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What Do Milankovitch Cycles Have to Do With Paleohistory, Paleoclimatology, Glaciation and Climate Change Theory?

Updated on July 5, 2013

What Does "Paleohistory" Mean?

Let's break down the etymology of the word "paleohistory" to get a sense of what it means. The term "paleo" means ancient. "History" is a study of the past events. Paleohistory, then, refers to the history of the ancient past. Scholars use the term paleohistory to refer to a variety of subjects ranging from ancient cosmic events to prehuman climate patterns on earth. When you see the word "paleohistory," understand that it refers to events that unfolded before the dawn of human civilization.

Paleohistory Versus Paleoclimatology

Paleoclimatology is a more specific word that refers to the study of ancient climates on earth. If you're making inferences about future climate change based on observations about ancient climates, it makes more sense to use the term "paleoclimate" instead of the term "paleohistory." Both paleohistory and paleoclimatology refer to events that unfolded in the ancient past, but paleoclimatology is more specific because it refers to the study of ancient climates on earth.

How Do Scientists Measure Ancient Climate Patterns?

Facts about ancient climates are difficult to know, because direct observations about weather date back only about 150 years. Scientists rely on proxies to find out about ancient climate patterns. Tree rings, ice cores, subfossil-pollen, and sediments can tell us something about what the weather was like millions of years ago.

What Is the Milankovitch Theory of Glaciation?

The earth rotates around the sun, but the shape of the orbit is not always the same. Sometimes, the shape of the orbit is elliptical, but at other times the earth's orbit is circular. Milutin Milankovic was the first scientist to discover this variation. When the earth is following an elliptical orbit, it draws closer to the sun. During this period of time the earth becomes warmer and glaciers tend to recede.

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What Can Ice Core Samples Tell Us About Global Warming?

Readings from ice core samples help us understand how much carbon dioxide was in the atmosphere during previous eras. Current levels of carbon dioxide exceed what we might expect, even accounting for Milankovitch cycles. While it's true that he earth's orbit changes about every 100,000 years and that levels of CO2 in the atmosphere fluctuate accordingly, natural cycles don't fully account for the current levels of CO2 in our atmosphere. Current CO2 levels are at 1,774 parts per million. Ice core analysis has revealed that over the past 650,000 years carbon dioxide has remained within the 320 to 790 range. That means that the current levels of CO2 are more than twice as high as the historical maximum.

Other Factors That Affect Climate Change

There are many factors that affect climate, making future climate changes incredibly hard to predict. Milankovic discovered that the earth's orbit around the sun changes. Additionally, variations in the output of solar energy can influence the climate because the amount of radiation produced by the sun can vary. Also Volcanic eruptions can have a significant impact on climate, causing global cooling. Another factor is that plate tectonics shift the continents around, causing changes in oceanic circulation which can then have effects on climate. Perhaps the most controversial cause of climate change is industrialized human society. Human beings release CO2 into the atmosphere via industrial processes, contributing to a net increase in the amount of greenhouse gasses circulating in the atmosphere.


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      Theresa Ast 4 years ago from Atlanta, Georgia

      Alex - Interesting. Concise and yet fully explicated topics. I really like that. And you used one of my favorite words in your first paragraph -- etymology." Etymology is not one of my primary writing subjects, but I have done a couple of hubs on word etymologies. Good Hub. Sharing.

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      Casimiro 5 years ago

      Super, concise hub Alex. I guess I hadn't internalized that CO2 number before. Wow! A lot of people just poo-poo the facts anyway, go figger. It's great to see a hubber incorporating video in the hubs consistently. I think it's the way forward, but I haven't gotten the hang of it yet.

      Welcome to HP!