Why carbon dioxide drives the long-term warming trend
The main greenhouse gas released by burning coal, oil, and natural gas is carbon dioxide (CO₂). When these fuels burn, their carbon combines with oxygen in the air, adding CO₂ that had been stored underground for millions of years.
CO₂ warms the planet by absorbing some of the heat Earth radiates toward space and sending part of that energy back through the atmosphere. The gas is transparent to most incoming sunlight, so the key effect is not blocking sunlight but slowing the escape of heat. As people add more CO₂, this heat-trapping effect strengthens.
Why the effect builds over decades
CO₂ does not disappear after a brief spell in the air. Oceans, forests, and soils absorb some of it, but the excess is removed only gradually; a portion remains in the atmosphere for centuries or longer. Each year’s emissions therefore add to the influence of past emissions. That persistence makes CO₂ especially important for explaining the steady rise in global temperatures over time.
Other human-produced gases also warm the climate. Methane, for example, traps heat strongly but breaks down much faster than CO₂. CO₂’s enormous, continuing emissions and long atmospheric persistence make it the leading cause of the long-term warming trend.
A heat wave is weather; the trend is climate
A particular heat wave can also be shaped by weather patterns, local conditions, and other influences. Climate change does not make every hot spell happen for one simple reason. Instead, the warming caused largely by accumulated CO₂ raises the baseline: when natural weather produces extreme heat, it now starts from a warmer world, making many heat extremes more likely or more intense.
