Climate Change : Past, Present, And Future

This mega drought matched up with the Lake Chichancanab sediment record, giving the authors more confidence in their results. They did this for multiple depths of low Ti content on the sediment cores that resulted in the dates of 910, 860, 810, and 760 A.D.. The intervals between these drought periods were all within approximately 40 to 47 years which also is supported in the Lake Chichancanab sediment record. Beginning with the drought in 760 A.D., a drying trend appeared for approximately the next 40 years until a more severe drought occurred at approximately 810 A.D. Another major drought occurred at roughly 860 A.D. based on very low Ti content results. This was finally capped of with another sever drought in 910 A.D. which lasted roughly 6 years.

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 of human civilization. Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.

Global climate change and variability, particularly at regional levels, are not completely understood. Therefore, there are many significant

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

Global climate change is more than just raising the concentration of GHG’s in the atmosphere, it’s a serious health threat. Dr. Howard Koh, of the Harvard T.H Chan School of Public Health, has stated that global warming is a threat to human health because of an increase in respiratory and allergy aggravation,

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.

Indirect measurements of atmospheric composition can host reliable sources of information around the climate of today in comparison with the historical climate. One way of gaining information about past

A climate interval from around 1300 to 1750, with beginning and ending dates varying by geography (Wolfe, 2014), the Little Ice Age was a period of time in which mean annual temperatures decreased by about 0.6C and mountain glaciers expanded across the Northern Hemisphere. This period of time occurred after the Medieval Warm Period, around the Middle Ages, and is followed by the current period of warming (Rafferty & Jackson, 2016). This idea of climate cycles—known as Milankovitch cycles—shows that climate change is not a new phenomenon.

Throughout history climates have drastically changed. There have been shifts from warm climates to the Ice Ages (Cunningham & Cunningham, 2009, p.204). Evidence suggests there have been at least a dozen abrupt climate changes throughout the history of the earth. There are a few suspected reasons for these past climate changes. One reason may be that asteroids hitting the earth and volcanic eruptions caused some of them. A further assumption is that 22-year solar magnetic cycles and 11-year sunspot cycles played a part in the changes. A further possibility is that a regular shifting in the angle of the moon orbiting earth causing changing tides and atmospheric circulation affects the global climate (Cunningham & Cunningham, 2009,

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).

Climate change is a rising issue of importance in our day and age, and one that is threatening our global society on many levels. In the past few decades, scientists have discovered that our planet’s climate has been changing at an alarming rate. The way in which we have changed the land to

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

Over the years there has been a lot of controversy on if climate change is an issue that needs to be discussed and solved. There is a constant debate among scientist on if human actions are contributing the changing of earth’s climates. Climate change is defined as the change in average weather patterns for a specific region or Earth as a whole. This could include the change in an average temperature for a city or the amount a rainfall it receives (Dunbar, 2015). The main difference between weather and climate is the period of time specific patterns are recorded. Weather patterns are looked at over a much shorter period of time, meaning that these patterns are going to be more sporadic and change more frequently. Climate on the other had is recorded over a much longer period of time and usually show less drastic changes in patterns when compared to weather. Some people may argue that climate change is not an issue because Earth’s temperature is always changing do to natural effects. What people don’t realize is that human activity has effected the rate that earth’s temperature is changing, and just the smallest changes can lead to drastic consequences (Dunbar, 2015).

Scientists have discovered 'climate forcing’s ' influence variations in climate systems and based on the depth and period of such forcing’s the adjustments to climate may be in a shorter or longer earth cycle. Natural forcing’s like variations in earth 's orbit, solar variation, volcanic eruptions and motion of tectonic plates have influence on the Earth 's climate