The week that's gone: 14 July 2013

This is a summary of the stories we published in the week ending Sunday 14 July

Ocean microbes feel climate’s effects

8 July – Climate change could be about to alter life in the sea, according to new research in Nature Geoscience. Researchers at the University of Southern California have been experimenting with common microbes, hoping to predict which will flourish in a warmer and more carbon dioxide-rich atmosphere. The microbes are two genera of cyanobacteria. These tiny creatures… are life’s bottom line: they fix nitrogen from the atmosphere and they photosynthesise atmospheric carbon to release oxygen, so they deliver staples for survival both for all plants and for all animals… David Hutchins and colleagues studied two groups of nitrogen fixers, Trichodesmium and Crocosphaera… They tested seven strains of the two microbes, from different locations in both the Pacific and the Atlantic Oceans, under laboratory conditions in artificial atmospheres that mimicked the predicted carbon dioxide concentrations under various climate scenarios… as carbon dioxide levels rose, nitrogen-fixing productivity rose too, by up to 125%. But the responses varied according to the strain under test: some did better under pre-industrial conditions; some flourished as they neared the levels predicted for a “greenhouse” world… What it means in practical terms for the rest of the planet is less certain.

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CO2 storage ‘needs tailoring to geology’

9 July – Anybody planning carbon capture and storage (CCS) – one way to burn fossil fuels without releasing greenhouse gases – will have to think long and hard about where to put the carbon dioxide: long, because it must be kept secure for thousands of years, hard because even the hardest rocks yield under pressure. The technology exists and CCS is already one potential amelioration of the greenhouse problem. Energy companies have been condensing carbon dioxide from power station exhausts and gas and oil fields, and finding places to store it, usually deep underground. But deep burial may not be a permanent solution, which is why James Verdon, an earth scientist at the University of Bristol in the United Kingdom, and colleagues report in the Proceedings of the National Academy of Sciences that they decided to take a more careful look at three cases of long-term disposal.

Greenland faces ‘modest’ but risky melt

10 July – Greenland’s contribution to sea-level rise between now and 2200 is likely to be relatively modest, scientists say. But they couple this with a warning against complacency over the possible consequences of even a fairly small rise. They say the Greenland ice sheet is expected to increase its contribution to higher sea levels over the next two centuries. But there will be significant changes in the way the island loses ice as glaciers retreat. Their findings, published in the Journal of Glaciology (Sensitivity of Greenland ice sheet projections to model formulations, by Dr Heiko Goelzer et al), suggest that ice melting from the land surface will be the dominant way of raising sea levels. Outlet glaciers, which form an ice shelf once they reach the sea and then discharge into it, are expected to play a smaller part.

Climate chaos ‘needn’t happen – IF…’

11 July – Two separate groups of researchers say there are grounds for hope that the world can escape the prospect of a possibly uncontrollable and very damaging level of climate change. But they agree that world governments will have to meet rigorous conditions to make this happen. The first study, published in the journal Environmental Research Lettsrs, is by a team from Chalmers University of Technology in Sweden. It makes the bold claim that ambitious temperature targets “can be exceeded then reclaimed” by around mid-century. The way to achieve this, the study says, is by combining bio-energy with carbon capture and storage – a marriage of technologies it calls BECCS. However many and serious the provisos and qualifications the study makes, it does strike a hopeful note, one which is echoed by the second study, from the publishers of the original Hartwell paper, co-ordinated at the London School of Economics (LSE) and published in 2010. This new Hartwell paper is entitled The Vital Spark: innovating clean and affordable energy for all…The study’s international team of 20 authors… argue that only a high-energy planet is morally defensible or politically viable.

Corals face problems by 2100

11 July – Without deep cuts in carbon dioxide emissions, the planet’s coral reefs could be in serious trouble. In a world in which humans continue to burn fossil fuels unchecked, ocean conditions will become ultimately inhospitable, according to US scientists. Katharine Ricke and Ken Caldeira of the Carnegie Institution in Washington and colleagues make their sombre prediction in Environmental Research Letters. Their argument on the face of it seems inconsistent with other recent research on reef response to climate change, which in one case suggests that some corals could vanish, and in another that some corals might adapt, very slowly. But the debate in all three cases is about the rate of warming, the levels of carbon dioxide in the atmosphere, and the ultimate impact of changes in the pH levels of the seas.

Food waste offers unforeseen benefits

12 July – Societies all over the planet are running out of holes in the ground in which to dump their waste, so they’re under increasing pressure to find alternative solutions. In the European Union one of the problem wastes is food – rich people buy too much in the supermarket and throw a lot away. This is a disaster for local authorities that have to find a way of disposing of it, and a problem for the planet because rotting food produces large quantities of methane, a global warming gas 23 times more potent than carbon dioxide. Pressure to do something about the problem has been increased by ever-growing taxes on local authorities and companies who throw away waste in landfill, making it more expensive every year to rely on holes in the ground. A successful solution to the problem has been found in Oxfordshire in England, which not only solves the waste problem but also produces gas to provide electricity and fertiliser for local farmers.

Great tits weather climate challenge

13 July – The great tit – Britain’s favourite bird table visitor – has what it takes to keep one jump ahead of climate change. Three biologists report in the Public Library of Science journal PLoS Biology that Parus major, a little woodland bird that has already happily adapted to the suburban garden, has phenotypic plasticity, which is another way of saying that it can adapt to changing circumstances. Zoologists have been observing the same population of great tits in Wytham Woods near Oxford in the UK, for decades. Ben Sheldon of the Edward Grey Institute at Oxford University and colleagues considered the hazards that tiny short-lived birds must face as spring arrives ever earlier. The big challenge for nesting birds is to time their egg-laying to coincide with a spring peak in caterpillar numbers… the Oxford scientists had a lot of data to work with, and… confirmed that the great tits are now laying eggs on average two weeks earlier than they did 50 years ago, and did the sums. They concluded that P. major could adapt to warming of 0.5°C a year, which is rather more than the worst case scenario predicted by climate models.

Science still puzzles over polar ice

14 July – Here is a non-conclusion: after nine years of close observation, researchers still cannot be sure whether the planet is losing its ice caps at an accelerating rate. That is because the run of data from one satellite is still not long enough to answer the big question: are Greenland and Antarctica melting because of global warming, or just blowing hot before blowing cold again in some long-term natural cycle? The question is a serious one. If the loss of ice that seems to be happening now is really going to accelerate, then by 2100, mean sea level will rise 43 centimetres higher than the original notional prediction, and hundreds of millions of people who live on estuaries, deltas, coral atolls and great city river basins face serious losses. Bert Wouters, a glaciologist at the University of Bristol in the UK and the University of Colorado at Boulder, Colorado, in the US, and colleagues report in Nature Geoscience that their most up-to-date and consistent measuring system, a satellite called Grace, needs to run for a lot longer before there can be a clear answer.