Rapid Climate Change Events During The Period Between 10ka And 50ka ( Steig )

Previous climate change predictions have provided scientists, archaeologist and ecologists with information about the past and future of humans. These indications are backed up by scientific research based off of the physics of the Earth’s atmosphere, ocean, land and ice. In addition, many researchers have recently turned their focus to past civilizations and their downfall. With information from Mark Kinver’s “Roman Rise and Fall ‘Recorded in Trees’” studies show that from the demise of the Argaric society to the fall of the Mayan, and Ancient Roman Empire, climate change has played a key role in regards to civilizations collapse and nuclear annihilation.

Earth has experienced many episodes of dramatic climate changes with different periods in earth history. There have been periods during which the entire planet has been covered in ice and at another time it has been scorchingly hot and dry. In this regards, earth has experienced at least three major periods of long- term frigid climate and ice ages interspersed with periods of warm climate. The last glacial period which current glaciers are the result of it, occurring during the last years of Pleistocene, from approximately 110,000 to 10,000 years age (Clayton, 1997). Indeed, glaciers present sensitive indicators of climate change and global warming and by estimating and monitoring the dynamic evolution of these ice masses, several

The Great Warming is a book written by Brian Fagan that encompasses the environment and history pertaining to most of the human race between A.D. 800 and 1300. Not only does the book give a new dimension to world history by looking at climate history, but it also provides the reader with an ominous warning of the impact that climate change may have on the human race in the future. Fagan references many civilizations in the book that were affected by the rise in surface temperatures. He goes in depth with them individually to show just how worldwide this climate change was, how each civilization adapted or failed to adapt, and who the winners and losers were during this medieval warming period.

An example of a catastrophic climate change is a period known as the “Younger Dryas,” an epoch in time when the mean global surface temperature dropped drastically in a couple of decades and lasted for one millennium. Although the circumstance of the Younger Dryas is quite different compared to the present, it shows how cataclysmic a drastic climate change could enforce. Two important or major definitions presented in the work are mean global surface temperature and (global) climate. Mean global surface temperature is defined as “average of the air temperature measured at the land surface and of the surface water temperature measured over large bodies of water” (Jordan, 2006, p. 159). As for global climate, according to Jordan (2006), “the average of the global weather…over a time interval appropriate to the rate at which the climate is changing” is the best definition. These two terms appear frequently throughout, which shows the significance of comprehending the meaning as it relates to the argument and explanation.

“Discuss how both direct and indirect scientific measurements of atmospheric composition over the last 10,000 years have informed the climate change debate”.

The Earth’s climate has changed throughout history and that’s why climate change is so important. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era and human civilization. Most of the climate changes are attributed to the very small variations in Earth’s orbit that change the amount of solar energy our planet receives. The current global warming trend is really significant because most of it is really likely greater than 95% probability to be the result of human activity since the 20th century. Global sea level rose

The first argument examined on the man-made global warning side is that increasing greenhouse gases caused by human activities is causing directly observed climate changes. The first resulting climate change discussed is warming global surface temperature. There has been an increase in global surface temperature of 0.74 degrees C since the late 19th century. In the last 50 years alone the temperature has increased by 0.13 degrees C per decade. North America and Eurasia have seen the largest increase in warmth. However, some areas of the earth have actually cooled some this past century (Easterling & Karl, 2011, para6). After the mid 20th century 70% of the global land mass saw reduced diurnal temperatures. From 1979 to 2005 the maximum and minimum temperatures have shown no change; both indicate warming (Easterling & Karl, 2011, para10). Furthermore, borehole temperatures, snow cover, and glacier recession data all seem to agree with recent warming (Easterling & Karl, 2011, para11).

The Great Warming by Brian Fagan claims that environmental changes (most commonly prolonged droughts, El Niños, and La Niñas during the Medieval Warm Period) affect human civilization, including human’s trading abilities, overall movement, and quality of life. He examines the world’s ancient climate warming, known as the Medieval Warming, between the 10th and the 15th centuries, also mentioning the preceding and succeeding centuries. Fagan gathers his research using studies conducted by archaeologists, historians, and paleoclimatologists. Throughout his book, he refers to direct methods to study climate change, such as instrument records and historical documents, and indirect methods, such as ice, deep sea cores, coral records, and tree rings. Fagan digs into the rise and fall of multiple civilizations around the world as an effect of The Medieval Warming Period. As well as examining civilizations across the world, he attempts to connect the climate change patterns during The Medieval Warming Period to the current global warming faced today. The Great Warming discusses positive and negative connections between climate change and human civilizations across the world, starting in Europe and working its way into Asia, North America, South America, Africa, and even covering the arctic ice caps; however, throughout the book, Fagan has a hard time connecting his various ideas back to one main topic and can easily stray from his point about the effects of climate change.

