Volume 11 Issue 1, January 2021

Body sizes have been declining in response to climate change, but an expected relationship between size and the hot temperatures organisms can tolerate has eluded detection. Now, research shows how body size and the duration of exposure to hot temperatures interact to determine the onset and consequences of thermal stress.

Agricultural systems are vulnerable to climate change, and global reservoirs of plant genetic diversity are proving to be a valuable means of crop adaptation. A study now shows that production of sweet potato is at risk from extreme heat events, but a few tolerant cultivars can still thrive and potentially provide climate resilience.

Education increases political polarization on climate change beliefs in the US. Here the authors find that this effect does not generalize to other contexts. Across 64 countries, education has positive effects on climate change beliefs, and interactions with ideology are more nuanced and contextual.

Global trade and transport depend on the resilience of the ports sector. Multi-hazard operational risks are estimated for 2,013 ports under historical climate and future warming; of the marine and atmospheric hazards considered, coastal flooding, wave overtopping and heat stress increase risk most.

An increase in ocean transport from the North Atlantic into the Nordic Seas and Arctic Ocean is warming the region. Observations from 1993 to 2016 show a significant increase in heat transport after 2001, with the heat being transported over the Greenland–Scotland Ridge.

The strength of a positive Indian Ocean Dipole (pIOD) is set by sea surface temperature gradient across the equatorial Indian Ocean. Modelling shows warming will increase strong pIODs but decrease moderate pIODs, as faster surface warming in the west sets up conducive conditions for the strong events.

The east–west gradient in equatorial Pacific sea surface temperature has strengthened, but models suggest the opposite in past and future climates. Model ensembles show that the observed trend can arise from internal variability but their gradient weakens in the long term, causing more climate warming.

Surface water availability will change under climate change and is impacted by feedbacks between the land and atmosphere. Soil moisture exerts a negative feedback on water availability in drylands, offsetting some of the expected decline.

Hydrological modelling is combined with soil moisture estimates to quantify climate change impacts on inland Ramsar wetlands. Net global changes are estimated to be modest, but individual sites with area reductions over 10% are projected to increase 19–243% by 2100, depending on emissions scenario.

The biological pump sequesters carbon to the deep ocean. Ocean acidification, through impacts on plankton and food-web structure, is shown to alter the carbon-to-nitrogen ratio of organic material export, with heterotrophic processes playing a key role.

Analysis of ectotherm thermal death curves in the context of both challenge intensity and duration shows that smaller animals exhibit higher tolerance to acute stress, but lower tolerance to chronic stress. The size-dependent impact provides one explanation for warming-related reductions in animal size.

Mass field testing of heat tolerance in 1,973 cultivars of sweet potato (Ipomoea batatas) from 50 countries identifies tolerant cultivars and reveals tolerance-predictive traits for breeding consideration. The work highlights the role of intraspecific diversity for future crop resilience.

Peatlands are impacted by climate and land-use changes, with feedback to warming by acting as either sources or sinks of carbon. Expert elicitation combined with literature review reveals key drivers of change that alter peatland carbon dynamics, with implications for improving models.