Volume 9 Issue 9, September 2019

Concern about the carbon footprint of Bitcoin is not holding back blockchain developers from leveraging the technology for action on climate change. Although blockchain technology is enabling individuals and businesses to manage their carbon emissions, the social and environmental costs and benefits of doing so remain unclear.

New research finds that global inefficiencies in power transmission and distribution infrastructure result in nearly a gigatonne of CO₂-equivalent annually. Countries can use this overlooked mitigation opportunity in their transition to a clean power sector.

Climate scientists cannot agree on what caused a recent spate of severe winters over North America and Eurasia. Now, a simple yet powerful physics-based approach makes it clear that record-low Arctic sea ice coverage was not the root cause.

The Southern Ocean is a major carbon sink, but knowledge of its variability is limited, especially in the coastal Antarctic. Now, results based on 25 years of observations in the West Antarctic Peninsula show that the carbon sink is increasing rapidly, driven by summertime biological production linked to sea ice dynamics.

Additional electricity generation is required to compensate for losses from inefficient transmission and distribution infrastructure. In this study, emissions from compensatory generation and the potential for reductions are estimated for 142 countries.

Climate models project an increase in summer weather persistence for the northern mid-latitudes. In a 2 °C world, two-week-long hot-and-dry conditions increase by up to 20% for eastern North America. The chance of a week of heavy rainfall increases by 26%, adding to the risk of extremes in the future.

Climate change will increase meltwater and iceberg discharge from Antarctica, with implications for future climate and sea levels. Iceberg melt will partly offset greenhouse warming in the Southern Ocean and dampen the positive feedback loop between ice-sheet melting and subsurface warming.

Along the West Antarctic Peninsula, a 25-year dataset indicates that oceanic CO₂ uptake depends on upper ocean stability and phytoplankton dynamics. Diatoms achieve high oceanic CO₂ uptake and uptake efficiency. There has been a nearly fivefold increase in oceanic CO₂ uptake due to sea ice changes.

Elevated CO₂ increases plant biomass, providing a negative feedback on global warming. Nutrient availability was found to drive the magnitude of this effect for the majority of vegetation globally, and analyses indicated that CO₂ will continue to fertilize plant growth in the next century.

Fires play an important role in ecosystem dynamics. Long-term controls on global burnt area include fuel continuity and moisture, with ignitions and human activity becoming dominant in specific ecosystems. Changes in fuel continuity and moisture are the main drivers of changes of fire globally.

Two independent methods, applied to observations and climate models, suggest that changes in atmospheric circulation drive cold winters in mid-latitudes and coincident mild Arctic winters. Reduced Arctic sea ice causes Arctic warming but has minimal influence on the severity of mid-latitude winters.

Satellite altimetry shows global mean sea-level rise acceleration; however, sparse tide-gauge data limit understanding of the longer-term trend. A hybrid method of reconstruction for 1900–2015 shows acceleration since the 1960s, linked to increases and shifts in Southern Hemisphere westerly winds.

There are large uncertainties in wind-wave climate projections that need to be resolved to allow adaptation planning. A multi-method ensemble of global wave climate projections shows robust changes in wave height, period and direction that put 50% of the global coast at risk.

The components of the ocean carbon cycle will respond differently to climate change, with anthropogenic impacts first seen on processes sensitive to chemical changes—the calcium carbonate pump and oceanic uptake of CO₂—with the soft-tissue pump (sensitive to the ocean’s physical state) emerging later.