you can take the same analysis to any other mangrove in any part of the world it will almost be the same but our concern will be how critical it is and Sundarban is an important geographical features and let us see what are the changes that are taking place what are its implications okay so that we remain inside the UPSC defined syllabus. See, in UPSC, one of the most important thing is to remain inside within the confines of the UPSC syllabus and the direction.
Otherwise, sometimes we go to such an extent, which is not at all required. So this is Bangladesh, this is India, this is West Bengal and this is Sundarban. Can you see this? From the backside, can you see this? This is Sundarban.
Now, it is a mangrove. Mangrove looks like this. It is a Bengal tiger, critically endangered.
Climate change impact on Sundarban. I will be reading all this. It's not so difficult. Whenever you require any kind of explanation, I will provide. Please interrupt me.
Otherwise, I'll just run through, okay? Because we need to finish some more topics. It is world's largest contiguous mangrove forest.
The Sundarban display high biodiversity as well as the occurrence of endangered and highly threatened species, including the only possible species of the Sundarban. population of critically endangered Royal Bengal Tigers found in a coastal mangrove habitat. Sundarban is also home to 300 species of flora and about 425 species of wildlife, including the Ganjatik dolphin and Irawade dolphin. The local population relies heavily on the mangrove as it provides fodder, fuel wood, fish, honey and medicine. Further, the mangrove swamps and backwaters form a natural barrier to cyclones.
Do you appreciate this? Because the casualty of cyclone in Bangladesh and the destruction of mangrove swamps in Bangladesh are not the same. mangrove is directly related it is proportional the more you destroy a mangrove the more casualty in Bangladesh during the cyclonic period and the occurrence of cyclone in Bangladesh or West Bengal or is It's a natural phenomenon. It is we who are not learning the lessons.
Otherwise, it's just a global air circulation. Cyclone, all those are just a circulation system. It happens. We all know their particular route.
Okay, so... Natural barriers to cyclone. The mangrove plays a very important role.
Tropical storms and tidal surges providing protection to the inhabited areas and to the coastal fringes and form a protective margin which is the... the shoreline. Now there is a threat to that particular man-craft environment.
What are the traits? Increasing temperature. This will accelerate, this accelerated increase in temperature temperature of the sea has severe implications on aquatic life.
These changes greatly impact the Sundarban areas as it is an estuarine delta. Okay, and I have already explained to you what is estuarine delta. The increase, because see, what is Sundarban?
This is Bay of Bengal. Okay, this is Bay of Bengal. This is River Ganga.
This is Sundarban. So what is Sundarban? It is a mangrove, but what mangrove? It is just an estuary. Means this environment is a little bit slimy, at the same time it's similar to a river ecology.
So it will have particular vegetation, means particular flora and fauna. So see increase any increase or decrease in temperature is going to hamper this very badly and it will if it affects one particular link because see again we have Yesterday I told you about how environmental works. Environment always works like a system. What is a system?
You all know, but just for understanding better, let me tell you. Suppose this is a system. This system, there is one input. one output.
Okay. And inside this system we have n number of other subsystems. All these subsystems effect in one subsystem is going to effect all the other subsystems and there will be certain churning that will takes place and after that there will be only one output, one input. Means what? The environmental output, the environmental input and the dynamics that go inside the system.
And what are the dynamics? Increase in temperature, decrease in temperature, agent, the volume of flow, the rate of deposition, the rate of erosion, everything will take place here. This is how you need to understand the ecosystem or the ecological approach of the geographical subject.
So the increase in temperature you know how it is going to affect. Further it determinedly affects the health of the mangrove ecosystem itself. Rising sea level. Due to continuous submergence in higher water, as an implication of rising sea level, the plants are being noted to be shorter, narrower, with fewer branches and leaves resulting in lower rate of photosynthesis.
and regeneration of the mangrove. The sea level is also affecting the availability of sediments, directly impeding the establishment of new mangroves. This term see, look. This is estuary environment, means this is water body.
Mangrove is growing here. Because of the rising temperature, rising sea level, this will come up here and the area of exposure that it gets to the Sun will get reduced. by this much. So the amount of photosynthesis will be reduced. When amount of photosynthesis is reduced for this entire plant before the sea level rise the protection was from this side means the food they were level say for example it was 80 but now by reducing it this it is just getting 60 for example but this food is for the entire mangrove so the health will deteriorate it will become less and less and gradually it will die out and that is how mangrove is destroyed due to rising sea level and the other thing there is a mud dike there is a term known as mud type okay mud dike is nothing but a special mud you will find in the sundarban region what will happen is this is directly related to the mangrove now mangrove tree will always try to reach the Sun means follow the Sun so when there is a rising sea level it will try to go up up up and up because they need food from where they get food from photosynthesis during that time the linkages between this mud and the mangrove destroys and that I will explain in the further slides but the mud tide in Sunderband is very important ecologically Cyclones, you know, rise in salinity, impact on agriculture.
