28 November 2016, Geophysical Research Letters (REPORT) Pine Island Glacier has undergone several major iceberg calving events over the past decades. These typically occurred when a rift at the heavily fractured shear margin propagated across the width of the ice shelf. This type of calving is common on polar ice shelves, with no clear connection to ocean-ice dynamic forcing. In contrast, we report on the recent development of multiple rifts initiating from basal crevasses in the center of the ice shelf, resulted in calving further upglacier than previously observed. Coincident with rift formation was the sudden disintegration of the ice mélange that filled the northern shear margin, resulting in ice sheet detachment from this margin. Examination of ice velocity suggests that this internal rifting resulted from the combination of a change in ice shelf stress regime caused by disintegration of the mélange and intensified melting within basal crevasses, both of which may be linked to ocean forcing. Read More here
Yearly Archives: 2016
26 November 2016, Climate News Network, Bolivian water crisis as glaciers vanish. Bolivia has declared a state of emergency as climate impacts shrink glaciers and leave cities without water. The government of Bolivia, a landlocked country in the heart of South America, has been forced to declare a state of emergency as it faces its worst drought for at least 25 years. Much of the water supply to La Paz, the highest capital city in the world, and the neighbouring El Alto, Bolivia’s second largest city, comes from the glaciers in the surrounding Andean mountains. But the glaciers are now shrinking rapidly, illustrating how climate change is already affecting one of the poorest countries in Latin America. The three main dams that supply La Paz and El Alto are no longer fed by runoff from glaciers and have almost run dry. Water rationing has been introduced in La Paz, and the poor of El Alto − where many are not yet even connected to the mains water supply − have staged protests. The armed forces are being brought in to distribute water to the cities, emergency wells are being drilled, and schools will have to close two weeks ahead of the summer break President Evo Morales sacked the head of the water company for not warning him earlier of the dangerous situation, but the changes produced by global warming have been evident for some time. Read More here
18 November 2016, Energy Post, Why the future belongs to decentralised renewables, not centralised hydrogen and giga-scale nuclear. What the future of our energy system will look like continues to be a subject of heated debate. According to one well-established tradition, writes Professor John Mathews of Macquarie University in Australia, the route to decarbonisation will run via massive nuclear power systems to the hydrogen economy. But China and to some extent India are emerging as the principal practitioners of an alternative vision of energy growth, underpinning their vast industrialisation efforts with conventional renewables that are the products of manufacturing. According to Mathews, the world is much more likely to follow the second route. Renewables, he argues, are benign, provide energy security, create jobs and above all are the least expensive option. How we envision the future of our energy systems is important as this tends to drive our policies and decisions. In a new scientific paper, “Competing principles driving energy futures: Fossil fuel decarbonisation vs. manufacturing learning curves”, published this month in the journal Futures, I contrast two broad energy visions. Read More here
22 November 2016, The Guardian, ‘Extraordinarily hot’ Arctic temperatures alarm scientists. The Arctic is experiencing extraordinarily hot sea surface and air temperatures, which are stopping ice forming and could lead to record lows of sea ice at the north pole next year, according to scientists. Danish and US researchers monitoring satellites and Arctic weather stations are surprised and alarmed by air temperatures peaking at what they say is an unheard-of 20C higher than normal for the time of year. In addition, sea temperatures averaging nearly 4C higher than usual in October and November. “It’s been about 20C warmer than normal over most of the Arctic Ocean, along with cold anomalies of about the same magnitude over north-central Asia. This is unprecedented for November,” said research professor Jennifer Francis of Rutgers university. Temperatures have been only a few degrees above freezing when -25C should be expected, according to Francis. “These temperatures are literally off the charts for where they should be at this time of year. It is pretty shocking. The Arctic has been breaking records all year. It is exciting but also scary,” she said. Read More here