By Henry Henderson

33,000,000,000.

That's the number of gallons of contaminated Chicago River water that have flowed into Lake Michigan—source of drinking water and quality of life for millions of Americans—in the last decade. The river normally flows away from the lake, so what gives?

Blame climate change. And infrastructure not designed or built to deal with the changes brought the changing climate.

Violent storms dump an incredible volume of rain in very short periods of time. Even with massive additions to the region's stormwater system, it cannot keep up. When that system cannot handle intense rainfall over the area, sewers fill and dump into the River. When the Chicago River fills with all that stormwater, which is now contaminated with all kinds of nasty stuff after comingling with whatever was in the sewer lines, it swells. And after a while, well, gravity takes over. The river level rises above the lake level and water heads downhill. The Chicago River literally changes direction and flows out into Lake Michigan.

But don't take my word for it—here is what David St. Pierre, executive director of the Metropolitan Water Reclamation District of Greater Chicago, told Chicago Public Radio this week:

"If you are in the business I am in, you absolutely believe in climate change. We are seeing more intense, shorter duration rain events. We used to see several years in a row where we wouldn't have any reversals. But lately we are experiencing reversals at least once a year."

He would know. MWRD manages the stormwater infrastructure for Chicagoland, a massive swath of pipes, pits and tunnels underlaying nearly 900 square miles.

As St. Pierre noted, climate change is reversing the flow of the Chicago River on a near-annual basis now. It already happened this year. It will probably happen again in 2018.



And, as I've noted before, climate scientists have predicted this phenomenon for decades; so as galling and shocking as the reversal of a river sounds, it shouldn't be a surprise.

Which is all a long way around to saying, I can think of 33 billion other reasons for the Trump administration to rethink its rumored departure from the Paris climate accords. Chicago is hardly the only city which will face immense costs if this country does not seriously address climate change in the face of startling problems already visible today.

Henry Henderson is director of the Midwest program at Natural Resources Defense Council.