20 February 2016, Climate News Network, Carbon rise keeps water in drylands. Increased carbon dioxide in the atmosphere because of climate change is helping to turn the world’s drylands a more luxuriant green − but that’s not necessarily good news. The drylands of the world are getting greener, and researchers think it is thanks to higher levels of carbon dioxide in the atmosphere. In a paradoxical discovery, even as landscapes become increasingly at risk of desertification, they may also look more luxuriant. Two scientists from Purdue University in Indiana, US, and a researcher in Saudi Arabia report in the journal Scientific Reports that they analysed 45 satellite studies from eight countries to confirm that the drylands of the world are responding to global warming and climate change by getting greener.Their conclusion is that rising levels of the greenhouse gas that is warming the planet – a consequence of humans’ combustion of fossil fuels over the last two centuries – are also delivering extra fertilisation to plants, so that photosynthesis can function with less water. In turn, this means that more soil water stays in the ground. Negative feedback “We know from satellite observations that vegetation is greener than it was in the past,” says Lixin Wang, an Earth scientist from Purdue, and one of the authors of the report. “We now understand why that is occurring, but we don’t necessarily know if it is a good thing or not.” The observation seems to suggest that nature is delivering what engineers call negative feedback: as the Earth warms because of the rising greenhouse gas levels, so vegetation is responding to grow more vigorously and soak up more carbon. This has been observed before, but it may not be a good thing because one consequence of climate change is that drylands everywhere – and they are home to around two billion people – are likely to become increasingly parched, with cruel consequences for the world’s poorest people who make up most of those two billion. Nor is it certain that all drylands will respond with more vigorous growth. For some terrains, ecological devastation could increase. Read More here
Category Archives: Ecosystem Stress
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
16 February 2016, The Conversation, Adapting to bushfires: a new idea of ‘fire-proof’ homes. This summer’s bushfires have destroyed homes, precious ecosystems and, tragically, lives. Fires in South Australia and Western Australia killed two and six people, respectively. On Christmas Day more than 100 properties were destroyed in Victoria, and ongoing fires in Tasmania’s wilderness have claimed ancient, fire-sensitive vegetation. Our key strategy to address this is to evacuate fire-prone areas extensively on days when fire weather is likely to present a risk. In essence, we are leaving our homes to fend for themselves, and rightly so. Homes can be replaced; lives cannot. We know the cost of fire. In a warming world, it is very likely we will see more frequent and more extreme fires. To adapt to these future fires we will need to change how we approach fire management and the safety of our homes. Fortunately there are good examples in contemporary Australia of how we might do so. Land of fire Before European settlement, Australia was a fire-adapted continent from the southern tip of Tasmania to the tropical north. Its indigenous citizens understood fire both as a threat and as a tool. Indigenous people regularly used fire to modify the vegetation so that fires could not reach an intensity that would damage to trees, animals or indigenous settlements. Unfortunately, most of Australia looks nothing like it did back then. The bush in many parts has reverted to a thick impenetrable scrub with fuel loads that can support fires so severe that agencies have no way of stopping them. Read More here
15 February 2016, Science Daily, Four billion people affected by severe water scarcity. There are four billion people worldwide who are affected by severe water scarcity for at least one month a year. That is the conclusion of University of Twente Professor of Water Management, Arjen Hoekstra, after many years’ extensive research. This alarming figure is much higher than was previously thought. His ground-breaking research was published in Science Advances. Professor Hoekstra’s team is the first research group in the world to identify people’s water footprint from month to month and to compare it to the monthly availability of water. “Up to now, this type of research concentrated solely on the scarcity of water on an annual basis, and had only been carried out in the largest river basins,” says Hoekstra. He defines severe water scarcity as the depletion of water in a certain area. “Groundwater levels are falling, lakes are drying up, less water is flowing in rivers, and water supplies for industry and farmers are threatened. In this research, we established the maximum sustainable ‘water footprint’ for every location on earth, and then looked at actual water consumption. If the latter is much greater than what is sustainable, then there can be said to be severe water scarcity.” More than previously thought Until now, it had always been assumed in the scientific community that 2 to 3 billion people were affected by severe water scarcity. “Previous research looked at the availability of water on an annual basis, but that paints a more rosy and misleading picture, because water scarcity occurs during the dry period of the year,” explains Hoekstra. In his research, he describes for each place the number of months in a year that people are affected by severe water scarcity. That varies from zero to twelve months per year. Problem areas Of the four billion people referred to, a large proportion feel the effects of water scarcity directly. Particularly in Mexico, the western US, northern and southern Africa, southern Europe, the Middle East, India, China, and Australia, households, industries and farmers regularly experience water shortages. In other areas, water supplies are still fine but at risk in the long-term. Read More here