The North Atlantic Oscillation (NAO) is an important driver of year-to-year weather variability in Europe and North America, but its behavior on longer timescales is disputed. We present a new reconstruction of the NAO over the last millennium using water isotope proxy data from ice cores, speleothems, trees, and other archives. We find pronounced but irregular multidecadal to centennial variability. Better accounting for such variability in climate models is crucial to better project future climate.

The currently observed climate changes are most intense in the Arctic region. This study utilized some of the oldest existing meteorological measurement series in this region. Atmospheric pressure and anemological conditions were analysed and then compared with contemporary measurements. This showed that the weakest low and strongest high systems occur in the same months. Prevailing wind directions have also remained unchanged, while the northerly wind carries less frigid air than in the past.

During the last ice age, Northern Hemisphere ice sheets reshaped global climate. They shifted North Atlantic winds southward, increasing summer rainfall across Eurasia. They also altered tropical and Southern Hemisphere weather patterns, affecting rainfall far beyond the ice-covered regions. Our results show that the height and shape of the ice sheets had a much greater influence on global wind and rainfall patterns than changes in Earth’s orbit, greenhouse gases, or surface reflectivity.

The end-Permian mass extinction was the most severe loss of life in Earth history, yet the role of ocean oxygen restriction remains debated. We examined rock records from South China and western Canada to track redox conditions before and after the crisis. Oxygen levels were already low prior to the extinction, and widespread seafloor anoxia developed at its peak. Afterwards, ferruginous conditions dominated, reducing nutrient availability, limiting productivity, and slowing life’s recovery.

In this work we implement a feedback mechanism with proposed relevance for Snowball Earth in a simple climate model, a salt-albedo feedback. Our results show that this mechanism could have amplified cooling during the initial phase of Snowball Earth, suggesting it may have played an overlooked role in the climate evolution of Snowball Earth.

Fossil pollen offers insights into past climates, yet results differ depending on reconstruction methods. By comparing multiple approaches across Europe during the Last Glacial Maximum, we highlight how method choice influences outcomes. Our work introduces a new methodological framework that reduces biases and improves the reliability of climate reconstructions.

This study uses lake sediments from Lake Sidi Ali in Morocco to understand how climate and the surrounding landscape changed over the past 11,000 years. The results show repeating climate patterns that influenced lake water levels and erosion in the catchment at different timescales. These findings help explain how regional climate and local landscape processes interacted at the North African desert margin.