What is the temporal resolution of the ice cores or whatever else is being used to measure when the last “hot house” periods were? Because today we are measurin

What is the temporal resolution of the ice cores or whatever else is being used to measure when the last “hot house” periods were? Because today we are measuring CO2 with minute-level resolution. But I feel like an ice core might be a year at best, probably much worse. Which if I’m right would mean we really don’t know how fast or slow we entered into the last hot period (the rate)