The main aim of REGTREND (Quantifying uncertainties in regional climate trends and its implications for adaptation decision-making) to revisit the uncertainties caused by natural variations in recent and future trends of user-relevant climate variables at regional scales, and assess how improved and more trustworthy information on uncertainties can be managed and reflected in decision-making processes.

Climate change will affect actors in all sectors of society. Thus it is imperative that authorities, municipalities, businesses and individual property owners all take action to adapt to the ongoing and future change. Municipalities and other local and regional actors are the ones that account for the bulk of the implementation of concrete measures and practical implementation of adaptation action.

Decision-makers do often only have access to a small part of the results from all existing climate model simulations as input for adaptation actions. At the regional scale, existing ensembles are generally too small to capture the full range of uncertainty caused by natural climate variability, which can have an overriding impact on the projected trends in time scales relevant for adaptation. This means that future changes can be foreseen to differ significantly from the information today´s decisions are based on.

To overcome this fundamental problem, REGTREND will analyze new, recently performed large ensemble simulations with global climate models. The available number of global model simulations is at least a factor of 10 higher than the number of regional model simulations, on which climate information to stakeholders are built today. 

We aim to identify the regions where the uncertainty of future climate changes is particularly large or small. The main focus will be on Europe and Sweden.

The results from the global models will be compared to the existing simulations with regional models over Europe and Sweden. It is important to find out to which degree the regional model simulations cover the climate change uncertainties and if there are systematic differences in the climate change signals between regional and global model simulations. Combining the probabilistic information from the high number of global model simulations with the higher-resolved but case-specific information from the limited number of regional simulations will lead to more trustworthy regional information to decision-makers.

REGTREND also aims to advance the understanding of the physical processes, which might govern the variability of regional trends. Possible linkages between specific regional trends and potential large scale drivers as atmospheric circulation patterns or ocean currents and surface temperature distributions will be investigated.

In collaboration with decision-makers and planners at the local and regional level, REGTREND aims to assess how improved and more trustworthy information on uncertainties can be managed. This will be assessed for different approaches including: adaptive management (the selection of a strategy that can be modified to achieve better performance as one learns more about the issues at hand and how the future is unfolding), scenario planning (with consideration of multiple plausible outcomes to compare how well alternative policy decisions perform), and robust or resilient strategies (that will work reasonably well across the predicted range of future climate).  We will also assess how more detailed information on uncertainties can be merged to already available information. In Sweden, this includes recently published reports with regional climate change assessments of a set of climate indexes based on RCP4.5 and RCP8.5 for each of Sweden´s 21 counties.

Project Partners



REGTREND will run from 2017-2019.


REGTREND is funded by FORMAS.

Contact person

Torben Königk