Studies suggest that in the last two decades, the runoff in the eastern rivers of Sundarban has reduced, resulting in ever-increasing salinity and seawater sulfate concentration. Because of extraction of water from the Brahmaputra, Ganga, all the rivers that are flowing in the formation of the Sundarban, the amount of fresh water that is coming in is becoming less and less. When the incoming fresh water becomes less, what will happen? The salinity level of that particular level will go up.
Because the other side, the contributing factor from other side is saline water from the Bay of Bengal. So one is contributing and the other contribution is from the rivers, from the north. What will happen when the supply of river from the north decreases?
The salinity of this will increase. Once the salinity increases, all the vegetation and flora and fauna that are dependent on the particular ecosystem will be disrupted. And you all know, you say we call food web. Why we call food web? It is a web.
That's why we call it a web. Web is what? It's a very intricate structure. Means the effect on the other is not linear.
If it is linear, it's okay. But it's not linear. It's a web-like structure. Means it's a very complex structure.
So in an ecology or ecosystem, of any environment if you change one parameter. Here suppose if you change the parameter of salinity it is going to affect the entire system and it will, a time will come when the entire structure will collapse. Okay. Deforestation, pollution, challenges, see.
Encroachment and poverty, these are the social aspects. While writing the exam, please cover these areas also. About the poverty of the particular geographical location.
Don't think writing poverty will become less of a geographical answer. See, you are targeting into a particular location. Here, suppose we are targeting in... In the Sundarban region, our analysis should be holistic in nature.
So while targeting in a holistic fashion, we need to look at the things which impact the geographic... feature and here population is one of the factor that is impacting the geographic feature which we are interested in are you getting my point okay now so poverty encroachment because it is highly populated it is typically witnessed that any measure to remove the encroachment from the forested area is likely to be strongly opposed by local politician as well as the people Because see, why encroachment is important? Because of inhabiting by human beings. there is going to be deforestation. There is going to be a human waste.
So creating garbage in a very large scale is going to affect the water bodies, the vegetation system. That is the importance why encroachment is very dangerous. I just read through. Overexploitation of forest produce. Fisheries and collection of non-limber forest produce do supplement the meagre agricultural income of the local population.
However, rampant deforestation and overfishing have put the environment under tremendous pressure. Fish stock is twinkling because of a combination of over exploitation and climate changes local population to abandon sustainable traditional fishing practices and adopt excessive prawns it culture this particular culture just remember it reduce it destroys the mud dikes it is mud dikes okay a new D that is a simple mud dy kes mud dikes it destroys the mud I see by traditional practice of fishing it is not destroyed but by the prawn sit culture the mud type environment destroys it completely collapses okay this has led to irreparable harm being caused to the environment due to erosion of the mangrove ecosystem which comprises of mud dikes that protects the Sundaram Sundarban from the onslaught of the sea do you realize the importance of mud dikes here further this has led to the destruction of the mangrove trees whose roots are essential to bind the mite dikes and the taking of a heavy toll of fish settlings which will adversely affect the Delta fish population spread of disease increase in man-animal conflict those are the factors just read through mitigation strategies there are two broad mitigation strategies one is a short term or the immediate and the other is a very long-term strategy. Now let us see some mitigating strategy that needs to be implemented immediately. Zoning of Sundarban according to vulnerability. Regional planning and rehabilitation relocation.
You read through. Protection and distribution of saline resistant food, grain and seed. Because complete relocation of a population is not at all possible.
You need to bring certain adaptation measures and that adaptation measure can be addressed through saline resistance because just now we have discussed the salinity of Sundarban is increasing when salinity of Sundarban is increasing see even in Sundarban there are people who are living a normal life So they need food to eat, so they need some agricultural piece to sow their crop. So suppose if you relocate the entire population that is not at all possible. Long-term strategies are clustering existing livelihood patterns, construction of disaster resistant home, awareness and information, release of additional fresh water. These are regarding the dam construction that we do on the upstream of the river. Because the dam is not a dam, it is a river.
construction of them on the upstream of the water affects the downstream flow and the one of the effects is increasing salinity with respect to the Sundarban environment protection of treason species and afforestation program okay now Let us also see one of the important geographical features and that is effect of sea surface temperature along India's coast. It is a very recent activity, just let us see this. I will just read through this very simply. If any doubt, please interrupt me and I'll clarify your doubt.
Until about mid-1980s, important fish species such as the mackerel and oil sardines used to be present no further north than the Malabar upwelling zone of the Kerala core. Because of global warming, sea surface temperature along India's west coast rose by 0.6 degree centigrade over 1967 to 2007, according to this. Consequently, this fish species began to find the ocean waters further north also rather celebrous.
So there was a migration of fish from the Malabar coast to the northern side. even reaching the Gujarat coast. What is the significance? See, mackerel and sardine, they are types of fish. Once upon a time, they were just confined to the Malabar region.
Malabar region will be around, see, India starts from around eight degree north latitude. So Malabar region will be around something around nine to 10 degree north latitude. So in this latitude, temperature will be different than the.
this latitude because temperature changes as we go or as we change different latitude. So in this particular latitude, particular temperature, so particular type of fauna and in this case the fauna is mackerel or the sardines. Now what happened is this fish remain in this region not From north of Malabar it was completely absent.
