This is a summary of the stories we published in the week ending Sunday 21 July.
15 July – Sea-level rise may be slow to show its hand but once it really starts, researchers say, it will keep going for centuries, with baleful effects. For each degree by which the Earth warms, they believe, sea levels will probably rise by over two metres. Some recent research has suggested that the future rate of sea-level rise may not be as fast as scientists had expected. But a study published in the Proceedings of the National Academy of Sciences, The multi-millennial sea-level commitment of global warming, paints a different picture. Today’s greenhouse gas emissions will cause sea levels to rise for centuries to come. “CO2, once emitted by burning fossil fuels, stays an awful long time in the atmosphere”, says Anders Levermann, lead author of the study and research domain co-chair at the Potsdam Institute for Climate Impact Research, Germany. “Consequently, the warming it causes also persists.”
16 July – The public may be more prepared for the demanding logic of climate change than many politicians. New research in the UK confirms that most people in Britain would like to see an energy system that is clean, safe, fair and efficient. Four out of five people are concerned about becoming too dependent on energy supplies from other nations; three out of four are concerned or very concerned about climate change, and four out of five questioned would like to reduce their overall energy use. The UK Energy Research Centre’s report, Transforming the UK Energy System – Public Values, Attitudes and Acceptability, is based on 30 months of study and is to be debated at the Royal Society (16 July). It is the first of its kind to examine in detail public attitudes to all the wider aspects of energy sources, energy use, pollution, new technologies, carbon dioxide emissions and planetary change. “Our participants saw the bigger picture of energy system transformation and they were overwhelmingly committed to moving away from fossil fuels towards renewable forms of energy production, and to lowering energy demand”, said Nick Pidgeon of Cardiff University, who led the research.
17 July – Climate change could literally throw new light on the dark submarine world. In the 20 years since the tempestuous break-up of the Larsen A ice shelf, off the Antarctic peninsula, the sea floor beneath has been colonised by a new set of citizens: glass sponges or Hexactinellida. The vast, floating glacier collapsed in a violent storm in 1995, and is no longer a consistent sheet of year-round ice. What has changed is not the temperature of the sea floor beneath, but the light that reaches it. The deep southern ocean waters flow at a pretty steady -2°C. But waters once completely masked by ice are now exposed to sunlight for more than six months of the year. German researchers report that a static, filter-feeding animal once believed to grow only very slowly has appeared in great numbers and with surprising speed. Laura Fillinger and Claudio Richter of the Alfred Wegener Institute and colleagues write in the journal Current Biology that where there were once mostly ascidians, or sea squirts, there were now none: they had been replaced by glass sponges that have taken advantage of the phytoplankton growth in the surface waters, which has led in turn to a steady supply of fresh food to the sea bed 140 metres below.
18 July – The best thing to protect your property from the sea is a sand dune – or a mangrove swamp, or a coral reef, kelp forest or sea grass meadow. Nature, which has been doing the job for three billion years, has had time to work out the surest and most enduring sea defences, according to US researchers. Katie Arkema of the Natural Capital Project at Stanford University in California and colleagues found that the conservation of natural habitat could reduce by half the people and property at risk from coastal storms. As planetary temperatures rise and the ice caps retreat, sea levels are expected to rise: more frequent or more intense storms and flooding are also forecast. In total, 23 of the 25 most populous counties in the US are on the coasts. Coastal engineering is expensive, and anyway may not be the best solution.
19 July – British scientists say estimates of the amount of iron dissolving into seawater around some of the world’s coasts may be drastically wrong. They say there is no standard, one-size-fits-all way to measure how much iron enters the water in different parts of the globe. Instead, they say, the amounts may vary by up to ten thousand times between one area and another, with profound implications for the impact of the iron on the oceanic carbon cycle. This uncertainty, they say, has probably led to iron’s impact being both exaggerated and underplayed. It is compounded by another discovery: that the iron enters the water by two mechanisms, not the one thought so far to be solely responsible. Iron is key to the removal of carbon dioxide from the atmosphere as it promotes the growth of microscopic marine plants (phytoplankton), which mop up the greenhouse gas and lock it away in the oceans.
20 July – Rising temperatures could be bad news for people with bad lungs. Two new lines of research are bleak reminders of the link between air quality and human health. A study from the University of York in the UK reports that ozone levels soar during heat waves – perhaps because the capacity of plants to absorb ozone is curtailed as the mercury goes up. When the ground is dry and the temperatures rise, plants become stressed: they shut their stomata – those tiny pores in their leaves – to conserve moisture. It means they can survive the high ozone levels that tend to follow traffic fumes and factory exhausts in hot weather. But it also means they cannot react to the ozone. “Vegetation can absorb as much as 20% of the global atmospheric ozone production, so the potential impact on air quality is substantial”, said Dr Lisa Emberson of the university’s Stockholm Environment Institute… Worldwide, according to a report in Environmental Research Letters, more than two million people die because of human-caused outdoor air pollution. Researchers report that, so far, climate change has had only a minimal effect on death rates.
21 July– People have been warning about an ice-free Arctic ocean for years. But Jiping Liu, an atmospheric scientist at the State University of New York in Albany in the US and colleagues have gone one better. They predict that the Arctic Ocean will be effectively free of ice for the first time in the month of September between 2054 and 2058. Once again, the prediction depends on climate models, and inevitably on the decisions governments take to control greenhouse gas emissions in the next decade. But the fact that a team of scientists can spread their bets over a span of four specific years is an indicator of how fast and how inexorable the Arctic melting has become. The polar icecap has been dwindling in area and losing its thickness for decades: the observations by satellite have been confirmed by submarine measurements and icebreaker journeys. An icecap that was, historically, impassable even in summer has for years given way each autumn to ever greater stretches of open water.