Abnormal Pathology Of Stomach

CLIMATE CHANGE ALSO HAPPENED IN THE PAST

The Earth has gone through many climate changes throughout history, some not so distant in time. Several natural agents in causing external Europe of the Middle Ages warmer weather than normal, a period which was subsequently low temperatures until the middle of the nineteenth century. These studies of past climate changes could serve to clarify the current predictions about climate change. However, scientists point out that its main cause is the rapid burning of fossil fuels and, therefore, its consequences are still difficult to estimate.

a thousand years ago, Europe has enjoyed centuries of rather high average temperatures. At that time, called "Medieval Warm Period", agriculture flourished in places as Greenland, a place name in English ("Greenland" green ground) evokes the past climate. However, the evidence shows clearly that the Greenland ice sheet persisted for millions of years and that during the "Medieval Maximum" could have released a small area of \u200b\u200bthe coast. So what qualifies Manuel Vázquez Abeledo, project coordinator of the Astrophysical Institute of the Canary Islands (IAC) and an expert on past climate changes.

This period was followed by another of lower temperatures, especially in northern areas of Europe. Although not considered an ice age as such, is known as the "little old ice. "Some experts say that this period lasted from the sixteenth century to the mid-nineteenth century. The chronicles how people during the winter skating on the frozen river Thames in London or the canals and rivers of Holland.

A group of scientists have described in the journal Science how natural changes in ocean conditions could cause these past climate changes. The fluctuations in solar luminosity and frequency of volcanic eruptions and other natural causes altered the activity of "El Niño" and "North Atlantic Oscillation. These phenomena climate are dynamic patterns that can cause changes in rainfall patterns and drought, or the activity of huracanesy are able to redistribute heat around the globe, so that an area is heated and another cooled.

The investigators found that the unusual warming period was succeeded by another feedback mechanism that science has known for years as "the effect of La Niña." One of the signers of the investigation, Michael Mann of Pennsylvania State University (USA), explained that La Niña causes temperatures cooler than normal in the tropical Pacific central and eastern and drier in the Desert Southwest U.S.

The researchers reconstructed models of the Earth's surface temperature during these two historical intervals, a period some 1,500 years. The information collected on ice, tree rings and corals, among other things, served as their shows to see what climate changes occurred during those years.

Research as published in Science could be used to refine climate models to the Intergovernmental Panel on Climate Change (IPCC) used to predict how global warming will result in the coming years. Most of them said that the Earth will respond to the effect "The Child." Only a few models recreate the dynamics of "La Niña effect."

Manuel Vázquez Abeledo explains that historical climate changes provide a good guide to understanding what happens today. But nobody thinks that this knowledge could be used to know when will be the following. The IAC expert recalled that in nature there is almost nothing cyclical, because the relationship between cause and effect is usually non-linear and involves different mechanisms of amplification and / or damping of the relationship. "The issue is not the result of climatic changes that have occurred, something that would be impossible to pin down, but the frequency with which they have occurred and the causes that have led," says Vázquez Abeledo.

For his part, Professor Mann has pointed out that the planet's response to climate change induced by greenhouse gases could be more complicated than just warming induced by natural phenomena. In this regard, Abeledo Vázquez explained that the main cause of warming today is clear: the rapid burning of fossil fuels by human activity. Consequences on civilization are still difficult to estimate.

By studying climate changes occurred in the history of the Earth, scientists have direct measurements only from the nineteenth century. To reconstruct the past climate using various indicators that change according to the timeline under consideration. The further back in time, be more vague in both its quantitative and temporal resolution.

Scientists also know that the Earth is not the only planet with climate change. Any planet is altered, especially if they have atmosphere. The causes are similar to those produced on Earth. IAC investigator indicates that the main difference is that the earth's climate changes have not been the same if I had not had life.

Consumer Published in the December 10, 2009