My Science School

Greta Tintin Eleonora Ernman Thunberg is a Swedish environmental activist who is internationally known for challenging world leaders to take immediate action for climate change mitigation. Thunberg initially gained notice for her youth and her straightforward speaking manner, both in public and to political leaders and assemblies, in which she criticises world leaders for their failure to take what she considers sufficient action to address the climate crisis.

Seeking to make a greater impact, Thunberg attempted to spur lawmakers into addressing climate change. For almost three weeks prior to the Swedish election in September 2018, she missed school to sit outside the country’s parliament with a sign that stated “Skolstrejk för Klimatet” (School Strike for Climate). Although alone for the first day of the strike, she was joined each subsequent day by more and more people, and her story garnered international attention. After the election Thunberg returned to school but continued to skip classes on Fridays to strike, and these days were called Fridays for Future. Her action inspired hundreds of thousands of students around the world to participate in their own Fridays for Future. Strikes were held in such countries as Belgium, Canada, the United States, the United Kingdom, Finland, Denmark, France, and the Netherlands.

Her sudden rise to world fame has made her both a leader and a target for critics, especially due to her age. Her influence on the world stage has been described by The Guardian and other newspapers as the "Greta effect". She received numerous honours and awards, including an honorary Fellowship of the Royal Scottish Geographical Society, inclusion in Time's 100 most influential people, being the youngest Time Person of the Year, inclusion in the Forbes list of The World's 100 Most Powerful Women (2019), and three consecutive nominations for the Nobel Peace Prize (2019–2021).

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Heat wave, also called heatwave, period of prolonged abnormally high surface temperatures relative to those normally expected. Heat waves may span several days to several weeks and are significant causes of weather-related mortality, affecting developed and developing countries alike.

The term is applied both to hot weather variations and too extraordinary spells of hot which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, and widespread power outages due to increased use of air conditioning. A heat wave is considered extreme weather that can be a natural disaster, and a danger because heat and sunlight may overheat the human body. Heat waves can usually be detected using forecasting instruments so that a warning call can be issued.

Heat waves form when high pressure aloft (from 10,000–25,000 feet (3,000–7,600 metres)) strengthens and remains over a region for several days up to several weeks. This is common in summer (in both Northern and Southern Hemispheres) as the jet stream 'follows the sun'. On the equator side of the jet stream, in the upper layers of the atmosphere, is the high pressure area.

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Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes. Hypoxia occurs when dissolved oxygen (DO) concentration falls to or below 2ml of O2/liter. When a body of water experiences hypoxic conditions, aquatic flora and fauna begin to change behavior in order to reach sections of water with higher oxygen levels. Once DO declines below 0.5 ml O2/liter in a body of water, mass mortality occurs. With such low concentration of DO, these bodies of water fail to support the aquatic life living there. Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated.

Dead zones can be caused by natural and by anthropogenic factors. Natural causes include coastal upwelling, changes in wind, and water circulation patterns. Other environmental factors that determine the occurrence or intensity of a dead zone include long water residence times, high temperatures, and high levels of sunlight penetration through the water column.

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The 2019 Amazon rainforest wildfires season saw a year-to-year surge in fires occurring in the Amazon rainforest and Amazon biome within Brazil, Bolivia, Paraguay, and Peru during that year's Amazonian tropical dry season. Fires normally occur around the dry season as slash-and-burn methods are used to clear the forest to make way for agriculture, livestock, logging, and mining, leading to deforestation of the Amazon rainforest. Such activity is generally illegal within these nations, but enforcement of environmental protection can be lax. The increased rates of fire counts in 2019 led to international concern about the fate of the Amazon rainforest, which is the world's largest terrestrial carbon dioxide sink and plays a significant role in mitigating global warming.

The increased rate of fires in Brazil has raised the most concerns as international leaders, particularly French president Emmanuel Macron, and environmental non-government organizations (ENGOs) attributed these to Brazilian president Jair Bolsonaro's pro-business policies that had weakened environmental protections and have encouraged deforestation of the Amazon after he took office in January 2019.

Other Amazonian countries have been affected by the wildfires in higher or lesser degree. The number of hectares of Bolivian rainforest affected by the wildfires were roughly equal to those of Brazil, being the area of Bolivia only about one-eighth of Brazil's. Bolivian president Evo Morales was similarly blamed for past policies that encouraged deforestation, Morales has also taken proactive measures to fight the fires and seek aid from other countries.

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Microbeads are small, solid, manufactured plastic particles that are less than 5mm in diameter and do not degrade or dissolve in water. They may be added to a range of products, including rinse-off cosmetic, personal care and cleaning products. Microbeads are a relatively cheap ingredient and are used in these products for a variety of purposes. This includes as an abrasive or exfoliant, a bulking agent, to prolong shelf-life, or for the controlled release of active ingredients.

Microbeads are not captured by most wastewater treatment systems. If washed down the drain after use, they can end up in our rivers, lakes, and oceans. These tiny plastics persist in the environment and have a damaging effect on marine life, the environment and human health. This is due to their composition, ability to adsorb toxins and potential to transfer up the marine food chain. The best way to reduce the impact of microbeads is to prevent them from entering the environment in the first place.

