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Check out Reddit at 1 apm. PST August 12 for an “Ask Me Anything” with Mathis Wackernagel, president of Global Footprint Network.

Here is more information, as posted on Reddit:

Hello Redditors!

I am Mathis Wackernagel, the co-inventor of the Ecological Footprint and the co-founder of Global Footprint Network. I am from Switzerland originally, but now live in California.

Our calculations show that we are using the natural resources equivalent to 1.6 planets. In other words, humanity’s demand on the planet is 60 percent larger than what the planet can renew. It is like spending 60 percent more than what we are earning. As a consequence we are using up Earth’s savings.

Similarly, our calculations show that we would need four Earths if everyone lived like Americans. Or three Earths if they lived like Danes.

Because we use more than what Earth can renew, we eat through the annual budget of nature way before the year ends. In fact, August 13 is Earth Overshoot Day, the date when we have exhausted the planet’s ecological budget for 2015. The date fell in October back in 2000.

We calculate those dates through our Ecological Footprint accounts. They track how much biologically productive space we have in the world, in the US, or in California. And then we can compare this to how much biologically productive space is needed for all that we consume—food, fiber, timber—and also to absorb our waste, particularly CO2 from fossil fuel burning.

You may want to test the results. This is what we have done with about 12 nations and international organizations ( They have confirmed the findings.

You can find out more about Earth Overshoot Day at, which will go live on Tuesday, August 11.