China’s 13th Five-Year Plan elevated the national mandate for environmental sustainability.Chinese fisheries are characterized by full retention of high diversity catch harvested using unselective gears,creating ecol...China’s 13th Five-Year Plan elevated the national mandate for environmental sustainability.Chinese fisheries are characterized by full retention of high diversity catch harvested using unselective gears,creating ecological risks.Therefore,China launched pilot projects in management by Total Allowable Catch(TAC)in five coastal provinces in 2017 and 2018 to build experience with output controls.Fujian province launched an important pilot in its swimming crab fishery,the first to adopt a multispecies approach.To guide Fujian and other provinces in multispecies management,a workshop in April 2018 shared international experience.The workshop considered 13 case studies spanning a wide range of underlying scientific models and types of harvest controls.Multispecies harvest controls based on simple survey-or index-based models that aggregate trends for many species are typically operationally easier for managers and fishers.However,inadequate management can cause declines of individual species,sometimes leading to adoption of species-specific models and then species-specific harvest controls.This transition often incurs economic costs through scientific and management demands,and constraints on harvest of co-occurring species.The lessons revealed by the case studies suggest multispecies TACs might be effective in the Fujian swimming crab fishery given the modest number of species with similar and productive life history traits,and the market demand for all species.Continued experimentation with different management approaches through pilot projects can enable China to maintain progress toward sustainable fisheries goals under the 14th Five-Year Plan.展开更多
Our Fair Plan to Safeguard Earth’s Climate reduces the emission of greenhouse gases to zero over the 80-year time period 2020 to 2100. To accomplish this, humanity must reduce its carbon intensity—the amount of CO&l...Our Fair Plan to Safeguard Earth’s Climate reduces the emission of greenhouse gases to zero over the 80-year time period 2020 to 2100. To accomplish this, humanity must reduce its carbon intensity—the amount of CO<sub>2</sub> emitted per unit of energy—and its energy intensity—the amount of energy needed to generate a unit of Gross World Product. As shown in our Fair Plan 8 paper, reducing the future growth of the human population can also contribute to the reduction in greenhouse-gas emissions. Here, we explore this further. We project the historical decrease in Total Fertility Rate (TFR) across the 21<sup>st</sup> century toward its logistical asymptotic Reference value of 2.04 Births Per Woman (BPW). We then engineer the asymptotic TFR beginning in 2020 to 1.95, 1.85, 1.75, 1.65 & 1.55 BPW. We project the population across the 21<sup>st</sup> century for the Reference and engineered TFRs. We do so using the results of Basten, Lutz and Scherbov (2013) for the population evolution across the 21<sup>st</sup> century for 8 constant TFR values (=2.50, 2.25, 2.00, 1.75, 1.50, 1.25, 1.00 & 0.75 BPW). We find that purposefully engineering the asymptotic TFR can significantly contribute to achieving the reduction in greenhouse-gas emissions needed to transition to our Fair Plan to Safeguard Earth’s Climate.展开更多
文摘China’s 13th Five-Year Plan elevated the national mandate for environmental sustainability.Chinese fisheries are characterized by full retention of high diversity catch harvested using unselective gears,creating ecological risks.Therefore,China launched pilot projects in management by Total Allowable Catch(TAC)in five coastal provinces in 2017 and 2018 to build experience with output controls.Fujian province launched an important pilot in its swimming crab fishery,the first to adopt a multispecies approach.To guide Fujian and other provinces in multispecies management,a workshop in April 2018 shared international experience.The workshop considered 13 case studies spanning a wide range of underlying scientific models and types of harvest controls.Multispecies harvest controls based on simple survey-or index-based models that aggregate trends for many species are typically operationally easier for managers and fishers.However,inadequate management can cause declines of individual species,sometimes leading to adoption of species-specific models and then species-specific harvest controls.This transition often incurs economic costs through scientific and management demands,and constraints on harvest of co-occurring species.The lessons revealed by the case studies suggest multispecies TACs might be effective in the Fujian swimming crab fishery given the modest number of species with similar and productive life history traits,and the market demand for all species.Continued experimentation with different management approaches through pilot projects can enable China to maintain progress toward sustainable fisheries goals under the 14th Five-Year Plan.
文摘Our Fair Plan to Safeguard Earth’s Climate reduces the emission of greenhouse gases to zero over the 80-year time period 2020 to 2100. To accomplish this, humanity must reduce its carbon intensity—the amount of CO<sub>2</sub> emitted per unit of energy—and its energy intensity—the amount of energy needed to generate a unit of Gross World Product. As shown in our Fair Plan 8 paper, reducing the future growth of the human population can also contribute to the reduction in greenhouse-gas emissions. Here, we explore this further. We project the historical decrease in Total Fertility Rate (TFR) across the 21<sup>st</sup> century toward its logistical asymptotic Reference value of 2.04 Births Per Woman (BPW). We then engineer the asymptotic TFR beginning in 2020 to 1.95, 1.85, 1.75, 1.65 & 1.55 BPW. We project the population across the 21<sup>st</sup> century for the Reference and engineered TFRs. We do so using the results of Basten, Lutz and Scherbov (2013) for the population evolution across the 21<sup>st</sup> century for 8 constant TFR values (=2.50, 2.25, 2.00, 1.75, 1.50, 1.25, 1.00 & 0.75 BPW). We find that purposefully engineering the asymptotic TFR can significantly contribute to achieving the reduction in greenhouse-gas emissions needed to transition to our Fair Plan to Safeguard Earth’s Climate.
