The week that's gone: 28 July 2013

This is a summary of the stories we published in the week ending Sunday 28 July.

Climate leaves Iberian lynx at last gasp

22 July – Climate change could be about to extinguish the world’s most endangered cat. As rabbit populations dwindle in the wilder parts of the Iberian peninsula, so do the chances of survival for their predator, the Iberian lynx. Most of the world’s wild felines are in trouble, but Lynx pardinus earned its unwelcome distinction in 2008 when – despite decades of conservation effort – its population fell to about 160 animals, in two locations, when only a decade before there had been at least nine surviving populations. Miguel Araújo of the National Museum of Natural Sciences in Madrid, Spain and colleagues report in Nature Climate Change that they took a model of predator-prey numbers specially designed for the lynx and ran it through a series of climate model simulations to see how the creature fared. The answer is it fared badly. Eighty per cent of the lynx’s natural diet is rabbit, and although rabbits are widely considered to be prolific pests in many parts of Europe, the combination of overhunting, introduced and natural infection has left the rabbit population in the peninsula impoverished.

More US insurers to reveal climate risks

23 July – The US insurance industry has been reluctant to recognise the dangers posed to its customers – and its revenues – by a warming climate. Now there are signs that attitudes in the multi-billion dollar sector are slowly beginning to change. In the last week the states of Connecticut and Minnesota announced they would be adopting regulations applying in California, New York and Washington states which require insurance companies to fully disclose their readiness to deal with climate change-related risks. “As insurance regulators, it is important that we identify those climate-related factors that can affect the marketplace and in particular the availability and cost of insurance”, says Thomas B. Leonardi, Connecticut’s Insurance Commissioner. Elsewhere in the US, insurers seem unwilling to contemplate the implications for their businesses of changes in climate. While some states, particularly California, have been pressing insurers to be more aware of the dangers posed by climate change, the remaining 45 states have so far refused to adopt the disclosure requirements.

Climate warming slows: no surprise yet

23 July – Here is an interim update on the uncertain future of climate change: it remains uncertain and all forecasts are, for the time being, interim. British scientists say that global warming has slowed down. Their climate models predicted periods in which warming would slow before speeding up again, and this slowing down is within their calculated limits of uncertainty: they had not, however, expected the slowdown to happen for a decade or more. But it is happening now. Between 1970 and 1998, the planet warmed at an average of 0.17°C per decade because of human impact on the atmosphere in the form of fossil fuel burning, forest destruction and other human activity. Between 1998 and 2012, it warmed at an average rate of 0.04°C per decade. This slowdown is not easily explained: greenhouse gas levels in the atmosphere have continued to rise at 3.1% per year, and are now 30% higher than at any time in the last 800,000 years.

Worse floods ahead as climate warms

24 July – Heavy and prolonged rainfall will cause both more frequent and more severe flooding across the United Kingdom and the rest of north-west Europe as the atmosphere continues to warm, say British and American scientists. A study in IOP Publishing’s Environmental Research Letters of what are known as atmospheric rivers pins the blame for the increasing flood risk firmly on man-made climate change and says the same problem will afflict other parts of the planet. Researchers at the University of Reading near London, and the US University of Iowa, describe how atmospheric rivers carry vast amounts of water vapour around the Earth, delivering heavy and prolonged rainfall, particularly to mountainous areas. They were responsible for the protracted winter and summer floods in the UK in 2012, which caused an estimated $1.6 billion (£1 bn) in damage. In a warming world the atmosphere can carry more water and the research showed that the rivers, typically running a kilometer above the earth, 300 kilometres wide and thousands of kilometres long, would become larger and capable of delivering even bigger quantities of prolonged rainfall.

Arctic methane melt ‘could cost $60 tn’

24 July – The true cost of an ice-free Arctic summer could be counted in lives lost, communities flooded and economies ruined, three scientists warn. Methane in the submarine permafrost could be released on such a scale that the cost to the world’s economy could reach $60 trillion. The value of the entire world economy in 2012 was $70 trillion. Gail Whiteman is at the school of management at Erasmus University in Rotterdam, Peter Wadhams is a professor of ocean physics at the University of Cambridge and Chris Hope is at the Judge Business School in Cambridge. All three argue, in the journal Nature, that while businesses consider the benefits of Arctic warming in terms of shorter sea routes and easier access to fossil fuel reserves, the potentially catastrophic consequences are being ignored. The problem they foresee is relatively straightforward and has been of concern to climate scientists for years. For all human history, the Arctic Ocean has been capped by ice. Beneath the ice is sunless ocean, and beneath the ocean is permanently frozen seabed, and within the seabed are billions of tonnes of marsh gas or natural gas stored as frozen methane hydrate.

