The building sector has gradually become a major contributor of carbon emissions in recent years. Its carbon emissions, which result from the long heating period and considerable consumption of coal in residential buildings during operation, must be reduced. To this end, the long-range energy alternatives planning system was adopted for the forecasting of carbon emissions in baseline scenarios, energy-saving, energy-saving–low-carbon, and low-carbon. On the basis of these predictions, the contributions of heating, cooling, cooking, illumination, washing, and other activities to carbon emissions were analyzed. The influencing factors in the reduction of carbon emissions from residential buildings in a cold region were identified. The results showed that energy-saving–low-carbon was the optimal scenario to reduce carbon emissions. Meanwhile, carbon emissions will peak in 2030, with a value of 42.06 Mt under the same scenario. As the top three influencing factors, heating, cooling, and cooking contribute 55.74%, 18.86%, and 17.29% of carbon emissions, respectively. Sensitivity results showed the differential effects of 32 factors on the reduction of carbon emissions in residential buildings. Carbon emissions could be reduced by 17.41%, 35.51%, 31.10%, and 14.10% by controlling the building scale, heating, cooling, and cooking, respectively. To this end, seven factors, including the rationing of central heating, were identified. Then, pathways to reducing carbon emissions were proposed under different scenarios. The present research fills the gap between reality and the predicted pathway, considering the heterogeneity of the climate.

The skin secretion of tree frogs contains a vast array of bioactive chemicals for repelling predators, but their structural and functional diversity is not fully understood. Paxilline (PAX), a compound synthesized by Penicillium paxilli, has been known as a specific antagonist of large conductance Ca2+-activated K+ Channels (BKCa). Here, we report the presence of PAX in the secretions of tree frogs (Hyla japonica) and that this compound has a novel function of inhibiting the potassium channel subfamily K member 18 (KCNK18) channels of their predators. The PAX-induced KCNK18 inhibition is sufficient to evoke Ca2+ influx in charybdotoxin-insensitive DRG neurons of rats. By forming π-π stacking interactions, four phenylalanines located in the central pore of KCNK18 stabilize PAX to block the ion permeation. For PAX-mediated toxicity, our results from animal assays suggest that the inhibition of KCNK18 likely acts synergistically with that of BKCa to elicit tingling and buzzing sensations in predators or competitors. These results not only show the molecular mechanism of PAX-KCNK18 interaction, but also provide insights into the defensive effects of the enriched PAX.