The climate of Turkey

The southern and western coastal areas have a Mediterranean climate, but further to the east and north a number of factors make the climate more complex. These factors include extremely varied topography, an inland sea (the Black Sea) to the north and, beyond that, the vast Russian plain which, in winter, acts as a close source of very cold air. Contrastingly, the east of Turkey adjoins Syria and the Middle East which become very hot in summer and the southern coastline is only around 500km across the Mediterranean from the hot continent of Africa. Most of Turkey is high plateau and the terrain becomes increasingly mountainous towards the east. Even in the lower-lying west the terrain is mostly hilly (5).

In general, Turkey is warm or hot in summer and cold or very cold in winter. However, coasts are much milder in winter than inland, especially the south and west coasts. Winter precipitation on the inland plateaux and mountains is often of snow which can lie for 3-4 months in the east. Annual mean temperatures are higher along the coasts and, inland, reduced by altitude. ... Typical summer daily maxima range from ~26-28°C along the Black Sea coastline to 34°C towards the east of the Mediterranean coastline. Typical winter daytime maxima range dramatically from 15°C at Adana to below freezing inland in the east, e.g. only -4°C at Erzurum (5).

In summer, southern coastal areas are mostly dry and sunny; precipitation amounts to around 650 mm/year at Adana, most of it in the winter half of the year. ... Inland, a double precipitation cycle emerges, peaking in both autumn and spring. Despite the higher altitude, inland areas have lower annual totals than on the coast – e.g. annual average precipitation only 382 mm at Ankara and 436 mm at Erzurum. Along the Black Sea coast, precipitation increases eastwards from around 680 mm at Istanbul to 823 mm at Trabzon (5).

Air temperature changes until now

Annual

Annual temperature over the period 1961–1990 showed a trend of statistically significant warming over land in south-east Europe of approximately 0.4–0.6°C per decade (14). For Turkey, annual mean temperature seems to have increased only after the first half of 1990s (16): statistical analyses of Turkish temperature series over the period 1950–2006 showed a turning point at the year of 1992 (1993). Following this year, annual temperatures began to increase gradually (16).  

Summer

The most prominent feature that one can observe is the widespread increase in summer temperatures. Summer temperatures increase mostly in the western and southwestern parts of Turkey. Urban heat island studies (4) indicate that temperature rise as a result of urbanisation is most notable in summer in Mediterranean cities when the region comes under the influence of high pressure systems. Thus, widespread increase in temperature in western stations in Turkey may be mainly related to this phenomenon (2).

The trend for Turkey is relatively large over summer at 0.34°C per decade (5). For southeastern Europe during 1961-1990 strongest warming was found for maximum spring temperature reaching up to 0.9°C per decade (14)

In summer the general trend is an increase of maximum temperatures, particularly in western Turkey. Several stations in eastern Anatolia also show significant increases in maximum temperature. Summer minimums exhibit significant increasing trends at almost all stations that have observations in the period considered in this study (2). Over the period 1950–2010 the numbers of both summer and tropical days showed statistically significant increasing trends for summer (tropical) days at 64 (71) stations out of 97 stations, of which 51 (58) of these positive trends are significant at the 0.01 significance level (13). Since 1980, night-time high air temperatures have increased more than daytime hot extremes (21).

Heatwaves

Since the 1960s the temperature of hot summer days and nights has increased. A hot day/night is defined as a day/night when the daily maximum/minimum air temperature exceeds the long‐term (1969–1998) daily 95th percentile within the June–September season (122 days). Also, the number, length and intensity of heat waves have increased significantly in this period. The observed trends agree with findings for other European regions and the western Mediterranean (3). In the eastern Mediterranean, the intensity, length and number of heat waves have increased by a factor of six to eight since the 1960s (9).

Overall, the strongest increase of these daily maximum and minimum air temperatures are found across the western Balkans, southwestern and western Turkey, and along the eastern parts of the Turkish Black Sea coastline. Stations that show non‐significant heat wave changes cluster in continental parts of the Balkan Peninsula, Greece, parts of western Turkey, eastern Anatolia and higher altitudes (1).