It has been observed through various researches that in the last century, average temperatures across the globe increased by over 1.3°F with an increase of more than two times in the Arctic. (Bates, Kundzewicz, Wu, & Palutikof, June 2008). The results of climate change can also be seen in changing precipitation patterns, increases in ocean temperatures, changes in the sea level, and acidity and melting of glaciers and sea ice (USEPA, 2014).

Earth’s climate can be observed as an ever changing continuum throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, the end of the last ice age occurring about 11,700 years ago. With climate change being a seemingly characteristic and even beneficial quality of Earth (the end of the ice age did mark the beginning of the modern climate era fit to sustain human civilization after all) it may be easy to disregard the significance of the current period of climate change our planet is in. However, most of the climate changes that occurred before the one beginning around 1950 were attributed to variations in the Earth’s orbit that affect the amount of solar energy received by it. The current

Glaciers are one of the most fundamental phenomenon on the planet, and much of their purpose and impact on earth has been well documented and published. Ice sheets, Ice Caps and Glaciers trap nearly 90% of the world's fresh water, and are replenished by snowfall each year. Their existence on this planet dates back 650,000,000 years and yet they are always moving, always shifting and always melting. Before, human existence and even during the brief era of humans, ice dominated all of the earth's landmass and have regulated, created and altered many of the landscapes around the world.

Evidence indicates, Earth’s natural climate has a history of dramatic changes from warmer and cooler periods that can last for a few centuries. Mankind geologically speaking lives in a time period of intense climate change, and over the past million years we have experienced a dozen or so major glaciations, with the greatest occurring around 650,000 years ago, long before the Industrial Revolution, The Ice Age. This cooling period in Earth’s climate lasted for somewhere around 50,000 years and included the extreme buildup of ice that covered major regions, such as the Midwest, Canada, Germany, and several smaller regions. During this time the sea level had dropped by approximately 400 feet and the overall global temperature dropped nearly 9

11,700 years ago the geological epoch the Holocene was thought to of began following the Pleistocene epoch, together these time periods make up the Quaternary period. The Holocene has been described as being relatively warm and with a fairly stable climate. Not only this, but it is thought to coincide with the start of agriculture as human populations rose throughout the Holocene technology became more sophisticated aiding the rise of agriculture (Holden, 2012). The early anthropogenic hypothesis was published in 2003 by Professor W.F. Ruddiman, this was a three part hypothesis in which Ruddiman proposed humans reversed natural decreases in CO2 values within the atmosphere by deforestation. That they reversed natural methane decreases after 5,000 years by irrigating rice, they also caused a warming sufficient to prevent a new glaciation within the last several thousand years and during the Holocene (Ruddiman 2005). This hypothesis has attracted a lot of attention with many people both supporting it and criticising it. Throughout this essay I will be exploring the many arguments for and against the early anthropogenic hypothesis and stating whether or not human kind could have prevented the start of an ice age during the Holocene.

The Medieval Warm Period (MWP) refers to a relatively warm period lasting from about the 10th to the 14th century.2 However, the initial evidence for the MWP was largely based on data3 gathered from Europe, and more recent analyses indicate that the MWP was not a global phenomenon. A number of reconstructions of millennium-scale global temperatures have indicated that the maximum globally averaged temperature during the MWP was not as extreme as present-day temperatures and that the warming was regional rather than global. Perhaps the most well-known of these is that of Michael Mann and colleagues (Nature, 392, 1998, pg. 779). Their reconstruction produced the so-called “hockey stick” graphic that contributed to this conclusion in the 2001 assessment of the Intergovernmental Panel on Climate Change: “The…'Medieval Warm Period' appear(s) to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries." The accuracy of the “hockey stick” graphic was widely discussed in the press when the Mann et al. methodology was criticized by McIntyre and McKitrick (Geophys. Res. Lettr, 32, 2005, pg. L03710). Less attention was given to subsequent studies, such as that of Moberg and colleagues (Nature, 433, 2005, pg. 613) and Osborn and Briffa (Science, 311, 2006, pg. 841) that were based on different, independent methodologies but reached conclusions similar to Mann. Observations of melting high altitude glaciers are

The climate changing was first suspected in the 19th century when scientists in britain debated whether Europe was covered by ice in the past. “Guy S Callender suggested that the warming trend revealed in the 19th century had been caused by a 10% increase in atmospheric carbon dioxide from the burning of fossil fuels.” (Harding) The debate intensified by 2005 when a study was published stating that a large scale disruption could occur by 2050 if we do not slow the process of climate change. The debate has now spiraled back to whether climate change is occurring or not. However the climate warming pattern has been increasing exponentially since the 1950’s.