My Science School

Noise from construction, industry, and the building of infrastructure such as roads and pipelines has increased dramatically in the recent years, and with urban growth, human establishments such as industries are being set up closer to forests. Scientists have been documenting how animals and birds respond to a noisy world - some birds sing at higher frequencies: bats have trouble finding prey: frogs struggle to find mates; and whales vocalise louder to communicate with each other. A recent study has shown how these effects trickle down to trees and plants, even after the sources of excess noise are removed. Scientists suggest that noise pollution can pose long-term risks that could change the habitat for a whole plethora of species.

Taking a toll

• Noise pollution is an unwanted or disturbing sound that can interfere with normal activities for humans and wildlife.
• Excessive noise harms human health and interferes with people's daily activities. It can disturb sleep, cause cardiovascular and psychophysiological effects.
• Animals use sound for a variety of reasons, including to navigate, find food, attract mates, and avoid predators. Noise pollution makes it difficult for them to accomplish these tasks, which affects their ability to survive.

How is vegetation affected?

Many plants and trees rely on birds and animals to carry their pollens to other flowers or to disperse their seeds, but noise pollution scares off these species. In order to adapt to noise, they change their behaviour or move to quieter places. This, in turn, affects vegetation.

Disruption of an ecosystem

• Researchers in the U.S. looked at tree populations in New Mexico that had been exposed to a high level of artificial noise created by natural gas wells in the region. The researchers looked at two species of trees namely the pinyon pine and the Utah juniper. They built upon research they had already done, which showed that westem scrub jays avoid noisy areas. (This, in turn. encouraged its prey species black-chinned hummingbird to build its nests and thrive despite the noisy environment).
• In 2007, the researchers found that noise pollution from the gas wells disrupted seedling dissemination and germination of the pinyon pine and the juniper. This was most likely due to the noise driving away the scrub jay, which disperses the seeds of the former tree species. and small mammals that disperse the seeds of the latter. They also found 75% fewer pinyon pine seedlings in noisy sites than quiet ones.
• Twelve years on, researchers sought to assess the long-term ecological impact of this noisy ecosystem. In the meantime, some of the gas wells and other industries in the region had shifted base. The researchers found that pinyon pine and juniper trees were found less in regions where there were more gas wells and more noise (in line with the 2007 findings) and their saplings were also less abundant in these regions.
• However, in the areas that were previously noisy but turned quiet. there was a difference. There were more saplings of juniper than pinyon pine, suggesting that species (mice and other small mammals) that spread the seeds of juniper have returned, whereas those of pinyons (jay birds) have not.
• Researchers pointed out that birds such as the scrub jay that are sensitive to noise learn to avoid particular areas. They have episodic memory and they can remember negative experiences. So if they did explore an area a couple of years ago and if it's noisy, then they would remember that and not go back to that area.
• The study thus pointed out that removal of the noise doesn't necessarily immediately result in a recovery of ecological function. While some plants do recope, others don't, depending on how the community of creatures around them changes. This can alter the entire ecosystem in the region. For instance, the absence of scrub jays could lead to the thriving of black-chinned hummingbirds, which, in fact, pollinate flowering plants. Perhaps, there will be more flowering plants than the pinyon pine in this region.

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ENVIRONMENT

As the human population grows and we exploit more of the world’s resources, we inflict a lot of damage on our environment. We are doing this partly by destruction of natural habitats, such as forests and wetlands, and partly by pollution of the land, oceans, and atmosphere. Many plants and animals are endangered and entire ecosystems such as coral reefs and rainforests are under threat.

• LAND AND SEA POLLUTION

A lot of the things that we throw away end up scattered over the landscape, or dumped in the sea. Most plastic never rots down and is dangerous to wildlife. Raw sewage and other waste is also poisoning enclosed seas such as the Mediterranean.

• GLOBAL WARMING

The most serious threat to the environment is global warming. This is caused by pollution of the air by gases that absorb heat and warm up the atmosphere. This may lead to changes in rainfall patterns and rises in sea levels as polar ice caps melt.

• AIR POLLUTION

Smoke and gases released by industry, power plants, homes, and vehicles have caused visible air pollution, known as “smog”, in many cities. Badly polluted air can be dangerous to breathe, but the main threat from this kind of pollution is global warming.

• ACID RAIN

Smoke and fumes from industry and power plants combine with moisture in the air to form weak sulfuric and nitric acids. When this acid rain falls it can kill trees and turn lakes too acidic to support life. This is a serious problem in Canada, Russia, and China.

• DEFORESTATION

All over the world, vast areas of forest are being destroyed each year. Tropical forests in particular are being felled for timber, and to clear land for farming. This is wrecking some of the richest natural habitats on Earth, and is one of the main causes of climate change.

