Climate change and its impacts in extreme events in Morocco (observation, monitoring, and forecasting)

Over the past century, our planet has grappled with a phenomenon known as global warming. This warming trend disrupts climate patterns at all levels, with increasing spatiotemporal variability. This variability translates to a rise in extreme weather events across various regions. Numerous studies, including those by the IPCC, highlight how climate change alters the intensity, frequency, and duration of these extreme events. The IPCC specifically identifies an impact on the number of such events, with observations pointing toward increases in both heat waves and cold snaps, alongside heavy precipitation events in certain regions (Qin et al. 2013). While Africa holds the distinction of being the continent least responsible for greenhouse gas (GHG) emissions, it is unfortunately projected to bear a significant brunt of the consequences associated with climate extremes. This vulnerability was underscored in the 2016 ‘Climate Risk Index’ released during COP22. The report designated Africa as the continent most impacted by such phenomena in 2015, with floods notably affecting the very continent hosting the climate summit (Kreft et al. 2015, 2016; Eckstein et al. 2018, 2021).

The Mediterranean basin is a climate change hotspot, experiencing a rise in extreme temperatures at a rate faster than the global average. This is due to a combination of factors, including the region's unique geography, atmospheric circulation patterns, and the influence of GHG emissions (Hammoudy et al. 2022).

Several studies have documented the increase in extreme temperatures in the Mediterranean. For instance, a 2021 report by the Intergovernmental Panel on Climate Change (IPCC) found that the Mediterranean is likely to experience a 2–3°C increase in mean temperatures by the end of the 21st century, under a high-emission scenario (IPCC 2021). This warming is projected to be accompanied by more frequent and intense heatwaves, droughts, and wildfires. These studies rely on global climate models (GCMs), advanced computer simulations that recreate the Earth's complex climate system. By incorporating the atmosphere, oceans, land, and ice, GCMs can model how these components interact to influence our planet's climate. These models are crucial for understanding past climate changes, predicting future climate trends, and assessing the potential impacts of human activities on the environment.

Morocco, situated in North Africa and bordered by the Mediterranean Sea on its northern facade, is another example. Despite its low GHG emissions, the country is not immune to the effects of climate change, which manifest in terms of diversity, intensity, and frequency. The meteorological extremes Morocco experiences today, such as rising average and extreme temperatures, more frequent and extensive heat waves, declining annual precipitation in some regions, and shifts in seasonal rainfall patterns, are undeniable consequences of climate change.

The late 20th century witnessed Morocco battling a series of such events, most notably a period of intensifying drought. Other regions have been struck by violent and atypical floods, including Ourika in 1995 and 1999, Casablanca-Mohammedia in 1996, Tetouan in 2000, Mohammedia in 2002, Er-Rachidia in 2006, the northern regions of Al Gharb, Al Haouz, and Sous in 2009 and 2010, Casablanca in 2010, the South in 2014, Ksarsghir in 2021, and most recently, Casablanca again in 2021 (Neil Ward et al. 1999).

The increasing impact of climate change is becoming evident in Morocco with a noticeable shift in the frequency and intensity of extreme weather events. We can expect this trend to continue in the coming years, potentially leading to more severe disasters (IPCC 2021).

The intensifying heat poses a significant threat to Morocco's climate. Global research indicates a quadrupling in the frequency of heat waves compared to what would be expected with a minor temperature rise of just 1 °C (Stour & Agoumi 2008). Similar trends are unfolding in Morocco, with documented evidence of rising average temperatures and increasingly frequent, severe heat waves (IPCC 2021).

Temperature records are shattered year after year. These extreme heat events are often accompanied by scorching nights, with minimum temperatures exceeding 30 °C. Additionally, Morocco experiences periods of intense rainfall leading to damaging floods (Hammoudy et al. 2022). Notably, 2015 witnessed the country's first encounter with heat waves exceeding 48 °C in some regions.

In this perspective, we analyzed the effects of climate change on extreme events in Morocco. This study examines both past and future climates. We employ two primary approaches. First, we analyze observed trends in temperature and precipitation extremes using data from 29 meteorological stations encompassing all of Morocco's climatic zones. Second, we quantify future changes in extreme events for various time horizons based on the RCP 4.5 climate change scenario.

Table 1 provides a summary of the data series for each weather station, including the time period covered and the corresponding climate region.

