Some key lessons have emerged from these efforts. The IPCC intellectual community has already proved to be quite cohesive and resilient in the face of determined attacks by powerful and well-financed “anti-climate change” lobbies. While addressing sustainable development issues, adaptation and learning within the IPCC have further strengthened the network. First, fresh ideas have been brought in to catalyze change. Transdisciplinary approaches are essential to deal with large-scale, long-term, complex, and interlinked issues like sustainable development and climate change. Second, the disciplinary mix has continued to evolve to meet the challenge. However, crossing disciplinary and cultural boundaries requires sound knowledge of one’s own discipline (especially its limitations), open-mindedness, great patience, and sincere effort on all sides. Third, IPCC internal processes have adjusted to facilitate beneficial changes, while limiting harmful dissension. E-mail has proved to be a powerful, but potentially risky tool. How something is said could be as important as what is said, to ensure effective communication. Despite some difficult moments, fair-mindedness and good will have prevailed. The IPCC has been able to accommodate different ways of thinking about the problem, as well as new modes of communication, while reinforcing desirable codes of conduct and behavioral norms.