What is climate change?
Climate change refers to the long-term alteration of global temperatures and weather patterns, primarily caused by human activities — especially the burning of fossil fuels — since the Industrial Revolution. The resulting increase in greenhouse gases has raised global temperatures by approximately 1.1 degrees Celsius, driving rising sea levels, extreme weather events, ecosystem collapse, and what scientists consider the defining crisis of the 21st century.
Climate change is arguably the most consequential challenge humanity has ever faced — a slow-moving crisis that threatens to reshape the planet's geography, ecology, and human civilization itself. Unlike the sudden catastrophes of war or plague, climate change unfolds over decades, making it both harder to perceive urgently and harder to reverse.
The science is well established. Earth's atmosphere contains greenhouse gases — carbon dioxide, methane, nitrous oxide — that trap heat from the sun. This greenhouse effect is natural and necessary for life. But since the Industrial Revolution, the burning of coal, oil, and natural gas has dramatically increased the concentration of these gases. Atmospheric CO2 has risen from roughly 280 parts per million in 1750 to over 420 ppm — the highest level in at least 800,000 years. Deforestation, agriculture, and industrial processes contribute additional emissions.
The consequences are already visible. Global average temperatures have risen approximately 1.1 degrees Celsius since pre-industrial times. Arctic sea ice is declining. Glaciers are retreating worldwide. Sea levels have risen about 20 centimeters since 1900 and are accelerating. Extreme weather events — heatwaves, hurricanes, droughts, floods — are becoming more frequent and severe. Coral reefs are bleaching. Species are shifting their ranges or going extinct. The Intergovernmental Panel on Climate Change (IPCC) warns that limiting warming to 1.5 degrees Celsius — the target of the Paris Agreement — requires halving global emissions by 2030 and reaching net zero by 2050.
The political challenge is immense. Climate change is a global problem that requires collective action, but the costs and benefits of action are distributed unevenly. Developed nations that industrialized early bear the most historical responsibility for emissions, but developing nations — particularly small island states and sub-Saharan Africa — face the most severe impacts. The fossil fuel industry has spent decades funding doubt about climate science and lobbying against regulation.
Solutions exist. Renewable energy — solar, wind, and battery storage — has become cheaper than fossil fuels in many markets. Electric vehicles are rapidly improving. Energy efficiency technologies can dramatically reduce demand. But the transition requires unprecedented international cooperation, massive investment, and the willingness to transform energy systems, transportation, agriculture, and industry within decades. Climate change tests whether human civilization can organize itself to address a threat that unfolds slowly, crosses national boundaries, and demands sacrificing short-term convenience for long-term survival.