But the recent survey we find, these fish are found up to this region now. The reason is the temperatures that were available... here is also available here today. What is the reason? Because of global warming.
Because of global warming the sea temperature becomes higher on the northern part of the... hemisphere okay because temperature decreases as we go from the quarter to the northern hemisphere but before it was confined to the Malabar course but now we can find even in with that course this is how and what is the significance of this after all see fish this is also water this is also water fish is also you can say a freedom of movement for a fish also that is not a big thing okay so fish can go ahead can go ahead can go ahead they also have a fundamental right right they can go anywhere they like but let us see the implication okay let us see the implication you know if in a food web or a food chain the cycle is the simple you can say the cycle is like this one affects the other so in this chain suppose you destroy this Just try this. It is going to behave very differently and the entire structure will collapse. Now, in the mackerel and sardine case, they feed on certain kind of algae that is available. So if that fish is absent, there will be algae boom.
And you know what is the implication of algae boom. The second thing, the bigger fish... might be dependent on the mackerel and sardine in the food chain and if that particular fish species is absent from that region the higher level of food chain is directly collapsed so they will have to also find some other place okay So, such is the intricacy of the arrangement we are talking about. Please try to appreciate this kind of intricacy.
Just by focusing on fish, you will find it is useless. But if you can appreciate the intricacies that is involved in the system, you will come to know about the importance. This shift in the range of species is taking is also taking place in India's river that was the oceanic part. Along the Ganga for instance four species of warm water fish can now be found swimming further north. even up to Haridwar.
So see, because the temperature is warming up, it is going even up to Haridwar. Now just imagine the thing which we have explained. When two, three species of fish is completely shifting its habitation to that part, Then you can just imagine, okay, shift in range or in the timing of life cycle events are climate change adaptation by species, okay, because there are changes in climatic condition in order to adjust that kind of changes there is a movement, there is a movement of the fauna that is dependent on that particular region but not all the things can adjust to such kind of changes because everything is not mobile say for example okay fish can move the temperature on the lower latitude was becoming higher and higher, higher and higher, and they find suitable places on much further north so fish can swim. But for example here is a flora, means the plant community. See it is also experiencing like the fish, even the plants are feeling like oh the temperature is becoming very hot, but can it go to the south coast of Gujarat?
No, because plants are not mobile. Fish can go but plants cannot go. So when there is a distachment between a flora and fauna community of one place, there is a complete collapse of system.
It affects human beings also. The livelihood of millions of people depends on the location and well-being of other species. How marginal farmers, fisher people and other communities in different parts of India are being affected by the impact of other species.
species merits much more detailed investigation. Imagine in the Ganga River suppose due to certain other reasons the fish is you know like affected badly. Then the fishing community, especially in the Bengal region, will have a very negative impact on the fishing community.
Because they are just living on a hand-to-mouth basis. They don't have any stocks, no security, nothing. Just by fishing, today's fish, they eat. So suppose if you affect that resource, then there is big economic, social implications. happens and it directly or indirectly affect the environmental region of the particular place.
Melting of glacier and ice sheets is other geographical feature okay let us run through they are the world largest reservoir of fresh water holding approximately 75 percent over the past century most of the world's mountain glacier and ice sheets in both Greenland and Antarctica have lost mass. Retreat of this ice occurs when the mass balance. The difference between accumulation of ice in the winter season versus the appellation or melting of summer in the summer is negative, such that more... eye melts each year then is replaced okay when the temperature exceed a particular level or warm temperature lasts for a long period enough period there is insufficient precipitation glaciers and ice sheets will will lose mass one of the best example is mount kilimanjaro in africa there were presence of glaciers but there is a significant reduction as of now and that is how it is Cn.
The melting of the glacier in Mount Kilimanjaro in Africa will affect the entire river that is dependent on this particular glacier because this glacier is feeding the rivers of different regions. East and West Antartica balance. See, I'll tell you, since yesterday we talked about the Arctic and Antartic region, because the polar regions are becoming very important, in Antartic region the basic physiography is like this.
It is eastern side, this is western side. Eastern side is much higher, western side is much lower. This side is much warmer, this is much colder, this is warmer.
So on this side there is accumulation of ice. In this side there is melting of an iron. So accumulation, melting.
So addition, subtraction. So the entire arrangement. and equation will turn out to be negative. Means melting is much more than accumulation. So that's why I say there might be a question like in Antarctic region, there is accumulation that is taking place, accumulation of ice.
So what is the implication? So you can just say the final output is negative or not. The impacts are severe water shortages as the glacier disappears, reduced capability to irrigate crops as fresh water dams and reservoirs more frequently go dry, as the volume of runoff decreases, then the energy.
dam on the river so the reduction of flow of the particular river is going to affect the availability of thermal power and that is how melting of a glacier affects the flow in the river and that will affect the energy security of our country that is the linkages okay Energy, urban and agricultural infrastructure of such locations are likely to be stressed. The melting of glaciers and ice sheets adds water to the ocean, contributing to sea level rise. Okay? Now, you want a break or we'll continue?
Let's take a break for five minutes.