The Big Apple is on track to face a simultaneous onslaught of climate catastrophes — and battling against them will be far worse than anything Hollywood could ever dream up, a new study warns.

Extreme rain, rising sea levels and devastating storm surges could slam the city all at once by the end of the century if nothing is done to substantially reduce greenhouse gas emissions, according to the study, published Monday in the journal Nature Climate Change.

The grim vision for the city is a part of a global predicament of looming weather disasters — from devastating heat waves and wildfires to biblical flooding, researchers outlined in the study.

“Facing these climatic changes will be like getting into a fight with Mike Tyson, Schwarzenegger, Stallone, Jackie Chan — all at the same time,” lead author Camillo Mora told CBS News. “I think we are way above our heads.”

The study’s 23 researchers identified 467 separate ways the world is impacted by extreme climatic changes — then examined how likely the threats are to compound into one another over the next several decades.

“A focus on one or few hazards may mask the impacts of other hazards, resulting in incomplete assessments of the consequences of climate change on humanity,” said Mora, a professor at the University of Hawaii, where many of the researchers are based.

It all depends on how rapidly greenhouse gas emissions can be reduced.

As an example, if humanity is able to cap global warming at 2 degrees Celsius (3.6 degrees Fahrenheit), New York City will likely face just one climate hazard in any given year at the end of the century.

The Paris climate treaty, a worldwide agreement among 195 nations which the United States pulled out of last year, is dedicated to holding the rise in temperature to “well below” 2C.

Last month, a troubling report by the United Nations issued similar serious warnings about devastating climatic consequences unless greenhouse gas emissions are drastically reduced by 2030.

With Post wires