First coined by historian Niall Ferguson and economist Moritz Schularick in late 2006, they argue that saving by the Chinese and overspending by Americans led to an incredible period of wealth creation that contributed to the financial crisis of 2007–08.[6] For years, China accumulated large currency reserves and channeled them into US government securities, which kept nominal and real long-term interest rates artificially low in the United States. Ferguson describes Chimerica as one economy which "accounts for around 13 percent of the world's land surface, a quarter of its population, about a third of its gross domestic product, and somewhere over half of the global economic growth of the past six years."[7] He suggests Chimerica could end if China were to decouple from the United States bringing with it a shift in global power and allowing China "to explore other spheres of global influence, from the Shanghai Cooperation Organization, of which Russia is also a member, to its own informal nascent empire in commodity-rich Africa."[7]