• LOSS OF BIODIVERSITY

As wild habitats are destroyed, plants and animals have fewer places to live. This makes survival harder for many species. As endangered species die out, it reduces the rich variety of life that is vital to the health of the planet.

• PROTECTING EARTH

Protecting the environment is not just the job of governments. We can all help by altering the way we live. By cycling to work instead of driving, these city workers are reducing the amount of pollution they produce.

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Last month, India was hit by back-to-back cyclones. While cyclone Tauktae formed in the Arabian Sea and affected coastal districts in Kerala, Karnataka, Goa, Maharashtra and Gujarat, cyclone Yaas formed in the Bay of Bengal and ravaged parts of Odisha and West Bengal. Scientists highlighted the impact of climate change in the intensification and frequency of tropical storms that hit India. And they also brought our attention to the role played by mangrove forests in reducing the impact in Odisha, West Bengal and Mumbai. Although there were losses to lives and property, it was highlighted by experts that mangroves safeguarded people and the inland against the severe storm surges of the cyclones.

While Mumbai has a mangrove cover of 66 sq km, Odisha and West Bengal boast luxuriant mangrove cover along the Bhitarkanika National Park in Kendrapara district and the Sundarbans respectively.

What are mangrove forests and why are they considered to be beneficial to coastal communities?

What is a mangrove?

A mangrove is a small tree or shrub that grows along coastlines, taking root in salty sediments, often underwater. The word 'mangrove' may refer to the habitat as a whole or to the trees and shrubs in the mangrove swamp. Mangroves are flowering trees, belonging to the families Rhizophoraceae, Acanthaceae. Lythraceae, Combretaceae, and Arecaceae. The upper trunk, including the branches and leaves, of a mangrove tree lives completely above the waterline. while the lower trunk and the large root system are partly covered by seawater. Many species have roots diverging from stems and branches and penetrating the soil some distance away from the main stem (like banyan trees).

What are some of the special features of mangroves?

• Saline environment: A speciality of mangroves is that they can survive under extreme hostile environment such as high salt and low oxygen conditions. Mangrove trees contain a complex salt filtration system and complex root system to cope with salt water immersion and wave action. The roots filter out 90% of the salt they come into contact with in the saline and brackish water they call home. Some species of mangrove excrete salt through glands in their leaves.
• Low oxygen: Underground tissue of any plant needs oxygen for respiration. But in a mangrove environment, the oxygen in soil is limited or nil. Hence the mangrove root system absorbs oxygen from the atmosphere. Mangroves have special roots for this purpose called breathing roots or pneumatophores. These roots have numerous pores through which oxygen enters the underground tissues.
• Mangroves, like desert plants, store fresh water in thick succulent leaves. A waxy coating on the leaves seals in water and minimises evaporation.
• Mangroves are viviparous - their seeds germinate while still attached to the parent tree. Once germinated, the seedling grows into a propagule. The mature propagule then drops into the water and gets transported to a different spot, eventually taking root in a solid ground.

How do mangrove forests help protect against strong cyclones?

• Mangrove forests act as natural barriers against storm surge, coastal flooding and sea level rise. Their intricate root system stabilises the coastline, reducing erosion from storm surges. Together with the tree trunks, they work like speed-breakers to slow down the tides.
• They protect shorelines from damaging winds and waves. A series of studies in the early 2000s discovered that mangroves with an average height of 6-10 metres could shorten a cyclone's waves by 60%.
• Mangroves also help prevent erosion by stabilising sediments with their tangled root systems.
• A 2013 study of mangroves in Florida estimated that a mangrove forest could reduce the effects of a Category 5 storm to the intensity and effects of a Category 3 storm.

What are the other benefits to the environment?

• Mangrove thickets maintain water quality by filtering pollutants and trapping sediments originating from land.
• They provide habitat for a diverse array of terrestrial organisms. Their branches provide homes for lizards, snakes and nesting birds. Many species of coastal and offshore fish and shellfish rely exclusively on mangroves as their breeding, spawning, and hatching grounds.
• Mangroves also have a big impact on climate. Mangroves are powerhouses when it comes to carbon storage. Studies indicate that mangroves can sequester (lock away) greater amount of carbon than other trees in the peat soil beneath. They store this carbon for thousands of years.
• Many people living in and around mangroves depend on them for their livelihood. The trees are a source of wood for construction and fuel. The ecosystem provides local fishermen with a rich supply of fish, crabs and shellfish. The ecosystem also supports tourism.

 

Where are mangroves ecosystems found?

