E-Mail New Haven, Conn. -- Researchers at Yale and Princeton say the scientific community sorely needs a new way to compare the cascading effects of ecosystem loss due to human-induced environmental change to major crises of the past. For too long, scientists have relied upon metrics that compare current rates of species loss with those characterizing mass extinctions in the distant past, according to Pincelli Hull, an assistant professor of Earth and planetary sciences at Yale, and Christopher Spalding, an astrophysicist at Princeton. The result has been projections of extinction rates in the next few decades that are on the order of a hundred times higher than anything observed in the last few million years of the fossil record.