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L. Carter

Publications and source records attributed to L. Carter.

2 recordsLinked to original sources

Climate change hotspots and implications for the global subsea telecommunications network

A global network of subsea telecommunications cables underpins our daily lives, enabling >95% of global digital data transfer, $trillions/day in financial trading, and providing critical communications links, particularly to remote, low-income countries. Despite their importance, subsea cables and their landing stations are vulnerable to damage by natural hazards, including storm surges, waves, cyclones, earthquakes, floods, volcanic eruptions , submarine landslides and ice scour. However, the likelihood or recurrence interval of many of these types of events will likely change under future projected climate change scenarios, compounded by sea-level rise; potentially increasing hazard severity, creating previously unanticipated hazards, or hazards may shift to new locations during the 20–30-year operational life of cable systems. To date, no study has assessed the wide-reaching impacts of future climate change on subsea cables and landing stations on a global scale. Here, for the first time we synthesize the current evidence base, based on published peer-reviewed datasets, to fill this crucial knowledge gap, specifically to assess how and where future climate change is likely to impact subsea cables and their shore-based infrastructure. We find that ocean conditions are highly likely to change on a global basis as a result of climate change, but the feedbacks and links between climate change, natural processes and human activities are often complicated, resulting in a high degree of geographic variability. We identify climate change ‘hotspots’ (regions and locations likely to experience the greatest impacts) but find that not all areas will be affected in the same manner, nor synchronously by the same processes. We conclude that cable routes should carefully consider locally-variable drivers of hazard frequency and magnitude. Consideration should be given both to instantaneous events (e.g. landslides, tropical cyclones) as well as longer-term, sustained impacts (e.g. seabed currents that circulate even in deep water). Multiple factors can combine to increase the risk posed to subsea cables, hence a holistic approach is essential to assess the compounded effects of both natural processes and human activities in the future.

Earth Science Reviews↗

Obliquity-paced Pliocene West Antarctic ice sheet oscillations

Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth's orbital geometry control the ice ages 1 , fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles 2 . Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch ( 5–3 Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming 3 . Here we present a marine glacial record from the upper 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, 40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth's axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to 3 °C warmer than today 4 and atmospheric CO 2 concentration was as high as 400 p.p.m.v. (refs 5 , 6 ). The evidence is consistent with a new ice-sheet/ice-shelf model 7 that simulates fluctuations in Antarctic ice volume of up to +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting paced by obliquity. During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt 8 under conditions of elevated CO 2 .

Nature↗