Mangroves can be found in over 118 countries and territories in the tropical and subtropical regions of the world. Asia has the largest coverage of the world's mangroves, followed by Africa, North and Central America, Oceania and South America. Approximately 75% of the world's mangrove forests are found in just 15 countries.

In India

The deltas of the Ganges, Mahanadi, Krishna, Godavari, and the Cauvery rivers contain mangrove forests. The backwaters in Kerala have a high density of mangrove forest. The Sundarbans in West Bengal is the largest mangrove region in the world and a UNESCO World Heritage Site. It spans from the Hooghly River in West Bengal to the Baleswar River in Bangladesh. The Bhitarkanika mangrove system in Odisha is India's second largest mangrove forest.

Pichavaram in Tamil Nadu has a vast expanse of water covered with mangrove forests. It is home to many aquatic bird species.

What are the threats to mangroves?

Scientists estimate that at least one third of all mangrove forests has been lost during the last few decades. Coastal development, including construction of shrimp farms, hotels, and other structures, is the primary threat to mangroves.

Mangrove forests are cleared to make room for agricultural land and human settlements.

• Mangrove trees are used for firewood, construction wood, charcoal production, and animal fodder. In some parts of the world, there has been overharvesting which is no longer sustainable
• Overfishing, pollution, and rising sea levels are the other threats to mangrove forests and their ecosystem.

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You might have heard your grandparents lament about how the greenery in your town has been replaced by buildings. They might have even shared their concern over rising pollution and missing birds and insects in the neighbourhood. The environment they grew up in has disappeared and what we are left with is just a concrete jungle.

Human settlements and urbanization have rapidly transformed the planet in the last few decades. The activities have greatly deteriorated the environment and wildlife. Climate change, global warming, habitat loss and pollution have pushed many species of plants and animals to the brink of extinction. And scientists and conservationists are now advocating several restoration efforts, chief among them being rewilding.

Rewilding is the reintroduction of locally extinct plants and animals to a landscape where they have the potential to restore ecosystems. It is a potential to restore ecosystems. It is a progressive approach to conservation – it’s about letting Nature take care of itself, by enabling natural processes repair damaged ecosystems and restore degraded landscapes.

Two types of rewilding

Passive rewilding focuses on reducing human intervention in the ecosystem and letting Nature recover and flourish on its own. It involves giving cultivated land back to Nature.

Translocation rewilding involves reintroduction of species. It is the deliberate release of a species from captivity or other areas into the wild, where the organism is capable of survival. Also called trophic rewilding, it focuses on re-establishing large-bodied animals or megafauna. Trophic rewilding aids in the restoration of balance in the entire ecosystem.

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Ukraine recently commemorated the 35th anniversary of the Chernobyl disaster, considered one of the world’s worst nuclear disasters. The disaster was the result of an explosion in the fourth reactor of the Chernobyl nuclear power station, in the former USSR, which led to radiation poisoning across Ukraine and neighbouring Belarus and Russia. The exact number of victims remains a subject of intense debate because the Soviet authorities kept most of the information about the disaster hidden. Hundreds of thousands of people were evacuated from the area around the disaster site, and the exclusion zone has now become a ghostly uninhabited region.

Ukrainian authorities say the area may not be fit for humans for 24,000 years, but the site has been attracting tourists in the recent years and Ukraine wants to make it a UNESCO World Heritage Site.

During the 35th year commemoration, Ukraine’s president Volodymyr Zelensky unveiled a new nuclear waste repository at Chernobyl, where the country could store its nuclear waste for the next 100 years. On the occasion, Ukrainian government also released a document claiming that the Soviet Union (which Ukraine was then part of) knew the Chernobyl nuclear plant was dangerous and covered up emergencies there even before the 1986 disaster.

What happened on April 226, 1986?

The Chernobyl nuclear power station was situated at the settlement of Pripyat, north of Kiev in Ukraine. Built in the late 1970s on the banks of the Pripyat River, Chernobyl had four reactors, each capable of producing 1,000 megawatts of electric power.

On the night of April 25, 1986, the reactor crew at Reactor No. 4 of experiment, which was found to be poorly designed during investigation. A series of mistakes, including the disabling of automatic shutdown mechanisms, led to the nuclear chain reaction going out of control. Reactor No. 4 exploded and caught fire on April 26, 1986, shattering the building and spewing large amounts of radioactive material from the graphite reactor core into the atmosphere, which soon spread across Ukraine, Belarus, Russia and many parts of Europe. Firefighters and helicopters attempted to put out a series of blazes at the plant, but to no avail

What happened after the explosion?

