In 1714 Gabriel Fahrenheit invented the first mercury thermometer. His scale had water freezing at 32 degrees F and boiling at 212 degrees F. Twenty-eight years later Anders Celsius used a scale that had water freezing at zero degrees C, and boiling at 100 degrees C. Thus, the use of thermometers to measure temperature has been used for the last three hundred years. But geologists and other scientists speak of temperatures that go back hundreds of thousands of years. There are two major ways that these measurements are made, and they give clues to the past climate of the world.
The first method involves the use of ice cores taken from polar ice caps and glaciers. In 1998 scientists had a project in the Antarctic when they drilled into the ice to a depth of over two miles. The cores were carefully removed, cut into 3-meter segments, labelled, and kept frozen for later investigation. Obviously, the oldest ice was at the bottom of the core. Discrete layers, varying in width, within the core showed yearly accumulations of snow and trapped bubbles of atmosphere. Thus, a long history of the climate at that spot was recorded. Each layer represented a year. The total number of layers indicated that the bottom ice was 420,000 years old.
Examination of the core showed that there were four climatic cycles. Four ice ages of extreme cold were indicated. (Later, a deeper drilling indicated six ice ages.) Throughout the long, long history of the planet it has warmed and cooled cyclically without any influence from mankind. The use and burning of fossil fuels had nothing to do with these cycles. Rather the orbital eccentricity of the sun relative to the earth is probably the cause as postulated by the mathematician and scientist Milankovitch.
The trapped bubbles from within the ice core give an indication of the atmosphere at the time the layer was deposited. The CO2 and methane levels were measured. It was found that every single ice age started when the CO2 levels were higher than they are today. So, when climate alarmists say that today's CO2 levels are "unprecedented" they are referring to the last few decades, not the geological time frame of the climate cycles.
The second method of tracking ancient temperatures is the use of tree rings. Mississippi trees grow to a maximum of one or two hundred years. A saw log from our trees has rings, the sum of which gives the age of the tree. A warm year will give a larger ring than a cooler year, so a history of the climate is given in that tree. In the mountainous west there is a species of tree named the bristlecone pine. This tree is found in several locations just below the tree line. These trees have extremely long lives and are probably the oldest living species on earth. One tree in an east Californian National Forest is named after the biblical character "Methuselah." It is over 4,800 years old, and its exact location is a closely guarded secret. Bristlecone pines therefore contain a detailed history of the climate in the region in the last several thousand years.
Of particular interest is the finding that rings showed an unusually warm period in about the years 950 to 1250 AD. This has come to be known as the Medieval Warm Period (MWP.) Several scientific sources say that temperatures in the MWP were even higher than they are today. Another finding is that during the 16th to mid-19th centuries there was a cooling period known as the Little Ice Age (LIA.). Both of these anomalies to the general slow warming of the last 10,000 years is probably due in part to the effects of increased solar activity. The LIA and particularly the MWP are events that are troublesome to the global warming alarmists. They interfere with their desire to project a nice tidy story of earth's warming due to man's burning fossil fuels since the industrial revolution. One alarmist said point blank: "We have to get rid of that MWP!"
Global warming alarmists say that the majority of scientists agree with them. This is far from the truth. Here is a statement from a geologist and former Apollo 17 astronaut Dr. Harrison Schmitt: " The human-caused global warming scare is being used as an ideological and unconstitutional tool to increase government control over American lives, incomes and decision-making. Observational science strongly supports 350 years of slow, erratic natural warming since the depth of the Little Ice Age, well before the extensive use of fossil fuels began."
Another statement often made is that "the time for debate is over." To my knowledge there has never been a substantial public debate on these matters. John Kerry was given the job of Climate Czar by the present administration. It is not a cabinet position and therefore did not require Congressional approval (requiring debate.) It is time for the flawed 'science' to be exposed, so that taxpayers can avoid subsidizing electric cars and 'filling' stations, and many other costs of the Green New Deal.
Peter Gilderson, Madison.