The SCCO2<\/sub>\u00a0has been calculated under a range of climatic and socioeconomic assumptions (Havranek\u00a0et al<\/em>\u00a02015<\/a>, Howard and Sterner\u00a02017<\/a>, Tol\u00a02018<\/a>), giving a wide range of best estimates. These contemporary estimates are often higher than values that have been used in policies or the economy-wide average price on CO2<\/sub>\u00a0emissions (Dolphin\u00a0et al<\/em>\u00a02020<\/a>), in part due to underestimates of impacts and strong discounting Cost-benefit integrated assessment models (CB-IAMs)<\/strong> representing climate-economy interactions in a highly aggregated manner and have been key tools to estimating the SCCO2<\/sub>. Unfortunately, these models lag behind both natural and social science understanding, often undervaluing the impacts of climate change (Diaz and Moore\u00a02017<\/a>, Howard and Sterner\u00a02017<\/a>, Rose\u00a0et al<\/em>\u00a02017<\/a>, Carleton and Greenstone\u00a02021<\/a>). In particular, CB-IAMs have only simple representations of climate and economy feedbacks, which are key determinants of climate change risks (Otto\u00a0et al<\/em>\u00a02013<\/a>, Calvin\u00a0et al<\/em>\u00a02019<\/a>). Many authors thus argue that rigorous inclusion of the feedbacks is crucial in calculating the SCCO2<\/sub>\u00a0(Burke\u00a0et al<\/em>\u00a02016<\/a>, Cai\u00a0et al<\/em>\u00a02016<\/a>, National Academies of Sciences Engineering and Medicine\u00a02017<\/a>, Stiglitz\u00a0et al<\/em>\u00a02017<\/a>, Piontek\u00a0et al<\/em>\u00a02021<\/a>).<\/p>\n As for climate feedbacks<\/strong>, previous research has calculated the mean discounted economic effect of climate change with selected state-dependent climate feedbacks, but provided no breakdown of regional or distributional implications of marginal damages of CO2<\/sub>\u00a0emissions (Cai\u00a0et al<\/em>\u00a02016<\/a>, Yumashev\u00a0et al<\/em>\u00a02019<\/a>). Here, we compare the PAGE-ICE CB-IAM which also introduced permafrost thawing and surface albedo climate feedbacks (Yumashev\u00a0et al<\/em>\u00a02019<\/a>) with PAGE09 (Hope\u00a02013<\/a>) and attribute the changes in the SCCO2<\/sub>\u00a0to the specific model changes.<\/p>\n In summary, we extend the PAGE-ICE CB-IAM<\/strong> (Yumashev\u00a0et al<\/em>\u00a02019<\/a>) to quantify the effect on the SCCO2<\/sub>\u00a0of including possible long-term temperature growth<\/strong> feedback on economic trajectories, mean annual temperature anomalies, and the already modeled permafrost carbon and surface albedo feedbacks. Together, these provide an indication of the magnitude and uncertainties of the contribution of climate and economy feedbacks and interannual variability to the SCCO2<\/sub>.<\/p>\n![\"\"](\"https:\/\/www.enerjigazetesi.ist\/wp-content\/uploads\/2021\/09\/iklim-degisikligi-nin-ekonomik-maliyet-tahminlerden-6-kat-yuksek-olacak.jpg\")
assumptions of future damages in policy-making (Carleton and Greenstone\u00a02021<\/a>, Wagner\u00a0et al<\/em>\u00a02021<\/a>). Current policy recommendations range from US$51 (Interagency Working Group\u00a02013<\/a>) to US$202 (Umwelt Bundesamt\u00a02019<\/a>), while a recent expert elicitation among economists and climate scientists yielded mean values of US$171 and US$310, respectively (Pindyck\u00a02019<\/a>). Other central estimates are even higher (Moore and Diaz\u00a02015<\/a>, Ricke\u00a0et al<\/em>\u00a02018<\/a>). Many challenges remain to improve estimates of the SCCO2<\/sub>\u00a0estimates as well as the related uncertainty range (National Academies of Sciences Engineering and Medicine\u00a02017<\/a>, Stern and Stiglitz\u00a02021<\/a>, Wagner\u00a0et al<\/em>\u00a02021<\/a>), which is of critical value for designing comprehensive climate mitigation and adaptation policies (Smith and Stern\u00a02011<\/a>, Hope\u00a02015<\/a>, Metcalf and Stock\u00a02017<\/a>).<\/p>\n