Environmental economics requires a transnational approach. An environmental economist could identify aquatic depopulation, resulting from overfishing, as a negative externality to be addressed. The United States could impose regulations on its own fishing industry, but the problem wouldn't be solved without similar action from many other nations that also engage in overfishing. The global character of such environmental issues has led to the rise of non-governmental organizations (NGO's) like the International Panel on Climate Change (IPCC), which organizes annual forums for heads of state to negotiate international environmental policies. The most prominent example of the use of environmental economics is the cap and trade system. The information can be published in our peer reviewed journal with impact factors and are calculated using citations not only from research articles but also review articles (which tend to receive more citations), editorials, letters, meeting abstracts, short communications, and case reports. The inclusion of these publications provides the opportunity for editors and publishers to manipulate the ratio used to calculate the impact factor and try to increase their number rapidly. Impact factor plays a major role for the particular journal. Journal with higher impact factor is considered to be more important than other ones.