Earth's Experiment Continues

The Editor’s Reply to my “Earth’s experiment” letter emphasized the lack of precision and uncertainty of scientists’ estimates of ancient global temperatures. While I would strongly differ with you alleging imprecision in the two-mile Greenland ice cores that indicate that we now live in the coldest 1,000-year period of the past 10,000, the purpose of my letter was to show that tree-rings and other proxies of temperature are not relevant to the determination that Earth was much warmer and sea levels significantly higher during the Holocene Climatic Optimum (9,000 to 5,000 years before present). 

However, since you quoted NASA’s Gavin Schmidt speculating that “…the Earth as a whole is probably the hottest it has been during the Holocene – the past 11,500 years or so…”, so I Googled “Holocene Climatic Optimum” and clicked on the Wikipedia link. There I found many references to hotter periods than the present without the use of Schmidt’s “probably” to convey Holocene climate change. 

Getting back to the Earth’s experiment, many signs of earlier hotter periods in the last 10,000 years are scattered all over the Earth’s surface. In Northern Europe, Asia, and Canada scientists found and carbon-dated tree stumps that proved that forests advanced to or near the current arctic coastline between 9000 and 7000 years ago and retreated to their present positions by between 4000 and 3000 years ago as Earth cooled.

Changes in sea level serve as Earth’s thermometer. Studies of fossil corals worldwide show that sea levels were much higher during warmer periods. During the most recent past interglacial period (125,000 years ago), sea level was over 26 feet higher than now, proof that temperature was also much higher. 

The NOAA U.S Climate Reference Network shows no significant warming since NASA created it in 2005. Mr. Schmidt “probably” doesn’t want to know.