To better constrain the response of Earth’s climate system to continuing emissions, it is essential to turn to the past. A key advance would be to understand the transition in Earth’s climate response to changes in orbital forcing during the 'mid-Pleistocene transition' (900 to 1200 thousand years ago) and in particular the role of greenhouse gases. Unravelling such key linkages between the carbon cycle, ice sheets, atmosphere and ocean behaviour is vital for society to better design effective mitigation and adaptation strategies. Only ice cores contain the unique and quantitative information about past climate forcing and atmospheric responses. But the ice providing essential evidence about past mechanisms of climate change more than 1 Ma ago required for our understanding of these changes (termed the “Oldest Ice” core), has not been found to date.The consortium BEYOND EPICA – OLDEST ICE (BE-OI), formed by 14 European institutions, takes on this challenge to prepare the ground for obtaining 1.5 million year old ice from East Antarctica. BE-OI has the objectives to:- support the site selection through creation and synthesis of all necessary information on Antarctic sites through specific geophysical surveys and the use of fast drilling tools to qualify sites and validate the age of their ice;- select and evaluate the optimum drill site for the future “Oldest Ice” core project and establish a science and management plan for a future drilling;- coordinate the technical and scientific planning to ensure the availability of the technical means to implement suitable drill systems and analytical methodologies for a future ice-core drilling, and of well-trained personnel to operate them successfully;- establish the budget and the financial background for a future deep-drilling campaign;- embed the scientific aims of an “Oldest Ice” core project within the wider paleoclimate data and modelling communities through international and cross-disciplinary cooperation.