Climate change and the greenhouse effect

Climate change is one of the most pressing issues facing humanity today. It refers to long-term alterations in temperature, precipitation patterns, and other atmospheric conditions on Earth. While natural factors, such as volcanic activity and solar variations, have contributed to climate fluctuations over the planet’s history, the current trend of global warming is primarily driven by human activities. These activities, including the burning of fossil fuels and deforestation, release vast amounts of greenhouse gases (GHGs) into the atmosphere, disrupting the Earth's natural processes and leading to significant environmental and societal impacts.

The greenhouse effect

At the heart of climate change is the greenhouse effect, a natural phenomenon that keeps the Earth's surface warm enough to sustain life. The Earth receives energy from the sun in the form of sunlight. Some of this energy is reflected back into space by the atmosphere and surface, but most of it passes through the atmosphere and is absorbed by the Earth, warming the surface. The Earth, in turn, radiates heat back towards space in the form of infrared radiation. Greenhouse gases, such as carbon dioxide (CO₂), methane (CH₄), water vapor, and nitrous oxide (N₂O), trap some of this outgoing heat, preventing it from escaping into space.

Without this natural greenhouse effect, the Earth’s average temperature would be about 33°C cooler, making the planet uninhabitable for most forms of life. However, human activities have significantly increased the concentration of greenhouse gases, particularly CO₂, which has led to an enhanced greenhouse effect. This additional heat trapped in the atmosphere is driving global warming, with consequences that include more extreme weather events, rising sea levels, and disruptions to ecosystems.

The Carbon Cycle

The carbon cycle is the process by which carbon moves between the atmosphere, oceans, plants, animals, and the Earth’s crust. It is a fundamental natural system that regulates the concentration of carbon in the environment, ensuring that life can flourish. Carbon exists in various forms, including as carbon dioxide in the atmosphere, organic carbon in living organisms, and carbonate in rocks and ocean sediments.

There are two main components of the carbon cycle: the fast carbon cycle and the slow carbon cycle. The fast carbon cycle involves the exchange of carbon between living organisms and the atmosphere. Plants absorb CO₂ during photosynthesis to produce energy, which is then consumed by animals and other organisms. When these organisms die, their carbon returns to the atmosphere through decomposition. This process operates on timescales of years to centuries.