Markku Rummukainen

A synthesis of regional climate change simulations—A Scandinavian perspective

Four downscaling experiments of regional climate change for the Nordic countries have been conducted with three different regional climate models (RCMs). A short synthesis of the outcome of the suite of experiments is presented as an ensemble, reflecting the different driving atmosphere-ocean general circulation model (AOGCM) conditions, RCM model resolution and domain size, and choice of emission scenarios. This allows the sources of uncertainties in the projections to be assessed. At the same time analysis of the climate change signal for temperature and precipitation over the period 1990–2050 reveals strong similarities. In particular, all experiments in the suite simulate changes in the precipitation distribution towards a higher frequency of heavy precipitation.

Environmental consequences of alternative practices for intensifying crop production

The increasing global demand for food will be met chiefly by increased intensification of production. For crops, this will be achieved largely by increased yields per area with a smaller contribution from an increased number of crops grown in a seasonal cycle. Production systems show a spectrum of intensification practices characterised by varying methods of site preparation and pest control, and inputs of germplasm, nutrients and water. This paper highlights three main types of intensification (based largely on the quantity and efficiency of use of external inputs) and examines both the on- and off-site environmental consequences of each for soils, water quantity and quality, and climate forcing and regional climate change. The use of low amounts of external inputs is generally regarded as being the most environmentally-benign although this advantage over systems with higher inputs may disappear if the consequences are expressed per unit of product rather than per unit area. The adverse effects of production systems with high external inputs, especially losses of nutrients from fertilisers and manures to water courses and contributions of gases to climate forcing, have been quantified. Future intensification, including the use of improved germplasm via genetic modification, will seek to increase the efficiency of use of added inputs while minimising adverse effects on the environment. However, reducing the loss of nutrients from fertilisers and manures, and increasing the efficiency of water utilisation in crop production, remain considerable challenges.

A model of the coupled dynamics of climate, vegetation and terrestrial ecosystem biogeochemistry for regional applications

Regional climate models (RCMs) primarily represent physical components of the climate system, omitting vegetation dynamics, ecosystem biogeochemistry and their associated feedbacks. To account for such feedbacks, we implemented a novel plant individual-based vegetation dynamics-ecosystem biogeochemistry scheme within the RCA3 RCM. Variations in leaf area index (LAI) of seven plant functional type (PFTs) in response to physical forcing and evolving vegetation state feed back to climate via adjustments in surface energy fluxes and surface properties. In an ERA-40-driven simulation over Europe, the model reproduces the recent past climate with comparable accuracy to the standard RCM. Large-scale patterns of LAI, net primary production and vegetation composition were comparable with observations, although winter LAI was systematically overestimated compared to satellite estimates. Analysis of the ERA-40 simulation and an A1B climate-change simulation revealed considerable covariation among dynamic variables of the physical climate and vegetation. At a Mediterranean site, periodic soil water limitation led to fluctuations in leaf cover and a likely positive feedback to near-surface temperature. At an alpine site, rising temperatures led to forest advance onto tundra areas, reducing albedo and effecting a likely positive feedback on temperature. Climate—vegetation coupling was less pronounced but still apparent at intermediate temperate and boreal sites.

The Swedish Regional Climate Modelling Programme, SWECLIM: a review.

The Swedish Regional Climate Modelling Programme, SWECLIM, was a 6.5-year national research network for regional climate modeling, regional climate change projections and hydrological impact assessment and information to a wide range of stakeholders. Most of the program activities focussed on the regional climate system of Northern Europe. This led to the establishment of an advanced, coupled atmosphere-ocean-hydrology regional climate model system, a suite of regional climate change projections and progress on relevant data and process studies. These were, in turn, used for information and educational purposes, as a starting point for impact analyses on different societal sectors and provided contributions also to international climate research.

Climate change: changing means and changing extremes

Ongoing global warming not only involves changes in temperature and the global mean; it affects more or less every part of the climate. Regional temperature changes are often greater or smaller than corresponding changes in the global mean. In some cases the direction of change may also be different. For example, temperature changes are higher over land than over the ocean. Precipitation increases in some regions but decreases in others. Changes in extreme events may differ from changes in the corresponding mean. Present scientific knowledge clearly indicates that the already observed global trend towards warmer conditions will continue and that it will be accompanied by changes in yet other aspects of climate. This paper highlights, as a brief review, aspects of our changing climate from the available scientific knowledge with a bearing on the energy sector. Its focus is on temperature and precipitation, with some consideration of wind and sea level, among others. While uncertainties remain as far as the magnitude of future global-scale changes is concerned, and even more so their many regional patterns, significant changes are foreseen in, for example, global and regional temperature and precipitation, sea level rise, and in the characteristics of various extreme events.

