Climate Change Impact - Part 11 - Turkey

Climate Change Impact

Part 11: Example –Turkey


The Yesilirmak Basin in northern Turkey drains into the Black Sea.  The basin is currently highly developed for hydropower and irrigation. The impact of climate change will be to reduce annual flow. Currently snow melt in late spring provides water at the start of the irrigation season; critically, the biggest reduction in flow will be during this period. To maintain current levels of irrigation will require additional storage. 


The Yeşilirmak basin in northern Turkey has a drainage area of around 36,000 km2 and flows into the Black Sea. The basin is mountainous with parts of the basin reaching elevations in excess of 2,000m. The aim of the study was to develop an understanding of the water balance of the basin and then to examine the potential effects of climate change on the basin. The basin is heavily developed, mainly for irrigation and hydropower.

Figure 1 Yesilirmak River Basin

Current situation

Meteorological data were available from two sources. The first source was supplied locally and covered the period 1961 to 2007. The second was from an internationally supported internet site which provided data from 1931 to 2006. There was considerable overlap in data from the two sources and we were able to create a consistent data set from 1931 to 2007. Annual precipitation reaches 1000mm/annum near the coast and is less than 500 mm/annum inland. Average annual temperature is around 14 °C to the north of basin and less than 10 °C in higher areas inland.

From 1931 to 2007 the data showed little trend in annual precipitation or temperature.

Figure 2 Monthly precipitation - Yesilirmak basin
 For both precipitation and temperature there were differences in seasonal values. Winter precipitation and spring temperature both showed increases.

Figure 3 Seasonal temperature - Yesilirmak basin

Reservoirs in the basin play an important part in flow regulation. The total storage is over 5,000 million m3. This is close to the annual average flow of 5,500 million m3/annum. The calculation of the effect of reservoirs was complicated by three factors:

  •         Little information was available on their operating rules.
  •         There are transfers of water between basins
  •         When a reservoir is newly constructed water is used to fill the reservoirs.

Annual irrigation use is 500 million m3/annum and is, of course, concentrated in the summer months when flows are at their lowest.

Climate change

The basin was modelled in two ways. First a water resources model was developed which simulated as far as possible the progressive changes in water use and reservoir storage over the period with data. This model was used to estimate the natural flow in the basin. Secondly the monthly rainfall/runoff model HYSIMM was used to simulate the flows in the basin.

The climate projections were based on the IPCC task force on Data and Scenario Support 2007 report “General Guidelines on the Use of Scenario Data for Climate Impact and Adaptation Assessment”. The SresA1B scenario, which assumes rapid growth and a balanced use of energy sources, was used

As an initial appraisal of the potential impacts of climate change, the simulated flow for the period 1980 to 1999 was compared with simulated flow for projected values for the period 2080 to 2099, i.e. 100 years in the future relative to observed.

The following chart shows three lines. The blue line is the observed average monthly flow – or, more accurately, the estimated natural flows after accounting for storage and abstractions. The red line shows the flow simulated by the hydrological model. The third line, in green shows the projected monthly flow after the impact of climate change. The impact of climate change is represented by the difference between the red and green lines.

Figure 4 Monthly flows - with and without climate change

This shows that two importance changes are projected:

  •         Overall flows will be lower,
  •         Currently the peak of flow is in late spring which coincides with the start of the growing season. In effect, snow in the mountains is acting as a reservoir. In the future, the peak flow will be in winter.

The conclusion is that to maintain current levels of agriculture additional reservoir storage will be needed.


Climate Change Impact - Part 10 - Zambia

Climate Change Impact

Part 10: Example –  Zambia


Zambia has a climate typical of Southern Africa with cool dry winters (June to August) with hot wet summers. The potential impact of climate change was studied as part of a project enhancing the country's skills in Integrated Water Resources Management (IWRM). Temperature are expected to rise throughout the year and over the whole country with slightly higher increases in the south-east. The changes in precipitation are less consistent with some months projected to have an increase and others to have a reduction.


