Reducing food wasted is not only a food security issue, but also vital in reducing greenhouse gases (GHGs) emissions and ecological protection. Based on the principles of life cycle, this paper constructs a restaurant food consumption model. Through in-situ and online survey, the main reasons caused the food wasted were systematically analyzed, the average GHG emissions per capita of the restaurant and GHGs emission reductions from reducing catering food surplus were quantitatively evaluated. The results showed that the total amount of GHGs emissions from the restaurant were about 225.28 t CO₂e per year, and the amount of GHGs generated was 2.50 kg CO₂e per capita in terms of catering consumption. Among them, around 97.2 g per capital of food was discarded each meal. The results also revealed that the surplus of food came from the invitation and public consumption was significantly higher than that of ordinary daily meals. Excessive ordering and unexpected taste are main reasons triggering surplus. Young consumers and those with lower education background are more likely to have more food remains. Under the scenario of no food remains, the emission reduction could reach 0.26 kg CO₂e per capital in each meal, which can potentially reduce GHGs emissions by 10.55% of total GHGs emissions from wasted food. Implementing feasible policies is not only for achieving emission reduction goal from food consumption, but also for the sustainable consumption.

The urban CO₂ emission peak judgment model based on the conditional judgment function and Mann-Kendall trend analysis test method was constructed to analyze their direct CO₂ emissions and total CO₂ emissions characteristics in the 36 typical large cities of China from 2005 to 2019, and determine whether the comprehensive CO₂ emissions of each city have reached its peaks. In-depth analysis on the characteristics of typical cities at different emission stages was also conducted. The results show that among the 36 typical large cities, Kunming, Shenzhen and Wuhan have reached their peaks, 8 cities are in the plateau period, and the remaining 25 cities have not reached their peaks comprehensively. It is recommended that cities that have not reached the peak of CO₂ emissions should learn the experience from the city that have reached the peak according to their own characteristics, such as adjusting the industrial structure and energy structure, reducing the intensity of carbon emissions, and strengthening the decoupling of carbon emissions from economic growth, so as to achieve the peak of carbon dioxide emissions as soon as possible.

In this paper, a mesoscale numerical model coupled with a single-layer urban canopy model (WRF/UCM) was used to conduct sensitivity tests on eight roof cooling schemes with different albedo and greening ratio to simulate the impact of different cooling roof schemes on the urban thermal environment of Yangtze River Delta urban agglomeration in summer of 2013, and the influence mechanism was also analyzed. The results show that: there is a strong linear relationship between the mitigation effect of different cooling roof schemes on urban agglomeration thermal environment and the roof parameters, and the mitigation effect on heat-wave is better than that on normal summer under the same scheme. During heat wave, the cooling degree days of HR4 (albedo of 1.0) and GR4 (green fraction of 100%) are reduced by 14.7% and 10.9%, respectively, which saves more energy than normal summer. Heat-wave can enhance the intensity of heat island, and the high albedo roof scheme can reduce the heat island by 1.36℃ in the daytime. On average, the cooling effect of high albedo roof and roof greening increased by 38.5% and 34.9%, respectively, and the humidification effect increased by 29.5% and 21.9%, respectively. This is mainly because the former can reduce more net radiation flux in heat wave, and the latter can release more latent heat flux in heat wave. In addition, the cooling effect of dense urban grid areas is better than that of scattered urban areas. The average cooling range of Changzhou area in urban agglomeration is 32% higher than that of Hangzhou area.

As the largest coal power provider in the world, China needs to give more consideration to assess the stranded coal-fired assets, which caused by meeting the Paris Agreement’s long-term goals of capping global warming rise to 2℃ by the end of the 21st century. With an integrated carbon lock-in curves (CLICs) approach, China’s stranded coal power assets were identified under different coal power capacity expansion scenarios (no additional, 200, 300 and 400 GW new coal power units). From a “top-down” perspective, the carbon emission allowances were estimated for China’s coal power sector under 2℃ climate target. From a “bottom-up” perspective, the cumulative carbon emissions of coal power units were calculated, based on the high-precision data of coal power unit in China. Then “interaction up and down” to screen out stranded coal power units. Stranded value of coal power was estimated based upon a cash flow algorithm, with sensitivity analysis on key factors. The counterintuitive finding is, if stabilizing coal power capacity during 2020-2030, China will only incur a sizeable yet acceptable stranded loss around CNY 382 billion, however, continued increase of another 200-400 GW coal power would significantly enlarge the loss to 3.7-8.2 times. Therefore, during the Fourteenth Five-Year Plan period, in order to avoid missing the best time to reduce CO₂ emissions, it is necessary to establish peak coal power capacity and strictly control new coal power plant.

