【历史人为温室气体排放】Richard E. Zeebe. Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions. PNAS
Climate sensitivity measures the response of Earth’s surface temperature to changes in forcing. The response depends on various climate processes that feed back on the initial forcing on different timescales. Understanding climate sensitivity is fundamental to reconstructing Earth’s climatic history as well as predicting future climate change. On timescales shorter than centuries only fast climate feedbacks including water vapor lapse rate clouds and snow-sea ice albedo are usually considered. However on timescales longer than millennia the generally higher Earth system sensitivity becomes relevant including changes in ice sheets vegetation ocean circulation biogeochemical cycling etc. Here I introduce the time-dependent climate sensitivity which unifies fast-feedback and Earth system sensitivity. I show that warming projections which include a time-dependent climate sensitivity exhibit an enhanced feedback between surface warming and ocean CO2 solubility which in turn leads to higher atmospheric CO2 levels and further warming. Compared with earlier studies my results predict a much longer lifetime of human-induced future warming (23000–165000 y) which increases the likelihood of large ice sheet melting and major sea level rise. The main point regarding the legacy of anthropogenic greenhouse gas emissions is that even if the fast-feedback sensitivity is no more than 3 K per CO2 doubling there will likely be additional long-term warming from slow climate feedbacks. Time-dependent climate sensitivity also helps explaining intense and prolonged warming in response to massive carbon release as documented for past events such as the Paleocene–Eocene Thermal Maximum.
【CO2和CH4对全球变暖的责任】Kirk R. Smith Manish A. Desai Jamesine V. Rogers and Richard A. Houghton. Joint CO2and CH4accountability for global warming. PNAS 2013 vol. 110