On Christmas Day 1971, the first Homo sapiens’ limping along for about 300,000 years, humanity’s demands on the earth have exceeded what the planet can provide in a year. That practice has continued, and worsened, over the last half century.

Since the early 2000s, the nonprofit Global Footprint Network has been calculating what it calls “Earth Overshoot Day,” the date on which we exceed our resources each year. Right now, human society is consuming resources at a rate that would take 1.75 Earths to sustain. So as of August 1 of this year, everything we consume adds to our collective debt. In the language of ecological economists: we’re in overshoot.

The date itself is a convenient construct, meant to highlight a larger problem: in reality, the Earth doesn’t reset itself every year. In the science of planetary accounting, overshoot is more like putting groceries on your credit card after you’ve already blown your monthly budget shopping online. It can’t go on forever. Eventually, those bills have to be paid.

The debt we’re racking up manifests itself in three ways: waste piles up, resources are depleted, and ecosystems degrade. As these effects increase, the Earth’s ability to regenerate diminishes. What that means in the long term is still unclear, but it seems likely that the consequences will become more severe as our debt increases. “We’re still living off the land,” says David Lin, chief science officer at the Global Footprint Network. Modern life makes that easy to forget. We’re removed, like most of us, from the touch and smell of soil and crops. The concept of overshoot, in a sense, has evolved to remind us of the demands we’re making on the land.

Two researchers at the University of British Columbia, Mathis Wackernagel and William Rees, created a metric called the ecological footprint in the early 1990s, and with it the idea of ​​overshoot. They wanted it to be a “comprehensive sustainability metric,” one that would capture not just one dimension, such as greenhouse gas emissions, but the full range of human impact on the planet. Wackernagel later founded the Global Footprint Network to track and hopefully end the overshoot that his metric had revealed.

Today, York University’s Ecological Footprint Initiative has taken on the responsibility of collecting and maintaining all the data needed to track, estimate, and project the metrics for every country in the world that can be used to understand and correct overshoot. These metrics include ecological footprint—which describes the cumulative impact, including carbon emissions, of humanity’s urban and industrial activities, such as logging, fishing, agriculture, construction, and mining—and biocapacity, which reflects the ability of forests, fisheries, soils, landscapes, and mountain slopes to recover from human demands. By comparing these two metrics, it is determined whether we are in overshoot territory, and if so, how bad.

Crunching these numbers is no easy task. “We stitched together about 47 million rows of input data to generate the system,” says Eric Miller, the environmental economist who leads the Ecological Footprint Initiative, with results going back to 1961.

These tables show not only how much we’ve exceeded our planetary budget this year, but also a running total of our debt. And while the date of Overshoot Day has remained similarly stable over the past decade, the debt continues to pile up. Right now, the Global Footprint Network estimates that our debt totals 20.5 Earth years. So if all human activity were to stop right now, the planet wouldn’t be able to repair itself from all the damage we’ve done to it until 2045.

Miller noted that discussing things in terms of ecological footprint and overshoot both helps quantify the problem of overconsumption and creates the space to discuss comprehensive solutions to the overlapping ecological crises facing the planet. It “involves not just reducing absolute emissions,” Miller said, “but also changing the way we use land and water.” For example, it can help us understand how certain climate solutions, such as biofuels for aviation, can solve one problem — carbon emissions — while introducing others, such as harvesting crops to feed airplanes instead of people.

From an ecological footprint perspective, climate change is not the core crisis. Instead, it is merely a symptom of overshoot, where the waste gases from our overactive industries are piling up in the atmosphere and warming the planet. Biodiversity loss is another symptom of overshoot. So are soil degradation, deforestation, water scarcity, and more.

Still, while the United Nations Climate Secretariat has published blogs on Earth overshoot, the topic has yet to appear in international agreements or national policies. The various commitments that have been drafted and adopted at the international, national, state, local and even corporate levels have placed an emphasis on planet-warming pollution. “So, understandably,” Miller said, “the world is a little more preoccupied with the issue of greenhouse gas emissions.”

But just trying to treat the symptoms of overshoot didn’t make sense to Phoebe Barnard, a global change scientist at the University of Washington. “We all need to talk about the root causes and be aware of them so we can work on them,” she said. She and two colleagues founded a nonprofit called the Stable Planet Alliance to focus on the problem of ecological overshoot, as well as the behaviors and practices that have caused it.

“We think of the Earth as a food bank for humanity, or that the resources are here for our own benefit,” Barnard said, “rather than as gifts that the Earth has given us.”

Barnard and her colleagues argue that addressing overshoot requires addressing harmful behaviors and beliefs, such as the pursuit of perpetual growth and profit.

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They focus on marketing as both the cause of the problem and the possible solution. The marketing industry has acted as an engine of overconsumption, making people want things they don’t need or have wanted before. But, Barnard said, “what if we could use the tools of the marketing industry — which has mastered the science of behavior change — to pull humanity out of its dead-end street on the edge of the abyss?”

Global Footprint Network’s approach includes not only raising awareness around Earth Overshoot Day, but also the #MoveTheDate campaign, which promotes actions to reduce overshoot (and move the date of Earth Overshoot Day closer to the end of the year). These include promoting things like ecosystem restoration, 15-minute cities, green electricity, and regenerative agriculture. While these overlap considerably with typical climate solutions, discussing these actions in terms of overshoot underscores the fact that we cannot pursue endless growth while striving to own more, fancier stuff to achieve ever-higher standards of living.

Both the Global Footprint Network and Barnard also tackle a controversial element that they see as central to combating overshoot: population growth and pronatalism, as Barnard and her colleagues describe the desire to expand human populations. In a post for Earth Overshoot Day, Global Footprint Network co-founder Wackernagel acknowledged the “brutal” history of attempts to limit population growth but called for reframing the discussion “in a compassionate and productive direction” that also advances sex and gender equality.

“Let’s take that conversation away from the old white men who dominate the conversation, and let women all over the world have the conversation,” Barnard said, pointing out that educating girls and women is often enough to reduce birth rates, and promote a host of other benefits.

But ultimately, the biggest challenge in addressing overshoot — as in addressing symptoms like climate change — isn’t understanding the problem or the range of solutions that exist, but implementing them. Thinking about what it will take to reduce overshoot and pay off our ecological debt is like asking what you can do to improve your personal finances. “You can ask that in a mathematical sense,” said Lin, the Global Footprint Network scientist. But for every possibility, he added, “Can you do that? Are you willing to do that?” That’s the question.

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