Germany's Chancellor Angela Merkel was on a whirlwind trip to Brazil on Thursday to cement trade ties with South America's biggest economy. She also used the occasion to urge Brazil to take the necessary steps to protect the Amazon rainforest, calling the country "key" to controlling global climate change.

As long as nation-states have distinctly different levels of energy-dependent economic development, and their self-interests are so varied, there is really no basis for the mutuality of interest required for a meaningful treaty.