# Attribution Science Attribution science quantifies the human fingerprint on climate — both the long-term warming and, increasingly, individual extreme events. It is the discipline that answers the two questions deniers most rely on blurring: did humans cause the warming, and is *this* heatwave, flood, or hurricane connected to it. ## Detection and Attribution of the Warming The first task, detection and attribution, asks whether observed warming exceeds natural variability and what caused it. The answer rests on fingerprinting: each possible driver leaves a distinct spatial and temporal pattern. Greenhouse warming cools the stratosphere while warming the troposphere, amplifies warming at the poles, and warms nights faster than days. Solar warming would do none of these. Volcanic and natural variability operate on different timescales. When [[Climate Models]] are run with and without human emissions and compared against observations, only the runs that include greenhouse gases reproduce the observed record. The IPCC's conclusion that human influence is "unequivocal" is a detection-and-attribution result, not a guess. ## Event Attribution and the Weather/Climate Distinction The newer branch, extreme-event attribution, emerged in the 2000s. It uses large ensembles of model simulations to compare two worlds — one with human emissions, one without — and estimate how much warming changed the probability or intensity of a specific event. A typical finding is that a given heatwave was made, say, five times more likely or 2°C hotter by climate change. The 2003 European heatwave, the 2021 Pacific Northwest heat dome, and numerous floods and droughts have been analyzed this way, often within days of the event. This directly defeats the most common rhetorical move in climate denial: pointing to a cold snap or a snowstorm as if it refutes warming — the gambit [[James Inhofe]] performed by carrying a snowball onto the Senate floor. Weather is the state of the atmosphere on a given day; climate is the statistics of weather over decades. A cold day no more disproves warming than a single tall person disproves that a population's average height is shrinking. Attribution science makes the relationship rigorous: it does not claim warming "caused" any single event in isolation, but it can state precisely how much warming loaded the dice. The Meteorology of individual storms and the climatology of their changing odds are different questions, and attribution is what connects them. ## Connections Attribution depends on [[Climate Models]] and on the detection of warming signals against natural noise; it quantifies the human role in impacts such as [[Sea Level Rise]] and extreme heat. It is the technical rebuttal to the weather/climate conflation cataloged across [[Climate Science]]. For the field overview, see [[Climate Science]].