The Soviet authorities made the catastrophe worse by withholding information from the public on what had happened, even though they began an evacuation of the 30,000 inhabitants of Pripyat on April 27, 1986. The world learned of the disaster only after heightened radiation was detected in Sweden on April 28. The Swedish radiation monitoring stations, more than 800 miles to the northwest of Chernobyl, reported radiation levels 40% higher than normal. After first denying any accident, the Soviet finally acknowledged the disaster on April 28. About 600,000 emergency workers and state employees who became known as “liquidators” were dispatched with little or no protective gear to help clean up the aftermath of the disaster. The details of the incident and the victim numbers were shrouded in secrecy.

Soon after the disaster, radioactive debris were buried at some 800 temporary sites, albeit at great risk to workers. Eventually, more than 100,000 people were evacuated from the vicinity and an exclusion zone was established around the station. The exclusion zone is a 30-kilometre radius area around the nuclear power plant that was evacuated in the aftermath of the explosion. It was deemed unsafe for humans to live in for thousands of years.

How many people died as an immediate result of the accident?

Thirty-one plant workers and firemen died in the immediate aftermath of the disaster, mostly from acute radiation sickness. Thousands more later succumbed to radiation-related illnesses such as cancer, although the total death toll and long-term health effects remain a subject of intense debate.

Why is it considered one of the worst disasters?

Between 50 and 185 million curies of radioactive material escaped into the atmosphere. It’s estimated that the amount of radioactive material was 400 times more than the atom bomb dropped on Hiroshima and Nagasaki during World War II.

The radioactivity was spread over large parts of Europe, including Belarus, Russia, Ukraine, Scandinavian countries, France and Italy.

The United Nations Scientific Committee on the Effects of Atomic Radiation reported that more than 6,000 children and adolescents developed thyroid cancer after being exposed to radiation from the incident, although some experts have challenged that claim.

Scientists are still in the process of gauging the extent of the damage and starting to answer questions about the long-term legacy of radiation exposure on the power plant workers, the people in the nearby community, and even their family members born years later.

What is the status of this exclusion zone and the station?

• No one is allowed to live in this exclusion zone. However, the Ukrainian government allows tourists and scientists to enter nearby areas and even the town of Pripyat for a limited period of time.
• The highly radioactive reactor core was enclosed in a concrete-and-steel sarcophagus by the end of 1986. In November 2016, a massive metal dome was erected over the remains of the reactor to stop future leaks and ensure the safety of people for generations. Containment efforts and monitoring continue and cleanup is expected to last until at least 2065.
• Regarding the other reactors of the station, Unit 2 was closed in 1991 after a fire and Unit 1 was shut down after 1996. Unit 3 of Chernobyl remained operational till 2000 when the power station was decommissioned.

What happened to the environment and animals after the accident?

Millions of acres of forest and farmland were contaminated, and in the subsequent years many livestock were born deformed. According to the International Atomic Energy Agency, mutations occurred in plants and animals after the explosion. Leaves changed shape and some animals were born with physical deformities. However, some animals are now returning in large numbers to the area. These animals include beavers, moose, wolves and wild boar, plus a wide variety of birds.

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The IEA’s Global Energy Review 2021 predicts carbon dioxide emissions would rise to 33 billion tonnes this year, up 1.5 billion tonnes from 2020 levels as global economics pour stimulus cash into fossil fuels to aid recovery from the COVID-19 recession.

The leap will be second only to the massive rebound 10 years ago after the financial crisis, and will put climate hopes out of reach unless governments act quickly, the IEA has warned.

The use of coal in Asia is expected to be key: the IEA says it will push global demand up by 4.5%, taking it close to the global peak seen in 2014.

However, renewable energy is also booming, with green sources set to supply 30% of electricity this year.

Coal ain’t cool

The expected rise in coal use dwarves that of renewables by almost 60%, despite accelerating demand for solar, wind and hydro power. More than 80% of the projected growth in coal demand in 2021 is set to come from Asia, led by China. Coal use in the United States and the European Union is also on course to increase but will remain well below pre-crisis levels, according to IEA.

Top of the list

Carbon dioxide is the leading greenhouse gas heating the planet. There are other gases that are much more powerful, but they are less abundant.

Did you know?

Concentrations of carbon dioxide in Earth’s atmosphere have scored since measurements began in 1958, at the pristine Mauna Loa mountaintop observatory in Hawaii. During the first measurement it stood at 316 parts per million (ppm) in 958.

The concentration of carbon dioxide in the atmosphere was 415 parts per million on May 2020.

