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Computable General Equilibrium (CGE) models have proven to be instrumental in the climate policy literature. Although their use at the sub-national level has increased, their application to assess the implications of national climate policies on cities is scarce due to the low availability of city-level economic and environmental data. Cities could play an instrumental role in the fight against climate change as they are home to more than half of the world population, generate more than 80% of global Gross Domestic Product (GDP) and are responsible for 75% of global greenhouse gas (GHG) emissions. National CGE assessments of climate policies overlooking cities could result in missing major opportunities to achieve ambitious reduction targets considering that cities are centres of innovation and wealth. Hence, the objective of this study is to fill that gap in the literature by developing and using a recursive dynamic, multi-regional CGE model to link a city's economy to the rest of the nation to assess the direct and indirect economic impacts from national GHG emissions reduction pathways. The city of Auckland, New Zealand (NZ) has been used as a case study due to the city's proactive climate mitigation plans. The model and scenarios used resemble the ones developed by the New Zealand Climate Change Commission (CCC) to inform national policy advise provided to the government. Additional scenarios were developed to incorporate Auckland's growth and climate strategies. The results showed that in contrast to the rest of New Zealand, the impacts on the Auckland economy are more pronounced as reflected by the more drastic percent changes (with respect to baseline) of the regional GDP (−6% for Auckland and −1% for NZ) and consumer welfare (−5% for Auckland and 1% for NZ). The more pronounced impacts on Auckland are due to the difference in profile emissions (e.g., urban versus rural sectors), fewer low-emission technological alternatives (e.g., rural technologies do not cater to urban sectors' needs), and indirect impacts from importing agricultural products with a higher price tag due to rising GHG prices. This study's contribution in the climate policy literature is to serve as evidence and precedent to carefully evaluate the nuances encountered in complex urban systems when developing national climate policies considering that the number of countries establishing legally binding reduction targets is continually increasing. [Display omitted] • CGE model used to assess climate policy implications on case of Auckland, New Zealand. • Study based on national assessment of pathways by the country's Climate Commission. • Impact on city's economy is higher than nation's due to differing emissions profiles. • National low-emission technological alternatives do not cater to urban sectors' needs. • Study is precedent to integrate urban systems' nuances in national climate policies. [ABSTRACT FROM AUTHOR]

• Temperature was most important regulator of plant litter decay and retention of C in soil. • Precipitation plays an interactive role with temperature. • More than ½ of litter C was lost <1 yr and only about 5–12% remained after 8–10 yr. • Soil properties did not play a discernible role in these processes. • No-till slowed plant litter decay, but only initially in arid environments. Identifying the primary regulators of plant litter decay in agricultural soils is important for understanding ecosystem function now and for managing post-harvest litter in a warmer world. We conducted a litter decay study at 11 sites in Canada and New Zealand with diverse soils and climates. We incorporated 13C-labelled barley litter into the surface 10 cm of soil and monitored amount remaining over 8–10 years; at five sites litter was also applied to the soil surface to simulate no-tillage. Our objectives were to evaluate litter decay as influenced by soil type, tillage practice, and environmental conditions, and quantify the most important factors controlling C retention in soil. Loss of C via decomposition occurred quickly – more than half was lost within 1 year and only about 5–12% remained at the end of the experiment. A double exponential decay model, based on temperature and developed from the first 5 years of the study, accurately described litter decay, but only after re-tuning using measurements from the full experimental period. Including precipitation in the model further improved its fit. Soil properties exerted minimal discernible influence on the amount of litter C remaining, implying that properties such as the amount and surface area of clay minerals, were less important than climate in limiting litter decay or enhancing retention of C in soil. Comparison of litter application treatments showed that no-till slowed decay of plant litter, but only for a short time (∼1 yr) and only in environments with a mean annual precipitation of <1000 mm. These findings have implications for the role of soils in climate mitigation. If only 10% of added plant litter C remains in soil beyond a few years, regardless of climate, residue placement, or soil type, then rates of soil gain are limited without substantive increases in residue inputs. [ABSTRACT FROM AUTHOR]