Not all studies confirm these results of increasing trends, however. Heatwave characteristics have been assessed for a number of stations in the eastern Mediterranean (including three in Turkey and one in Cyprus) and the Middle East for the period 1973−2010. In this study a heatwave is defined as a period where daily maximum temperature exceeds the 95th percentile of the time series of daily maximum temperature data for the summer season (here taken from the first of June to the first of November). The results showed that the number of heatwaves increased during 1973−2010 at all stations. On the other hand, the maximum temperature during these heatwaves did not change, implying no change in heatwave intensity. Furthermore, no significant trends in the heatwave duration are observed (15). 

A trend analysis of heatwave characteristics covering the period 1950-2018 indicates that the annual number of heatwaves and heatwave days, and heatwave duration has significantly increased in Turkey, especially from 1993 onwards. Trends in heatwave magnitude and amplitudes are smaller and mostly insignificant over Turkey. Geographically, the largest changes in heatwave characteristics since the middle of the 1980s were found for the Black Sea and the Mediterranean coasts (20).

Winter

Winter temperatures show a general tendency to decrease. It can be noted that the more significant ones are mostly concentrated in the coastal stations. During transition seasons, stations with significant trends are usually sporadic in nature, and they do not show a coherent regional behavior (2).

The trend for Turkey in winter is very small at -0.01°C per decade (5).

The maximum temperatures for winter exhibit significant downward trends in the coastal stations of the Black Sea region and widespread decreasing tendency in the central Anatolian region. Winter minimums show significant decreases only in the northern and southern coastal regions (2).

Urban Heat Island

Data over the period 1960-2012 show a strengthening of the Urban Heat Island of Istanbul with the expansion of the city (increase of built-up areas and paved roads, decrease of green areas) due to increased population. Nighttime and daytime Urban Heat Island intensities reached values up to 1.74 °C and 2.61 °C, respectively. In general, Urban Heat Island effects in Istanbul are strongest in summer and weakest in winter (19).

Precipitation changes until now

Throughout the period 1951-2004 winter precipitation in the western provinces of Turkey has decreased significantly. Fall precipitation, on the other hand, has increased at stations that lie mostly in the northern parts of central Anatolia. In the spring and summers, there are only a few stations with statistically significant changes; still, they do not show a coherent regional behavior (2). For the period 1961-1990, precipitation trends differ between regions and seasons; a decrease in spring and winter precipitation was found to be statistically significant over Turkey (14).

Turkey in general receives much of its precipitation in winter. Precipitation makes a peak in January in southern and western parts of Turkey, in February and March in most of the central Anatolia, in December in northern Marmara region including Istanbul, in October and November in Black Sea coasts, and in May and June in far eastern parts. Degree of seasonal concentration of precipitation is the highest in the Mediterranean and Aegean coasts of Turkey, and it decreases towards Black Sea coasts. It seems that the general picture of seasonality of precipitation has remained constant during the last 70 years (2).

Glacier changes until now

The Ararat mountain is an ice-capped volcano in Eastern Anatolia (Turkey), close to the borders with Iran, Armenia, and Azerbaijan. The evolution of the Ararat mountain glaciers has been investigated for the period 1976-2014. The glacier area has decreased in this period by 30% (2.38 km2) of the initial area. This decrease seems to be driven by increasing temperature and decreasing winter snow cover at the highest altitudes, especially since the 1990s (18).

Air temperature changes in the 21st century

According to results from different climate change scenarios, an increase of 1.2⁰C in mean annual temperature can be expected for 2030. In 2050, the mean annual temperature increases by around 2⁰C. In the context of model estimations, increase in monthly temperatures indicate that warmer winters are expected, while summers get hotter (2).

Projected temperature increases over Turkey for 2100 compared with 1960-1990, based on a large number of climate models and the A1B emission scenario, are around 2.5-3°C in the north, 3-3.5°C over central and south-western regions, and 3.5-4.0°C in the east (5). For the A2 emission scenario a temperature increase of 2–5°C for 2100 compared with 1960-1990 has been projected (10).

Summer

In the period 2071-2100 with respect to 1961-1990, estimated temperature increase in summer time is highest in the western half of the country. Especially the Aegean Region experiences temperature increases up to 6⁰C (2,10). These two regions are prominent on tourism and industrial sectors in Turkey; the projected increase in summer temperature may cause serious economic and social implications (10).

