Although so far XXI century there have been several years of record highs and that in regions of the world, especially at high latitudes, the observed warming is tenacious, what had been an upward trend of annual average temperatures of the Earth’s surface has stagnated in the past 15 years. Scientists look for an explanation of why global warming seems to have been put on hold, at maximum levels, bearing in mind that the concentration of greenhouse gases in the atmosphere has not only increased inexorably in that period seems to break climate. The stagnation in escalating temperatures due to cooling of the tropical Pacific waters associated with cyclical oceanic phenomenon El Niño / La Niña, explains now some scientists in the U.S.. They claim that when the ocean hot again will resume rising global average temperatures had been so marked that in the last decades of the twentieth century.
“Our results demonstrate that the current interval [in the escalation of the temperature] is part of natural climate variability, specifically associated with La Niña cooling rate of a decade,” writes Yu Kosaka and Shang-Ping Xie ( Scripps Institution of Oceanography, USA) in the journal Nature . “While there may be intervals in the future, the trend of decades of warming is likely to continue with increasing greenhouse gases”, added.
carbon dioxide concentration in the atmosphere has already exceeded 400 parts per million in some observatories measures, compared with 280 ppm before the industrial revolution. This increase in greenhouse gases should be reflected in a parallel increase in warming as basic physics of climate. However, in recent years the average temperature curve in the land surface, rising sharply from the seventies until nearly the end of the last century, it has become an almost flat line. Not that they have lowered the thermometer through the planet, is that it has stopped rising at the rate above. According to climate simulations, it should have been an increase of 0.25 degrees Celsius over the past 10 years, however, were only 0.06 degrees, recently explained the German meteorologist at the University of Hamburg Hans von Storch in an interview in Spiegel .
“There are two possible explanations, and neither is very nice for us [climate scientists],” said the German expert. The first possibility is that global warming is producing less than expected because of greenhouse gases, especially CO 2 , have less effect than was presumed. “This does not mean that no enhanced greenhouse effect from human activity, but that their influence on climate is not as big as we thought,” explained von Storch. “The other possibility is that, in our simulations, we have overestimated the climate fluctuations due to natural causes,” he added, warning that the scientific problem would be serious if the current is prolonged much more stable temperatures. It is in this second option will fit the work of scientists from Scripps.
Yu Kosaka and Shang-Ping Xie recall that several explanations have been proposed, as the cooling effect of aerosols in the upper atmosphere or the solar minimum phase by 2009. But his response is associated with reciprocating cyclic heating / cooling of the tropical Pacific, which was also on the minds of many as a good candidate to explain the current warming hiatus. They describe in Nature the development of a climate model that fits well in the oceanic oscillation effect of El Niño / La Niña, whose effect is known historically by extreme rainfall and droughts caused cyclically, especially, but not only South America. Its methodology, they say, allows multi quantify the influence of these variations and results obtained with the model correctly reproduces the stagnation (hiatus, they say) in average global temperature curve recorded at the beginning of the century, namely that “reconciles climate simulations with observations ”.
The ocean is full of microscopic algae take carbon dioxide from the atmosphere to grow, and when the amount of CO2 available low, seek alternative fuel supplementary for photosynthesis, such as baking present in the water, with the added cost for energy and nutrients. When increasing the amount of carbon dioxide, stop using the resource, and that is reflected in the tiny shells that some do and microscopic algae that accumulate on the seabed. Two researchers from the University of Oviedo have used these shells now as a record of atmospheric CO2 concentrations in the past to measure the chemical changes that occur in the shells of algae when they need extra fuel, as bicarbonate. Have been traced to the last 60 million years and have found that these algae began to rely heavily on these carbon sources added relatively recently, seven to five million years. Heather Stoll and Clara Bolton explained in Nature this study, funded by th e
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