We do not know everything that we would like to know about ice ages. Technically we are still in an ice age with permanent ice at the poles.
However:
We do know they happened regularly during the evolution of our species during the last million years.
The massive glaciations last tens of thousands of years with hot breaks lasting a few thousand years. These end with elevated CO2 and CH4. The timing roughly correlates with the orbital changes of our Earth which changes the insolation.
The recent 10000 years (the Holocene) are not typical, but benefitted us. We are in an ice age with annual ice variation and well established Ocean currents which may explain the anomaly by a complex set of feedback loops, such as the AMOC with our tilted planet.
But we know we humans pushed unusual amounts of CO2 into the atmosphere and this might have extended the Holocene. Extending the Holocene seems to be a good idea!
Global climate change through warming might benefit Russia and Canada but makes many other places harder to to live in. But then we must consider the Atlantic Meridional Overturning Circulation. AMOC.
Complex! The Ocean currents are controlled by land masses, which have changed over time. The rotation of the Earth and being a sphere cause Coriolis accelerations as masses of water migrate from the equator. The salt concentration fights with the temperature changes. These complexities may explain the Holocene anomaly.
But scientists studying the AMOC are predicting a slow down and maybe a collapse within a few years.
That process is a positive feedback to cooling the Arctic and other changes. Cloud albedo is also linked to the warmer Oceans with their huge heat content today.
Larger ice at the Arctic and longer survival of that ice in the northern summer reduces Albedo and apart from significant local changes, can be a massive feedback towards much more ice, higher sea levels at New York, and huge disruption.
There is an irony that global warming might lead to another ice age, but that is what the historical record shows.
The main question is how quickly an ice age can develop. And many experts think in decades. And to be clear, an ice age is not helpful to our civilisation. Not fatal to human life, we survived many ice ages, but massively disruptive.
Geo engineering could manage it, prevent it, perhaps, it is surely worth considering.