Future projections (based on the SRES A1B emissions scenario) for the period 2070–2099 compared with 1961–1990 suggest increases of the number of warm days, hot days and tropical nights. The projected increase of the number of “hot” days (defined as days with maximum temperature >35°C) is up to two months by the end of the 21st century. The number of warm days (defined as days with maximum temperature >25°C) is found to increase by 50–60 additional days per year by the end of the 21st century (14).

Winter

In the period 2071-2100 with respect to 1961-1990, estimated temperature increase in winter time is highest in the eastern half of the country (2). During winter season, projected warming over the western part of Turkey at the end of this century (just over 2°C) is much less than during the summer (10).

Eastern Mediterranean and the Middle East (EMME) - Warming 

For the Eastern Mediterranean and the Middle East an analysis was carried out of long-term meteorological datasets (period 1901-2006) along with regional climate model projections for the 21st century (SRES scenario A1B) (6). The results suggest a continual, gradual and relatively strong warming of the area of about 1-3°C in the near-future (2010–2039), to 3–5°C in the mid-century period (2040–2069) and 3.5–7°C by the end of the century (2070–2099). Daytime maximum temperatures appear to increase most rapidly in the northern part of the region, i.e. the Balkan Peninsula and Turkey. Maximum daytime temperature increases more strongly than mean night time minimum temperature (11).

Extremely high summer temperatures are projected to become the norm by 2070–2099; the coolest summers at the end-of-century may be warmer than the hottest ones in the recent past. As an example, the hottest summer on record in Athens in 2007 would be among the 5% coolest ones by the end of the century (6,11). 

Current and future daytime mean temperature trends in the Eastern Mediterranean and the Middle East typically vary from 0.28° to 0.46°C per decade. The largest increases appear in some continental locations such as Belgrade, Sofia, Ankara, Baghdad and Riyadh with trends in excess of 0.4°C/decade. The same analysis was performed for daytime maximum and night-time minimum temperature; for daytime maximum temperature the largest upward trends are calculated for Belgrade, Sofia, Tirana and Ankara with 0.48°, 0.46°, 0.45° and 0.44°C per decade, respectively. For night-time minimum temperature, large positive trends exceeding 0.40°C/decade are derived for Belgrade, Riyadh, Baghdad, Athens, Sofia and Ankara (6,11).

A1B scenario results suggest that by the end of the century, the frequency of very hot days (maximum day time temperature >35°C) may increase up to 1–2 weeks per year in mountainous parts of the northern EMME and by about a month in much of the rest of the region. The frequency of ‘‘tropical’’ nights (mean night time minimum temperature > 25°C) also increases strongly, by nearly a month per year in the Balkans and coastal areas, and more than two months in the Gulf region, exacerbating the daytime heat stress. By the end of the century in most cities, the coolest summers may be warmer than the hottest ones today (11).

Eastern Mediterranean and the Middle East (EMME) - Heat wave characteristics

The relatively strong upward trend in the northern parts of the Eastern Mediterranean and the Middle East indicates a continuation of the increasing intensity and duration of heat waves observed in this region since 1960 (7). 

Changes in heat wave characteristics for the eastern Mediterranean and the Middle East have been estimated for the end of this century, as compared with the period 1961 - 1990 (17, see also 11). This was done for a low-end (optimistic), intermediate and high-end (pessimistic) scenario of climate change (the so-called SRES scenarios B2, A1B and A2); one regional climate model was used. Reference point for the definition of heat waves in this study is the maximum daily temperature that is exceeded 10% of the year: heat waves were defined as periods with at least six consecutive days with maximum temperatures exceeding this 10% value. This reference point was calculated for the period 1961 – 1990. The heat waves with respect to this referent point were calculated for 1961 – 1990 and the future horizon of 2071 – 2099.