The four climate models used in this study are:

• GFDL-ESM2G: This model is developed by the NOAA Geophysical Fluid Dynamics Laboratory (GFDL) and is part of a suite of earth system models (ESMs) created by NOAA to understand the interactions between Earth's biogeochemical cycles (including human influences) and the climate system (Dunne et al. 2012).

• INMCM4: Developed by the Institute of Numerical Mathematics, this model consists of separate atmospheric and oceanic circulation components. It incorporates the effect of aerosols on radiation and condensation rates. A particular strength of this model is its ability to simulate 10 different aerosol types and their radiative properties. Notably, INMCM4 performs well in simulating historical global warming trends (Volodin & Gritsun 2020).

• MIROC-ESM-CHEM: This ESM is a product of collaborative efforts led by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), involving institutions like the University of Tokyo and the National Institute for Environmental Studies (NIES). The current version of the MIROC model includes representations of chemical processes and aerosols, enabling it to realistically reproduce transient surface air temperature variations between 1850 and 2005, alongside present-day climatology for winds and zonal mean temperatures across various atmospheric layers (Watanabe et al. 2011).

• MPI-ESM-MR: Developed by the Max Planck Institute for Meteorology (MPI-M), MPI-ESM is a comprehensive model coupling atmospheric, oceanic, and land surface components through exchanges of energy, momentum, water, and carbon dioxide (CO₂). This model is widely used in the new CMIP6 simulation projects and is further extended to include the carbon cycle and its interactions with the physical climate system (Ilyina et al. 2013).

This study investigates future changes in climate extremes over Morocco. The analysis is based on two main stages: historical and future climate extremes.

• • Historical climate extremes (1984–2018):

• • 1. Data preparation: Daily maximum temperature, minimum temperature, and precipitation data from 29 observed synoptic stations were subjected to rigorous quality control procedures using standard methods like boxplots and thermal amplitude analysis. The R programming language, with its rich statistical functionalities, facilitated this data processing using the following packages: stringr, precintcon, SPEI, trend, and ggplot2.

  • 2. Climate index calculation and trend analysis: Four climate indices (defined later) were calculated for each station. The Sen's slope method was employed to assess trends in these extremes, and the Mann–Kendall test was used to determine their statistical significance.

• • Future climate extremes (2041–2060):

• • 1. Climate index calculation on grid points: For future projections, we are based on the study of five climatic indices. Climate indices were calculated across all grid points encompassing the study area. Averages were computed for each grid point for two time periods: the historical period (1984–2018) and the future period (2041–2060). The analysis focused on the same three meteorological parameters: daily maximum temperature, minimum temperature, and daily precipitation.

  • 2. Future anomaly detection: The core aspect involved calculating the difference between historical and future averages for each grid point. This difference quantifies the anomaly, indicating potential increases or decreases in climate extremes by the mid-21st century. This analysis helps us evaluate future trends in extreme weather events.

• • Data manipulation and visualization:

• • 1. Large climate model database: Due to the vast amount of climate model data utilized, we employed the Shell environment within Ubuntu (Linux) along with CDO commands to manage these NetCDF format files.

  • 2. Mapping results: Finally, ArcGIS software was used to pinpoint and visualize the results on maps, allowing for a clear spatial representation of future climate extremes.

To improve understanding of extreme weather events, the World Meteorological Organization (WMO) Commission for Climatology (CCl) and the Expert Team on Climate Change Detection and Indices (ETCCDI) established a set of over 20 climate indices for precipitation and temperature (Alexander & Herold 2016). These indices are calculated using thresholds, which can be either fixed values or determined based on a chosen reference period. The calculations are performed using the open-source ClimPACT2 libraries for R software, available on GitHub (https://github.com/ARCCSS-extremes/climpact2). The specific definitions for each index are as follows (Tables 2 and 3).

In hydrology, climatology, and environmental studies, analyzing trends in time series data is crucial. We employ Sen's slope, a robust non-parametric statistical method, to estimate these trends. Unlike parametric methods, Sen's slope is less susceptible to outliers, making it well-suited for analyzing data potentially containing extreme values.

Sen's slope trend is a robust measure of linear trend, as it is unaffected by outliers. This means it is less sensitive to extreme values in the data than other trend estimation methods, such as linear regression. Sen's slope trend is also easy to interpret. A positive slope value indicates an increasing trend, while a negative slope value indicates a decreasing trend. A slope value of 0 indicates that there is no significant linear trend. Sen's slope trend is a useful method for analyzing trends in non-linear or noisy time series. It is often used in conjunction with other trend estimation methods, such as linear regression, to gain a more complete understanding of data trends.

