Why Is Earth Getting Warmer? The Causes of Climate Change

Imagine wrapping yourself in a thick blanket on a warm night. You'd soon overheat. Earth has something like a blanket too — a layer of gases in the atmosphere. For thousands of years, this blanket kept our planet at just the right temperature. But what happens when that blanket gets thicker? Think about what you already know: have you heard the words 'greenhouse effect' or 'carbon footprint' before? Where did you come across them?

Earth's climate is shaped by the greenhouse effect. Here is how it works: the Sun sends energy to Earth as light. Earth's surface absorbs this energy and releases it back as heat. Greenhouse gases in the atmosphere trap some of that heat, keeping Earth warm enough for life. Without them, our planet would be about 33 °C colder — frozen and largely uninhabitable. The problem is not the greenhouse effect itself. The problem is that human activity is releasing extra greenhouse gases, thickening the 'blanket' and trapping more heat than before. This is causing global average temperatures to rise — a process scientists call enhanced global warming. **The main greenhouse gases and their sources:** • Carbon dioxide (CO₂) — Released when we burn fossil fuels (coal, oil, and natural gas) for electricity, heating, and transport. Deforestation also adds CO₂ because trees that stored carbon are cut down and often burned. • Methane (CH₄) — A more powerful greenhouse gas than CO₂ over a short period. It comes from livestock (cattle produce methane during digestion), rice paddies, landfill sites, and leaks from gas pipelines. • Nitrous oxide (N₂O) — Released mainly from agricultural fertilisers and some industrial processes. • Water vapour — Naturally the most abundant greenhouse gas, but human activity raises temperatures, which increases evaporation and adds more water vapour, amplifying warming in a feedback loop. **Natural causes also exist.** Volcanic eruptions release CO₂ and can temporarily cool the climate by sending ash into the upper atmosphere. Variations in Earth's orbit (called Milankovitch cycles) and changes in solar output have driven natural climate shifts over thousands of years. However, the rapid warming since the mid-20th century is far faster than any natural cycle can explain. The scientific consensus is that human activity is the dominant cause of current climate change. **A real-world example:** The Arctic is warming nearly four times faster than the global average. As permafrost (permanently frozen ground across Siberia, Canada, and Alaska) thaws, it releases methane that was trapped for thousands of years — a feedback that accelerates warming further.