Understanding the boron isotopic composition of seawater (δ¹¹B_sw) is key to calculating absolute estimates of CO₂ using the boron isotope pH proxy. Here we use the boron isotope gradient, along with an estimate of pH gradient, between the surface and deep ocean to show that the δ¹¹B_sw varies by ~ 2 ‰ over the past 23 million years. This new record has implications for both δ¹¹B-CO₂ records and understanding changes in the ocean isotope composition of a number of ions through time.

We simulate the climate, ice sheet, and sea-level evolution during the Last Interglacial (~130 to 115 kyr BP), the most recent warm period in Earth’s history. Our Earth system model includes components representing the atmosphere, the ocean and sea ice, the terrestrial biosphere, and the Greenland and Antarctic ice sheets. Our simulation is in good agreement with available data reconstructions and gives important insights into the dominant mechanisms that caused ice sheet changes in the past.

Within the framework of the PAGES NAm2k project, we estimated regional trends in the ground surface temperature change for the past 500 years in North America. The mean North American ground surface temperature history suggests a warming of 1.8^°C between preindustrial times and 2000. A regional analysis of mean temperature changes over the last 5 centuries shows that all regions experienced warming, but this warming displays large spatial variability and is more marked in high-latitude regions.

Throughout the last millennium, several cold periods occurred which affected humanity. Here, we investigate an exceptionally cold decade during the 15th century. The cold conditions challenged the food production and led to increasing food prices and a famine in parts of Europe. In contrast to periods such as the "Year Without Summer" after the eruption of Tambora, these extreme climatic conditions seem to have occurred by chance and in relation to the internal variability of the climate system.

This paper focuses on early Holocene rapid climate changes in the Mediterranean zone, which are under-represented in continental archives, and on their impact on prehistoric societies from the eastern to central Mediterranean (central Anatolia, Cyprus, NE and NW Greece). Our study demonstrates the reality of hydrogeomorphological responses to early Holocene RCCs in valleys and alluvial fans and lake-marsh systems. We finally question their socio-economic and geographical adaptation capacities.