Following the calculation of trends for each climate index at all observation stations, we employed the Mann–Kendall significance test to evaluate the statistical significance of these trends (Mann 1945; Kendall 1975). This non-parametric test, highly recommended by the WMO, is particularly useful for detecting monotonic trends (either increasing or decreasing) within time series data.

However, a probability must be calculated and compared with the ‘α’ % (p-value) threshold. The hypothesis H₀ will be rejected if the probability is below the ‘α’ % threshold. This is done using the statistical test Z which is defined as follows:

With Z a normal random variable of mean 0 and standard deviation 1 and the p-value (‘α’) taken equal to 0.05.

The inverse distance weighted (IDW) method is a popular technique for interpolation in spatial analysis. It estimates values for unsampled locations by considering a weighted average of nearby sampling points. Weights are assigned based on distance, with closer points having a greater influence on the estimated value.

• • Strengths of IDW for our project:

• • (1) IDW is particularly well-suited for scenarios with dense and well-distributed sample points: When sampling points are closely spaced and evenly distributed within the study area (as in our project), IDW leverages the detailed spatial information effectively.

  • (2) Proximity matters: The core principle of IDW aligns with our project's theoretical foundation. It assumes that closer sampling points hold greater similarity and relevance than distant ones, accurately reflecting the spatial relationships within the data.

• • Computational considerations:

• • Despite its advantages, IDW has a notable drawback in that processing large datasets can be time-consuming. Compared to faster methods, IDW calculations can take up to five times longer (Nistor et al. 2020).

    

    (6)

    where is the estimated value of the variable at point i; is the sample value of the variable at point i; is the distance between sample point i and the point of estimation (point i); N is the weighting coefficient that determines the influence of each sample point based on its distance to the estimated point; and n is the total predictions number (samples) used for each validation case.

This section delves into observed changes in climatic extremes across Morocco and the Mediterranean basin. We specifically examine precipitation patterns, maximum temperatures, and minimum temperatures. To ensure the reliability of any detected changes, a thorough data quality check was conducted beforehand. Subsequently, we mapped the observed trends across the network of 29 weather observation stations.

This analysis examines temperature trends at several stations between 1984 and 2018. We employ Sen's slope to estimate the magnitude of these trends, expressed in degrees Celsius per year (°C/year). Additionally, the Mann–Kendall test is used to assess the statistical significance of the trends identified by Sen's slope.

Analysis of Figure 3 reveals a warming trend in average maximum (TXmean) and minimum (TNmean) temperatures across most stations during the 1984–2018 period.

• Maximum temperatures: The rate of increase ranged from 0.02 °C/year in Nouasser to 0.08 °C/year in Taza, with these increases being statistically significant. Dakhla station was the only exception, exhibiting a non-significant decrease.

• Minimum temperatures: Similar to maximum temperatures, minimum temperatures also showed a warming trend. The increase varied between 0.02 °C/year at Meknes and 0.06°C/year at Nouasser. However, Rabat and El-Hoceima stations experienced slight decreases, though not statistically significant (refer to Tables 5 and 6 for detailed station data).

Table 5

Detecting statistically significant trends in TXmean index: a combined Sen's slope and Mann–Kendall approach between 1984 and 2018 (+°C/year), colored blue is near or part of the Mediterranean basin

View Large

Table 6

Detecting statistically significant trends in TNmean index: a combined Sen's slope and Mann–Kendall approach between 1984 and 2018 (+°C/year), colored blue is near or part of the Mediterranean basin

View Large

The upward trend in maximum temperature in Agadir (+0.05 °C/year) is equivalent to an increase from 1984 to 2018 of 1.75°C, while the rise in minimum temperature is equivalent to 2.1 °C.

The IPCC published a report dedicated to the region in 2022, concluding a trend toward warming in the Mediterranean basin. The observed data showed an average increase of 1.5 °C in temperatures since 1984 until 2018.

Although the trend is not significant, the observed increase in Rx1day for a majority of stations suggests a potential rise in extreme precipitation events across Morocco. However, the lack of significance for most stations warrants further investigation. The spatially variable trends in CDD highlight the complexity of changes in dry periods across the country. While some regions might experience a decrease in dry spells, others might see an increase. It is important to note that these findings are based on a limited set of indices and a specific timeframe. Further analysis with additional climate data and models could provide a more comprehensive understanding of long-term trends and potential future changes.

