Here's the basics from the Global Footprint Network that tracks this stuff:
Unlike governments, nature doesn’t do bailouts. Yet as of today, humanity will have placed more demand on ecological services – from filtering CO2 to producing food, fiber and timber– than nature can provide in this year, according to Global Footprint Network calculations. From now until the end of the year, we will meet our demand for ecological services by depleting resource stocks and accumulating carbon dioxide in the atmosphere.
...Because of the global economic slowdown, we will reach Earth Overshoot Day one day later than last year, according to Global Footprint Network projections. By comparison, in the past, Earth Overshoot Day has steadily moved four to six days closer to January 1st each year.
See yesterday's post about the Planetary Boundaries for a little more explanation on what it means to cross these thresholds, the implications of irreversibility, etc.