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Scientists at the Duke University and the University of Virginia have recently documented how sea-level rise in triggering forest die-offs in coastal regions. Studying the vegetation in North Carolina, they find that rising seas are inundating the State’s coast, and the saltwater is seeping further into the land and wetlands. This salt is killing huge swaths of contiguous forest, which the scientific community calls ‘ghost forests’. Using satellite images, they have shown that more than 10% of forested wetland within the Alligator River National Wildlife Refuge in North Carolina have been lost over the last 35 years. They point out that the widespread loss of forests has cascading impact on wildlife. Ghosts forests have been witnessed in other parts of the world too.

What is sea-level rise?

Sea-level rise is an increase in the level of the world’s oceans due to the effects of global warming. The rise in sea levels is linked to two primary factors…

Thermal expansion:

The oceans are absorbing more than 90% of the increased atmospheric heat associated with greenhouse gas emissions. When water heats up, it expands. The ocean water expands and takes up more space. This is called expansion, and it is responsible for one-third of the sea-level rise.

Melting of glaciers and ice caps:

Warmer temperatures cause land-based ice such as glaciers and ice sheets to melt, and the meltwater flows into the ocean to increase sea level. Melting ice causes about two-thirds of the rise in sea level.

In 2019, a study projected that in low-emissions scenario, sea level will rise 30 cm by 2050 and 69 cm by 2100. In high-emission scenario, it will be 34 cm by 2050 and 111 cm by 2100. In the worst-case scenario – in which the planet heats up by 5 degrees Celsius in the next 80 years – melted ice could raise sea levels worldwide by more than 198 cm, according to another study published in May 2019.

Impact of sea-level rise on coastal region

• The impact of sea-level rise includes flooding, habitat destruction, soil erosion, and disappearance of low-lying islands. Rising sea levels also made storm surges capable of much greater damage. (Storm surge is the abnormal rise in seawater level during a storm. Storms surge can penetrate well inland.) Higher sea levels are coinciding with more hurricanes, contributing to more powerful storm surges that can strip away everything in their path.
• Many birds use coastal ecosystems to find food, live, and breed. Sea turtles lay their eggs on beaches returning to the same location every year. When beaches erode, these animals and birds will be affected.
• Rising sea levels will lead to the displacement of people. It could create 187 million climate refugees by 2100, according to a study.

About ghost forests

Rising seas often conjure the threat to faraway, low-lying nations, coastal cities or island-States sometime in the future. But the fact is the effects are already being felt by coastal vegetation. Ghost forests, which are landscapes filled with ghostly dead trees, are the immediate consequences of sea-level rise. These leafless, limbless trees can last decades in this dried-up barren state.

Sea-level rise connection

Sea-level rise increases the risk of saltwater intrusion. It is the flow of seawater into wetlands and rivers. As sea level rises, more and more saltwater encroaches on the land and overtakes freshwater that trees rely upon for sustenance. The salty water slowly poisons trees and eventually kills them. (Dead trees with pale trunks are a telltale sign of high salt levels in the soil.)

The rising salt water also leaves soil unhealthy and forests unsuitable for new growth. What scientists witness is that, while large patches of trees are dying simultaneously, saplings of the same species aren’t growing to take their place. Instead, shrubs and grasses that are more salt-tolerant are moving in to take their place.

Scientists also note that extreme weather events, fuelled by climate change, are causing further damage to vegetation in the form of heavy storms, more frequent hurricanes and drought. This is causing mass tree die-offs across coastal regions.

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In our fight against global warming and climate change, trees are considered part of the solution. But emerging research suggests that trees are also part of the problem.

Trees are carbon sinks locking up vast amounts of carbon dioxide from the atmosphere. This way, they help protect the planet from the harmful effects of the greenhouse gas. But there seems to be another face to trees, that scientists have uncovered only recently. They find that trees emit methane, which is a greenhouse gas 45 times more potent than carbon dioxide at warming our planet. Scientists unofficially call this treethane (tree methane). However, it's currently unknown just how much of methane is emitted by trees.

Emission of methane from cottonwood trees was first observed in 1907, but the finding was reported mainly as a novelty and was largely ignored. Subsequent research has picked up only recently, but in a big way. An expanding network of researchers has discovered methane release from trees from the vast flooded forests of the Amazon basin to Bomeo's soggy peatlands, from temperate upland woods in Maryland and Hungary to forested mountain slopes in China.

Source of methane

Some lowland forest trees such as cottonwood emit flammable methane directly from their stems, which is likely produced by microbes living within. Scientists think trees may also be emitting methane from a direct photochemical reaction thought to be driven by the ultraviolet wavelengths in sunlight Research in this area is still in its early stages and so there is a lot left to be understood.

But understanding why, how and which trees emit the most methane is crucial, as trillions of trees are being planted across the world in an effort to mitigate climate change. However, scientists point out that the amount of methane emitted by trees is generally dwarfed by the amount of carbon dioxide they take in over their lifetime. Forests are still key to maintaining a safe climate, they point out.

