That's how many metric tons of greenhouses gasses have been dumped into the atmosphere by humanity. Three trillion, six hundred and forty two billion, two hundred and ninety one million, nine hundred and ninety two thousand, two hundred and thirty one* metric tons.

Deutsche Bank and MIT just put up a giant billboard in New York City's Madison Square Garden that shows the running tally.

The 70-foot tall sign currently shows over 3.6 trillion metric tons, another 800 metric tons are added every second to the number generated by the climate pros at MIT's Joint Program on the Science and Policy of Climate Change.

Most people don't have the slightest clue what 3.6 trillion metric tons of greenhouse gasses really means (here's what just one metric ton of CO2 looks like), but I think the value comes when the 500,000 or so people who walk by the sign every day (and however many see it on the web) see how quickly the number rises. We're pumping a lot of gas into the smogulously smokey skies.

Swing over to the "Know the Number" campaign if you'd like to read more about it.

h/t to Anythony McCune

*- More or less

Are you on TwitterFollow me (@sheagunther) there, I give good tweets.

And if you really like my writing, you can join my Facebook page.

Also on MNN: 

• MNN Local correspondent gives her take on this topic.

Shea Gunther is a podcaster, writer, and entrepreneur living in Portland, Maine. He hosts the popular podcast "Marijuana Today Daily" and was a founder of Renewable Choice Energy, the country's leading provider of wind credits and Green Options. He plays a lot of ultimate frisbee and loves bad jokes.

Greenhouse gas counter shows our impact
A new sign in NYC's Madison Square Garden shows an updated total of how much greenhouse gas we've pumped into the atmosphere.