Increases in global warming has stopped for at least the next thousand years, even if a complete ban of greenhouse emissions from 2100, and this will lead to the melting of glaciers in western Antarctica to the year 3000. This is reported in a paper published in the journal Nature Geoscience on Sunday.
"We tried to simulate the effects of climate scenario in which the use of fossil hydrocarbons will be phased out and will no longer anthropogenic CO2 emissions to the atmosphere. We were wondering how fast can happen to reverse the current trends in climate and whether these trends are worse," — said lead author of the publication — Professor Sean Marshall (Shawn Marshall) University of Calgary (University of Calgary), as quoted by the press service of the organization.
The authors of the model study using its computer model showed that the northern and southern hemisphere differ markedly in their susceptibility to warming — in the Northern Hemisphere at the end of the third millennium will be a slow return to baseline climate parameters, while the climate of the southern hemisphere will respond to changes in CO2 concentration in the air with a long delay.
As a result, these regions of the world, as the territory of modern Canada, the year 3000 can largely return to modern climatic parameters, whereas in the Southern Hemisphere will be a permanent increase in average temperatures. This will lead, in particular, 30% of the desertification of fertile lands of northern Africa and the warming of waters off the coast of Antarctica by about 5 degrees Celsius, which will inevitably lead to a complete melting of the glaciers of the western part of the continent.
According to a recent study published in the journal Nature, the development of agriculture in the Sahel region of Africa over the last 200 years has been the cause of increasing the amount of dust in the atmosphere, which may lead to increased desertification in the region.
Agricultural development in the African Sahel region over the last 200 years has led to increase the amount of dust in the atmosphere that may lead to increased desertification in the region, the authors of the study, to be published Thursday in the journal Nature.
Sahel — this African region, a strip extending from the east to the west coast of the continent and includes countries such as, for example, Senegal, Mauritania, Mali, Niger and Sudan. Hot winds in this region often create sandstorms that can cross the Atlantic and polluting the ocean dust.
Mulitsa Stefan (Stefan Mulitza) from the University of Bremen and his colleagues evaluated the dynamics of dust entering the atmosphere from the Sahel. Using data on the structure of the deposits, which are formed from the drop down into the ocean of dust, the scientists concluded that the sharp increase in the amount of dust in time coincides with the rise of commercial agriculture in the region.
"In this paper, we reconstruct the history of 3.2 thousand years of dust deposition to the north-west of Africa, exploring the chemistry and variations in the size of grains of sand in the clastic sediments in the area of the ocean, is right under the West African dust plume … Our findings suggest that the dust emissions the air of the Sahel region, caused by humans, contribute in a dusty atmosphere for about 200 years, "- wrote the authors of the article.
The results Mulitsey and his colleagues suggest that from 600 to 1700 AD, the amount of dust into the air, depended mainly on rainfall. However, after 1700 this relationship breaks down: after a rainfall decrease returns to average levels, while the dust continues to grow rapidly, "unprecedented in the previous three millennia."
The authors write that a significant change coincides with the equally dramatic changes in the structure of agriculture: after the so-called "cash crop revolution" in the mid-19th century the economy of many countries in the region is export-oriented, and spread the peanut and other crops led to a rapid increase in the cultivated area and deforestation.
"It is possible that increased dust emissions associated with human activities, also one of the reasons for the dry climate of the Sahel, because it reduced the amount of rainfall in the monsoon season," — they wrote, noting that this might explain the steady trend of desertification observed in the region in the last 400 years.
Such differences scientists explain the slow mixing of waters of the North Atlantic Ocean and the southern waters of the Atlantic. "Such persistence medium and deep currents that flow into the southern waters of the Atlantic, means that CO2 emissions that have occurred in the last century, only now beginning to lead to an increase in water temperature," — said Marshall.
The scientists also demonstrated that further warming will lead to increased winds and will be accompanied by vigorous agitation of water, and therefore — and more intense heat transfer from surface waters to the deep water masses.
Now scientists more accurately determine the time frame within which to happen melting ice in West Antarctica.