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Plastic bags. They are everywhere, aren’t they? If you go shopping in the mall, you end up with a number of them. If you buy some clothes from a store, they are given to you in plastic bags. Picking up some groceries from the road-side vendor? They hand it to you in small plastic bags. There’s no escaping plastic bags, really. And very few even try to…

For an item that is now present everywhere, it has a rather short history. While plastics had been around in the first half of the 20th Century, it was only in the 1950s that a process to produce high-density polyethylene was first figured out.

How to best use it?

Once that came about, some products made of plastics started to get a move on. Yet, companies were still trying to find out how best to utilise the new substance at hand and maximise their advantage.

Among these companies was a Swedish company called Celloplast, which had sold cellulose film. Finding themselves with these plastics, the company invested resources to identify better ways of using and selling it.

Packaging purposes

It was in 1960 that Celloplast filed for a U.S. patent for “tubing for packaging purposes”. Designed by a team of three employees, their idea was to lay flat a tube of plastic and seal it at regular intervals in order to create the bottom of a bag. Left open at the top, anything could be placed inside these bags, which then could be packaged.

By the time this patent made its way in March 1962, Sten Gustaf Thulin, one of the three employees, was onto a better idea that would further enhance their existing one. Instead of just sealing the bottom and leaving the top open, Thulin realised that punching out part of the plastic tubes at the top would create handles for these bags.

Thulin’s “bag with handle”

Celloplast filed a patent for Thulin’s idea in July 1962. On April 27, 1965, they received the U.S. patent for “Bag with handle of weldable plastic material”. Thulin’s idea, what is now often called the “T-shirt plastic bag”, is the design behind every plastic bag that we see these days.

As the years went by, plastic bags started replacing every other type of bag in existence. By the end of the 1970s, 80% of the bag market in Europe was controlled by plastic bags. They were then introduced in the U.S., where they were marketed aggressively as superior to existing alternatives.

Solution turns problem

When Thulin came up with the idea, he was hoping to protect the environment as well. Back then, paper bags were the most popular type of carrier bags. For these paper bags, they not only had to cut down a lot of trees, but they also require more energy and water to produce, all of which have an impact on the planet we reside in.

Thulin believed that his plastic bags, which were both lighter than paper bags and also more energy efficient to make, would be used repeatedly by everyone. Speaking to BBC in 2019, Raoul Thulin, son of Sten Gustaf, said that “the idea that people would simply throw these away would be bizarre” to his dad. He also mentioned that his father always carried one of these folded up plastic bags in his pocket in order to make sure he could reuse the same bag.

Somewhere along the way, however, these plastic bags became so convenient, easily accessible, and cheap that people started throwing them away after a single use. Even though they weren’t supposed to be single-use products, they ended up being that way.

Use, reuse, mend, recycle

While plastic pollution is a huge problem and one to which we don’t have sound answers yet, simply ditching plastic to other alternatives isn’t a great idea either as they too can have adverse effects, including climate change. Research suggests that in order to be as environmentally friendly as a single-use plastic bag that gets recycled, a paper bag needs to be used at least three times. As for bags that are made of cotton, which is an intensive crop requiring a lot of water, it would have to be used 131 times to have the same environmental impact as a single-use plastic bag that is recycled.

Though all this might make the simple choice of selecting a bag seem daunting and confusing, an easy way to navigate it might be using the bag that you already have over and again. Do this for as long as you can and when the bag breaks, try to repair it. And when the bag reaches a stage where it can no longer be mended either, make sure that you recycle the bag. Remember, if we all take these simple steps, we will be protecting our Earth a little better.

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 As parts of India prepared to welcome the south-west monsoon, a powerful cyclonic system named Tauktae (pronounced ‘tau-tay’) wreaked havoc on the coastal areas of Gujarat, Maharashtra, Goa, Karnataka, and Kerala, mid-May.

Categorised as Extremely Severe Cyclone, Tauktae made landfall in Gujarat on May 17 and weakened into a ‘Very Severe’ category, with wind speeds of up to 160kmph. Unleashing a fury of rainfall and winds in the States along the west coast, the cyclone left a trail of destruction. Off the coast of Mumbai and Gujarat, two barges (freight-carrying boats) and an oil rig with hundreds of personnel on board were underway. Rains from the storm also killed many in Kerala, Karnataka, and Goa.

Cyclone Tauktae was the fifth-strongest cyclone ever in recorded history in the Arabian Sea. Scientists have been observing something unusual in the Arabian Sea in the recent years. There has been an increase in the frequency and strength of storms that originate in the sea.

What is cyclone?

