Climate Change Scenario: From Climate Model Ensemble to Local Indicators

Abstract

The aim of this task within the COIN framework is the preparation of the climatological information for all involved sectors for the past and the possible range of future developments. As a basis for the historical observations, products of the Austrian weather service (ZAMG) are used. The climate change scenarios are derived from 31 regional and global climate models forced with four different emission scenarios.

Impact relevant climate depending indicators have been developed and calculated from observational data and climate change scenario on a NUTS3 level. In total, 63 impact relevant indicators have been defined. The majority of the indicators are a kind of “peak over threshold” analyses like the temperature threshold heat day (Tmax ≥ 30 °C).

All climate scenarios indicate a warming within the twenty-first century. The whole ensemble indicates a warming of 0.5 up to 4 °C till 2050 and at the end of the century the warming reaches from ~2 °C up to 6 °C in winter and up to 9 °C in summer. The low border stems from models forced with the RCP 4.5 emission scenario and the high border from models forced with RCP 8.5.

The climate change signal for precipitation is not that clear. The annual sum shows no clear trend. For summer precipitation, the majority of the model indicates a decrease till −20 % and in winter an increase of the same magnitude.

The derived indicators reflect the same trends. In general, it can be said that temperature depending indicators at the middle of the century derived from the hottest realisations have a similar climate change signal as the “mid-range” scenarios at the end of the century.