Climate Justice in Sports: Quantifying the Thermally-Induced Competitive Inequality

This study examines the impact of thermal stress on competitive inequality in professional football. Using a labor productivity framework and a dataset of over 39,000 matches from the Big Five European leagues (France, England, Germany, Spain, and Italy) spanning 1996 to 2019, we analyze the effect of Wet-Bulb Globe Temperature (WBGT) on match outcomes through ordinal logistic regression. We find that higher WBGT significantly erodes the home advantage, functioning as a physiological equalizer. Mechanism analysis reveals that heat reduces home teams’ relative offensive output and degrades defensive discipline. Crucially, we introduce a previously unquantified component of home advantage, the adaptation gap, demonstrating that this climate acclimatization advantage erodes when the away team is better adapted to the prevailing heat than the home side. These findings reframe home advantage as a measurable physio-environmental phenomenon central to understanding climate justice in elite sports.