This could cost, by 2050, five trillion dollars less in net present value, that is expressed as a lump sum today, than business as usual -- assuming that carbon emissions and all other hidden or external costs are worth zero -- a conservatively low estimate.
到2050年，这一切开销 将比现在净价值少5万亿美元 这里是指总价 是与照常营运相比—— 假设碳排放 以及所有其他隐性或外部成本为零 这只是保守的估计