7 weather phenomena that will become more frequent due to climate change

Weather hazards have always been part of our daily lives. In 1947, a wave of heat exceptional event hit Europe with peaks of over 40°C recorded at the end of July in the Paris region, and we suspect a drought history of being at the origin of the fall of the Assyrian Empire more than 2,700 years ago. Only here: these hitherto unusual phenomena are aggravated by climate change, and could well become the norm in the future. Here’s how a hotter planet leads to more disasters.

Record rainfall

In July 2021, torrential rains fell in Germany, the Netherlands and Belgium. They have led to floods catastrophic with several hundred deaths. If it is common to know Cevennes episodes in fall, such a deluge in the heart of summer is quite unusual. According to a study by the World Weather Attribution (WWA), the probability of this type of event today is 1.2 to 9 times higher than during the pre-industrial era, due to the global warming. Another study from the University of Newcastle also points out that “slow storms” (which increase the amount of precipitation over a given area) could become 14 times more frequent over Europe by the end of the century. The explanation is quite simple: the more theair hot, the more water it retains. For each increase of 1°C, scientists estimate that theatmosphere retains approximately 7% more moisture.

cyclones

In 2020, 29 tropical storms were recorded in the Atlantic, a record! However, weather models do not indicate that warming will make hurricanes more frequent, but on the other hand they will be more intense, with more powerful winds and precipitation higher. According to a Japanese studyhurricanes also penetrate deeper into land : by growing on warmer oceans, they absorb and store more moisture, which prevents them from weakening when they arrive on land. The hurricanes could also cause more damage by staying longer in the same place. ” Anthropogenic warming could lead to a significant slowing of the movement hurricanes, especially in some heavily populated areas of the latitudes medium, such as Japan or the East Coast of the United States “says Gan Zhang, author of a study published in 2020 in the journal ScienceAdvance.

Heatwaves

In June 2021, Canada experienced an unprecedented heat wave with temperatures exceeding 45°C in several cities, sometimes more than 20°C than seasonal norms! A ” heat dome favored by climate change, confirm the scientists. According to a study by the Zürich Polytechnicthe waves intense heat events will become two to seven times more likely over the next three decades if emissions of greenhouse gas continue at the same pace. Another study from 2020 shows that the duration heat waves increased by 6.4 days per decade between 1980 and 2017 in the Mediterranean region. In France, a heat wave equivalent to that of 2003 could occur every two years by the end of the century, attests Météo-France.

lightning

According to calculations from the University of Berkeley in the United Statesthe lightning strike could increase by 12% per degree celsius of rglobal warming and about 50% this century in the United States. ” This phenomenon is explained by the increase in water vapor in the atmosphere which feeds the movement of currents of hot air.explains David Romps, lead author of the study. The faster the ascent of the air masses hot in the upper atmosphere, the more there islightning. “. A other study reveals that the frequency of lightning could double over the Arctic by the end of the century. All this is not without consequences: besides the danger of lightning strikes for humans and animals, lightning causes significant damage to forests: according to a study of Smithsonian Tropical Research Institutea stroke of lightning damages a total of 23.6 trees and destroys 5.5 of these trees per year in the tropics. Lightning is also likely to trigger Forest fires devastating.

Coastal flooding

Global warming leads to melting accelerated from ice caps and thermal expansion of ocean water. Two phenomena that combine to raise the sea level, and thus threaten the cities located on the coasts. A rise in sea level of 5 to 10 centimeters will double the frequency of flooding at sea level. tropics between 2030 and 2050, attests a 2017 study. Rising waters also accentuate flooding due to tides and to storms, because the water starts from a higher level. An American study thus shows that, in particular because of these tropical storms, 100-year floods (which have a 1 in 100 chance of occurring in any given year) could recur every year on some US coasts. Coastal towns are all the more threatened because they are also suffering from thecoastal erosion : the more land the ocean gains ground, the more sand it carries with it and weakens the rocks, increasing the risk oflandslide.

forest fires

In 2019, no less than 350 million hectares of forest burned around the world, the equivalent of six times the surface of France. Australia, Siberia, Europe, United States, Indonesia, Amazonia… no region is spared. According to a meta-study published in 2020, global warming clearly increases the risk of forest fires, due to a combination of unfavorable phenomena: high temperatures, low humidity, low rainfall and high winds. A 20% elongation of the season global fires, resulting in more burned areas. ” The anthropogenic signal of climate change will lead to a 33% to 62% increase in the area of ​​land burned by 2050 says one of the studies cited in the report. The phenomenon generates a vicious circle: in 2019, forest fires generated the emission of 6,375 megatons of CO₂is around 20% of total greenhouse gas emissions of the year. CO₂ which itself contributes to global warming.

The extreme cold

It may seem counter-intuitive, but warming may also increase the likelihood of extreme cold episodes. Researchers have found that recent outbreaks of cold air observed in North America and East Asia were linked to global warming. stratosphere and retreating ice in the northern seas. Phenomena that disturb the polar vortex, the cold air then being moved towards more southerly areas. On the other hand, the poles tend to warm faster than the equator. “ As the temperature difference between the two decreases, the atmospheric currents will tend to weaken », explains François Gourand, forecasting engineer at Météo-France. By no longer playing their role of “barrier”, these jet streams allow more cold air masses from the polar regions to pass through.