Weather hazards/man-made actions are partially responsible for the extreme weather in Europe
By Kate Roylos, Guardian
What can be harmful in planting trees? The benefits are obvious: the trees stabilize the soil, absorb excess water, consume carbon dioxide from the atmosphere and provide a home for animals and other plants. The popularity of trees is currently at its peak. The National Forestry Commission in Great Britain provides grants that encourage landowners to plant trees, and giving trees as wedding favors has become a fashionable custom when the couple is ecologically conscious. Ironically, it turns out that this practice may exacerbate the greenhouse effect.
The roots of the trees keep the dirt well, and fasten it firmly to the ground, safe from the claws of the wind. A swirling dust storm can be turned into a confusing patch of forest by planting a few trees. The problem is, some of these dust clouds play an important role in absorbing carbon dioxide.
In satellite images, massive sandstorms are visible, drifting from dry areas towards the oceans, as happens in North Africa and Central Asia. During stormy periods, tons of dust are picked up by the wind and sink as a thin layer on the surface of the ocean. This supply of dust animates the oceans. Dr. Andy Ridgewell, a researcher in environmental sciences from the University of East Anglia, has spent the last few years studying dust, and the results of his research show that sometimes dust is a positive factor.
"Microscopic sea plants (phytoplankton) rely on the iron in the dust, which is an essential component of their food supply," says Ridgewell. These tiny organisms are devourers of atmospheric carbon dioxide. "They use carbon to build their bodies, and when they die, they sink, along with the carbon in their bodies," explains Ridgewell. The phytoplankton responds to changes in dust supply.
From experiments that included dispersing an iron solution in the Pacific Ocean, it emerged that iron is indeed an essential element for the survival of the phytoplankton. "Fertilization with iron in parts of the Pacific Ocean, near the equator, caused such a noticeable increase in the number of phytoplankton plants that the color of the water changed," said Ridgewell. Alternatively, a decrease in dust supply may well lower their numbers.
Ridgewell decided to calculate how much carbon dioxide the phytoplankton consumes, compared to the trees. Using a computer model, Ridgewell showed that even a small reduction in the supply of dust to the ocean can lower the ocean's ability to absorb carbon dioxide. "For example, reducing the amount of dust reaching the ocean by 20% will reduce phytoplankton production enough to reduce the absorption of carbon dioxide from the atmosphere by the ocean by up to 150 million tons of carbon per year. This amount is equivalent to the carbon dioxide emissions of the whole of Great Britain," says Ridgewell.
His calculations even indicated that the amount of carbon dioxide absorbed by the newly planted trees may not be enough to offset the results of the decrease in the amount of phytoplankton.
But how high is the chance of a significant decrease in the amount of plankton in the future? The Chinese government has a huge reforestation plan to combat soil erosion and dust storms in the relatively dry northern regions of the country, especially around the capital Beijing. Dust originating in this part of Asia is carried by the wind to the east, and much of it reaches the Pacific Ocean. If China's tree planting project is successful, and the supply of dust does decrease, then the net result will be less carbon dioxide being trapped in the ocean. Planting trees in such a sensitive area can cause the incredibly strange effect of increasing global warming.
And maybe it's the urbanization and not the forest
A series of extreme weather phenomena have caused severe natural disasters in many regions of the world in recent weeks. In addition to Europe, which was hit by floods, Australia is currently suffering from a severe drought and fierce storms are raging in India. In China too, unusual weather phenomena have occurred in the last six months: the last winter was the warmest in the last fifty years; In the spring there were heavy dust storms; And in recent days there have been heavy floods, precisely in relatively arid areas, which were not at all prepared for the rain.
In recent years, the accumulation of extreme weather phenomena has repeatedly provoked explanations that are not regional in origin but international, chief among them the warming of the earth - a phenomenon that scientists call "climate change".
A team of scientists on behalf of the United Nations determined seven years ago in a special report that man is causing climate change manifested in warming. The reason for the warming is the greenhouse effect that creates polluting gases emitted by humans, which serve as a barrier to the energy of the sun's radiation, which reached the earth and was supposed to be released back into the atmosphere. Among other things, the scientists determined that climate change will create a variety of extreme weather phenomena. It will cause not only dryness and desertification processes, but also large amounts of rain and floods. The reason for this is that the increase in heat also affects the wind regime and the amount of vapor in the air, in a way that leads to the development of storms and heavy rain clouds.
It should be noted that among climate researchers there are several approaches regarding the effect of the climate change in question. Some researchers claim that the warming phenomenon has already manifested itself, and see a direct connection between it and natural disasters. Another group of researchers is more cautious. These researchers have no doubt that human activity has affected the climate, but they point out that there is still no statistical accumulation that would allow diagnosing an actual increase in abnormal weather events associated with such a change. Another group emphatically states that so far no proof has been found of human influence on the climate and the formation of warming. This is a group that currently represents a minority among climate researchers, but it also has some prominent scientists.
In Europe, several researchers prepared for the European Union's Environmental Protection Agency, a comprehensive report on extreme weather phenomena, and also referred extensively to the problem of floods. The report was published a few months ago and it indicates that a flood is the most frequent natural disaster in Europe, and also the disaster that causes the heaviest economic damage. In the years 1996-1975, 163 major flood events occurred on the continent. The most vulnerable areas to floods are the Mediterranean coast, the flat areas in Germany, part of the Danube river basin and the Rhine, Seine and Loire river valleys. The report indicates some of the main factors that lead to an increase in the intensity of floods: climate change, natural characteristics of the land and human land use.
The soil softeners may increase the intensity of floods as in various areas in Germany, where a layer of frost develops on the surface of the ground. This layer prevents water seepage, thus increasing the intensity of the flow after heavy rains. Land uses affect flow, because they disrupt it (in the case of railways and roads), or they block water seepage into the soil, especially in urban areas. It is estimated that in these areas in Germany, 75% of the land surface is blocked for water seepage.
Another problem is that in almost all the major rivers in Europe, man has disrupted, due to the construction of various structures, the connection between the river and its floodplain. The plain is the natural plain to which river water flows during a flood, where it seeps into the ground, is absorbed by vegetation or evaporates.
As for climate change, the report states that according to several scientific works, there is already a change in the characteristics of winter in Central Europe, and there is an increase in extreme rain events, and overall in the general amount of precipitation. According to some of the researchers, the change in the amount of precipitation caused an increase in the number of flood events in southwest Germany in the last three decades.
Zafarir Rinat
Major floods in Europe
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