Famed climate scientist James Hansen and colleagues from a diverse array of disciplines, including economist Jeffrey Sachs, make the case that warming needs to be kept below the widely cited figure of 2 degrees Celsius, by means of a carbon tax.
International climate negotiators agreed in the Copenhagen Accord, a global agreement onclimate change that took place at the 2009 United Nations' Climate Change Conference, that warming this century shouldn't increase by more than 2 degrees Celsius (3.6degrees Fahrenheit) to avoid the worst impacts of climate change. But in a new paper published in the open-access journal PLOS ONE, Hansen and a cadre of co-authors from a wide array of disciplines argue that even 2 degrees is too much, and would "subject young people, future generations and nature to irreparable harm," Hansen wrote in an accompanying essay distributed to reporters.
The new study is a departure from the typical climate science paper, both for the wide variety of fields represented in the list of co-authors, which includes economist Jeffrey Sachs, as well as for the policy implications it raises, something climate scientists tend to shy away from. The authors also plainly state that humanity has a moralobligation to future generations, the type of statement scientists also tend to avoid.