Project Overview PalMod Phase 3

Project Overview

PalMod is a modeling project aiming at understanding the spectrum of climate variability from the last interglacial, through the last glacial to the present and at projecting the climate of the next millennia with comprehensive Earth system models under different scenarios.

The motivation of PalMod relies on the following assumption:

if we could successfully simulate the spectrum of climate variability during the last glacial cycle, such a simulation might enable us to more reliably assess the future climate and to assess whether, for example, a regime shift in the variability or abrupt events could occur during the next centuries and millennia in response to global warming. Will the future climate be more or less variable, and what is the probability of rapid climate transitions? Could polar ice sheets collapse catastrophically? How quickly can sea level rise under present and future climate conditions? What is the potential for rapid carbon release from thawing permafrost in a warming world? To this end, PalMod aims at filling knowledge gaps about climate processes and climate modeling, in particlar with respect to non-linear behavior and long-term feedbacks that may become important as the Earth’s surface temperature continues to warm due to increasing atmospheric greenhouse gas concentrations.

Whereas the first two phases of PalMod focused on model development and validation, Phase III of PalMod is envisioned as a production phase, in which multi-millenial transient climate simulations will be perfomed under different greenhouse-gas concentration scenarios that will pescribed to the models which compute the radiative forcing internally. At the same time, we will continue to develop a “complete” Earth system model, in which we can drop the constraint of prescribing the radiative effects of the greenhouse gases. Major scientific questions during the Phase III are the degree of nonlinearity that we can expect in the future, which could lead to extreme events in the atmosphere and in the oceans. For the first time, we will be able, for example, to explicitly answer qestions regarding sea-level rise acceleration, abrupt climate changes due to re-organizations of the atmospheric or ocenic ciculations, or the response of permafrost on land in a warming world.