NSFGEO-NERC: Dynamics of Warm Past and Future Climates,

Earth's climate has changed considerably in the past, and is predicted to change in the future. By studying past climates we gain a broader understanding of what climates are possible and likely in the future.

In this proposal we focus on the very warm climates of the past and their relationship to global warming. In the far past, some 60 million years ago, the planet was very warm. However, the warming was not distributed uniformly over the globe. Rather, the high latitudes warmed much more than low latitudes, to the extent that palm trees grew in Wyoming and crocodile-like animals roamed Northern Canada. The evidence for this is very robust, since fossil remains are unambiguous. Crocodilians are intolerant to cold, meaning there were no long periods of very cold weather, even in winter, in northern North America. This is a complete mystery that current climate models cannot explain. We will study this problem using a novel suite of models, and apply what we learn to better understand the global warming ahead of us.

(i) An improved ability to understand possible future changes in climate, especially in high latitudes and with regard to potentially abrupt and large changes. It is especially important to be able to anticipate qualitatively different climate behaviors as opposed to quantitative changes to present-day climate.

(ii) The training of two female graduate students (one at each institution, and another US student to be recruited) as well as of undergraduate students doing term and summer research projects, and high school student summer interns. The Harvard PI has consistently involved undergraduates in his research activities, and has joined a recent effort of connecting Boston-area high school students from under-represented backgrounds with opportunities to become engaged in summer research.

(iii) The UK PI has given and will continue to give talks of a semi-popular nature to general audiences. Such talks have most impact if they are informed by up-to-date science and if the presenter has a credible scientific reputation.

(iv) Further development of the open-source Isca modelling framework, built using the GFDL's FMS infrastructure, and provides a number of 'ready-made' models that work out of the box, and other models to be readily constructed, and therefore enables the much-discussed model hierarchy to actually be implemented for both the atmospheric circulation and the coupled ocean-atmosphere system.

(v) Maintaining an international collaboration in evidence-based science, that transcends national boundaries and emphasizes the need for a global perspective in climate science.