Precipitation extremes

Indicator Assessment
Prod-ID: IND-92-en
Also known as: CLIM 004
Created 11 Aug 2014 Published 12 Sep 2014 Last modified 04 Sep 2015, 07:00 PM
Topics: , ,
The length of the wet period has significantly increased in north-eastern Europe and decreased in south-western Europe. Changes in other regions are not statistically significant. Data availability is insufficient for assessing trends of extreme daily precipitation across Europe. However, available studies generally point to a trend over recent decades towards more heavy precipitation, in particular in central and eastern Europe in winter. No significant changes in the annually averaged duration of dry spells have been observed across Europe. However, increasing summer dryness has been observed in central and southern Europe since the 1950s. Heavy precipitation events are likely to increase in most parts of Europe, especially in central and eastern Europe in winter. The length of dry spells is projected to increase significantly in southern and central Europe, in particular in summer, and to decrease in northern Europe.

Key messages

  • The length of the wet period has significantly increased in north-eastern Europe and decreased in south-western Europe. Changes in other regions are not statistically significant.
  • Data availability is insufficient for assessing trends of extreme daily precipitation across Europe. However, available studies generally point to a trend over recent decades towards more heavy precipitation, in particular in central and eastern Europe in winter.
  • No significant changes in the annually averaged duration of dry spells have been observed across Europe. However, increasing summer dryness has been observed in central and southern Europe since the 1950s.
  • Heavy precipitation events are likely to increase in most parts of Europe, especially in central and eastern Europe in winter.
  • The length of dry spells is projected to increase significantly in southern and central Europe, in particular in summer, and to decrease in northern Europe.

What is the trend in the length of dry and wet periods, and in heavy precipitation events across Europe?

Projected changes in heavy precipitation in winter (left) and summer (right)

Note: Projected changes in heavy precipitation (in %) in winter and summer from 1971-2000 to 2071–2100 for the RCP8.5 scenario based on the ensemble mean of different regional climate models (RCMs) nested in different general circulation models (GCMs).

Data source:
Downloads and more info

Projected change in the length of dry spells

Note: Projected changes in the length of dry spell (in days) from 1971-2000 to 2071–2100 for the RCP8.5 scenario based on the ensemble mean of different regional climate models (RCMs) nested in different general circulation models (GCMs).

Data source:
Downloads and more info

Past trends

This indicator assesses two aspects of extreme precipitation: heavy precipitation, which may lead to flooding, and long dry spells, which can cause droughts. Heavy precipitation can be further distinguished into multi-day heavy precipitation, which often covers large regions and can lead to large-scale river floods, and short-term heavy precipitation, which is often localized and can lead to flash floods. The observed changes in heavy precipitation in Europe are region and season specific (Zolina 2012). The dominating tendency for many regions, using several indices, is that heavy precipitation has been increasing.

Observation records show significant increases in the duration of wet spells since 1960 in north-eastern Europe, whereas significant decreases (by up to 4 days per decade) have been observed in south-western Europe (Besselaar et al. 2013) (Fig. 1 left). Seasonal changes have also been noted with an increase in the frequency and intensity of winter precipitation in central and eastern Europe (Hov et al. 2013, Zolina 2012).

Data availability is insufficient for assessing trends in short-term heavy precipitation across Europe. Available studies found increasing trends in extreme daily winter precipitation in many regions, including central and western Europe, whereas in some regions decreasing trends were found (Hov et al. 2013).

No significant changes in the annually averaged duration of dry spells since 1960 have been observed across Europe (Fig. 1 right). However, there is high confidence of increasing summer dryness since the 1950s in central and southern Europe, with the largest increases in western and central Mediterranean (Sousa et al. 2011, Hov et al. 2013).


Projections

Global warming is projected to lead to higher intensity of precipitation and longer dry periods in Europe (Hov et al. 2013, IPCC 2012).  Model-based projections for the period 2071-2100 show an increase (compared to the period 1971-2000) in heavy precipitation in most parts of Europe, with the exception of the Iberian Peninsula and Mediterranean regions in summer (Fig. 2). Heavy precipitation events are likely to increase in most parts of Europe in winter by up to 35 % (Jacob et al. 2013, Rajczak et al. 2013, IPCC 2012). During summers decreases (between 15 and 25 %) are projected in the Mediterranean region.

Projected changes in length of dry spells show significant increases  by up to 24 days in southern Europe and decreases (between 1 and 2 days) in northern Europe (Jacob et al. 2013) (Fig. 3). Other drought indices show similar geographical and seasonal patterns (IPCC 2012, 2014).

Indicator specification and metadata

Indicator definition

  • Trends in consecutive wet days and consecutive dry days
  • Projected changes in heavy precipitation in summer and winter

Units

  • days/decade
  • length of dry spell (in days)
  • %

Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.

Targets

No targets have been specified.

Related policy documents

  • Climate-ADAPT: Mainstreaming adaptation in EU sector policies
    Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
  • Climate-ADAPT: National adaptation strategies
    Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
  • DG CLIMA: Adaptation to climate change
    Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives later. This webportal provides information on all adaptation activities of the European Commission.
  • EU Adaptation Strategy Package
    In April 2013 the European Commission adopted an EU strategy on adaptation to climate change which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it will enhance the preparedness and capacity of all governance levels to respond to the impacts of climate change.

Methodology

Methodology for indicator calculation

The number of consecutive wet days is defined as the number of days in a row during which every day is a wet day (daily precipitation amounts are more than 1 mm in every day during the period). Respectively, consecutive dry days show less than 1 mm per day. Ensemble of RCMs driven by different GCMs all using RCP8.5 scenario has been used to calculate changes in heavy precipitation and dry spells. Heavy precipitation is defined as the intensity of the heavy precipitation events defined as the 95th percentile of daily precipitation (only days with precipitation higher than 1 mm/day are considered). Dry spells are defined as periods of at least 5 consecutive days with daily precipitation below 1 mm.

Methodology for gap filling

Not applicable

Methodology references

No methodology references available.

Uncertainties

Methodology uncertainty

Not applicable


Data sets uncertainty

The risks posed by precipitation-related hazards, such as flooding events (including flash floods) and landslides, are also influenced by non-climatic factors, such as population density, floodplain development and land-use change. Hence, estimates of future changes in such risks need to consider changes in both climatic and non-climatic factors. Estimates of trends in heavy or extreme precipitation are more uncertain than trends in mean precipitation because, by their very nature, extreme precipitation events have a low frequency of occurrence. This leads to greater uncertainties when assessing the statistical significance of observed changes.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/


Rationale uncertainty

No uncertainty has been specified

Data sources

Generic metadata

Topics:

Climate change Climate change (Primary topic)

Water Water

Tags:
europe | climate change | dry period | heavy precipitation | precipitation | precipitation extremes
DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CLIM 004
Dynamic
Temporal coverage:
1960-2014, 2071-2100
Geographic coverage:
Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom

Contacts and ownership

EEA Contact Info

Blaz Kurnik

EEA Management Plan

2014 1.4.1 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 4 years
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100