KAZALCI OKOLJA

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In the period 1960-2015, the mean sea level along the Slovenian coast rose by 10 cm. On average, this means a rise of 1.7 mm/year and, in the last 20 years, 5 mm/year. It is estimated that the rise of mean sea level is affected by global sea level rise and, in the last period, by extreme weather conditions in the region. Over the past twenty years, the sea level along the Slovenian and Adriatic coast has been rising at a rate surpassing European and global trends. If the current trend continues and if infrastructure is not adapted accordingly, daily flooding of low-lying urban areas along the Slovenian coast is expected by the end of the century. It is estimated that the sea level in Europe will rise by 20 to 80 cm. The frequency of floods will therefore be increased by a factor of 10-100.


This indicator shows fluctuations of the average annual sea level in the Gulf of Koper from 1960 onwards, the highest annual sea level in Koper for the period 1963–2015, occurrence of extreme sea levels in Slovenia in the period 1960–2013, anticipated relative sea level changes by 2100 and increased frequency of flooding due to expected sea level changes by 2100.

The indicator indirectly follows the impact of climate change on sea level variation. Global sea level rise is mostly affected by global climate change and is reflected in the level of European seas. The sea level in Europe is monitored by satellite measurements that reflect the contribution of global climate change, as well as by measurements from tide gauges used for measuring sea levels at low and high tide. These reflect local sea level variation, which is important for the development of local strategies for adaptation to climate change.


Charts

Figure MR02-1: Annual average sea level on Koper measuring station
Sources: 

Slovenian Environment Agency, 2016

Show data
1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
annual average level cm 218 216 213 219 211 217 220 214 215 214
1970 1971 1972 1973 1974 1975 1976 1977 1978 1979
annual average level cm 220 216 215 213 216 212 215 216 217 216
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989
annual average level cm 217 217 216 216 218 216 218 218 217 211
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
annual average level cm 211 212 216 217 221 219 220 216 217 219
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
annual average level cm 219 219 217 217 222 220 223 221 222 227
2010 2011 2012
annual average level cm 232 223 222
Figure MR02-2: Annual highest high water, Slovenia (tide gauge Koper), 1963-2015
Sources: 

Slovenian Environment agency, 2016

Show data
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972
maximal sea level cm 314 313 323 352 327 330 394 325 310 320
1973 1974 1975 1976 1977 1978 1979 1980 1981 1982
maximal sea level cm 314 308 331 325 320 318 356 361 330 361
1983 1984 1985 1986 1987 1988 1989 1990 1991 1992
maximal sea level cm 316 326 326 345 309 305 320 311 333 327
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
maximal sea level cm 340 310 334 329 330 320 319 321 311 325
2003 2004 2005 2006 2007 2008 2009 2010 2011
maximal sea level cm 305 342 322 316 326 372 338 342 321
Figure MR02-3: Frequency of extreme sea level
Sources: 

Slovenian Environment Agency, 2016

Show data
1961 1962 1963 1964 1965 1966 1967 1968 1969 1970
number of days per year when the high water exceeded 3m number of days per year 3 7 11 5 10 9 6 8 7 6
1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
number of days per year when the high water exceeded 3m number of days per year 4 2 2 3 3 4 1 5 15 5
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
number of days per year when the high water exceeded 3m number of days per year 11 7 8 10 3 4 6 1 2 7
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
number of days per year when the high water exceeded 3m number of days per year 3 16 9 5 7 16 16 7 10 12
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
number of days per year when the high water exceeded 3m number of days per year 8 10 3 16 3 6 4 14 25 31
2011
number of days per year when the high water exceeded 3m number of days per year 2
Figure MR02-4: Change in global sea level, 1960-20133
Sources: 

EEA, Global and European sea level rise, 2016

Figure MR02-5: Projected change in relative sea level (year 2100)
Sources: 

EEA, Global and European sea level rise

*Note: Scenario RCP4.5.

Figure MR02-6: Increase in the frequency of flooding events under projected sea level rise (year 2100)
Sources: 

EEA, Global and European sea level rise

Note: Scenario RCP 4.5


Goals

  • Providing information to managing authorities that allows for better adaptation to anticipated changes.
  • Early detection of current and long-term sea level deviations, which will improve forecasting of and warning against extraordinary hydrological events at sea.

 

The European Union has adopted the EU Strategy on adaptation to climate change. It includes measures such as building of infrastructure for flood protection, reduction of water consumption, adaptation of building regulations and development of drought-resistant crops. Each Member State is obliged to prepare its own strategy on adaptation to climate change by 2017.

 


In the Gulf of Koper, sea level changes have been monitored since 1960. The tide gauge is primarily intended for monitoring and forecasting sea levels during coastal flooding, while a longer time range of data and analyses of influential parameters provide insights into the effects of climate change.

In the observation period, the annual mean sea level ranged from between 211–232 cm. The greatest deviation from the mean sea level value of 218 cm in the multi-annual period 1960–2015 was recorded in 2010, with a deviation of 14 cm.

Due to the characteristic dynamics of the Adriatic Sea and the location of the Koper mareographic station in its northern area, the rise in sea levels along the Slovenian coast is mostly a consequence of the frequency of weather changes. In the global assessment of sea level rise, however, the rise is mostly attributed to sea water expansion caused by higher temperatures of the sea and the melting of glaciers.

Extreme sea levels along the Slovenian coast are caused by dropping air pressure, strong southerly winds and, in particular, the resonance between weather impacts and long-period 23-hour oscillations of the Adriatic Sea.

In the observation period, the sea level reached or exceeded the flood point (300 cm) 471 times. The highest sea level measured was 394 cm. Coastal floods mainly occur in autumn and winter and occasionally during the spring months. They occur up to 31 times a year, with an average of slightly more than eight times a year. Under unfavourable weather conditions, the number of cases in which sea level exceeds 300 cm is frequently increased due to long-term sea oscillation that can continue to occur in the form of damped oscillation for several days after the beginning of a weather disturbance.

Rising sea levels, as a result of climate change, require numerous adaptations. The urbanised Slovenian coast is partly adapted to the current flood situation and the predicted sea level rises.

Depending on various climate change scenarios and regional differences, the sea level worldwide, as well as European seas, will rise by 20–80 cm by 2100 (EEA, 2016). Regional differences are difficult to predict, as sea level rise depends on seawater density and salinity, ocean currents, local changes in the Earth's gravitational field, vertical movements of land and atmospheric storms. According to the RCP 4.5 scenario, the sea level in the Mediterranean will rise by 40–50 cm and the level of the Adriatic Sea will rise by 30–40 cm.

By 2100, the frequency of coastal flooding will increase by a factor of 10 in most locations in Europe and up to a factor of 100 or even 1000 in some locations. The greatest change in the frequency of flooding is expected on the Atlantic coast of Spain and Portugal and the smallest on the Baltic Sea coast, as relative sea level is expected to drop there. On the Adriatic coasts, the frequency of flooding is expected to increase by a factor of 26–50. In general, a 10 cm rise in sea level increases flooding frequency by a factor of 10.

 

 



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