Yesterday marks Earth Overshoot Day 2021—the point in the year when humanity's demand for ecological resources and services exceeds what Earth can regenerate during that year. In other words, from Overshoot Day onward, humanity is conceptually operating in an ecological deficit for the remainder of the calendar year.
The 2021 global date as July 29. The previous year's date had arrived later, on August 22, 2020, amid the COVID-19 pandemic, while the 2021 date returned close to the timing seen in 2019.
Until around 1970, humanity's annual resource demand remained within what Earth could regenerate by year's end. Population growth and expanding economic activity subsequently increased extraction and consumption of natural and mineral resources.
If the trend then assumed were to continue through the end of the twenty-first century, Earth's annually renewable resource budget could be exhausted very early in each year. Such a future would require much greater reliance on recycling, reduced demand, and more sustainable use of resources.
It should be emphasized that countries do not possess equal natural-resource endowments and do not consume resources at equal rates. Countries depleting resources rapidly would need recycling infrastructure, lower resource demand, and sufficient economic capacity to obtain necessary raw materials from elsewhere.
Sustainable development and optimization of economic, industrial, extractive, and agricultural activity is the principal way to reduce this pressure. [source]
How Overshoot Day is calculated [source] [source] [source]
The calculation can be described as:
Earth Overshoot Day = (biocapacity ÷ ecological footprint) × 365
Biocapacity represents the biological resources Earth can regenerate in a year, while the ecological footprint represents human demand on those resources during that year.
The same framework can be applied to individual countries. The 2021 country Overshoot Day for Iran is around the middle of the year which indicates that the resource demand associated with the country's consumption pattern exceeded its corresponding annual regenerative capacity before year's end.
From an economic analogy, Overshoot Day is the date on which an annual ecological “budget” has been spent; subsequent consumption represents an ecological deficit.
Indonesia's 2021 country date was much later in the year, while some countries' calculated demand remained within a full year's regenerative capacity and therefore did not appear on the referenced country chart. Many industrialized economies, by contrast, reached their country Overshoot Days before midyear.
A long-term shift toward earlier dates
Over preceding decades, humanity's ecological and carbon footprints had increased while the source describes Earth's regenerative capacity as coming under growing pressure. The global Overshoot Day consequently shifted from near the end of the year around 1970 to July 29 in 2021.
Consumption patterns
Ecological overshoot is linked to consumer lifestyles and industrial economies. It is argued that high-consumption lifestyles place particularly heavy demands on natural resources and contribute to greenhouse-gas emissions.
Using the ecological-footprint comparisons, if everyone consumed resources at the rate associated with the United States, humanity would require roughly five Earths. Larger illustrative figures belong to Qatar, Luxembourg, and the United Arab Emirates, while noting that their small populations limit their absolute global contribution compared with larger economies.
The ellustrative “number of Earths” for several European countries contrasts with India, whose 2019 consumption pattern was represented as requiring less than one Earth's annual regenerative capacity if applied globally.