Warmer climate will hit Volta river levels

25 July – Plans to boost food and energy production in one of West Africa’s most rapidly populating regions are likely to be put in jeopardy by water shortages brought about by rising temperatures, falling rainfall and increased evaporation, says a new report. The Volta River is one of Africa’s main waterways. More than 24 million people in Ghana, Burkina Faso, Benin, Ivory Coast, Mali and Togo depend on the river and its tributaries for water. The output of hydro-electric plants on the river is also a key element in providing power for irrigation systems and for driving the region’s industrial growth. The study, The Water Resource Implications of Changing Climate in the Volta River Basin by the International Water Management Institute and partner organisations, says there are indications that temperatures will rise by up to 3.6°C in the Volta River Basin over the next century – leading to significant water loss due to evaporation – while rainfall in the region could drop by 20%. As a result water flows in the Volta and its tributaries could fall by 45%, “depriving the basin of water that countries are counting on to drive turbines and feed farms”, says the study.

Alaska’s forest fires burn more fiercely

26 July – There have always been fires in the cold forests of Alaska. Periods of burning are part of the ecological regime, and fires return to black spruce stands of the Yukon Flats at intervals of tens to hundreds of years. But recent evidence suggests that fire is about to come back with a vengeance – or, in the language of science, “a transition to a unique regime of unprecedented fire activity”. Ryan Kelly and Feng Sheng Hu, two biologists at the University of Illinois, Urbana, have examined charcoal records from 14 lakes in Yukon Flats to reconstruct the history of burning for the last 10,000 years. They and colleagues report in the Proceedings of the National Academy of Sciences that during the Medieval Climate Anomaly – the warm period that brought monastery vineyards to Britain a thousand years ago – the dry conditions favoured what they call “peak biomass burning”. But this apparent limit has, they report, been surpassed during recent decades, characterised by “exceptionally high fire frequency and biomass burning.”

Traditional knowledge ‘vital to science’

23 July – Climate change often seems to be seen as the preserve of scientists and environmental journalists. But what about the accumulated wisdom of traditional and indigenous peoples? A Brazilian anthropologist says they have an important contribution to make to knowledge about climate change, and it is about time they were heard. Manuela Carneiro da Cunha, emeritus professor of the Department of Anthropology at Chicago University and the University of São Paulo, says scientists should listen to traditional and indigenous peoples because they are very well informed about their local climate as well as the natural world around them, and they can share this knowledge with scientists. This knowledge, she says, is not a “treasure” of data to be stored and used when wanted, but a living and evolving process: “It is important to understand that traditional wisdom is not something simply transmitted from generation to generation. It is alive, and traditional and indigenous peoples are continually producing new knowledge”.

Scientists mull Arctic’s slow CO2 loss

28 July – The levels of Arctic permafrost that thaw each year and freeze again are growing at depths of 1cm a year, but the carbon locked away in the soils is – so far – not being released at an accelerating rate. This is good news for climate change worriers, but only for the time being. Bo Elberling of the Centre for Permafrost at the University of Copenhagen in Denmark and colleagues report in Nature Climate Change that the soggy summer soils of Greenland, Svalbard and Canada where they have taken samples are not releasing carbon dioxide at the rate some had feared. But the results are based on preliminary research and they still have to work out why carbon release is so slow – and whether it will remain slow. The “active permafrost” is a natural feature of sub-Arctic life: there is a shallow thaw each summer, plants flower, insects arrive, migrating birds follow the insects, grazing animals forage, predators seize a chance to fatten, and then winter returns with the shorter days. But of all the climate zones, the Arctic is responding fastest to global warming, with a startling loss of sea ice; the glaciers, too, are in retreat almost everywhere.