Spatially varying increases:

• - The models, particularly GFDL-ESM2G and MPI-ESM-MR, show a clear warming gradient from southeast to northwest. GFDL-ESM2G projects the highest increases (+0.9–1.8°C) in coastal areas and the southern Draa-Tafilalt region.

• - MIROC-ESM-CHEM depicts a distinct pattern with the most significant warming (+2.7 °C) concentrated in the northwest to central-eastern regions, while coastal areas experience a milder increase (+2.2 °C). MPI-ESM-MR aligns with this trend, projecting a maximum increase of +2°C in the northeast and central east.

• - A common finding across all models is a pronounced warming zone exceeding +1.5 °C in the Middle East, along with other regions experiencing increases between +0.9 and +1.3°C (Table 6).

The southeastern regions of Morocco (Oriental, Drâa-Tafilalet, and Laâyoune-Sakia Al Hamra) are likely to see the biggest temperature rises, with values of up to 2.6 °C (MIROC-ESM-CHEM) in the Oriental region. The central regions of Morocco (Fès-Meknès and Beni Mellal-Khénifra) should also see significant temperature rises, with values of up to 2.7 °C (MIROC-ESM-CHEM) in the Fès-Meknès region.

The coastal regions of northwest Morocco (Tangier-Tetouan-Al Hoceima and Rabat-Salé-Kénitra) are likely to see the smallest temperature rises, with values of up to 1.7 °C (GFDL-ESM2G and MPI-ESM-MR) in the Tangier-Tetouan-Al Hoceima region (Table 7).

Table 7

Projected shifts in thermal mean anomaly index (RCP 4.5): a range analysis in each region of Morocco (2041–2060 compared to 1971–2010), colored blue is part of the Mediterranean basin

View Large

The regions exposed to the Mediterranean basin colored in blue in Table 7 could also experience an increase in average temperature by 2060. This increase will reach a maximum of 2.7 °C according to the MIROC model and a minimum of 0.4°C according to the INMCM4 model.

The projected temperature changes exhibit significant regional variations. In general, the eastern and southern regions are expected to experience the most substantial warming, while the Atlantic coast regions are projected to have slightly lower increases.

There is a general consensus among the four climate models regarding the relative distribution of temperature changes across the different regions. However, the specific magnitude of the projected increases varies between the models. The projected temperature increases are quite substantial, with some regions potentially experiencing an average increase of up to 47%. This highlights the potential for significant climate change impacts in Morocco (Table 8).

Table 8

Projected shifts in hot days index (RCP 4.5): a range analysis in each region of Morocco (2041–2060 compared to 1971–2010), colored blue is part of the Mediterranean basin

View Large

All models project increased heat waves across Morocco. Future projections under the RCP 4.5 scenario show a consistent increase in heat waves across all regions of Morocco as predicted by all four climate models. This increase is expected to surpass 30 additional heat wave days per year compared to the historical reference period.

Spatial variations in heat wave increase:

• - Eastern and Fès-Meknès regions: Three models (excluding INMCM4) project the most significant rise in heat waves for the eastern and Fès-Meknès regions. The projected increase varies between 80 (GFDL-ESM2G) and 145 occurrences (MIROC-ESM-CHEM) per year. In addition to these areas, which are part of the Mediterranean basin, other areas bordering the Mediterranean Sea in Morocco are likely to see an intensification and increase in episodes of heat waves by 2060.

• - Atlantic coast: The MPI-ESM-MR model predicts a rise in heat waves along the Atlantic coast, stretching from Tangier to Kenitra. This increase could reach as high as 140 additional occurrences per year.

• - INMCM4 model: This model presents a distinct spatial distribution, with the highest heat wave increases predicted for the southernmost region (Draa-Tafilalet) and the Mediterranean coast. The increase in these areas could reach 47 additional occurrences annually.

Table 9 presents projections of the number of hot days (WSDI) for 12 regions of Morocco for the period 2041–2060 under the RCP 4.5 scenario, derived from four different climate models: GFDL-ESM2G, INMCM4, MIROC-ESM-CHEM, and MPI-ESM-MR. WSDI represents the annual number of days with at least two consecutive days when the maximum temperature exceeds the 90th percentile of the 1971–2010 reference period.

