Many data quality problems occurring in manned weather station observations are hardly detected with common data quality control methods. We investigated the effects of undetected data quality issues and found that they may reduce the correlation coefficients of station pairs, deteriorate the performance of data homogenization methods, increase the spread of individual station trends, and significantly bias regional trends. Applying adequate quality control approaches is of utmost importance.

The Colle Gnifetti (CG) glacier is the only drilling site in the European Alps offering ice core records back to some 1000 years. We aim to fully exploit these unique long-term records by establishing a reliable long-term age scale and an improved ice core proxy interpretation for reconstructing temperature. Our findings reveal a site-specific temperature-related signal in the trends of the mineral dust proxy Ca²⁺ that may supplement other proxy evidence over the last millennium.

Past periods of rapid global warming such as the Paleocene–Eocene Thermal Maximum are used to study biotic response to climate change. We show that very high peak PETM temperatures in the tropical Atlantic (~ 37 ºC) caused heat stress in several marine plankton groups. However, only slightly cooler temperatures afterwards allowed highly diverse plankton communities to bloom. This shows that tropical plankton communities may be susceptible to extreme warming, but may also recover rapidly.

We reconstructed the minimum temperature for 505 years and found cold and warm periods, which correlate with reconstructed data for the Northern Hemisphere and neighboring territories. Our reconstructions are reflected in the fluctuations in ENSO, the short-term solar cycle, PDO, and the de Vries 200-year solar activity cycle. This is the first temperature reconstruction for this region and it is important for studying the climatic processes in the study region and in all of northeastern Asia.

Measuring deuterium and stable carbon isotopes of higher plant wax extracted from marine sediments offshore of Mauritania, we recovered a record of hydrology and vegetation change in West Africa for two Pliocene intervals: 5.0–4.6 and 3.6–3.0 Ma. We find that changes in local summer insolation cannot fully explain the variations in the West African monsoon and that latitudinal insolation and temperature gradients are important drivers of tropical monsoon systems.

At a bog site at Totes Moor in northwest Germany a layer of pine tree stumps at the fen–bog transition was exposed by peat mining. The lateral expansion of ombrotrophic bog between 6703 BC and 3403 BC was reconstructed using the locations and dendrochronological dates of the tree stumps. The spatial pattern relates to the elevation a.s.l. of the mineral base beneath the peat. The temporal distribution of bog expansion pulses relates to climatic variation.

Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from North Atlantic, Siberia and Alaska regionally averaged records. A focus on the last 2 centuries shows a climate variability linked to anthropogenic forcing but also a multidecadal variability likely due to regional natural processes acting on the internal climate system. It is an important issue to understand multidecadal variabilities occurring in the instrumental data.

In this study we carried out a multiproxy high-resolution analysis on a sediment record from the Padul Basin in the Sierra Nevada (southern Iberian Peninsula). Padul is a classical and very unique site from the Mediterranean area as it contains a very long and continuous Quaternary sedimentary record. However, the uppermost part of the record was never recovered. In this study we focus on the last 4700 cal yr BP of Holocene climate variability and human activity in the Mediterranean area.