4.1. Environment, Global Warming and Climate Change

The term ‘global warming’ refers to the long-term heating of the Earth’s surface observed since the beginning of the Industrial Era due to ‘greenhouse effect’ caused by human activities, primarily attributed to burning of fossil fuels and industrial processes, and deforestation which leads to significant greenhouse gas emissions.

Global warming describes a gradual increase in Earth’s temperature predominantly due to human activities that release greenhouse gases (GHGs), like carbon dioxide, methane, and nitrous oxide, into the atmosphere. These gases trap heat, leading to a rise in the planet's average temperature. The Industrial Era, starting in the late 1700s, marked a significant rise in the burning of fossil fuels for energy, which has accelerated this warming. It's crucial to note that global warming is specifically about temperature increase, while "climate change" encompasses broader changes in weather patterns.

Think of the Earth as a car with the windows closed on a sunny day. As the sun shines through the glass, the temperature inside the car rises significantly, similar to how greenhouse gases trap heat in the Earth's atmosphere, leading to an overall warming.

This term should not be used interchangeably with Climate change, as the latter refers to the long-term change in the average weather patterns – temperature, precipitation, wind and tidal patterns, and is not limited to the adverse effects of human activities alone.

While global warming pertains specifically to rising temperatures, climate change represents a more comprehensive set of changes in weather patterns over extended periods. This can include shifts in precipitation, the frequency and intensity of storms, and changes in wind patterns. While human activity is a major driver of current climate change, natural processes also play a role, such as volcanic eruptions and variations in Earth’s orbit.

Consider a person’s individual health: global warming is like the increase in body temperature caused by a fever, while climate change is akin to a mix of various health issues like diet, exercise, and genetics that influence overall well-being.

Climate change has far-reaching consequences beyond temperature increase, as it affects ecosystems, agriculture, water availability, human health, and socio-economic systems.

As the climate changes, numerous aspects of life on Earth are impacted. Ecosystems experience shifts, leading for example to migrations or extinction of certain species. Agriculture may suffer or benefit from altered rainfall patterns and temperatures, affecting food supply. Water sources may change in availability or quality, leading to shortages. Additionally, human health might be negatively impacted by increased heatwaves, and socio-economic systems can become strained as resources become scarce or as populations are displaced.

Think about how a family farm relies on a consistent climate to grow crops. If rainfall patterns drastically change or temperatures increase beyond comfort levels, their ability to produce food is compromised, similar to how broader societal systems can destabilize under climate stress.

Key indicators of Climate change are; frequency and severity changes in extreme weather such as hurricanes, heatwaves, wildfires, droughts, floods, and precipitation; ice loss at Earth’s poles and in mountain glaciers; rising sea levels; cloud and vegetation cover changes, as well as the global land and ocean temperature increases.

Certain signs clearly indicate ongoing climate change. These include an increase in extreme weather events, such as more intense hurricanes and heatwaves, melting polar ice caps resulting in higher sea levels, and shifts in ecosystems, evidenced by changes in land and ocean temperatures. Monitoring these indicators helps scientists understand the severity and urgency of climate change.

Just like a car dashboard lights up to warn you of problems, these climate indicators alert us to the health of our planet and the urgent need for action.

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 which disallows the solar radiation emitted by the earth’s surface to escape and instead absorbs the heat, thereby increasing the surface temperature.

Greenhouse gases trap heat in the atmosphere, leading to the greenhouse effect, which is essential for maintaining Earth’s temperature. However, human activities have increased the concentration of these gases significantly, enhancing this effect and causing global temperatures to rise. Key sources of GHG emissions include burning fossil fuels, agricultural practices, and deforestation.

Imagine putting on a thick blanket on a warm day: the blanket traps the heat close to your body, making you warmer. Similarly, Earth’s atmosphere filled with excessive GHGs traps solar energy, causing the planet to heat up more than it normally would.

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.

Fossil fuels like coal, oil, and natural gas are the main contributors to CO2 emissions when burned for energy. Agriculture adds to greenhouse gases through methane released during digestion in livestock and nitrous oxide from fertilizers. Understanding these sources helps focus efforts on mitigation strategies effectively.

Think about how a car produces exhaust when running. Similarly, our energy systems create emissions when fossil fuels are burned, and farms produce their own 'exhaust' in the form of greenhouse gases from livestock and crops.

As the concentration of greenhouse gases increases, more heat is trapped within the Earth's atmosphere, causing a rise in average global temperatures, in turn, leading to the melting of polar ice caps and rising sea-level.

An increase in greenhouse gases leads to increased heat retention in the atmosphere, resulting in higher global temperatures. This exacerbates issues such as ice melting in polar regions, resulting in rising sea levels that threaten coastal communities and ecosystems. The interconnection between rising temperatures and polar ice melt highlights the urgency in tackling GHG emissions.

Picture an ice cube melting in a warm drink. As the drink warms up (representing rising temperatures), the ice melts faster, leading to a rise in liquid levels (similar to rising sea levels).

The UN’s Intergovernmental Panel on Climate Change (IPCC) forewarns that to limit global warming to 1.5°C, GHG emissions must peak before 2025 at the latest and decline 43% by 2030, as they indicate that crossing the 1.5°C threshold risks unleashing severe climate change impacts.

The IPCC warns that urgent action is needed to curb GHG emissions to prevent catastrophic climate outcomes. The aim is to keep global temperature rise below 1.5°C compared to pre-industrial levels, which would require significant and immediate reductions in emissions. International cooperation, like the Paris Agreement, aims to unite countries in this critical endeavor.

Think of it as a team sport where all players must work together to avoid losing the game (the climate) and aim to stay below a certain score (the 1.5°C threshold), cooperating with strategies and rules that each player agrees to follow.

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