Draft 1: Milankovitch Cycles

This topic submitted by Rob Greene, Jesse Murphy ( greenerr@muohio.edu, murphyj4@muohio.edu ) on 3/9/04 .

Global Climate Change -Western Program-Miami University

Milankovitch Cycles

In the beginning of the year 1909, Milutin Milankovitch, a Serbian astrophysicist began to dedicate his career to understanding and Òdeveloping a mathematical theory of climate based on the seasonal and latitudinal variations of solar radiation received by the Earth.Ó (http://earthobservatory.nasa.gov/Library/Giants/Milankovitch/). He would continue a life long pursuit into developing his theory and pushing for a public consensus to accept his results. The overall theory Milankovitch envisioned can be broken into three main parts:

1. Variations in the Earth's orbital eccentricity
2. Changes in Obliquity and itÕs relation to seasonal change
3. Precession

As the Milankovitch Cycles continues as a natural phenomenon, it is hard to speculate the exact path or the exact impact it will have in the future. So far several theories such as the Heinrich-Bondand and Dansgaard-Oeschger models have tried to explain the correlation between climate, solar output, and the ice ages. As we continue to impact the Earth, the questions we must first answer: should we worry since according to Milankovitch's cycle we are do for another ice age? "What are they? How do they impact the earth's climate? What data exists that "prove" that they actually happened?"(Courtesy of Hays Cummins)What effects will we have on this cycle? Will Global Warming also accelerate the cool down period in which another ice age may take precedence?

Introduction

It is our belief that what happens to one will happen to the other. In other words it would seem likely that within the next millennia we will experience a cool down period to either back to normal temperatures or continue to decrease into another ice age like environment. If we look at this diagram of the milankovitch cycle we can see that there is a decrease with in the total amount of solar radiation. It suggests that in the next 25,000 years we will experience temperatures much like the last ice age.

Ironically this notion of another ice age already approaching has been an excuse for many to not to focus on the issues of rising sea-water changes and global warming that might directly influence another ice age. To view this argument, we suggest looking at this link: http://www.nature.com/nsu/020819/020819-9.html. Since this is a continuing idea among scientists and is yet fully accepted within the general public, it is our intentions to look at both sides, for and against this theory, and develop our own idea of which argument is more believable. We will look at MilankovitchÕs original data and compare it to other graphs and compare it to past climate changes along with possible outcomes. Finally, we are going to collaberate with the snowball earth on part of the project to look at the full impact of global affects and glacier cycles disruption.

Links and On-line References

http://aa.usno.navy.mil/faq/docs/seasons_orbit.html
Gave a detailed description on the seasons relationship to the Milankovitch cycle.

http://geography.about.com/library/weekly/aa121498.htm

http://earthobservatory.nasa.gov/Library/Giants/Milankovitch/
Biography of Milankovitch and details on his theory of climate change.

http://journalofscience.wlu.edu/archive/Spring2000/GlobalWarming.html
This article discusses global warming and climate change as related to several causes, including the Milankovitch cycle.

http://lwf.ncdc.noaa.gov/oa/climate/globalwarming.html#Q1
A large FAQ on climate change and global warming. Discusses the Milakovitch cycle as well as several related topics such as solar output and sun spots.

http://www.ngdc.noaa.gov/stp/SOLAR/solarda3.html
A data base that hold global climate change models related to solar changes and orbital paths.

http://www.physicalgeography.net/fundamentals/6i.html
Earth-Sun relationships in terms of Insolation

http://www.whoi.edu/institutes/occi/currenttopics/climatechange_wef.html#n1
nice link with animations and global cooling ideas

http://www.nature.com/nsu/020819/020819-9.html
One person's view that we should not worry about global climate change

Journal Articles and Books

Milankovitch Climate Cycles Through the Ages

Milankovitch Cycles and their effects on species in ecological evolutionary time.
*Looks at the biological aspects of the effects the Milankovitch Cycles has on our planet.

Ice Rhythms: Core Reveals a Plethora of Climate Cycles
*Discuses how ice core samples aid in determining past changes in climate and further illustrates the concept of the Milankovitch cycle.

Possible Forcing of Global Temperature by the Oceanic Tides
*Further discuses fluctuation in global temperatures and the trends due to solar output

The Ice Chronicles: The Quest to understand Global Climate Change
*The study of glacial changes from ice cores to form a record of past climate changes.

Mapping Orbital Effects on Climate
*Gives and breakdown on the effects of the Milankovitch cycles and there effects on different aspects of our climate.

Terrestrial, Solar and Galactic Origin of the Earth's Geophyscial Variables
*Gives a excellect break down of changes to the earth that have resulted from galatic, solar and terrestrial changes.

A New View on The Driving Mechanism of Milankovitch Glaciaiton Cycles
**This article discusses how glacial cycles could be strongly influcenced by one of the Milankovitch cycles in particular.

*Milanovitch Climate Reinforcements
**Disscusses how the Milankovitch cycles may play a lesser role in global climate change. Serveing only to reinfornce and enhance current patterns.

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