The term cyclone refers to any spinning storm that rotates around a low-pressure centre. It is referred to by different names, depending on where it originates. If it forms over the South Pacific and the Indian Ocean, it is called a cyclone, if it originates in the Atlantic basin, it is a hurricane; and if it originates in the Northwestern Pacific Basin, it is called a typhoon.

In general such storms form over tropical or subtropical waters, and hence are called tropical cyclones.

How does a cyclone form?

Cyclones occur when warm, moist air over a warm ocean rises. As the air moves up, there is less air left on the surface, causing an area of low air pressure below. This area soon gets filled by air from the surrounding areas. Because of its proximity to the warm ocean water, this ‘new’ air gets warmer rapidly. It rises and condenses to form clouds and winds. This cycle continues. The whole system of clouds and winds gathers momentum and begins to swirl like a top, due to the rotation forms a relatively calm centre. This is called the eye of the storm.

High pressure air from above flows down into the eye, whipping up huge waves that are carried makes landfall at a coast, it not only brings very strong winds, but also heavy rains, causing a lot of damage. The cyclone gets stronger as it crosses the ocean, but loses strength once it hits the land.

Impact of cyclones

• The cyclone comes with a wind speed ranging from 63 kmph to more than 200 kmph. At such speeds, the winds can be destructive, causing extensive damage to people and property.
• The wind also brings heavy rains, sometimes leading to flooding.
• Another deadliest outcome of a cyclone is a storm surge. A storm surge occurs when water level rises dramatically, with powerful winds pushing the ocean water towards the land. Storm surge is a threat to life and property. Surges can extend for dozens of miles inland, overwhelming buildings and cutting off roads quickly. The walls of water can begin even before a storm makes landfall, leaving little time to save lives. One of the best protections is evacuation of people to areas of higher elevation.

Different types

The wind speed of a cyclone determines its type. Based on the Tropical Cyclone Intensity Scale, which IMD uses, a cyclone is categorized in the following ways…

• Super cyclonic storm (wind speed more than 221 kmph).
• Extremely severe cyclonic storm (166-220 kmph).
• Very severe cyclonic storm (118-165 kmph).
• Cyclonic storm (63-88 kmph).

How cyclones get their names

• Tropical storms and cyclones were earlier tracked by year and order of occurrence. Over time, they were given names for easy recognition. The World Meteorological Organisation, a UN body, maintains a list to name tropical cyclones around the world. Countries in the regions of hurricanes, typhoons and cyclones send suggestions for the list to the global met authority. Tauktae has been suggested by Myanmar, and in Burmese, it refers to a type of gecko.
• The IMD is among six regional specialized meteorological centres in the world that have been mandated to name tropical cyclones in the north Indian Ocean region. Countries such as Bangladesh, the Maldives, Myanmar, Oman, Pakistan, Sri Lanka and Thailand suggest names for cyclones that form over the Bay of Bengal and the Arabian Sra, and they are used sequentially.

Spotlight on Arabian Sea

Historically, the Arabian Sea sees an average of two or three cyclones, that were typically weak, in a year. It is also a lot cooler than the Bay of Bengal, which is why it had fewer severe cyclones than the Bay of Bengal.

A study by the Indian Institute of Tropical Meteorology has shown that both the frequency and intensity of cyclones in the Arabian Sea are on the rise. Cyclone Tauktae is the first time since the start of satellite records in 1980 in India that there have been four consecutive years of pre-monsoon cyclones in the Arabian Sea. This is also the third consecutive year when a cyclone has come so very close to the west coast of India.

The experts believe the key reason is a rise in the ocean temperature as the Arabian Sea has become one of the fastest warming basins across the global oceans. Arabian Sea temperatures prior to cyclone formation are now 1.2-1.4  higher in the recent decades, compared to those four decades ago. This has led to an increase in the frequency and intensity of cyclones in the Arabian Sea, they say.

Role of global warming

Oceans soak up more than 90% of the heat generated by greenhouse gases, leading to rising water temperatures.

As cyclones draw their energy from warm waters, rising temperatures are causing intense storms to become more common.

The intensity of cyclones, hurricanes and typhoons might increase in the next century due to global warming, a joint British-American study published in April 2021, has said. Scientists, part of the study, analysed 90 peer-reviewed articles to understand the impact of a changing climate on tropical cyclones. They concluded that there could be a 5% increase in maximum cyclonic wind speeds if the world warmed by two degree Celsius by 2100.

Moreover, rising sea levels could also boost storm surges from cyclones, making them even more deadly and destructive.

