We analyze a tree-ring network from several sites distributed along the Italian Peninsula with the aims of detecting common climate drivers of tree growth and of reconstructing the past climate. We detect the main climatic drivers modulating tree-ring width (RW) and tree-ring maximum latewood density (MXD) and we reconstruct late summer temperatures since the early 1700s using a MXD chronology: this reconstruction is representative of a wide area around the Italian Peninsula.

Continuous, highly abundant and well-preserved fossil ostracodes were studied from radiocarbon-dated sediment cores collected on the Lomonosov Ridge (Arctic Ocean) that indicate varying oceanographic conditions during the last ~50 kyr. Ostracode assemblages from cores taken during the SWERUS-C3 2014 Expedition, Leg 2, reflect paleoenvironmental changes during glacial, deglacial, and interglacial transitions, including changes in sea-ice cover and Atlantic Water inflow into the Eurasian Basin.

Regional Antarctic snow accumulation derived from 79 ice core records is evaluated as part of the PAGES Antarctica 2k working group. Our results show that surface mass balance for the total Antarctic ice sheet has increased at a rate of 7 ± 0.13 Gt dec^-1 since 1800 AD, representing a net reduction in sea level of ~ 0.02 mm dec^-1 since 1800 and ~ 0.04 mm dec^-1 since 1900 AD. The largest contribution is from the Antarctic Peninsula.

Tree rings are long-term recorders of past climate variations, but the origin of the climate signals imprinted is difficult to interpret. Here, using a complex model we show that the temperature signal recorded in tree rings from two species from North and South America is likely related to processes occurring at the leaf level. This result contributes to the quantitative interpretation of these proxies for their future exploitation for millennium-scale climate reconstructions.

Recent warming in the high latitudes has prompted the accelerated retreat of ice caps and glaciers, especially in the Canadian Arctic. Here we use the radiocarbon age of preserved plants being exposed by shrinking ice caps that once entombed them. These ages help us to constrain the timing and magnitude of climate change on southern Baffin Island over the past ~ 2000 years. Our results show episodic cooling up until ~ 1900 CE, followed by accelerated warming through present.

We present projections of long-term changes in climate, produced using a statistical emulator based on climate data from a state-of-the-art climate model. We use the emulator to model changes in temperature and precipitation over the late Pliocene (3.3–2.8 million years before present) and the next 200 thousand years. The impact of the Earth's orbit and the atmospheric carbon dioxide concentration on climate is assessed, and the data for the late Pliocene are compared to proxy temperature data.

This paper presents the extent to which climate, harvest and prices influenced the major migration waves from southwest Germany into North America during the 19th century, a century of dramatic climatic and societal changes.

We apply evolving functional network analysis, a tool for studying temporal changes of the spatial co-variability structure, to a set of Late Holocene paleoclimate proxy records covering the last two millennia. The emerging patterns obtained by our analysis are related to long-term changes in the dominant mode of atmospheric circulation in the region, the North Atlantic Oscillation (NAO). We obtain a qualitative reconstruction of the NAO long-term variability over the entire Common Era.

Within PAGES Antarctica2k, we build an enlarged database of ice core water stable isotope records. We produce isotopic composites and temperature reconstructions since 0 CE for seven distinct Antarctic regions. We find a significant cooling trend from 0 to 1900 CE across all regions. Since 1900 CE, significant warming trends are identified for three regions. Only for the Antarctic Peninsula is this most recent century-scale trend unusual in the context of last-2000-year natural variability.

Stratigraphic trends in the carbon isotope composition of calcium carbonate rock can be used as a stratigraphic tool. An important assumption when using these isotope chemical records is that they record a globally universal signal of marine water chemistry. We show that carbon isotope scatter on a confined centimetre stratigraphic scale appears to represent a signal of microbial activity. However, long-term carbon isotope trends are still compatible with a primary isotope imprint.

A selection of climate models have been used to simulate both pre-industrial (1750 CE) and mid-Holocene (6000 years ago) conditions. This study presents an assessment of the temperature, rainfall and flow over Australasia from those climate models. The model data are compared with available proxy data reconstructions (e.g. tree rings) for 6000 years ago to identify whether the models are reliable. Places where there is both agreement and conflict are highlighted and investigated further.

In order to interpret the paleoclimatic record stored in the air enclosed in polar ice cores, it is crucial to understand the fundamental lock-in process. In our study, we present the first extensive data set of direct firn microstructure measurements and use it to show that the critical porosity of gas enclosure is independent of the climatic site conditions (such as temperature and accumulation rate). This leads to significant changes in dating and interpretation of ice-core gas records.