To limit global warming well below 2℃, transport sector needs to be deeply decarbonized in China. This paper presents a review analysis of current greenhouse gas emission and future trend of transport sector, and a discussion about the low carbon pathways based on the potentials and costs of different mitigation strategies. Greenhouse gas emissions from transport sector will keep increasing rapidly in future several years. Road transport remains the highest proportion, while emission from civil aviation enjoys the most rapid growth. The available mitigation options can be categorized into four groups: structural changes including new customer behavior and demand, disruptive technologies including autonomous vehicles, alternative fuel technologies and fuel economy improvement. To decarbonize transport sector, stricter fuel economy standards should be implemented, alternative fuel vehicles should be prompted and feasible measures should be adopted to lead the structural transition.

To clarify the challenges and potentials faced by the transition of the power system under the constraint of the climate change agreement to form an effective key, this paper starts from the impact analysis of climate change target on electricity demand, sorting out the pathway selection of power system transition systematically, then summarizes the issues related to power system transition process closely including the coal-fired power drop out, the renewable energy integration, the grid optimization, and proposes policy suggestions at last. The scale of coal-fired power needs to decline rapidly, the high-share integration and long-distance transmission of renewable energy generation will become the most significant features for the power system in the future, gas-fired power will assume greater responsibility than it is now, and nuclear power needs to abandon disputes to accelerate its development under the constraints of temperature rise target. Accelerating the improvement of market-oriented mechanisms, controlling the scale of coal-fired power capacity strictly, focusing on improving energy efficiency, coordinating and strengthening flexible resource management, and optimizing cross-regional load management should be the concerns of regulatory agencies in the future.

Under the 1.5℃ target of the Paris Agreement and China’s goal of achieving carbon neutrality before 2060, a comprehensive energy-economy-environment system model has been established to explore China’s additional emission reductions, sector contributions and key emission reduction measures to achieve 1.5℃emission pathway based on 2℃ emissions scenarios. The results show that the 1.5℃ scenario requires carbon emissions to be reduced to 0.6 Gt CO₂ by 2050, total primary energy consumption to peak at 6.8 Gtce in 2045, and the energy structure to be significantly optimized, with non-fossil energy accounting for 67% and coal proportion dropping to 16%. Compared with 2℃, 1.5℃ requires an additional cumulative emission reduction of 38.0 Gt CO₂, and the additional emission reduction mainly comes from the power sector. In terms of emission reduction measures, the additional emission reduction mainly comes from new low carbon energy and Bioenergy with Carbon Capture and Storage (BECCS) technology. The emission reduction measures are different by sector. The power sector relies more on BECCS and other emission reduction technologies to achieve a relatively large negative emission, which is the key to achieve the 1.5℃ target path. The industrial sector still relies heavily on energy efficiency. The construction and transportation sectors are more dependent on the adjustment of terminal energy structure in which hydrogen energy plays a greater role.

By now, EU, China, Japan, Korea, Canada, together with South Africa etc., have announced their carbon or GHGs neutrality targets. And it is also very possible that United States will announced its carbon neutrality target. All these countries’ CO₂ emission accounts for around 70% of global emission. Because these countries are technology and economy dominating countries, it is possible that the global will reach carbon neutrality by 2050. Carbon neutrality by 2050, is matching with the emission pathways under the Paris Agreement targets, even with its 1.5℃ warming target. Researches show that it is feasible to make carbon neutrality by 2050, and there is strong need for innovative technologies, and there will be technology and economy competition in future to make their pathways towards to the carbon neutrality targets.