 

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Positive impact

CO2 Emission

Reports that emerged late 2020 showed that the pandemic did have an impact on the CO2 emission last year. Widespread shutdowns, drastic reduction in industrial activities and commuter traffic led to significant drop in the level of greenhouse gases in the atmosphere. In November 2020, the World Meteorological Organisation (WMO) estimated that the annual global CO2 emission reduced 4.2-7.5 % in 2020. April 2020 saw a drop of about 17% in global monthly CO2 emissions from fossil fuels, but the annual CO2 emissions for the globe were only 7% lower than they were in 2019. However, the WMO called it a blip on the planet’s uncontrolled emission scenario. Scientists pointed out the Earth’s atmosphere has a heavy concentration of greenhouse gases, including CO2. The temporary reduction in emission due to the pandemic would not curb global warming and resultant climate change. However, we can consider this a positive impact because the pandemic has shown us that it is not impossible to reduce CO2 emission and it has offered us many lessons on Nature conservation – lessons, albeit learnt the hard way.

Pollution

Besides CO2, the concentration of other pollutants such as carbon monoxide, NO2 and PM2.5 also saw a sharp reduction in major cities of the world last year.

Water quality

Water quality too improved in 2020. For the first time in decades, the water of river Ganga was found to be fit enough for drinking as per a study conducted by the Indian Institute of Technology, Roorkee. Scientists attributed it to the lockdown induced by the pandemic. There was 500% reduction in sewage and industrial effluents, and human activities in the vicinity of the river were almost nil. Studies conducted in the U.S., European countries, and China had also found an improvement in water quality in the rivers and lakes of their respective countries.

Less noise

With industries and traffic falling silent for a major part of the pandemic, there has been a reduction in noise pollution. A short-term study conducted in Pune last year showed that commercial areas witnessed the maximum drop from 74.56 decibels (dB) in March 2020 to 66.55 in April 2020, and residential areas saw it drop from 49.75 dB to 47.48 dB and silent zones from 49.53 dB to 47.11 dBIn Kanpur, the average noise levels before and during the lockdown were found to be in the range of 44.85 dB to 79.57 dB and 38.55 dB to 57.79 dB respectively. Similar reduction in noise was also found in other parts of the world. However, it is to be remembered that these improvements won’t last if the world goes back to its pre-pandemic ways.

Wildlife

After several early cases of COVID-19 were linked to a wet market in China, wildlife trade became central to discussions on public health. Countries such as China and Vietnam acted quickly to introduce large-scale prohibitions of wildlife trade. China upgraded the legal protections for pangolins to the same status as the nation’s beloved panda, prohibiting nearly all domestic trade and use. This is among the biggest positive outcomes of the pandemic.

Meanwhile, the lockdown brought wildlife to the cities. Animals in urban areas were exploring empty streets and waterways. Those in the nature reserves and parks caught some quiet time without the disturbances from tourists. Even sea turtles were spotted returning to areas they once avoided to lay their eggs, all due to the lack of human interference. Scientists reported that plants were growing better because there was cleaner air and water.

Negative impact

Biomedical waste

The management of biomedical waste such as personal protective equipment (PPE), gloves, face masks, head cover, among other gear and medical equipment used by both healthcare providers and patients is the biggest challenge that governments around the world are facing. According to the data shared by Central Pollution Control Board, India generated over 18,000 tonnes of COVID-19-related biomedical waste between June and September last year. India’s Covid vaccination drive is also seeing thousands of syringes being disposed of every day. The Indian government has defined standards, protocols and guidelines for different categories of biomedical waste but unsafe disposal of such waste in open dustbins is not uncommon in the country.

Plastic is back

Just a couple of years ago, the world woke up to the problem of plastic and was taking measures to find an alternative to single-use plastic. Many countries and States of India had restrictions on the usage of single-use plastic. But those commitments were thrown out the window when the pandemic hit us. Moreover, plastic products play a significant role in protecting people during the COVID-19 pandemic. Materials such as PPE suits, face shields, masks and gloves are plastic, and they are meant to be disposed of after single use. Besides, the fear of surface contamination has made disposal cups, cutleries, and plastic bags make a swift comeback. The amount of plastic waste generated worldwide since the COVID-19 outbreaks estimated at 1.6 million tonnes / day. This could cause a surge in plastics washing up on the ocean coastlines and littering the seabed.

Deforestation and poaching

Many people have lost their jobs and livelihood due to COVID-19 and this has contributed to illegal tree felling, illegal mining and wildlife poaching. There are reports of increased deforestation in Asia, Africa, and Latin America.

Areas that are economically dependent on tourism face reduced resources as tourism has come to a halt. This is leaving animals in the reserves with much less protection. There has been an increase in wildlife poaching – either to provide food for hungry families or for illegal sales.

 

Picture Credit : Google