Climate change is leading to both decreased annual rainfall and increased variability in the timing and intensity of rainfall in dry areas, resulting in more extreme weather events like floods. Consequently, rain isolines are becoming more variable due to these climate impacts.

Its my understanding that climate change seems to be leading to decreased mean annual rainfall in some arid areas, but increased mean annual rainfall in some other arid areas, and no statistically discernable change in mean annual rainfall in other arid areas. Also, in some arid areas (including much of California, USA) the inter-annual variability of annual precipitation has been increasing significantly (i.e. wetter flood years and drier drought years).

There are dust clouds which has created deserts from western India to Morocco for the last 2,000-5,500 years, that you can read about at https://www.ecoseeds.com/cool.html

What the dust in the air does, is it changes the dew point, so that moisture cannot form rain clouds. The other thing it does, is forms a wall against rain clouds, so they stall and pour rain on that barrier. This dust cloud is so strong, it can stop Category-5 cyclones like GONU you can see at https://www.ecoseeds.com/GONU.html

However, since 1985, the amount of moisture in the air has increase due to Global Warming, so that is cancelling out the effects of the dust. In the past in Arabia, the torrential rains used to happen every few centuries. Now if is several times a year, that you can read about at https://www.ecoseeds.com/cool2.html

By replanting the local native grasses, wildflowers and trees, that insulates the land and settles the dust, so that the dew point can change and produce gentle rains instead of torrential flood. Also, by cloud seeding on a weekly basis, then the rain clouds and moisture can be dispersed and directed somewhat and keep it moving instead of flooding a particular spot.

We have been having four years of discussions about this issue at https://www.researchgate.net/post/How_we_can_reach_the_food_security_in_country_90_is_desert

and for two years at https://www.researchgate.net/post/Climate_change_or_water_resource_management_Which_has_caused_the_intensification_of_dust_storms_in_the_Middle_East

Image of the "Pakistan-Arabia Dust Cloud" trapping a cyclone last year.

Isam Mohammed Abdulhameed

I'd suggest you to look IPCC models (at best something plausible like RCP 4.5 scenario) for the region that you are interested in.

Seriously, there should be globally slightly more moisture in air potentially increasing rainfall and presumably a bit more torrential rain, but the local impact can be completely different. (For example northern Europe there seems to be no blatant change in overall rainfall, while southern Europe is going to get somewhat drier)

Here are the Dust Clouds as they were situated in April 2022. These Dust Clouds can do at least four actions:

1.) Droughts where they exist, because the dust in the air retains heat and changes the dew point so moisture cannot form rain clouds.

2.) When moisture moves into the Dust Cloud and rain clouds cannot form, then the world's highest Heat Indexes are created. This is probably one of the worst effect of Global Warming and very dangerous for any people, animals, birds or insects trying to live where organisms cannot reduce their body heat.

In August 2023, a weather station near Dayrestan Airport in Iran reported a heat index of 178°F (81°C).The extreme heat was the result of an air temperature of 102°F (38.9°C) and 85% relative humidity.

3.) Acts as a wall and stalls rain cloud or cyclone movement which causes floods and torrential rain.

4.) Dissipates or changes the direction of cyclones like GONU, and both things happened at the same time at https://www.ecoseeds.com/GONU.html.

First GONU was trapped by the dust in the Straits of Hormuz where it was being worn down and dissipated. When it got free, and when released it was flung to the NE into Iran and caused $216 million in damage and 28 deaths in Iran in 2007.

The highest heat index ever recorded in Iraq was 152°F (66.7°C) at Persian Gulf International Airport in Iran when the heat index in the Middle East reached levels that are close to the limit of human survival on July 20, 2023, with an air temperature of approximately 120°F (49°C) and a relative humidity around 50%.

Cloud seeding once a week plus ecological restoration of the desert grasses and wildflowers, could cool that part of the world, as outlined at https://www.ecoseeds.com/cool.html

The Saudi government adopted this proposal in August 2010, and are doing cloud seeding along with their country's ecological restoration by planting one million trees per week until 10 billion are planted, as part of the "Middle East Green Initiative"

Climate change does not necessarily reduce annual rainfall in dry areas but often alters its patterns. It causes shifts in the timing, intensity, and distribution of rains, leading to more extreme weather events like floods and torrential downpours. These changes increase variability and unpredictability, disrupting traditional seasonal cycles. Rainfall isolines, therefore, are not fixed; they shift over time due to the dynamic impacts of global warming, influenced by regional climatic systems. This variability highlights the need for adaptive water management strategies.