10 March 2016, Climate News Network, Antarctic techno-fix cannot slow rising seas. Pumping seawater onto the Antarctic landmass to form ice and stop sea levels rising stands little chance of success, scientists say. Sea level rise is likely to be a problem too big to handle. Geoengineers will not be able to magic away the rising tides, according to new research. In particular, they will not be able to pump water from the sea and store it as ice on the continent of Antarctica. That is because, unless they pump it enormous distances, that will only accelerate the flow of the glaciers and it will all end up back in the sea again, a study in the journal Earth System Dynamics says. Geoengineering is sometimes produced as the high-technology solution to the environmental problems of climate change: if humans don’t change their ways and start reducing greenhouse gas emissions, say the proponents of technofix, human ingenuity will no doubt devise a different answer. But, repeatedly, closer examination has made such solutions ever less plausible. Scientists have dismissed the idea that the melting of the Arctic can be reversed, have only tentatively conceded that technology could dampen the force of a hurricane, and have found that – instead of cooling the Earth – attempts to control climate change could either make things worse or seriously disrupt rainfall patterns. On balance, scientists believe that most of the big geo-engineering ideas won’t work. Deep freeze And now a team from the Potsdam Institute for Climate Impact Research has poured cold water on the idea of pouring cold water onto the ice cap. The idea is a simple one. Are sea levels rising 3mm a year because the world is warming? Then pump the sea high onto the Antarctic landmass where it will freeze and stay frozen for a millennium. But to be sure of that, say the Potsdam team, at least 80% of the water would have to be pumped 700 km inland. That would take more than 7% of the annual global primary energy supply just to balance the current rate of sea level rise.But even in a world recently committed to a warming of less than 2°C, the seas are going to go on rising. Sea levels could rise at least 40cms by the end of the century – or possibly 130cms, with devastating consequences for low-lying coastlines: rich megacities might be able to build defences, but the poorest communities would be swept away. Read More here
Tag Archives: oceans
3 March 2016, Science Daily, Greenland’s ice is getting darker, increasing risk of melting. Feedback loops from melting itself are driving changes in reflectivity. Greenland’s snowy surface has been getting darker over the past two decades, absorbing more heat from the sun and increasing snow melt, a new study of satellite data shows. That trend is likely to continue, with the surface’s reflectivity, or albedo, decreasing by as much as 10 percent by the end of the century, the study says. While soot blowing in from wildfires contributes to the problem, it hasn’t been driving the change, the study finds. The real culprits are two feedback loops created by the melting itself. One of those processes isn’t visible to the human eye, but it is having a profound effect. The results, published in the European Geosciences Union journal The Cryosphere, have global implications. Fresh meltwater pouring into the ocean from Greenland raises sea level and could affect ocean ecology and circulation. “You don’t necessarily have to have a ‘dirtier’ snowpack to make it dark,” said lead author Marco Tedesco, a research professor at Columbia University’s Lamont-Doherty Earth Observatory and adjunct scientist at NASA Goddard Institute of Space Studies. “A snowpack that might look ‘clean’ to our eyes can be more effective in absorbing solar radiation than a dirty one. Overall, what matters, it is the total amount of solar energy that the surface absorbs. This is the real driver of melting.” The feedback loops work like this: During a warm summer with clear skies and lots of solar radiation pouring in, the surface starts to melt. As the top layers of fresh snow disappear, old impurities, like dust from erosion or soot that blew in years before, begin to appear, darkening the surface. A warm summer can remove enough snow to allow several years of impurities to concentrate at the surface as surrounding snow layers disappear. At the same time, as the snow melts and refreezes, the grains of snow get larger. This is because the meltwater acts like glue, sticking grains together when the surface refreezes. The larger grains create a less reflective surface that allows more solar radiation to be absorbed. The impact of grain size on albedo — the ratio between reflected and incoming solar radiation — is strong in the infrared range, where humans can’t see, but satellite instruments can detect the change. Read More here
17 February 2016, The Guardian, The key to halting climate change: admit we can’t save everything. Climate change, and human resistance to making the changes needed to halt it, both continue apace: 2015 was the hottest year in recorded history, we may be on the brink of a major species extinction event in the ocean, and yet political will is woefully lacking to tackle this solvable problem. Given these dire ecological trends, limited public funding and legislative gridlock, the time is ripe for a budget-neutral, executive-branch approach for managing our natural resources: triage. A science-based triage approach should be used to classify areas and species into one of three categories: not at immediate risk, in need of immediate attention or beyond help. Refusing to apply triage implicitly assumes that we can save everything and prevent change, which we cannot. Prioritization will occur regardless, just ad hoc and shrouded. This triage system would replace the status quo of inadequately managing our full portfolio of over 1m square miles of public land and 1,589 threatened and endangered species. For areas or species not at immediate risk, we can delay action while monitoring to detect changes in that status. For example, increased temperatures and prolonged periods of drought may increase both wildfires and populations of tree-killing beetles in forests of the Pacific north-west. Knowing this, we can track these variables and explore management options that minimize risk without prematurely devoting disproportionate resources. For areas needing immediate help, we must act now. For the coral reefs of the Florida Keys and US Virgin Islands, all anthropogenic impacts (such as overfishing, pollution and coastal development) must be dramatically reduced. Otherwise, because the health of these coral reefs is currently so compromised, they are unlikely to survive the sea level rise, rising ocean temperatures and increasing acidification resulting from climate change. For species protections, it would be wise to focus on keystone species such as oysters (water filterers), parrotfish (algae eaters on overgrown coral reefs), bees (pollinators) and wolves (key predators). For areas we can no longer maintain, we must make the most difficult of choices – give up, and accept that change is not always preventable. In Alaska, it may be too late to prevent the climate change-induced shift from coniferous-dominated to deciduous-dominated stands, with unfortunate impacts on forest-dwelling species and the logging industry. In the ocean, entire fisheries can be lost from an area when species shift due to warming waters. Read More here
3 February 2016, Nature Communications, Evidence for the stability of the West Antarctic Ice Sheet divide for 1.4 million years. Past fluctuations of the West Antarctic Ice Sheet (WAIS) are of fundamental interest because of the possibility of WAIS collapse in the future and a consequent rise in global sea level. However, the configuration and stability of the ice sheet during past interglacial periods remains uncertain. Here we present geomorphological evidence and multiple cosmogenic nuclide data from the southern Ellsworth Mountains to suggest that the divide of the WAIS has fluctuated only modestly in location and thickness for at least the last 1.4 million years. Fluctuations during glacial–interglacial cycles appear superimposed on a long-term trajectory of ice-surface lowering relative to the mountains. This implies that as a minimum, a regional ice sheet centred on the Ellsworth-Whitmore uplands may have survived Pleistocene warm periods. If so, it constrains the WAIS contribution to global sea level rise during interglacials to about 3.3 m above present. Read More here