Earth's climate has shifted many times over its history. What distinguishes the current episode is its speed and its cause. Since the industrial revolution, burning coal, oil, and gas has released billions of tons of carbon dioxide into the atmosphere. Other greenhouse gases, including methane and nitrous oxide, add to the effect. These gases trap heat that would otherwise escape to space. Global average temperatures have risen about 1.1 degrees Celsius since the late 19th century, and the pace is accelerating.

The consequences are already visible. Heat waves are more frequent and intense. Heavy rainfall and flooding have increased in many regions. Droughts last longer. Polar ice sheets are losing mass, and sea levels are rising. Coral reefs are bleaching in warmer water. Species are shifting their ranges toward the poles and up mountains. Scientists project that without rapid emission cuts, warming could reach 2 to 4 degrees Celsius by 2100, with severe effects on food systems, coastlines, and human health.

Main drivers

• Fossil fuel combustion for energy and transport.
• Deforestation and land-use change.
• Agriculture, especially livestock and fertilizer.
• Industrial processes like cement production.

Climate change is not a future problem. It is a present one. The question is not whether to respond, but how quickly and at what scale.