Climate Science 101

Martha Klein

Aristotle had a static view of the climate, and that thinking predominated for much of human history. The study of climate began in earnest in 16th century Europe. When the Austro-Hungarian empire was formed in 1526, it encompassed vast sections of Central Europe that included virtually every type of climate on the planet from temperate zones to alpine glaciers. Due to the diverse nature of both peoples and climate zones, leaders believed that the empire would be strengthened by studying and understanding all the different areas that now fell under their control. 

 

In 1851, the Central Institute for Meteorology and Geomagnetism, which is considered the oldest weather service on earth, was founded in Vienna. This institute mapped the distribution of atmospheric pressure across Central and Southeast Europe. They began to understand that weather was not fixed by location, but was a product of interacting global phenomena including atmospheric pressure, and this field came to be known as Dynamic Climatology. 

 

In other parts of the world, scientists were also studying the climate. The first professional paper on climate in English was written by Eunice Foote, which she presented in 1856 at the annual meeting of the American Association for the Advancement of Science, held that year in Albany, NY. The paper was titled “Circumstances Affecting the Heat of the Sun’s Rays.” 

The sun’s rays, called solar radiation, reach our earth’s atmosphere. Some radiation is reflected back into space, and the remaining energy is absorbed by land and oceans, warming the earth.   Earth’s atmosphere is composed largely of water vapor, carbon dioxide, methane, and ozone. 

In 1824, Joseph Fournier posited the existence of a greenhouse effect, wherein these atmospheric gases trap solar radiation and contribute to planetary warming. John Tyndall in 1859 measured the radiative or warming properties of greenhouse gases. 

 

Swedish researcher Suante Arrhenius in 1896 made the first quantitative prediction of global warming based on a hypothetical doubling of carbon dioxide in the atmosphere. In 1901, the term “greenhouse effect” was coined and is still in use, although we now know that the greenhouse gas effect is misnamed. In a greenhouse, the sun heats the air inside, and at night the air cools in the absence of solar radiation. In our atmosphere, so called greenhouse gases trap heat inside the atmosphere, and that heat can’t always escape even in the absence of solar radiation. 

 

In 1966, the World Meteorological Association coined the term “climate change”, which refers to long term variations in weather. By the 1980’s, climate scientists used the study of tree rings to create the “reverse hockey stick” graph, which showed how, over millions of years, the temperature of this planet and the amount of carbon dioxide in the atmosphere remained stable, but after 1750 and the dawn of the industrial era, global temperature and atmospheric carbon dioxide both began to rise precipitously, and in correspondence with each other. 

 

Increasingly sophisticated methodology allowed for measurements of thousands of years old ice cores, which demonstrated that for about a million years, atmospheric carbon was steady at 170 to 330 parts per million. Any changes in atmospheric carbon occurred over millennia. 

 

But since 1750, atmospheric carbon has risen to what it measures today, 452 parts per million. By 2018, scientist’s research of ancient ice cores showed that the level of carbon dioxide has historically corresponded to warming periods. 

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The increased burning of fossil fuels, land clearing and agriculture increase the amount of greenhouse gases in the atmosphere, particularly carbon dioxide, and cause excess heating. All of these activities are done by humans, and are therefore called “anthropogenic.” The greatest drivers of carbon release and excess heating are transportation, energy use (industrial, commercial and residential), and deforestation and agriculture. Whereas historically, warming or cooling periods occurred over tens or hundreds of thousands of years, current warming changes have happened over one generation. This is an unprecedented change in the course, not of human history which is quite short, but in geologic history. 

The impacts of global warming are already being felt worldwide. The most noticeable effects are the temperature on land and water which continues to rise to record levels. There are also marked changes in sea level, in atmospheric precipitation, and an increase in extreme storm activity. The

Intergovernmental Panel on Climate Change has concluded that there is greater than a  95% certainty that human-created greenhouse gases have caused most of the planet’s warming over the last 50 years. (1)

  1. https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_summary-for-policymakers.pdf.


 

Look for Part 2 in the September Newsletter.