Pollution particles cool climate and offset part of the global warming. However, they are washed out by rain and thus their effect responds quickly to changes in emissions. We show multiple datasets to demonstrate that aerosol emissions and their concentrations declined in many regions influenced by human emissions, as did the effects on clouds. Consequently, the cooling impact on the Earth energy budget became smaller. This change in trend implies a relative warming.

Surface winds fluctuate. From around 1980 to 2010, surface onshore winds generally became weaker, and they have gained in strength since then. While these fluctuations are well known, we currently do not fully understand why they happen. To investigate the reasons, we use a large set of climate simulations with one model, a so-called large ensemble. We find that the observed long-term wind fluctuations occur naturally under current and future conditions and do not require a specific trigger.

Solar photovoltaics (PV) matters for the carbon neutrality goal. We use climate scenarios to quantify climate risk for PV in Europe and find higher PV potential. The seasonal cycle of PV generation changes in most places. We find an increase in the spatial correlations of daily PV production, implying that PV power balancing through redistribution will be more difficult in the future. Thus, changes in the spatiotemporal structure of PV generation should be included in power system design.

Spatio-temporal disparity to assess global dimming and brightening phenomena has been a critical topic. For instance, few studies addressed surface solar irradiation (SSR) long-term trend in South America. In this study, SSR, sunshine duration (SD) and the diurnal temperature range (DTR) are analysed for São Paulo, Brazil. We found a dimming phase, identified by SSR, SD and DTR, extending till 1983. Then, while SSR is still declining, consistent with cloud increasing, SD and DTR are increasing.

In this study we compare solar radiation at the surface from observations and Earth system models from 1961 to 2014. We find that the models do not reproduce the so-called global dimming as found in observations. Only model experiments with anthropogenic aerosol emissions display any dimming at all. The discrepancies between observations and models are largest in China, which we suggest is in part due to erroneous aerosol precursor emission inventories in the emission dataset used for CMIP6.

This paper proposes a novel and accurate method for estimating and reconstructing aerosol optical depth from sunshine duration measurements under cloud-free conditions at any place and time since the late 19th century. The method performs very well when compared to AErosol RObotic NETwork measurements and operates an efficient detection of signals from massive volcanic eruptions. Reconstructed long-term aerosol optical depths are in agreement with the dimming/brightening phenomenon.

We report a model sensitivity study on the impact of aerosol–radiation interaction (ARI) changes in Europe between 1990 and 2010 on summer surface ozone via effects on photolysis rates and biogenic emissions. The overall impact of ARI changes on ozone was relatively small when compared to the total ozone concentrations, but it was more important when compared to the order of magnitude of ozone trends, indicating a potential partial damping of the effects of ozone precursor emissions' reduction.

A large number of radiometers used to measure solar and terrestrial broadband radiation are traceable to World Standard Groups at PMOD/WRC in Davos, Switzerland. A small correction of each group may be required in the future, and this study examines the methods and implications of this on data sets collected at four remote baseline stations since the 1990s. The goal is to develop a better estimate of the solar and terrestrial radiation budget at the Earth's surface.

The Global Energy Balance Archive (GEBA) is a database for the central storage of worldwide measured energy fluxes at the Earth's surface, maintained at ETH Zurich (Switzerland). This paper documents the status of the GEBA version 2017 database, presents the new web interface and user access, and reviews the scientific impact that GEBA data had in various applications. GEBA has continuously been expanded and updated and to date contains around 500 000 monthly mean entries from 2500 locations.

Through the selection of 172 urban–rural station pairs, this study noted that urbanization significantly influenced the dimming trend in sunshine duration in China from 1960 until it leveled off after 1990. During 1960–1989, rural dimming was around two-thirds the rate of urban dimming; this ratio generally shows a positive correlation with urbanization level. There may be an overestimation of dimming in China when a dataset with more urban-scale sites than rural-scale sites is applied.

Surface solar radiation observed in Japan generally shows a strong decline until the end of the 1980s and then a recovery up until around 2000. A substantial number of measurement stations are located close to populated areas and are speculated to have been influenced by air pollution. However, data obtained at 14 meteorological observatories suggest that the large decadal variations in surface solar radiation occur on a large scale and not limited to urban areas.

This paper presents the temporal evolution of solar radiation over Italy for the 1959–2013 period and discusses possible reasons for differences between all-sky and clear-sky conditions in order to understand which part of the solar radiation variability depends on aerosols or clouds. The results give evidence of a relevant influence of both anthropogenic and natural aerosols on solar radiation long-term variability.

The strong decadal variations in surface solar radiation, known as "global dimming and brightening", are considered to be related to anthropogenic activities. Based on a comprehensive set of sunshine duration measurements in China, the present study investigates to what extent these changes occurred, only in cities or also in remote areas. The quantification of this "urbanization effect" enables a more accurate determination of the large scale variations of surface solar radiation over China.

Systematic measurements of surface solar radiation revealed a worldwide decrease from the 1960s to the mid-1980s. The role of urbanization for this so called global dimming is still under debate. We developed a set of population-data based urbanization indicators and found no correlation between urbanization and global dimming for Europe and Japan, while an urbanization impact can't be precluded for Asia. It is thus called into question whether the global dimming was mainly a local phenomenon.

Many climate models have difficulties in properly reproducing climate extremes such as heat wave conditions. We use a regional climate model with different atmospheric physics schemes to simulate the heat wave events of 2003 in western Europe and 2010 in Russia. The five best-performing and diverse physics scheme combinations may be used in the future to perform heat wave analysis and to investigate the impact of climate change in summer in Europe.

Particulate matter (PM) constitutes one of the most challenging problems both for air quality and climate change policies. This paper reviews the most recent scientific results on the issue and the policy needs that have driven much of the increase in monitoring and mechanistic research over the last 2 decades. The synthesis reveals many new processes and developments in the science underpinning climate-PM interactions and the effects of PM on human health and the environment.