The results show that in the summer season May to September heat waves in the eastern Mediterranean and the Middle East are expected to change from events with a return period of about once every 2 years on average to a common phenomenon with multiple occurrences per year. The mean number of heat wave days will increase dramatically by 20 - 130 days per year and will be the most pronounced over the Arabian Peninsula and the Gulf area. Currently, these heat waves have an average duration that varies from 6 to 12 days. At the end of this century these heat waves will last for several weeks (under the optimistic scenario) to months. In addition, much hotter heat extremes are expected by the end of the century: changes in severity of heat waves in terms of peak temperatures will probably exceed by far the projected mean summertime warming that ranges from 3 to 9°C (depending on the scenario of climate change) (11,17).

Precipitation changes in the 21st century

In general, precipitation decreases in the period 2071-2100 with respect to 1961-1990 along the Aegean and Mediterranean coasts and increases along the Black Sea coast of Turkey. Central Anatolia shows little or no change in precipitation. The most severe (absolute) reductions will be observed on the southwestern coast; in contrast, Caucasian coastal region is expected to receive substantially more precipitation. These observations are valid both for the annual and the winter totals (2).

According to results from different climate change scenarios, a decrease of 5% in mean annual precipitation can be expected for 2030. In 2050, mean annual precipitation decreases by approximately 10%. Although decreases are expected in precipitation in all months, the sharp decreases in spring and autumn are significantly important, because summers in the region are already dry (2). 

Projected precipitation change over Turkey for 2100 compared with 1960-1990, based on a large number of climate models and the A1B emission scenario, indicate mainly decreases in precipitation, in common with the wider Mediterranean and majority of the Middle East. Decreases of over 20% are projected in the south of the country, with strong ensemble agreement. Smaller changes are projected towards the north, between 0-10%, but with more moderate agreement between the models (5). According to projected results for the period 2071-2100 compared with 1961-1990 based on the A2 emission scenario, precipitation in all seasons and in almost all regions decreases except for the autumn season. All the major precipitation changes for the climatic regions of Turkey are found statistically significant. The range of decrease is 10–35 % (10). For the A1B emissions scenario, decreases in the number of wet days and the heavy precipitation events are projected towards the end of the 21st century; the number of wet days may decrease by 10–30 days per year, while heavy  precipitation is likely to decrease in the high-elevation areas by about 15 days year per by the end of the 21st century (14).

Eastern Mediterranean and the Middle East

From the analysis of long-term meteorological datasets (period 1901-2006) along with regional climate model projections for the 21st century (SRES scenario A1B) a decline of annual precipitation is projected of 5–25% in 2040–2069 and 5–30% in 2070–2099 relative to the reference period 1961–1990 (6). The decreases will be particularly large (>15%) in Cyprus, Greece, Israel, Jordan, Lebanon, the Palestine territories and Syria. As a result of precipitation decrease, and also due to population growth rates, the per capita available internal water resources may decline strongly, for example by 50% or more by mid-century in Cyprus (12).

In the Balkans, Turkey, Cyprus, Lebanon and Israel, the number of rainy days may decrease, e.g. by 5–15 days at mid-century and by 10–20 days per year at the end-of-century (6). This appears to be a continuation of a trend observed in Greece since about 1960 (8).

The intensity of precipitation (maximum amount of rain per day) is expected to decrease except over the northern Balkans and the Caucasus (6).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Turkey.

1. Kuglitsch et al. (2010)
2. Güven (2007)
3. Moberg et al. (2006), in:Kuglitsch et al. (2010)
4. Ezber et al. (2006); Karaca et al. (1995), both in: Güven (2007)
5. MET Office (2011)
6. Lelieveld et al. (2012)
7. Kuglitsch et al. (2010), in: Lelieveld et al. (2012)
8. Nastos and Zerefos 2009, in: Lelieveld et al. (2012)
9. Kuglitsch et al. (2010), in: Coumou and Rahmstorf (2012)
10. Önol and Unal (2014)
11. Lelieveld et al. (2014)
12. Chenoweth et al. (2011), in: Lelieveld et al. (2014)
13. Erlat and Türkeş (2013)
14. Kostopoulou et al. (2014)
15. Tanarhte et al. (2015)
16. Dogan et al. (2015)
17. Zittis et al. (2016)
18. Baldasso et al. (2019)
19. Ünal et al. (2020)
20. Erlat et al. (2021)
21. Erlat et al. (2022)