Letters in 2017

Combining historical aerial surveys, expedition photographs, and both spy and modern satellite imagery reveals a pronounced retreat of peripheral glaciers in east and west Greenland, linked to changes in precipitation associated with the NAO.

The subduction of Subantarctic Mode Water (SAMW) moves heat into the upper ocean. Changes in wind forcing has thickened, deepened and warmed SAMW; increases in wind forcing could further deepen this water mass, increasing ocean heat content.

Climate change is predicted to increase soil carbon losses. However, manipulation experiments suggest detritivore feeding activity — a key driver of organic matter decomposition — will decline with warming and drying, reducing positive soil feedbacks.

Ice loss from Antarctica is sensitive to changes in ice shelves. Finite-element modelling reveals that localized ice-shelf thinning, particularly in locations vulnerable to warm water intrusion, can have far-reaching impacts via tele-buttressing.

The cost of preserving ecosystem storage of carbon varies depending on local land-use and socio-political pressures. A survey of experts suggests a cost-minimizing distribution would be more effective for mitigation than equitable distribution.

Changes in deep-water ventilation could potentially cause acidification from organic matter breakdown. The Sea of Japan has an acidification rate 27% higher at depth than at the surface, showing how reduced ventilation from warming could impact the deep ocean.

Reductions in precipitation and water storage increased fire emissions in pan-tropical forests by 133% during and following El Niño events (1997–2016). Fires follow a predictable cascade across tropical continents that may improve seasonal fire forecasts.

Climate and CO₂ trends have driven significant changes in global crop water demand over the last 30 years but with variation by region and crop type. If trends continue, it could be a challenge for adaptation efforts to keep pace with water demand.

The Arctic is under-represented in surface temperature datasets and this could affect estimates of global warming. A new dataset with greater coverage of the Arctic shows a higher warming rate of 0.112 °C per decade compared to 0.005 °C from IPCC AR5.

Limitations with climate models have previously prevented accurate diagnosis of future changes in mesoscale convective systems (MCSs). A convection-permitting model now indicates that summer MCSs will triple by 2100 in the United States, with a corresponding increase in rainfall rates and areal extent.

Achieving the longer-term goals of the Paris Agreement and transformation to a low-carbon society requires an acceleration in electricity generation investment and capacity addition above that outlined in the US Nationally Determined Contribution.

Post-monsoon season severe cyclonic storms were first observed over the Arabian Sea in 2014 and 2015. Highresolution modelling reveals their increased frequency can be attributed to anthropogenic forcing, and not natural variability.

Warming interacts with forest disturbance and drought to shape the energetic structure of soil food webs; these changes can undermine the provision of multiple ecosystem functions in transitional boreal–temperate forests.

Water-cooled power plants will be affected by changes in water availability and temperature. A system approach examines US thermoelectric power generation and finds whilst individual plants may face constraints, overall the current system can adapt.

Soil carbon release remains a highly uncertain climate feedback. Research now shows that the temperature control on carbon turnover is more sensitive in cold climates, supporting projections of a strong carbon–climate feedback from northern soils.

Biofuels have lower CO₂ emissions than fossil fuels, but competing land demands can limit expansion of production. This study shows Brazilian sugarcane ethanol could displace up to 13% of global crude oil consumption by 2045 whilst balancing forest conservation and future land demand for food.

Changes in European river flow have amplified the dry-south–wet-north contrast. Model simulations show that anthropogenic climate change accounts for this change with strong decreases in the Mediterranean and weak increases in northern Europe.

Past studies suggest the North American monsoon will weaken in the future. Correcting for model sea-surface temperature biases, however, reveals a reduction in monsoon-related precipitation due to increased atmospheric stability.

Distribution modelling of vascular plants, butterflies and grasshoppers in central Europe suggests that habitat-based conservation strategies will be insufficient to save species from regional extinction under twenty-first-century climate change.

As a global media event, COP 21 had the potential to enhance understanding and motivate political action. This study shows that although media coverage reached the German public and promoted conference-specific knowledge, this did not translate into active engagement.