Spatio-Temporal Heterogeneity of Climate Warming in the Chinese Tianshan Mountainous Region

The Chinese Tianshan mountainous region (CTMR) is a typical alpine region with high topographic heterogeneity, characterized by a large altitude span, complex topography, and diverse landscapes. A significant increase in air temperature had occurred in the CTMR during the last five decades. However, the detailed, comprehensive, and systematical characteristics of climate warming, such as its temporal and spatial heterogeneity, remain unclear. In this study, the temporal and spatial heterogeneity of climate warming across the CTMR had been comprehensively analyzed based on the 10-day air temperature data gathered during 1961–2020 from 26 meteorological stations. The results revealed local cooling in the context of general warming in the CTMR. The amplitude of variation (AV) varied from −0.57 to 3.64 °C, with the average value of 1.19 °C during the last six decades. The lapse rates of the elevation-dependent warming that existed annually, and in spring, summer, and autumn are −0.5 °C/100 m, −0.5 °C/100 m, −0.7 °C/100 m, and −0.4 °C/100 m, respectively. The warming in the CTMR is characteristic of high temporal heterogeneity, as represented by the amplified warming at 10-d scale for more than half a year, and the values of AV were higher than 1.09 °C of the global warming during 2011–2020 (GWV2011–2020). Meanwhile, the amplitudes of warming differed greatly on a seasonal scale, with the rates in spring, autumn, and winter higher than that in summer. The large spatial heterogeneity of climate warming also occurred across the CTMR. The warming pole existed in the warm part, the Turpan-Hami basin (below 1000 m asl) where the air temperature itself was high. That is, the warm places were warmer across the CTMR. The cooling pole was also found in the Kuqa region (about 1000 m asl). This study could greatly improve the understanding of the spatio-temporal dynamics, patterns, and regional heterogeneity of climate warming across the CTMR and even northwest China.

Climate warming may increase the frequency of cold-adapted haplotypes in alpine plants

Modelling of climate-driven range shifts commonly treats species as ecologically homogeneous units. However, many species show intraspecific variation of climatic niches and theory predicts that such variation may lead to counterintuitive eco-evolutionary dynamics. Here, we incorporate assumed intraspecific niche variation into a dynamic range model and explore possible consequences for six high-mountain plant species of the European Alps under scenarios of twenty-first century climate warming. At the species level, the results indicate massive range loss independent of intraspecific variation. At the intraspecific level, the model predicts a decrease in the frequency of warm-adapted haplotypes in five species. The latter effect is probably driven by a combination of leading-edge colonization and priority effects within the species’ elevational range and was weakest when leading-edge expansion was constrained by mountain topography The resulting maladaptation may additionally increase the risk that alpine plants face from shrinkage of their ranges in a warming climate.

Changes in forest composition and associated biophysical climate feedbacks across boreal North America

Deciduous tree cover is expected to increase in North American boreal forests with climate warming and wildfire occurrence. This shift in composition can generate biophysical cooling effects via increased land surface albedo. Here we use newly derived maps of continuous tree canopy and fractional deciduous cover to assess change over recent decades. We find on average a small net decrease in deciduous fraction cover from 2000 to 2015 across boreal North America, and from 1992 to 2015 across Canada, despite extensive fire disturbance that locally increased deciduous vegetation. We further find a near-neutral net biophysical change in radiative forcing across the domain due to relatively small net changes in albedo. Thus, while there have been widespread changes in forest composition over the past several decades across the domain, the net changes in composition and associated post-fire radiative forcing have not yet induced systematic negative feedbacks to climate warming.

The AI Carbon Footprint and Responsibilities of AI Scientists

This article examines ethical implications of the growing AI carbon footprint, focusing on the fair distribution of prospective responsibilities among groups of involved actors. First, major groups of involved actors are identified, including AI scientists, AI industry, and AI infrastructure providers, from datacenters to electrical energy suppliers. Second, responsibilities of AI scientists concerning climate warming mitigation actions are disentangled from responsibilities of other involved actors. Third, to implement these responsibilities nudging interventions are suggested, leveraging on AI competitive games which would prize research combining better system accuracy with greater computational and energy efficiency. Finally, in addition to the AI carbon footprint, it is argued that another ethical issue with a genuinely global dimension is now emerging in the AI ethics agenda. This issue concerns the threats that AI-powered cyberweapons pose to the digital command, control, and communication infrastructure of nuclear weapons systems.

Leaf Physiological Responses of Three Psammophytes to Combined Effects of Warming and Precipitation Reduction in Horqin Sandy Land, Northeast China

The decreasing precipitation with global climate warming is the main climatic condition in some sandy grassland ecosystems. The understanding of physiological responses of psammophytes in relation to warming and precipitation is a possible way to estimate the response of plant community stability to climate change. We selected Lespedeza davurica, Artemisia scoparia, and Cleistogenes squarrosa in sandy grassland to examine the effect of a combination of climate warming and decreasing precipitation on relative water content (RWC), chlorophyll, proline, and antioxidant enzyme activities. We found that all experimental treatments have influenced RWC, chlorophyll, proline, and antioxidant enzyme activities of three psammophytes. L. davurica has the highest leaf RWC among the three psammophytes. With the intensification of precipitation reduction, the decreasing amplitude of chlorophyll from three psammophytes was L. davurica > C. squarrosa > A. scoparia. At the natural temperature, the malondialdehyde (MDA) content of the three psammophytes under severe drought treatment was much higher than other treatments, and their increasing degree was as follows: A. scoparia > C. squarrosa > L. davurica. At the same precipitation gradient, the proline of three psammophytes under warming was higher than the natural temperature. The differences in superoxide dismutase (SOD) among the three psammophytes were A. scoparia > L. davurica > C. squarrosa. Moreover, at natural temperature, more than 40% of precipitation reduction was most significant. Regardless of warming or not, the catalase (CAT) activity of A. scoparia under reduced precipitation treatments was higher than natural temperature, while the response of L. davurica was opposite. Correlation analyses evidenced that warming (T) was significant in L. davurica and precipitation (W) was significant in A. scoparia and C. squarrosa according to the Monte-Carlo permutation test (p = 0.002, 0.004, and 0.004). The study is important in predicting how local plants will respond to future climate change and assessing the possible effects of climate change on sandy grassland ecosystems.