Further research needs to be conducted to determine how damaging the beads are for marine life, but current evidence suggests that sea-dwelling creatures at the bottom of the food chain are ingesting the plastic. It is possible that this has wider implications across our food chain as a whole. The fear surrounding marine microplastic pollution has led to a cross-party Environmental Audit Committee warning that increasing amounts of damage to sealife can lead to potential harm to human health, as a result of plastic being ingested and accumulating in marine life such as mussels and oysters.

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Methane (CH4) is the second most important greenhouse gas. It is more potent than CO2, but exists in far lower concentrations in the atmosphere. CH4 also hangs around in the atmosphere for a shorter time than CO2—the residence time for CH4 is roughly 10 years, compared with hundreds of years for CO2. Natural sources of methane include many wetlands, methane-oxidizing bacteria that feed on organic material consumed by termites, volcanoes, seepage vents of the seafloor in regions rich with organic sediment, and methane hydrates trapped along the continental shelves of the oceans and in polar permafrost. The primary natural sink for methane is the atmosphere itself; another natural sink is soil, where methane is oxidized by bacteria.
As with CO2, human activity is increasing the CH4 concentration faster than it can be offset by natural sinks. Human sources (rice cultivation, livestock farming, the burning of coal and natural gas, biomass combustion, and decomposition in landfills) currently account for approximately 70 percent of total annual emissions, leading to substantial increases in concentration over time.

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EXTREME LIVING

Humans have found a way of living in some of the most inhospitable environments on Earth – including the scorching deserts, the icy Arctic, and the steamy rainforests. Desert dwellers have to cope with the daily problem of finding water. In the Arctic, the challenges are keeping warm and finding food to eat. The rainforests are full of life, but many of the animals are dangerous, and some of the plants are poisonous.

ARCTIC

The frozen Arctic is one of the toughest places on Earth to survive. There are no plant foods, so Arctic people came to rely on hunting seals, walruses, whales, birds, and fish. Without timber, they used skins and bones to build shelters, sleds, and boats. Modern inventions, such as the snowmobile, have made life in this frozen wilderness easier.

RAINFOREST

Unlike the Arctic and the desert, the South American rainforest has a wide variety of animals and plants. The problem is that many of the animals and birds suitable for eating live high up in the canopy. Hunters scan the trees above for prey, such as monkeys, and then shoot them down using blowpipes firing poison darts.

DESERT

The extremes of temperature faced in the desert – extremely hot during the day, and very cold at night – is the main problem desert dwellers face. They are constantly on the move, searching for fresh water supplies, sometimes using the flight of birds and insects as their guide. Having found water, they must make sure that not a drop is wasted.

Ostrich egg: The San people of the Kalahari Desert, in southern Africa, fill ostrich eggs with water and bury them for using later.

Camels: Bedouins travel using camels, which can go without water for long periods thanks to the fat stored on their backs.

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When we talk about greenhouse gases, we often think of carbon-dioxide (CO2). But did you know nitrous oxide (N2O), also called laughing gas, is a potent greenhouse gas, with ozone-depleting property?

You must be aware that a greenhouse gas is a gas that traps heat in the atmosphere and keeps the planet warm. This process called the greenhouse effect is a good thing. Without it the world would be a frozen, uninhabitable place. However, too much greenhouse gases in the atmosphere can cause the temperature to increase out of control. The more greenhouse gases in the atmosphere, the hotter the earth will become. It changes the Earth's climate system and affect all forms of life.

The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapour. While carbon dioxide and to some extent methane have gained the recognition as climate change villains, N20 emission has largely been ignored in climate policies, despite its significant contribution to climate change.

A 2020 review of nitrous oxide sources and sinks found that emissions rose 30% in the last four decades. Nitrous oxide is responsible for roughly 7% of global warming since preindustrial times. Most N20 emissions have come from emerging countries like India, China and Brazil.

What are the sources of N20?

Nitrous oxide in the atmosphere comes from both natural and anthropogenic sources. The largest source of nitrous oxide is agriculture (73%), and the majority of agricultural emissions result from usage of nitrogen fertilizers and ill-management of animals waste.

Fossil fuel combustion and industrial processes are the other important source of nitrous oxide emissions. Biomass burning, atmospheric deposition and wastewater treatment are the other sources.

Why is N20 a cause for concern?

Like other greenhouse gases, nitrous oxide absorbs radiation and traps heat in the atmosphere. N20 has a long lifespan in the atmosphere-about 114 years.

N20 is nearly 300 times more potent at warming the planet than carbon dioxide, which means that even small sources of emissions can have a significant impact on the climate.

N20 has emerged as the most critical ozone depleting substance. It is stable in the lowest level of the atmosphere, the troposphere and acts like a greenhouse gas. When it migrates up to the stratosphere, it reacts with ozone and depletes it.

The growing demand for food and feed for animals and increased usage of fertilizers will further increase global nitrous oxide emissions.

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