Mean precipitation (CLIM 002) - Assessment published Nov 2012

Key policy question: What is the trend in precipitation across Europe?

Trends in annual precipitation across Europe

Note: The trends are calculated using a median of pairwise slopes algorithm. Black dots represent high confidence in the sign of the long-term trend in the box (if the 5th to 95th percentile slopes are of the same sign). Boxes which have a thick outline contain at least three stations. Area averaged annual time series of percentage changes and trend lines are shown below each map for one area in northern Europe (blue line, 5.6 to 16.9 °E and 56.2 to 66.2 °N) and one in south‑western Europe (red line, 350.6 to 1.9 °E and 36.2 to 43.7 °N).

Data source:

• E-OBS gridded dataset provided by Royal Netherlands Meteorological Institute (KNMI)

Downloads and more info

Projected changes in annual and summer precipitation

Note: Projected changes in annual (left) and summer (right) precipitation (%) between 1961-1990 and 2071-2100 as simulated by ENSEMBLES Regional Climate Models for the IPCC SRES A1B emission scenario.

Data source:

• ENSEMBLES FP6 project provided by ENSEMBLE FP6 project

Downloads and more info

Key assessment

Past trends

Annual precipitation records averaged across Europe show no significant changes since 1950 according to the E-OBS dataset [i], based on the European Climate Assessment dataset [ii]. At the sub-continental scale, the trend in precipitation is most significant in north-eastern and south-western Europe. The majority of Scandinavia and the Baltic States have observed an increase in annual precipitation of greater than 14 mm per decade, with an increase of up to 70 mm per decade in western Norway. In contrast, annual precipitation has decreased in the Iberian Peninsula, in particular in north-western Spain and in northern Portugal (Figure 1). While there is some evidence linking land use, in particular forest cover, to local and regional precipitation patterns[iii], it is not clear if the relatively minor land-use changes since 1950 have influenced the observed precipitation trends.

Projections

Seasonal mean precipitation values and inter-annual variability is better reproduced by an ensemble of RCMs than by any single RCM [iv]. Recent work, building on the two EU-funded research projects PRUDENCE [v] and ENSEMBLES [vi] has shown that RCMs have a reasonably strong consensus across Europe in predicting changes in seasonal average rainfall [vii]. These projections indicate a general increase in annual precipitation in northern Europe and a decrease in southern Europe. The change in annual mean between 1961-1990 and 2071-2100 according to the ENSEMBLES project varies between 10% and 20 % in northern Europe and between -5 to -20 % in southern Europe and the Mediterranean (Figure 2 left). Projections for summer precipitation show a decrease over southern, central and northwest Europe, which can reach of up to 60 % in parts of southern Europe. Precipitation is projected to remain constant or to increase slightly in northeast Europe [viii] (Figure 2 right).

[i] MR Haylock et al., „A European daily high-resolution gridded data set of surface temperature and precipitation for 1950–2006“, Journal of Geophysical Research 113, Nr. D20 (2008): D20119, doi:10.1029/2008JD010201.

[ii] E. J. Klok and A. M. G. Klein Tank, „Updated and extended European dataset of daily climate observations.“, International Journal of Climatology 29 (2009): 1182–1191, doi:10.1002/joc.1779.

[iii] M.M. Millán, Drought in the Mediterranean and summer floods in the UK and central and eastern Europe: What global climate models cannot see regarding the hydrological cycles in Europe and why Unpublished internal Gammeltoft-RACCM CIRCE report produced for the European Commission (Brussels: EC, 2008).

[iv] Martin Beniston et al., „Future extreme events in European climate: an exploration of regional climate model projections“, Climatic Change 81, Nr. S1 (März 22, 2007): 71–95, doi:10.1007/s10584-006-9226-z; F. J. Tapiador, „A Joint Estimate of the Precipitation Climate Signal in Europe Using Eight Regional Models and Five Observational Datasets“, Journal of Climate 23 (2010): 1719–1738, doi:10.1175/2009jcli2956.1.

[v] J.H. Christensen et al., „PRUDENCE employs new methods to assess European climate change“, EOS, Transactions American Geophysical Union 82, Nr. 147 (2002), doi:10.1029/2002EO000094.

[vi] P., van der Linden and J.F.B. Mitchell, ENSEMBLES: Climate Change and its Impacts: Summary of research and results from the ENSEMBLES project Technical report (FitzRoy Road, Exeter EX1 3PB, UK: Met Office Hadley Centre, 2009), http://ensembles-eu.metoffice.com/docs/Ensembles_final_report_Nov09.pdf.

[vii] Tapiador, „A Joint Estimate of the Precipitation Climate Signal in Europe Using Eight Regional Models and Five Observational Datasets“.

[viii] P., van der Linden and J.F.B. Mitchell, ENSEMBLES: Climate Change and its Impacts: Summary of research and results from the ENSEMBLES project; Tapiador, „A Joint Estimate of the Precipitation Climate Signal in Europe Using Eight Regional Models and Five Observational Datasets“.