TRADUCCION

CLIMATE, WEATHER AND GLOBAL WARMING

The progressive increase in global average temperature driven mainly since studies and according to records, by increasing emissions of greenhouse gases constitutes one of the challenges facing humanity in this century given the trend towards possible climate change. Although differing insights and points of view regarding the estimated time that could be spent in the line of no return towards the perception of conditions totally different from today, and with regard to the possibility that these are met, a matching point discussion is the warming of the climate system at a rapid pace the last 35 years.

The manifestations of this warming are clear. Apart from the striking news with doomsday dyes, you can not deny that the climate system is responding positively and consistently to the increase of temperature, so it reveals the last IPCC report. However, there are still many things to ignore especially when we try to address such a complex concept such as climate change, or we try to simplify the simple explanation of current evidence or imputing the occurrence of any weather event. It is normal today be informative dam boom that has raised this subject , rich in news medias without the educational rigor with which should be reported . Yet global warming is a reality.

Climate changes have been present during the life of the planet and have been instrumental in establishing the various stages through which this has happened, from the eons to the times when the history of the land is divided , but have been incubated during the passage of thousands of years , going from very cold stages to other very warm . In this alternation, among other features, has been running the climatic conditions of the planet, so different yesterday and today.

For the sample , the last period of favorable climate, almost similar to the present (called Eemian) takes between 130,000 and 115,000 years ago , before the start of the last major glaciations of the Quaternary (called Würm) stage in which presented the last glacial maximum , where the average temperature should be 10 degrees lower than today. The temperature of the areas near the poles was about 15 degrees cooler than now and in the equatorial cooling was perhaps just 5 degrees below. Sea level dropped to almost 150 meters less than the Sahara and today, it is estimated that extended not only throughout much of Africa, but to the entire Middle East and much of Asia. According to studies, this ended about 18,000 years ago and from there the temperatures began to be tempered , but not before presenting two periods of setbacks to the cold , one with at least 15,000 years ago (old Dryas) and another with a minimum makes 12,000 years ( Younger Dryas).

Then again the increasing of the temperature reaching resumed similar to those of present day levels about 10,000 years ago. From there begins the most recent times, which we know as Holocene.

But despite the age of climate change is relatively little is known about it, even there is no great certainty regarding the triggers of their occurrence in some stages of the distant past (which makes sense).

What has gotten to know him mainly to sciences such as geology and paleoclimatology, which, through the study of fossils , the bark of trees and ice cores have provided historical information broadly in time, typically millions of years later, but not strictly accurate in stages as short as hundreds or even thousands of years. For this reason at the time to publicize findings or opinions should be very careful.

Some of the most common mistakes , especially in the media , is to use the terms interchangeably Global Warming and Climate Change, which is confusing and time and that is climate as well as their associated changes and temporal scales. In this regard I will try to make clear.

Global warming is the gradual increase in the average temperature of the planet today led mainly by the rapid increase in greenhouse gases in the atmosphere, due to rising emissions from the activities of mankind, especially in regards industry, the waste of natural resources and the change in land use.

According to the latest IPCC report, the total temperature increase from 1850-2005 is 0.76 degrees Celsius, a finding that is consistent with the increased content of water vapor (gas more meaningful and more powerful as a greenhouse accumulator heat) in the atmosphere , at least since the 1980s, both on land and in the oceans and in the upper troposphere.

Likewise with the deviations show that the average temperature of the oceans has increased to depths of over 3000 meters, mountain glaciers and snow cover have declined on average in both hemispheres, the average sea level rose to an average annual rate of 1.8 millimeters from 1961-2003 among others. This information is consistent with the behavior shown and measured the level of greenhouse gases, especially carbon dioxide (CO2) present in the atmosphere.

The IPCC makes clear in terms of increasing atmospheric concentrations of carbon dioxide, methane and nitrous oxide world. Carbon dioxide gas is the most important anthropogenic greenhouse gas, its concentration has increased from a pre-industrial value of about 280 ppm (parts per million) to 381 ppm in 2006.

Methane (CH4) has increased from a concentration of 715 ppb (parts per billion) in pre-industrial times to 1732 ppb in the early nineties, and in 2005 its value was 1774 ppb. Nitrous oxide increased from pre-industrial value of 270 ppb to 319 ppb in 2005. However it should be noted that not all the temperature increase must be attributable to greenhouse gases.

Climate change is a much broader concept, is conceived as the ultimate result of a cumulative process, either heating or cooling, and which can change based on sustained averages of climatic variables over a significant period of time. There is talk of climate change as beyond the anomalies that characterize the sequential and periodic climate variability already known, change the conditions that characterize the climate system to make way for other classes with different phenomena, intensities or frequencies. If we looked the world according Koppen climate classification, we could know the aspects that characterize each type of climate, and from this point one might consider that regional climate change would occur when moving from one type to another.

When referring to climate changes in the distant past is, the sequence of events that led cataclísticos radical changes in the world is understood from its morphological constitution to the chemical components of the atmosphere, from excessive heating stages glaciations by space millions of years and even billions. In the

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