when would the next ice age start if man made global warming wasn't a factor

The next ice age would likely begin around 10,000 to 11,000 years from now if human-made warming were not affecting the climate.

Why that estimate

Earth’s glacial cycles are driven mostly by slow changes in orbit and tilt, not by short-term weather swings. Newer research summarized in 2025 suggests ice sheets would probably start expanding again in roughly 10,000 years, with the next glaciation well underway by about 11,000 years.

Important caveat

That estimate assumes natural climate cycles only. Human greenhouse-gas emissions are now strong enough to delay or prevent the next ice age from starting on that natural schedule.

Plain-language version

So the short answer is: without man-made global warming, the next ice age probably would have started in about ten thousand years.

TL;DR: Natural orbital cycles point to the next glaciation starting in roughly 10,000–11,000 years, but current human warming likely pushes it much farther out.