Table 9

Projected shifts in heat waves day index (RCP 4.5): a range analysis in each region of Morocco (2041–2060 compared to 1971–2010), colored blue is part of the Mediterranean basin

View Large

All regions are expected to experience an increase in the number of heatwave days by 2041–2060 compared with the 1971–2010 reference period. The magnitude of the projected increase in the number of hot days varies from region to region.

Climate models show a certain degree of convergence in their projections, but there are also notable differences between models. The southeastern regions of Morocco (Oriental, Drâa-Tafilalet, and Laâyoune-Sakia Al Hamra) are expected to experience the greatest increases in the number of heatwave days, with values of up to 150 days per year (MIROC-ESM-CHEM) in the Oriental region.

The central regions of Morocco (Fès-Meknès and Beni Mellal-Khénifra) are also likely to see a significant increase in the number of hot days, with values of up to 150 days per year (MIROC-ESM-CHEM) in the Fès-Meknès region. The coastal regions of northwest Morocco (Tangier-Tetouan-Al Hoceima and Rabat-Salé-Kénitra) are expected to see the smallest increases in the number of heatwave days, with values of up to 65 days per year (MPI-ESM-MR) in the Tangier-Tetouan-Al Hoceima region.

There is a strong agreement among the models, projecting a decrease in annual precipitation across most of Morocco. This decrease is most pronounced in central and southern regions, with potential deficits reaching −64% (GFDL-ESM2G), −40% (INMCM4), −65% (MIROC-ESM-CHEM), and −80% (MPI-ESM-MR).

• - Localized increase in southern regions:

Interestingly, all models also predict an increase in precipitation for specific southern regions. This surplus could be substantial, reaching 160% (GFDL-ESM2G), 700% (INMCM4), 450% (MIROC-ESM-CHEM), and 160% (MPI-ESM-MR). This significant rise is likely linked to the already low baseline precipitation levels in these southern areas.

• - Explanation of increased percentages:

The exceptionally high projected increases in some southern regions should be interpreted with caution. Since these areas currently receive very low precipitation, even a small absolute increase can translate into a large percentage change.

Table 10 presents a range analysis of projected shifts in the annual cumulative precipitation index (PRCPTOT) for 12 regions in Morocco under the RCP 4.5 emission scenario for the 2041–2060 timeframe compared to the 1971–2010 reference period. PRCPTOT represents the annual cumulative precipitation, expressed as a percentage change relative to the baseline.

Table 10

Projected shifts in annual cumulative precipitation index (RCP 4.5, unit is %): a range analysis in each region of Morocco (2041–2060 compared to 1971–2010), colored blue is part of the Mediterranean basin

View Large

All regions are projected to experience a shift in the annual cumulative precipitation index. This means that the total amount of precipitation is expected to change compared to the historical reference period.

The direction and magnitude of the projected shifts vary across regions. Some regions are expected to see a decrease in precipitation, while others may experience an increase.

There is a general consensus among the four climate models (GFDL-ESM2G, INMCM4, MIROC-ESM-CHEM, and MPI-ESM-MR) regarding the direction of change for most regions. However, the magnitude of the projected shifts varies between the models.

Projections indicate a variety of increases and decreases in rainfall in regions surrounding the Mediterranean basin near Morocco by 2060. Some models predict a decrease of up to −50% in deficit at the indicated horizon. On the other hand, some models predict an increase of up to 40%.

Interestingly, all models also project a decrease in drought intensity (increase in SPI) for some southern regions. This improvement could range between 0.4 and 0.9 on the SPI scale.

For these areas, an SPI of −1 during the reference period would translate to an SPI of −0.1 by 2041–2060, which falls within the ‘normal’ climate category according to Table 4.

Furthermore, GFDL-ESM2G and MPI-ESM-MR even suggest a potential improvement beyond ‘normal’ conditions, with SPI values increasing in the eastern and east-central parts of the country.

Table 11 presents a range analysis of projected changes in the SPI for 12 regions in Morocco under the RCP 4.5 emission scenario for the 2041–2060 timeframe compared to the 1971–2010 reference period. SPI is a widely used indicator of drought conditions, with values below −1 generally considered indicative of drought.

• - Worsening drought conditions across most of Morocco: The projected SPI changes for most regions indicate a decrease in the index, suggesting an overall trend toward more severe drought conditions in the future.

