This paper is the first of a series of four GMD papers on the PMIP4-CMIP6 experiments. Part
2 (Otto-Bliesner et al., 2017) gives details about the two PMIP4-CMIP6 interglacial …

Current understanding of the long-term carbon cycle posits that Earth's climate is stabilized
by a negative feedback involving CO 2 consumption by chemical weathering of silicate …

The Paleocene–Eocene Thermal Maximum (PETM; 56 Ma) is one of our best geological
analogs for understanding climate dynamics in a “greenhouse” world. However, proxy data …

As the world warms due to rising greenhouse gas concentrations, the Earth system moves
toward climate states without societal precedent, challenging adaptation. Past Earth system …

Abstract The Cretaceous Period (145 to 66 Ma) was a prolonged warmhouse to hothouse
period characterized by high atmospheric CO 2 conditions, elevated surface temperatures …

The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time
that Earth's atmospheric CO 2 concentrations exceeded 1000 ppm. Global mean …

The Early Eocene, a period of elevated atmospheric CO2 (> 1000 ppmv), is considered an
analog for future climate. Previous modeling attempts have been unable to reproduce major …

We present results from an ensemble of eight climate models, each of which has carried out
simulations of the early Eocene climate optimum (EECO,∼ 50 million years ago). These …

Accurate estimates of past global mean surface temperature (GMST) help to contextualise
future climate change and are required to estimate the sensitivity of the climate system to …

Anthropogenic climate change is increasing rapidly and already impacting biodiversity.
Despite its importance in future projections, understanding of the underlying mechanisms by …