Cap-and-trade systems are dominating worldwide the policy-makers' choices about the design of climate policies. This is an issue for several of economists, who are arguing that the structure of the costs and damages of climate change gives a strong presumption to price-type approaches. Those who advocate optimality at any cost are looking at the 2009 United Nations Climate Change Conference in Copenhagen as an opportunity to move towards a price-oriented global climate policy. However, according to the new mainstream uncertainty analysis, a quantitative standard is preferable to avoid "dangerous" climate change. Moreover a price-type approach may be detrimental to a large-scale development of renewable energy. If decisions makers wish to follow the Precautionary Principle and want to guide society to a more sustainable world, then they should stick to the existing quantity-oriented policy framework and work hard to find a compromise in order to expand the global cooperation.