On the occasion of the forthcoming UN-climate conference in Paris, four scientists, among Axel Ockenfels and Peter Cramton, have addressed climate politicians with an article published in the renowned science magazine “Nature”. In their article “Price carbon — I will if you will”, the researchers explain why, despite diplomatic calculated optimism, a lasting success in the fight against climate change is also unlikely to be achieved at the climate conference in Paris. To render climate negotiations successful, they recommend aiming for a common obligation first of all. Axel Ockenfels, expert for cooperation research and negotiations design, explains: “All science disciplines which address cooperation have shown that mutuality is the key to success: I cooperate, if you also cooperate’. This applies to the question of who is responsible for the dish-washing in the flat share and equally to international trade- or military agreements. This is how incentives to cooperate and ultimately trust, which is essential for cooperation, develop. However, mutuality can only work with a common obligation. Unfortunately, the climate conference in Paris favors hundreds, self-defined and incomparable plans of the states; thus one creates mistrust at most.” The authors suggest that negotiations should focus on internationally binding prize targets for the emission of CO2, which would become a focal point for national self-obligations and which would be consistent with many popular political instruments, like emissions trading and fuel tax.