Among opponents of the mainstream scientific assessment , some say that while there is agreement that humans do have an effect on climate, there is no universal agreement about the quantitative magnitude of anthropogenic global warming (AGW) relative to natural forcings and its harm to benefit ratio.  Other opponents assert that some kind of ill-defined "consensus argument" is being used, and then dismiss this by arguing that science is based on facts rather than consensus.  Some highlight the dangers of focusing on only one viewpoint in the context of what they say is unsettled science, or point out that science is based on facts and not on opinion polls or consensus.  
If increases in carbon dioxide concentrations do become a problem, a policy of ocean fertilizationto stimulate the growth of phytoplankton and speed up the natural absorption of CO 2 into the ocean, as recently documented in field testingseems more prudent (and cheaper) than energy rationing. Ocean fertilization would also likely bring an important side benefit: vast ocean deserts could be turned into thriving fisheries. Developing countries in particular would benefit from this less expensive policy by investing the saved wealth in strengthening the resilience of their economies, safeguarding against naturally occurring harmful climate events, and improving their health care systems.