• - Spatial variability in drought intensity: The magnitude of the projected SPI decline varies across regions, with some areas facing more severe drought than others.

• - Potential for extremely dry conditions: In some regions, the projected SPI values could fall below −1.5, indicating a potential shift toward extremely dry climatic conditions.

• - Potential improvements in some southern regions: Interestingly, a few southern regions are projected to experience an increase in SPI, suggesting a potential improvement in drought conditions in these areas.

Table 11

Projected shifts in SPI (RCP 4.5, unit of SPI): a range analysis in each region of Morocco (2041–2060 compared to 1971–2010), colored blue is part of the Mediterranean basin

View Large

In the Mediterranean basin, a future trend toward drying is predicted by the three models GFDL, INMCM4, and MIROC showing a value of the SPI going up to −1.5 reflecting a severe drought on the horizon 2041–2060. The MPI model confirms the same result of the intensification of drought except for certain regions for which it predicts an improvement in the situation; this is the extreme north of Morocco and the extreme northeast as well.

The first part of the study investigates trends in extreme weather events within the 20 N to 40 N latitude ranges. Our findings align with global warming trends reported in the IPCC's 5th Assessment Report, demonstrating increases in both maximum and minimum temperatures across the study area of Morocco and the broader Mediterranean basin near Morocco (Driouech & El Rhaz 2017; Driouech et al. 2020).

Significance of trends: While the observed trends are not statistically significant for all locations, Fez stands out as an exception for the long-term total precipitation accumulation in a single day (Rx1day). This highlights the importance of considering location-specific factors when analyzing climate change impacts.

Data considerations and methodology: Unlike most studies that homogenize data before analysis, we chose to utilize raw data to capture the full spectrum of climate factors influencing long-term trends. This necessitated the application of Sen's slope, a robust method for trend analysis in univariate time series.

Increased heavy precipitation events: The sole statistically significant result, observed at the Fez station, indicates a rising trend in the maximum daily precipitation amount. This suggests a potential increase in the frequency and intensity of heavy rainfall events in recent years.

Impact of non-homogenized data: The contrasting results across different locations emphasize the potential influence of non-homogenized data on trend analysis. A test using linear trend methods on non-homogenized data yielded a significant number of non-significant results, further supporting the value of using Sen's slope with raw data.

Confirmation of rising hot extremes: Our findings on rising temperature extremes concur with predictions from previous research (Born et al. 2008).

Potential causes of increased extremes: The observed increase in extreme events can be attributed to several factors. The rise in greenhouse gases, human impact on forest resources, and the influence of the North Atlantic Oscillation (NAO) regimes (Driouech & El Rhaz 2017) likely play a combined role in redistributing air masses and contributing to the intensification of extreme weather events, including heavy precipitation episodes that have resulted in significant floods across certain regions in Morocco as documented (Ilmen et al. 2016).

The second part of result of this study shows the ranges of increase in average temperatures, the ranges of increase in the percentage of hot days, the ranges of increase in the occurrence of heat waves, the ranges of change in precipitation quantities, and the SPI under the RCP 4.5 scenario:

• - Rising temperatures across Morocco and the Mediterranean basin:

Our analysis of future climate projections for the Mediterranean basin, specifically focusing on Morocco, reveals a concerning trend of significant warming under the RCP 4.5 emission scenario. This scenario outlines a moderate increase in greenhouse gases.

The timeframe of greatest concern lies between 2041 and 2060, when compared to the baseline period of 1971–2010. All four climate models used in this study unanimously predict a rise in average temperature across Morocco.

The most dramatic warming is expected in the central and eastern regions of the country, exceeding a potential 1.5 °C increase on average. This substantial rise signifies a significant shift in the climatic conditions of these areas.

While the central and eastern regions face the most significant warming, other areas like the northwest, coastal regions, and the south are also projected to experience warming, ranging from an average of 0.9 to 1.3°C. This widespread warming trend extends throughout Morocco.

Furthermore, this warming is likely to be accompanied by a rise in extreme heat events, such as an increased number of hot days and heatwaves. These extreme events pose serious threats to human health, ecosystems, and infrastructure.

• - Projected temperature increases:

Under the low-emission scenario (RCP 4.5), the temperature anomaly by 2050 (2041–2060) could range from 0.9 to 2.2°C, potentially exceeding the 1.5 °C target by a temporary 2.7 °C (Legg 2021).

