Future changes in the distribution of rainfall will affect the lives of at least 3 billion people (Shutterstock)

A new scientific study, the first of its kind, has shown that future changes in the distribution of rainfall in the world may include more than two-thirds of the landmass, affecting the lives of at least more than 3 billion people due to increased rainfall or drought.

A study conducted by Australian researchers, which used climate models to simulate future rainfall patterns, revealed that the Mediterranean basin region will be one of the regions where rainfall will decline the most by the end of the current century, while regions near the poles and the tropical regions in Africa and Asia will be more humid.

Integrating data from 146 climate models

Climate models are one of the main ways that scientists can explain past climate phenomena and determine future climate changes. Models are used to calculate these forecasts of potential emissions scenarios for warming gases.

However, using climate models to simulate future rainfall patterns is a difficult task for researchers, resulting in varying rainfall forecasts, especially at the regional level.

Researchers studied data from 146 climate models to determine which areas will experience disturbances in rainfall (Nature Communications)

In the study recently published in the journal Nature Communications, researchers from the Australian University of Queensland used an innovative approach based on data from 146 climate models covering historical and future projections from 1980 to 2100. They were able to identify areas that will witness disturbances in rainfall in the future, whether Whether it increases or decreases.

But these disturbances do not mean that the total amount of water on the planet will change, according to Dr. Habib Ben Boubacar, professor of geography and climatology at the Tunisian University of Manouba, who confirmed in an exclusive interview with “Al Jazeera Net” that the total amount of water on the planet in its three physical states - liquid, frozen and gaseous - is 1,400 million cubic kilometers, which is a fixed quantity that does not increase or decrease, and the changes are only related to its distribution across regions and the difference in its proportions between its physical states, whether liquid, frozen, or gaseous.

Global hotspots

The results of the new study, according to a report published by the study’s lead researcher on the “The Conversation” website, showed that many countries will face drier conditions in the future, and revealed that the five countries that will be most affected by the decline in rainfall belong to the Mediterranean basin region, which is Greece. Spain, Palestine, Portugal and Morocco, where at least 85% of models predict a significant reduction in annual rainfall by the end of this century if very high emissions continue until the end of the century.

On the other hand, more than 90% of the models agreed that the annual average rainfall in Finland, North Korea, Russia, Canada and Norway will take an upward trend until the end of the current century.

The Mediterranean basin region will witness a significant decline in rainfall by the end of the century (NASA)

The results also revealed that 70% of the models expected increased rainfall in most regions of China and India, the two most populous countries, which together contain more than 2.7 billion people. Researchers expected that some European countries, including the United Kingdom, Germany, and France, would witness less rainfall in the summer and more in the winter, with the annual average remaining unchanged.

According to the study's lead author, rainfall forecasts remained unclear in other regions of the world, and these regions include Central Europe, southwest Asia, parts of the west coast of Africa and South America, as well as most of Australia.

In total, the areas facing changes in precipitation due to global warming will cover a third of the land, affecting 38% of the world’s population according to moderate scenarios that expect emissions to be reduced by the end of the century to about half the levels of 2050. However, this percentage will reach To 66% of the world's population if emissions of polluting gases continue without decline.

The Mediterranean Basin: a fragile region subject to low rainfall

In the results of the study, the Mediterranean region emerged as a hotspot that most climate models expected to be drier by the end of the century due to climate change. In addition to the five Mediterranean countries that occupied the highest ranking of the countries most affected in the future as a result of the decline in rainfall, this ranking also included other Mediterranean countries such as Tunisia, Syria, Turkey, and Italy.

Regarding the reasons behind the vulnerability of this region to climate change, Dr. Habib Ben Boubacar says: The peculiarity of the Mediterranean region, which includes most of the Arab countries, is that it is not an independent climatic zone in itself, but rather a transitional zone between two main zones, which are the tropical zone and the temperate zone. Therefore, it is called a subtropical region, and this means that the influences of the two aforementioned bands alternate in dominance over it. Sometimes the influences of the desert tropical influences, which carry hot and dry currents, dominate, and at other times, the influences of the temperate band, which carry northern air currents, dominate.

Although these conditions give the Mediterranean climate the characteristic of diversity in seasons, they also make the region more vulnerable to climate change.

The Tunisian researcher adds that when we talk about the water cycle and the changes that can occur to it, this cannot be separated from temperature data, as the rise in average temperature as a result of global warming automatically leads to an imbalance in the water cycle by accelerating the evaporation process.

On the other hand, the hot southern currents are increasingly dominating the Mediterranean basin, especially on its southern bank, and they represent a barrier that prevents fluctuations coming from the northern, temperate, rain-bearing region.

Ben Boubacar stressed that the dangers of climate change in the Arab and Mediterranean region and the rest of the world do not lie only in the trend of the average temperature rising, but also in the increasing cases of thermal and climatic extremes in general, which are represented by waves of extreme heat and cold waves - especially during the winter - as a result of the collision of masses. Warm air masses and moderate air masses.

As a result, the amount of rainfall is witnessing two dangerous extreme trends: They are an increase in extreme cases of rainfall, represented by long periods of drought followed by very heavy rains, with the emergence of unusual climatic phenomena such as the phenomenon of tornadoes.

The researcher noted that these changes will have impacts on the water, food and social security of the inhabitants of the Mediterranean Basin, as well as on the right of future generations to a healthy environment.

Source: Al Jazeera + websites