4.1.1. Global warming phenomena and GHG emissions

The phenomenon of global warming occurs when greenhouse gases or GHG, such as carbon-dioxide (CO₂), chlorofluorocarbons, water vapour, methane (CH₄), and nitrous oxide (N₂O), which are heat-trapping pollutants create a layer in the Earth’s atmosphere that disallows solar radiation emitted by the earth’s surface to escape and instead absorbs the heat, thereby increasing the surface temperature.

The greenhouse effect is a natural process that allows the Earth to maintain a habitable temperature. It happens when certain gases in the atmosphere trap heat from the sun, preventing it from escaping back into space. This is necessary for life as it keeps our planet warm enough. However, human activities have significantly increased the concentration of these greenhouse gases, causing more heat to get trapped and thus raising the Earth's temperature.

Imagine a car parked in the sun with the windows closed. The sunlight enters the car and warms it up, but the heat can't escape, making the interior become very hot. This is similar to how greenhouse gases work in our atmosphere.

Human activities, especially the burning of fossil fuels (coal, oil, and natural gas), deforestation, and industrial processes, have significantly increased greenhouse gas emissions over the past century. The burning of fossil fuels for electricity generation, transportation, and industrial processes is the primary source of CO₂ emissions. Agricultural practices, such as livestock production and rice cultivation, contribute to CH₄ and N₂O emissions.

Over the past century, human activities have led to an increase in greenhouse gas emissions. The biggest contributor is the burning of fossil fuels to generate electricity, power cars, and run factories, which releases CO₂ into the atmosphere. Additionally, certain agricultural practices such as raising livestock (which produces methane, CH₄) and rice farming (which also releases methane) contribute to the problem. These emissions are changing the balance of gases in our atmosphere and accelerating global warming.

Think of our atmosphere like a balloon. When we burn fossil fuels, it’s like adding more air into that balloon. If we keep adding air (or greenhouse gases) without letting any out, eventually the balloon bursts! Similarly, our atmospheric balance is being disrupted, leading to more severe weather and climate changes.

As the concentration of greenhouse gases increases, more heat is trapped within the Earth's atmosphere, causing a rise in average global temperatures, leading to the melting of polar ice caps and rising sea levels. Increased CO₂ absorption by the oceans can lead to ocean acidification, which has detrimental effects on marine life.

Higher levels of greenhouse gases trap more heat, which results in a rise in global temperatures. This warming causes ice caps to melt, which contributes to rising sea levels that can inundate coastal areas. Additionally, the oceans absorb some of this excess CO₂, leading to a decrease in pH levels, a condition known as ocean acidification. This shift can have harmful effects on marine ecosystems, especially organisms like corals and shellfish that rely on calcium carbonate to build their shells.

Consider boiling a pot of water. As you heat the pot (representing rising temperatures), the ice cubes (representing polar ice caps) inside begin to melt, causing the water level to rise (similar to rising sea levels). If you added acidic substance to the water (like increased CO₂ in oceans), it would affect how some types of seafood could develop, just as higher CO₂ levels harm marine life.

The changing temperatures can intensify extreme weather events, such as hurricanes, heatwaves, droughts, and alter precipitation, which disrupts ecosystems and affects plant and animal species' distribution and migration patterns.

As the climate warms due to the increased greenhouse gas concentration, it affects weather patterns globally. This means that extreme weather events, like hurricanes and prolonged droughts, become more common and severe. Additionally, shifts in temperature and rainfall can change where plants and animals can live, making it harder for some species to survive. This disturbance affects not only wildlife but also human agricultural practices, as crops may struggle to grow in altered climatic conditions.

Imagine a plant that thrives in a specific temperature range. If the temperature becomes too hot for too long, that plant may die out, or it may be forced to move to a cooler area. Just like this plant, many animals are also changing migration patterns due to shifting climates, often leading to their struggle for survival.

The biggest GHG emitting nations are China, USA, Russia, and India. The top 10 emitters account for over two-thirds of annual GHG emissions, together accounting for over 50% of the global population and 75% of the world’s GDP.

Certain countries contribute more to greenhouse gas emissions than others, mainly due to their industrial activities and energy consumption. For instance, China, the USA, Russia, and India rank among the largest emitters, with their combined activities making up a significant portion of global emissions. This concentration not only represents a large share of the population but also a substantial part of the global economy, indicating the challenge these nations face in mitigating emissions while balancing economic growth.

Think of a team project where just a few people do most of the work. In this case, if those few who are contributing heavily don’t cooperate, the project might not succeed. Similarly, the world needs these major emitters to work together to reduce greenhouse gas emissions effectively—otherwise, global efforts might be less impactful.

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