This warming is projected to occur rapidly, with a particularly sharp increase starting in the 2020s. All four climate models used in this study predict a similar trend, with an average projected increase of approximately 1 °C per decade.

• - Changes in precipitation patterns:

Climate models paint a concerning picture of Morocco's precipitation future by the mid-21st century (2041–2060). All four models analyzed consistently predict a significant decrease in annual rainfall across a large portion of the Mediterranean basin within Morocco.

The most substantial decrease in rainfall is projected to hit central and southern regions bordering the Mediterranean. These areas could face dramatic deficits, with potential reductions ranging from −64% (GFDL-ESM2G) to −80% (MPI-ESM-MR). This decrease in precipitation poses a significant threat to water security in these regions, impacting agriculture, drinking water supplies, and ecosystems.

Interestingly, all models also project an increase in annual precipitation for some southern coastal regions bordering the Mediterranean. This potential increase is significant, ranging from 160% (GFDL-ESM2G) to a staggering 700% (INMCM4). However, it is important to note the high variability between models, with MIROC-ESM-CHEM and MPI-ESM-MR suggesting increases of 450 and 160%, respectively. This large spread highlights the uncertainty surrounding these projections.

The findings on future precipitation changes are further supported by the analysis of the SPI, a well-established drought indicator. The consistency between model projections and the SPI analysis strengthens the concern about future water scarcity in the Mediterranean regions of Morocco. Because there is a variation between the models concerning the increase and the decrease of the SPI, which shows that certain regions will experience an intensification of drought and others will experience a future trend toward humidification.

This study aligns with the IPCC's predictions (Arias et al. 2021; Sebbar et al. 2021) of rising temperatures in the Mediterranean basin. While global average temperatures may stay below 1 °C above baseline throughout the 21st century, temporary spikes exceeding 1.5 °C by 2050 are possible (Legg 2021). This highlights the potential for the Mediterranean to experience significant warming episodes, particularly during heatwaves.

This analysis explores the projected climate changes in Morocco and especially the Mediterranean basin, focusing on temperature and precipitation.

• - Projected changes in wet period:

A decrease in precipitation is anticipated by 2050, accompanied by a shortened maximum wet period and a lengthened maximum dry period in certain regions. This aligns with the IPCC's projections for the Mediterranean region (Masson-Delmotte et al. 2021).

• - Challenges in model validation:

While the overall trends are consistent, validating the specific results remains challenging due to difficulties in establishing clear relationships between the four models and the climate indices studied (Filahi et al. 2017; Woillez 2019; Acharki 2020).

• - Precipitation uncertainties in southern Morocco:

The projections do not offer a conclusive picture regarding a definitive increase in annual rainfall for southern Morocco within the study period (Tramblay et al. 2012; Ouhamdouch et al. 2019; Yves et al. 2020; Saloui & Karrouk 2021). Further investigation is needed to clarify this aspect.

Table 12 provides compelling evidence for a connection between rising average temperatures and the increased frequency and intensity of climate extremes. The table demonstrates that with each half-degree increase in average temperature anomaly, we observe corresponding changes in the ranges of:

• - hot days (increased),

• - heatwave occurrences (increased),

• - changes in precipitation patterns, and

• - drought events (intensified).

These findings strongly suggest that rising temperatures are a significant driver of extreme weather events.

This study examines the impact of climate change on extreme weather events in Morocco situated in the Mediterranean region. We analyzed observed trends in temperature and rainfall extremes using data from 29 weather stations across all climatic zones (1984–2018). Sen's slope was employed to calculate trends, and the Mann–Kendall test assessed their significance.

• Observed trends (1984–2018):

  • - Temperature: Analysis revealed a general rise in both maximum and minimum temperatures across most regions. Notably, this increase was statistically significant for many stations.

  • - Rainfall: Extreme rainfall events generally showed no significant trend across most of the country. Interestingly, 41% of stations exhibited a decrease, while only Fez displayed a significant increase (0.48 mm/year or 16. mm over the study period).

Our results on the rise in temperatures in Morocco are consistent with numerous studies carried out in the Mediterranean basin. These studies collectively highlight the worrying potential impacts of increasingly frequent and intense hot extremes. More specifically, the Moroccan study observed an increase in average minimum and maximum temperatures, confirming a trend toward higher extreme temperatures. This corresponds well to thermal patterns observed in other Mediterranean countries such as Turkey. Research from Turkey demonstrates a similar increase in extreme temperatures (Lois-González 2021).