Modelling Climate Change Impacts on Water Resources in the Swedish Regional Climate Modelling Programme

The Swedish Regional Climate Modelling Programme (SWECLIM) focuses on interpretation of climate scenarios for the Nordic Region. Water resources studies include hydrological model simulations both at the large scale to simulate trends for the entire Baltic Basin and at smaller basin scales to simulate local impacts in Sweden. Global climate model simulations (GCMs) provide lateral boundary conditions to drive the finer resolution Rossby Centre regional atmospheric climate model (RCA) in dynamical downscaling. Two different GCMs—HadCM2 and ECHAM4/OPYC3—have thus far been used. Analyses of future climates are created from differences in 10-year time slices between RCA control runs of the present climate and RCA scenario climate runs with transient greenhouse gas simulations. These differences drive the offline hydrological impacts assessment models. Both of the RCA climate scenarios show overall increases in temperature and precipitation for the Nordic Region, although spatial and temporal distribution varies between them. Hydrological model scenario simulations show a strong decrease in snowmelt peak river discharge. Modelled changes to average annual freshwater inflow to the Baltic Sea vary from +8% to 21% from present day conditions. The interface between atmospheric models and hydrological impact models is a weak link in the process, as is representation of evapotranspiration in the hydrological models for a future climate.

Communication and use of climate scenarios for climate change adaptation in Finland, Sweden and Norway

This paper assesses the communication and the use of climate scenarios at the science–science and science–policy interface in Finland, Sweden and Norway. It is based on document analysis and stakeholder questionnaires. The questionnaires targeted three stakeholder groups, all engaged in the communication and the use of climate scenario information: climate scenario producers; impact, adaptation and vulnerability (IAV) experts; and policy-makers. The respondents were asked to identify issues associated with the communication of scenarios and other needs pertaining to the usefulness and availability of such information. Despite the relatively long history of climate change adaptation in the three countries, climate scenarios are not utilised to their full potential. Climate scenarios have been used in awareness raising, problem understanding and strategy development. However, far less examples can be found on adaptation actions, particularly on harnessing the benefits of climate change. The communication between climate scenario producers and IAV experts functions well; however, communication between climate researchers and policy-makers is less efficient. Each country has developed boundary services to enhance dissemination of the climate scenario information to policy-makers. They are cost-efficient but do not necessarily enhance the comprehension of the information and encourage the actual dialogue between scenario producers and the end-users. Further translation of scenario information to impact and vulnerability estimates together with established boundary work could improve the use of climate research information. As adaptation policy in these countries further progresses towards implementation, there are increasing expectations of support from research, further challenging the communication of climate scenarios.

Climate projections for 2050

Climate models provide the means of making projections of the future climate, under assumptions on alternative future land-use changes and greenhouse gas emissions. The basis for such climate projections is discussed in this chapter,´together with the presentation of overall climate scenario results of relevance for agriculture. The focus is on the period until 2050.

Contributions of soil moisture interactions to future precipitation changes in the GLACE-CMIP5 experiment

Changes in soil moisture are likely to contribute to future changes in latent heat flux and various characteristics of daily precipitation. Such contributions during the second half of the twenty-first century are assessed using the simulations from the GLACE-CMIP5 experiment, applying a linear regression analysis to determine the magnitude of these contributions. As characteristics of daily precipitation, mean daily precipitation, the frequency of wet days and the intensity of precipitation on wet days are considered. Also, the frequency and length of extended wet and dry spells are studied. Particular focus is on the regional (for nine selected regions) as well as seasonal variations in the magnitude of the contributions of the projected differences in soil moisture to the future changes in latent heat flux and in the characteristics of daily precipitation. The results reveal the overall tendency that the projected differences in soil moisture contribute to the future changes in response to the anthropogenic climate forcing for all the meteorological variables considered here. These contributions are stronger and more robust (i.e., there are smaller deviations between individual climate models) for the latent heat flux than for the characteristics of daily precipitation. It is also found that the contributions of the differences in soil moisture to the future changes are generally stronger and more robust for the frequency of wet days than for the intensity of daily precipitation. Consistent with the contributions of the projected differences in soil moisture to the future changes in the frequency of wet days, soil moisture generally contributes to the future changes in the characteristics of wet and dry spells. The magnitude of these contributions does not differ systematically between the frequency and the length of such extended spells, but the contributions are generally slightly stronger for dry spells than for wet spells. Distinguishing between the nine selected regions and between the different seasons, it is found that the strength of the contributions of the differences in soil moisture to the future changes in the various meteorological variables varies by region and, in particular, by season. Similarly, the robustness of these contributions varies between the regions and in the course of the year. The importance of soil moisture changes for the future changes in various aspects of daily precipitation and other aspects of the hydrological cycle illustrates the need for a comprehensive and realistic representation of land surface processes and of land surface conditions in climate models.