Observation, mathematics, teamwork and good science track global warming.
An all-important heat diffusion equation was developed during the late 1790s by the mathematician, Jean-Baptiste-Joseph Fourier. A man arrested, imprisoned and labeled a terrorist during the French “time of the guillotine." Thankfully he survived. He was stationed in Egypt under Napoleon where the heat emanating from the hot desert was the inspiration for his now famous “bell jar” hypothesis.
Fourier wanted to understand why the sun’s heat when reflected from the earth’s surface did not all go back out into space. He hypothesized that the atmosphere containing gasses and water vapor re-radiates enough of the sun’s heat to the surface to sustain life on earth. So the atmosphere acts like a dome (or as a bell jar) under which enough heat is re-radiated and held. Explaining his theory Monsieur Fourier compared the trapping of gasses to what happens in a greenhouse.
The Effect took on a practical importance when the Industrial Revolution produced great quantities of carbon dioxide, sulfur, black smoke and ash due to the burning of coal, a fossil fuel, for energy. New technology was not developed to clean the air pollution out of the smoke before the dirty smoke could leave the chimneys; instead the chimneys of coal-burning furnaces were built taller and taller to move the pollution higher from the ground. The atmosphere absorbing more heat than in the past. (Absorbing heat is not exactly like the greenhouse effect where gasses are held inside the greenhouse).
Those taller chimneys dispersed the pollution further into the atmosphere. Now during contemporary times, the Antarctica ice core record has helped determine the concentrations of carbon dioxide which were belched out of the coal furnaces. The concentrations of carbon dioxide from the Law Dome, East Antarctica ice cores clearly demonstrate that the stable concentration of atmospheric carbon dioxide immediately changes, rising from the beginning of the Industrial Revolution from a base rate of 280 ppm (parts per million) with a quick rise to 330 ppm during the 1800s.
Paleoclimatoligists who study the ice cores must verify their conclusions with other scientists in the field of paleoclimatology as well as other various fields of science. The data is compared to ice core data from other parts of the world, sea sediment samples, ocean data and atmospheric measurements as well as other scientific data.
Climate is a complicated system and many different kinds of scientists study the phenomena. Science has changed as the disruption of the climate has been made obvious; instead of scientists of one field keeping to themselves, communicating with only each other; all of science and engineering has opened up as scientific teams with various ways of measuring and studying learn to work together in a team.
Three major sites for climate study each do a different type of analysis on global temperature data so that the end result can be compared and verified. The University of East Anglia gathers data from about 4200 sampling stations from around the world and uses the “climate anomaly method” for analysis. The National Aeronautics Space Administration (NASA) uses the “reference station method” which relies on about 6000 sampling stations to gain data on temperature readings. The National Oceanic and Atmospheric Administration (NOAA) uses a technique developed in the late 1990’s called the “first difference method” to calculate the amount of temperature change at approximately 7200 sampling stations.
Gathering and studying the above data requires much time and careful use of arithmetic, calculus and statistics to best discern the amount the global temperature is different from the average. The average global temperature is calculated from 30 years of data in order to ameliorate effects of the highs and the lows which makes each year unique. Computers are used to a great advantage to run the redundant calculations and for communication with sampling sites around the world.