Turkey and Morocco as part of the Mediterannean basin show significant changes in temperature and precipitation observations, highlighting trends observed across the Mediterranean basin. Those studies also highlight an increase in tropical nights (over the last 5 years), the same in Morocco. Our study observed an increase in minimum and maximum temperatures, confirming a trend toward higher extreme temperatures. However, it explicitly addresses changes in hot days in the future and projects an increase over the 2041–2060 horizon (Acar Deniz and Gönençgil 2015; Lois-González 2021).

Like precipitation, the study reports a weak decreasing trend during extremely humid days (winter) and a weak increasing trend during days of heavy precipitation (Black Sea and central Anatolia). We also note a downward trend in very heavy precipitation (Mediterranean region) and an overall increase in consecutive dry days. This confirms our study which only briefly mentions extreme precipitation, indicating a trend although it is not significant but converges toward the same direction except the city of Fez, which is part of the Mediterranean basin with a decrease to 41% of stations and a significant increase only in Fez.

Several studies have identified drought periods in 1989–2001 based on the SPI. Longer-term droughts occurred between this period showing a tendency toward drying. Similarly, our study revealed a decrease in rainfall extremes at 41% (especially in the extreme northern part of Morocco) of the stations in the observed period of 1984–2018 (Deniz et al. 2016).

Our study focused on certain parts of the future projection of the SPI. The results on the decrease of this index in Morocco agree with the broader analysis of Tramblay et al. (2020). Drought intensification (SPI < –1) contributes to intensifying precipitation decreases in Morocco. The multimodel ensemble approach used to make future projections under several mid-century RCP scenarios (2031–2060) for the Mediterranean region, of which our study area is part, conclude on the results obtained on drought intensification and improvement in some areas, highlighting an increasing frequency and intensity of extreme climate events in the Mediterranean region (Tramblay et al. 2020; Vogel et al. 2021).

Also, projections of the heat wave magnitude index (HWMI) published by Molina et al. (2020) suggest an increase in the intensity and duration of future heat waves in the region under a high emissions scenario, although it highlights a worrying trend for the Mediterranean basin as a whole and over the period 1971–2100. This is in line with the findings of our study based on the medium- and short-term scenarios, which predicted an increase in hot days and heat waves, suggesting a trend toward higher thermal extremes.

This study also investigates future climate projections for the Mediterranean basin and Morocco, a region particularly vulnerable to extreme weather events. While definitively linking individual extremes to rising temperatures can be difficult (Masson-Delmotte et al. 2021), research suggests an undeniable increase in their frequency and intensity.

To ensure objective analysis, this study employs four high-resolution climate models (25 km) under a moderate emissions scenario (RCP 4.5). This scenario avoids exaggeration and allows for clear interpretation of the results. Even within this relatively optimistic framework, the models project an irreversible warming trend for the Mediterranean basin between 2041 and 2060. This warming will be accompanied by more frequent heatwaves and a drying trend.

However, the complex topography of the Mediterranean region, including Morocco's diverse geography, creates microclimates that complicate regional projections of extreme weather events. To address this limitation and provide more comprehensive insights, future studies should consider:

• • Expanding the model ensemble: Utilizing a wider range of climate models (more than four) can offer a more robust understanding of future projections and capture a broader range of potential outcomes.

• • Shifting to socioeconomic pathways (SSP) scenarios: Employing the latest SSP scenarios can provide a more nuanced view of the combined effects of climate change and socioeconomic factors specific to the Mediterranean region.

• • Enhancing regional focus: By focusing on specific subregions or water basins within the Mediterranean, the study can offer climate projections directly relevant to the needs of impacted socioeconomic sectors, such as water management. This regional focus would provide actionable insights for adaptation strategies.

• • Building on this initial assessment, future studies will:

• • - Analyze national level changes in Morocco using drought indices (SPI, SPEI, etc.) recommended by the WMO Commission on Climatology Expert Team (Mckee 1993; Vicente-Serrano 2010; Murray & Ebi 2013).

  • - Integrate additional climate indices for a more comprehensive analysis.

  • - Shift the focus to regional scales, examining observed and future changes in each climatic zone using validated climate models.

This refined approach will enable a more comprehensive and regionally relevant assessment of climate change impacts in Morocco.

The authors are very grateful for all the people who contributed to the writing of this article in any way.

The authors received no financial support for the research.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.