Environmental studies

Global Warming: It is time to act now!

Global warming is one of the major challenges that humans face in the 21st century. What do you know about global warming and what are its effects?

The 18th and 19th centuries were the industrial eras. During this time, massive quantities of fossil fuels were burnt in factories around the world. Burning of fossil fuels leads to the production of greenhouse gasses like carbon dioxide.

So, what is a greenhouse gas?

Many of you may have visited a greenhouse. A greenhouse is a building that is covered by glass on all sides. The glass allows heat inside the building, but it does not allow the heat to escape from the building. This, it traps heat within the building. Greenhouse gasses like carbon dioxide act in a similar manner. These gasses trap the heat produced by the sun within the earth?s atmosphere. Therefore, the temperature of the earth?s (including ocean surface) surface increases. Greenhouse effect is the name of this phenomena. Apart from carbon dioxide, the other major contributors to the greenhouse effect are oxides of nitrogen and sulfur and methane.

global warming

Image from countrymedia.blogspot.com

Cattle produce copious amounts of methane (in their gut). Therefore, large-scale cattle farming leads to increased release of methane and is an important cause of global warming.

Simply put, global warming is the gradual increase in earth?s temperature due to the accumulation of greenhouse gasses in the atmosphere.

How does global warming affect us?

Global warming affects us in many ways. We have heard from our parents and grandparents that the summers are becoming hotter, and winters are reduced in duration in intensity. This (climatic changes) is an outcome of global warming.

Global warming has more sinister outcomes as well. The average temperature has increased by over 2 C in the past one century. The increase in temperature leads to melting glaciers and polar ice caps. This (melting of ice) results in an increase in sea levels. As sea levels increase, low-lying coastal areas get flooded leading to the displacement of millions of human beings living in these regions. Global warming also leads to rapid melting of glaciers. Glaciers are the source of almost all rivers in the world. Rapid melting of glaciers leads to floods along the course of rivers. Apart from these, global warming also leads to unpredictable climate changes like droughts, extremely severe winters, and massive hail storms. Global warming also leads to reduced agricultural productivity thus impacting food security.

What is the relationship between global warming and other forms of pollution like noise pollution?

Apart from atmospheric pollution, water pollution, and noise pollution are also increasing due to human activities. Do these forms of pollution have any relationship with global warming?

Water pollution makes water unfit for consumption. But, it does not increase the temperature of the water. Therefore, water pollution is unlikely to contribute to global warming. Similarly, noise pollution also does not contribute to global warming. On the contrary, global warming may contribute to noise pollution.

Let us do an experiment to demonstrate this effect. Take some ice cubes in a glass and pour hot water over the cubes. What do you see?

You will note that the ice cubes crack and break into small pieces before melting. When the ice cracks, it produces sound, thus leading to noise pollution.

Many researchers have studied the disintegration of icebergs and its effects on the marine environment. They (researchers) have found that the noise produced by disintegration of icebergs is equal to the noise produced by hundred supertankers. The noise produced by breaking of ice affects marine animals and leads to deleterious consequences to the marine ecology.

To conclude, global warming is a major challenge to the human race in the 21st century. If we do not act now, then it may be too late.

More class 10 science notes.

Here is an excellent collection of CBSE books for class 10 science.

The Pacific garbage patch

In our article on non-biodegradable materials, we had learned a little about the Pacific garbage patch. So what exactly is the Pacific garbage patch? Human activity generates close to 300 million tons of plastic waste every year. About 10-15 tons of this waste finds its way to the rivers, and then the oceans. In the oceans, the plastic waste breaks down into tiny particles under the effect of waves and sunlight.

The oceans, as you know, are interconnected. Water in the oceans is steadily flowing from the warmer regions to the colder areas. These ocean currents carry the plastic waste to convergence zones. Convergence zones behave like a slow whirlpool. The water slowly rotates around a central axis, and this causes the plastic particles to aggregate. Thus, a large patch of plastic waste is formed. There are four such spots in the oceans of the earth. Amongst these, the Pacific garbage patch is the largest.

As imagined, the Pacific garbage patch is not an island made of plastic. In fact, most of the Pacific garbage patch floats beneath the water. Therefore, it is not visible from a satellite or space. The Pacific garbage patch weighs nearly seven million tons. Within this garbage patch, the minuscule fragments of plastic are in close association with the marine flora like plankton and small fish. These fishes eat the plastic particles and finally the plastic finds its way into the food chain.

Apart from entering the food chain, the plastic waste also endangers marine life. Birds and fish eat this plastic and choke to death. The garbage patch also hinders movement of ships through the world?s waterways.

So, how do we clean up this muck?

There is no way to clean up the Pacific garbage patch. It is not possible to scoop up the waste with machines. Nor is it possible to degrade it by biological means. The only thing we could do is to stop it from getting bigger.

We have learned before that plastics stay in the environment for many years. Reducing the use of plastic is the only way to halt the growth of the garbage patch. For starters, we could carry our cloth or jute bags to the market. We can also reduce the use of plastic by recycling the plastic waste.

