地球超载日（EOD）

The concept of Earth Overshoot Day was conceived by Andrew Simms of the New Economics Foundation, a UK-based think tank. The primary goal was to create a simple, powerful, and easily understandable communication tool to highlight the scale of global resource unsustainability. While the underlying data and calculations are complex, framing the result as a specific calendar date makes the abstract notion of ecological deficit tangible and relatable to the general public. Each year, the Global Footprint Network, which partnered with Simms’ organization in 2006 to launch the first global EOD campaign, calculates the date. The campaign uses this date to raise awareness and encourage action from individuals, organizations, and governments. The narrative is compelling: the earlier the date falls in the year, the greater the ecological deficit. For instance, in 1971, the date was in late December, indicating a near balance. By the 2020s, it has consistently fallen in July or August, visually demonstrating that humanity is using approximately 1.7 Earths’ worth of resources annually. This framing helps to catalyze discussions on topics like 循环经济, renewable energy, sustainable agriculture, and population growth, making it a cornerstone of modern environmental advocacy.

计算

地球超载日的日期是由一个相当简单的公式决定的，这个公式比较了地球的生态供应和人类需求。计算公式为：[latex]/frac{text/{世界生物容量}}/{text{世界生态足迹}}。\乘以 365[/latex]。计算结果就是一年中地球再生能力足以满足人类消耗的天数，第二天就是地球过剩日。.

The formula’s two core components are the Ecological Footprint and Biocapacity, both developed by Mathis Wackernagel and William Rees. The Ecological Footprint represents the demand side, quantifying the biologically productive land and sea area required to produce all the resources a population consumes and to absorb its waste, particularly carbon emissions. The Biocapacity represents the supply side, measuring the productivity of a region’s ecological assets, such as forests, croplands, and fishing grounds. Both metrics are measured in a standardized unit called a ‘global hectare’ to allow for aggregation and comparison. The Global Footprint Network calculates these values for the entire world and for individual nations using data from sources like the United Nations Food and Agriculture Organization (FAO) and the International Energy Agency (IEA). The calculation is performed annually using the most recent available data, which typically has a lag of a few years. The result of the fraction (Biocapacity / Footprint) represents the portion of the year that humanity lives within the planet’s means. For example, if the ratio is 0.75, it means humanity’s demand is met for 75% of the year, or approximately 274 days, making the 275th day Earth Overshoot Day.