What Causes Global Warming
Some of the natural changes in Europe’s climate over the past 1,000 years, including the deadly, cold winters of the 16th and 18th centuries, can be actually explained by variations in sun’s activity. According to the Earth scientists, the solar output drops correlate with the cool-down periods in the North Atlantic – when the output goes down, so do the temperatures. This may have cooled the European climate.
When the sun’s activity decreases, a high-pressure system may form in the atmosphere over the North Atlantic, claims the study in Nature Geoscience. Such system stops warm winds flowing from east to west, called westerlies, and thereby allows cold northern air to flow over Europe.
As lead author Paola Moffa-Sanchez of Cardiff University comments in a press release: “Indeed we propose that this combined ocean-atmospheric response to solar output minima may help explain the notoriously severe winters experienced across Europe between the 16th and 18th centuries, so vividly depicted in many paintings, including those of the famous London Frost Fairs on the River Thames, but also leading to extensive crop failures and famine as corroborated in the record of wheat prices during these periods”.
Thanks to fossils, sun-spot records and computer simulations, scientists were able to analyse the interplay between sun, sea and climate. The chemicals residing within fossils of marine microorganism were crucial in gaining information about the historical temperatures and salinity of the ocean.
Clues to solar activity are extracted from sun-spot records, where low number of spots equals to low solar activity, or output. This data together with the fossil information were used to build a digital model that simulates the influence of solar changes on European climate.
The results of this study and other historical trends are in line with other research on recent interactions between solar activity and climate. And although some climate change deniers have attempted to blame solar activity for global warming, the authors of the Nature Geoscience study says that human activity has a much more profound impact than Sun’s output variations.
The Sun-Earth Connection (Source: http://goo.gl/ipRngl)
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