'Business as Usual' is not an environmentally viable option

Sir, We fully agree with Robin Harding, in "A high price for ignoring the risks of catastrophe" (February 18), that the current academic discourse focuses too narrowly on optimal pricing, and ignores the potentially catastrophic nature of climate change. We would like to add two items to the list: first, the concept widely used in economics to evaluate catastrophic risks is plainly not helpful in informing decisions about rare but disastrous events, and second, carrying on with "business as usual" is neither environmentally viable nor economically sensible. [...]