Click here for more class 10 science notes.

Here is an excellent collection of CBSE books to help you with your board exams.

The hazard of non-biodegradable materials

Non-biodegradable materials cannot degrade by natural means. Can you name four non-biodegradable materials? Metals are non-biodegradable as they cannot degrade by naturally. Similarly, glass also cannot be degraded by bacteria. Hence, they are also non-biodegradable. What about plastic? Can plastic be degraded naturally? No, plastic cannot be degraded naturally. In fact, plastic lasts in the environment for many years. Therefore, plastic is the most harmful non-biodegradable material we use in everyday life.

Non-biodegradable waste like metal cans and glass bottles can be recycled. They can recycled in a factory where smelters melt the metal items and new metal items produced. Similarly, glass can also be melted to produce new glass. However, plastics cannot be recycled this way. Melting plastic releases a lot of smoke. This smoke not only pollutes the environment, it also has many chemicals that can cause harm to living beings. Therefore, melting is not an appropriate way to dispose of plastic waste. So, how do we dispose of non-biodegradable plastic waste?

There is no environmentally safe way to eliminate non-biodegradable materials like plastic. As of now, most of the plastic we use is dumped in landfills or thrown into rivers. Humans generate up to 300 million tons of plastic every year. About 5-10% of this plastic finds its way to the oceans. In the oceans, waves and sunlight break this plastic into minuscule particles. The ocean currents carry these particles a convergence zone. Here, these plastic particles float as a loose aggregate to form a garbage patch. There are three such garbage patches in our oceans. The largest garbage patch is the Pacific garbage patch. We will learn more about the Pacific garbage patch in another article.

Thus, you see that these is no environmentally safe way to dispose of plastic. Therefore, if we indiscriminately use plastics, then our earth would be filled with plastic waste, thus choking our rivers and causing significant harm to living beings. The only way to prevent the accumulation of plastic waste is by reducing the use of plastic.

Can you think of a few ways how you can minimize the use of plastics?

For starters, you could carry a cloth or jute bag to the market thus reducing the use of plastic bags. Another thing we could do is to recycle most of the waste we generate. Paper, cardboard, metals and glass can be recycled. Recycling, apart from saving trees and water, ?also provides employment opportunities to millions of people.

You could do a small activity that will demonstrate how much your role as an individual can improve the environmental conditions of the planet. Segregate household waste into non-biodegradable and biodegradable materials. Weigh them both and compost the biodegradable waste and send the non-biodegradable for recycling. Waste like plastic that cannot be recycled should be separately stored. At the end of a week, do to math as to how many kilograms of waste your house generates. How much is biodegradable and how much is not? How much plastic waste did you generate? You will now have an idea how much waste you can prevent by composting and recycling your waste.

Click here for more class 10 science notes.

Here is an excellent collection of CBSE books for your board exams.

Biodegradable materials

We have often heard of biodegradable materials. Can you recollect a few places where you may come across this word? You may have seen this printed on milk cartons, or on a paper bag used for shopping. You may also have noted how your mother segregates waste based on whether it is biodegradable or not. So what are biodegradable materials?

Let us do an activity to know more about biodegradable materials.

Collect waste from your house for one full day. Do not segregate the waste. What kind of waste are you likely to receive? Kitchen waste like leftover food, vegetable and fruit peels, waste paper, packaging, glass, metal cans and plastic are some of the wastes commonly generated in our houses. Bury this waste in your backyard. If you do not have a garden, you can store the waste in a bucket and cover it with about 15 cm of mud. Check on this waste once every few days. What will you observe?
You will note that the kitchen waste (vegetable peels, fruits peels, residual food) degrades within a few days into compost. Waste like newspapers and packaging made of paper degrade next, and glass and plastic do not degrade at all. In fact, plastics can last in the environment for thousands of years.

So why does kitchen waste degrade so quickly? In the chapter on human nutrition, we had learned about enzymes. Enzymes are proteins that catalyse the breakdown of food within the digestive tract. Bacteria in the soil produce similar proteins that break down the kitchen waste to produce compost. The compost is an excellent source of nutrients for plants and using it in the garden can improve yields. Biogas plants produce methane and compost using the?same principle.The enzymes can also act on paper. However, cellulose, the main component of paper takes a longer time to break down, therefore, paper and paper products stay in the environment longer. Enzymes have no action on plastic and metals. Therefore, these items are not degraded by the enzymes.

Therefore, substances that are degradable by biological means are biodegradable materials.Non-biodegradable materials like plastic and glass are not degraded by natural means. Hence, they can persist in the environment for thousands of years. Can you now imagine what would happen if we keep using plastic indiscriminately? All the plastic will stay on earth for thousands for many years and cause immense environmental damage. See this video below to get an idea of the risk posed by plastic to animals and environment, in general.

Click here for more class 10 science notes.

Here is an excellent collection of CBSE books to help you study for the board exams.