Settled science: We know what the Earth's temperature was at a point in time thousands of years ago, based on shell and pollen evidence with a median sampling interval of 120 years?

Scientists Find an Abrupt Warm Jog After a Very Long Cooling - NYTimes.com

[Mann] I’m relatively convinced that they have the resolution to capture a century-long warming trend in the past were there one comparable to the recent trend.
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[Robert Rohde] They rely on proxy data that is widely spaced in time (median sampling interval 120 years) and in many cases may also be subject to significant dating uncertainty.