Quantifying the physical processes leading to atmospheric hot extremes at a global scale

Catalpol alleviates heat stroke-induced liver injury in mice by downregulating the JAK/STAT signaling pathway

BACKGROUND

Heat stroke (HS) generated liver injury is a lethal emergency that occurs when the body is exposed to temperatures up to 40 °C for a few hours.

PURPOSE

This study aimed to evaluate the therapeutic prospects of Catalpol (CA) from the blood-cooling herb Rehamanniae Radix on liver injury by HS.

STUDY DESIGN AND METHODS

A murine HS model (41 ± 0.5 °C, 60 ± 5 % relative humidity) and two cell lines (lipopolysaccharide + 42 °C) were used to assess the protective effects of CA on physiological, pathological, and biochemical features in silico, in vivo, and in vitro.

RESULTS

CA treatment significantly improved survival rates in vivo and cell viability in vitro over those of the untreated group. Additionally, CA treatment reduced core body temperature, enhanced survival time, and mitigated liver tissue damage. Furthermore, CA treatment also reduced the activities of AST and ALT enzymes in the serum samples of HS mice. Molecular docking analysis of the 28 overlapping targets between HS and CA revealed that CA has strong binding affinities for the top 15 targets. These targets are primarily involved in nine major signaling pathways, with the JAK-STAT pathway being highly associated with the other eight pathways. Our findings also indicate that CA treatment significantly downregulated the expression of proinflammatory cytokines both in vivo and in vitro while upregulating the expression of anti-inflammatory cytokines. Moreover, CA treatment reduced the levels of JAK2, phospho-STAT5, and phospho-STAT3 both in vivo and in vitro, which is consistent with its inhibition of the apoptotic markers p53, Bcl2, and Bax.

CONCLUSIONS

Heat stroke-induced liver injury was inhibited by CA through the downregulation of JAK/STAT signaling.

Role of atmospheric resonance and land-atmosphere feedbacks as a precursor to the June 2021 Pacific Northwest Heat Dome event

We demonstrate an indirect, rather than direct, role of quasi-resonant amplification of planetary waves in a summer weather extreme. We find that there was an interplay between a persistent, amplified large-scale atmospheric circulation state and soil moisture feedbacks as a precursor for the June 2021 Pacific Northwest "Heat Dome" event. An extended resonant planetary wave configuration prior to the event created an antecedent soil moisture deficit that amplified lower atmospheric warming through strong nonlinear soil moisture feedbacks, favoring this unprecedented heat event.

Storylines for unprecedented heatwaves based on ensemble boosting

Recent temperature extremes have shattered previously observed records, reaching intensities that were inconceivable before the events. Could the possibility of an event with such unprecedented intensity as the 2021 Pacific Northwest heatwave have been foreseen, based on climate model information available before the event? Could the scientific community have quantified its potential intensity based on the current generation of climate models? Here, we demonstrate how an ensemble boosting approach can be used to generate physically plausible storylines of a heatwave hotter than observed in the Pacific Northwest. We also show that heatwaves of much greater intensities than ever observed are possible in other locations like the Greater Chicago and Paris regions. In order to establish confidence in storylines of 'black swan'-type events, different lines of evidence need to be combined along with process understanding to make this information robust and actionable for stakeholders.

Addressing path dependencies in decision-making processes for operationalizing compound climate-risk management

The need for a compound risk governance system and management practice is argued in this paper. We find that, historically, risk management strategies have been developed for single hazards and are often subject to path dependency. It is thus difficult to adapt them to a situation that has compound risks. The lack of attention to compound risks in current risk management practices often leads to potential side effects-positive or negative-on other risks and can also result in related management strategies being overlooked. This can ultimately cause barriers to larger transformational adaptation efforts and lead to the intensification of existing societal inequalities or to the creation of new ones. To alert policy- and decision-makers to the need to move toward compound-risk management strategies, we argue that risk management must explicitly highlight various elements of path dependencies, the positive and negative side effects of single-hazard risk management, the appearance of new social inequalities, and the intensification of existing ones.