The Government of Zambia was fully aware of the principles of Integrated Water Resources Management.  The need for climate change to integrated in water resources planning was recognised in the National Water Plan of 1994. The Water Resources Management Act of 2011 took this a stage further. This act sought to create a National Water Authority. Section 8 of the Act on ‘Functions of the Authority’ said its functions should include:

  •         minimising the effects of climate change
  •         support proactive climate change planning and management
  •         in consultation with the institution responsible for national statistics, establish and maintain an information system, which will be accessible by both gender, in accordance with regulations issued by the Minister providing for the content of the system, which shall include relevant hydrological, hydrogeological, meteorological, climatological, water quality, water storage and supply and use data, and relevant information on potentials for the use of water
  •         publish forecasts, projections and information on water resources

The aim of this project was to assist the Government in the integration of climate change into Integrated Water Resources Management.

The first, and at the time of the project only, National Communication on Climate Change prepared under the auspices of the United Nations Framework Convention on Climate Change was produced by the Ministry of Tourism and Natural Resources (MoTNR) in 2002. The report considered mitigation options. Under the heading ‘Vulnerability and Adaptation Assessment” it was estimated that maize production might fall but sorghum could increase and groundnuts remain steady. There was no clear indication of the effect on livestock. In terms of water resources, it was suggested that southern parts of the country might be particularly vulnerable.

A report on the National Adaptation Programme of Action on Climate Change was produced by the MoTNR. Zambia had experienced a number of climate related hazards over several decades. Using multi-criteria analysis, it had identified most urgent needs to prioritize ten immediate adaptation interventions. Zambia was divided into 3 ecological-climatic regions based on rainfall. The wettest regions were toward the north of the country. According to the report, the projections suggested that the wettest region would have an increase in rainfall but the drier regions would have less rainfall. The driest region is projected to produce less agricultural produce and livestock. Wildlife could be heavily stressed due to reduced rainfall and increased migration. Malaria is likely to increase in areas with increasing rainfall.

Current Climate

The average annual temperatures for four stations are shown on figure 1. All four stations show a similar trend: a maximum around 1930, a general fall until about 1975 and then an increase to a new maximum around 2005. Temperatures during the 5 years 1927 to 1931 were about 0.5 °C higher than temperatures from 2001 to 2004.

Figure 1 Average annual temperature in Zambia - four representative stations

Temperatures are lowest in June and July. In terms of geographical distribution of temperatures, they are highest in the south-east and the north though the variation is not great – most of the is in the range 22°C to 24°C.

Figure 2 shows the seasonal distribution of precipitation. It shows that rainfall is highly seasonal with very little rain in the period June to August.

Figure 2 Average monthly precipitation - three representative stations

There is considerable variation in rainfall from year to year. The wettest station showed a slight increasing trend and the driest station showed a slight decreasing trend. The geographical distribution of rainfall showed it as being higher to the north of the country.

Climate change projections

Climate change projections were based on the A1B scenario. This is considered to be the ‘business-as-usual’ scenario. The projection used was the average of 23 climate models used to inform the IPCC Assessment Report.
Temperatures are expected to increase by from 3.2°C to 3.9°C by the end of the century. Figure 3 shows the geographical distribution of the temperature changes.

Figure 3 Geographical distribution of climate change

In the case of temperature, the increases are fairly uniform throughout the year. In the case of precipitation there is a marked difference in the changes at different times of the year.

Figure 4 Projected change in precipitation

This shows that rainfall will decrease in the currently driest periods of the year and will increase most in the wettest periods.


Temperatures are projected to rise throughout the year and over the whole country with slightly higher increases in the south-east. In the case of precipitation there are seasonal variations in the changes. In January, there are increases in precipitation over the whole country but larger increases in the north. In November, precipitation is expected to fall over the whole country with larger falls in the south.  December could be considered a ‘pivot’ month with increases in the North and reductions in the South.

See Older Posts...