We present a continuous humidity history in arid Central Asia over the past millennium based on the ~1.8-year high-resolution multiproxy record from Lake Dalongchi. Our findings emphasize that the Gleissberg solar cycle and quasi-regular period of ENSO amplitude play critical roles in controlling the effective humidity at century and multidecadal timescales, respectively. Our analysis provides new insights for hydroclimate predictions and climate simulations in arid Central Asia in the future.

Our proxy-based observations of the glacial inception following MIS 11 advance our mechanistic understanding of (and elucidates antecedent conditions that can lead to) high-magnitude climate instability during low- and intermediate-ice boundary conditions. We find that irrespective of the magnitude of climate variability or boundary conditions, the reorganization between Polar Water and Atlantic Water at subpolar latitudes appears to influence deep-water flow in the Nordic Seas.

We present a melt event record from an ice core from central Greenland, which covers the past 10 000 years. Our record displays warm summer events, which can be used to enhance our understanding of the past climate. We compare our data to anomalies in tree ring width, which also represents summer temperatures, and find a good correlation. Furthermore, we investigate an outstandingly warm event in the year 986 AD or 991 AD, which has not been analyzed before.

Palaeoenvironmental records only provide a fragmentary picture of the lake and wetland extent in North Africa during the mid-Holocene. Therefore, we investigate the possible range of mid-Holocene precipitation changes caused by an estimated small and maximum lake extent and a maximum wetland extent. Results show a particularly strong monsoon precipitation response to lakes and wetlands over the Western Sahara and an increased monsoon precipitation when replacing lakes with vegetated wetlands.

Since the orbital parameters of the past are different from today, applying the modern calendar to the past climate can lead to an artificial bias in seasonal cycles. With the use of multiple model outputs, we found that such a bias is non-ignorable and should be corrected to ensure an accurate comparison between modeled results and observational records, as well as between simulated past and modern climates, especially for the Last Interglacial.

Descriptions of climate held in archives are a valuable source of past climate variability, but there is a large potential for error in assigning quantitative indices (e.g. −2, v. dry to +2, v. wet) to descriptive data. This is the first study to examine this uncertainty. We gave the same dataset to 71 postgraduate students and 6 professional scientists, findings that error can be minimized by taking an average of indices developed by eight postgraduates and only two professional climatologists.

The mid-17th century saw several volcanic eruptions, deteriorating climate, political instability, and famine in Europe, China, and Japan. We analyze impacts of the eruptions on climate but also study their socio-political context. We show that an unambiguous distinction of volcanic cooling or wetting from natural climate variability is not straightforward. It also shows that political instability, poor harvest, and famine cannot only be attributed to volcanic climatic impacts.

A large drought potentially occurred roughly 4200 years ago, but its impacts and significance are unclear. We find new evidence in carbonate oxygen isotopes from a mountain lake in southeastern Wyoming, southern Rocky Mountains, of an abrupt reduction in effective moisture (precipitation–evaporation) or snowpack from approximately 4200–4000 years ago. The drought's prominence among a growing number of sites in the North American interior suggests it was a regionally substantial climate event.

A new Greenland ice-core timescale, covering the last 3800 years, was produced using the machine learning algorithm StratiCounter. We synchronized the ice cores using volcanic eruptions and wildfires. We compared the new timescale to the tree-ring timescale, finding good alignment both between the common signatures of volcanic eruptions and of solar activity. Our Greenlandic timescales is safe to use for the Late Holocene, provided one uses our uncertainty estimate.

New proxies and improvements in existing methodologies are needed to advance paleoclimate research. This study explored dendroanatomy, the analysis of wood anatomical parameters in dated tree rings, of Engelmann spruce from the Columbia Icefield area, Canada, as a proxy of past temperatures. Our new parameters compare favorably with state of the art proxy parameters from X-ray and visible light techniques, particularly with respect to the temporal stability of the temperature signal.

We studied eight New Zealand tree species and identified differences in their responses to large volcanic eruptions. The response is dependent on the species and how well it can tolerate stress, but substantial within-species differences are also observed depending on site factors, including altitude and exposure. This has important implications for tree-ring temperature reconstructions because site selection and compositing methods can change the magnitude of observed volcanic cooling.

We present a method to reconstruct burnt area using a relationship between pollen and charcoal abundances and the calibration of charcoal abundance using modern observations of burnt area. We use this method to reconstruct changes in burnt area over the past 12 000 years from sites in Iberia. We show that regional changes in burnt area reflect known changes in climate, with a high burnt area during warming intervals and low burnt area when the climate was cooler and/or wetter than today.

Determining seasonal temperatures demands proxies that record the highest and lowest temperatures over the annual cycle. Many record neither, but oxygen isotope profiles from shells in principle record both. Oxygen isotope data from late Pliocene bivalve molluscs of the southern North Sea basin show that the seasonal temperature range was at times much higher than previously estimated and higher than now. This suggests reduced oceanic heat supply, in contrast to some previous interpretations.

The Leeuwin Current transports warm water along the western coast of Australia: from the tropics to the Southern Hemisphere midlatitudes. Therewith, the current influences climate in two ways: first, as a moisture source for precipitation in southwestern Australia; second, as a vehicle for Equator-to-pole heat transport. In this study, we study sediment cores along the Leeuwin Current pathway to understand its ocean–climate interactions between 4 and 2 Ma.