Mankind will have used up its allowance of natural resources such as water, soil and clean air for all of 2019 by Monday, a report said.
The so-called Earth Overshoot Day has moved up by two months over the past 20 years and this year's date is the earliest ever, the study by the Global Footprint Network said.
The equivalent of 1.75 planets would be required to produce enough to meet humanity's needs at current consumption rates.
"Earth Overshoot Day falling on July 29 means that humanity is currently using nature 1.75 times faster than our planet's ecosystems can regenerate. This is akin to using 1.75 Earths," the environmental group, which is headquartered in Oakland, California, said in a statement.
"The costs of this global ecological overspending are becoming increasingly evident in the form of deforestation, soil erosion, biodiversity loss, or the buildup of carbon dioxide in the atmosphere. The latter leads to climate change and more frequent extreme weather events," it added.
Calculated since 1986, the grim milestone has arrived earlier each year.
In 1993, it fell on October 21, in 2003 on September 22, and in 2017 on August 2.
"We have only got one Earth -- this is the ultimately defining context for human existence. We can't use 1.75 (earths) without destructive consequences," said Mathis Wackernagel, founder of Global Footprint Network.
Maria Carolina Schmidt Zaldivar, Chile's environment minister and chair of the Climate COP25 scheduled this December in Santiago, said a major cause of the date falling earlier and earlier was growing amounts of CO2 emissions.
"The importance of decisive action is becoming ever more evident," she said.
Individuals can get involved by calculating their own ecological footprint at http://www.footprintcalculator.org.
