by Liz Kalaugher
Since 1960, the golf industry in southern Portugal’s Algarve region has boomed, with the number of courses rising to 40. As the climate is Mediterranean and rain falls mainly in the winter, the golf lawns need irrigation during the rest of the year. But with precipitation rarely exceeding 500 mm a year, that puts pressure on water resources.
At this year’s EGU meeting in Vienna, Celestina Pedras from Portugal’s University of the Algarve and University of Lisbon explained how she has used data from Landsat to assess the health of the Algarve’s golf courses since the 1980s.
Lower values for the Normalized Difference Vegetation Index (NDVI) – a measure of greenness – indicated that the vegetation was undergoing more water stress. “That means that the greenkeepers are implementing water deficit strategies – saving water – and the grass still has a good appearance,” Pedras told environmentalresearchweb.
Pedras and colleagues have also used weather data to calculate daily evapotranspiration rates and predict irrigation demand; managers typically irrigate at 85% of the daily evapotranspiration rate.
The team believes monitoring of climate and NDVI in this way could help predict and reduce water consumption by the golf industry. This has boomed in the Algarve in line with the growth in the number of courses, rising from 4 million cubic metres in 1980 to 18 million cubic metres in 2010.
But in the ten years since the Millennium, Pedras explained, this water use has become more efficient with the introduction of measures such as deficit irrigation strategies, technology for measuring plant water demand, continuous monitoring of climate parameters, different types of grass, identifying hydrozones to group plants by their water needs, employing several sources of water for irrigation, and improving the knowledge of golf course maintenance employees.
As climate changes, it’s likely that the Algarve will see more drought so sustainable golf course management will become even more vital.
by Liz Kalaugher
The IPCC reports are a massive undertaking but have they had their day? Myles Allen of the University of Oxford, UK, believes it’s now time to move away from international assessments and focus on regional impacts.
The statement “it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century” is becoming analogous to saying that “the Earth moves round the Sun” in the 1700s, Allen said at the EGU meeting in Vienna. “It’s still important,” he added, “but no longer very interesting”.
Allen reckons the focus of climate science has shifted to quantifying the impacts of local changes and extreme weather events, and is no longer appropriate for international assessment.
Thomas Stocker of the University of Bern, who was working group 1 co-chair for the IPCC’s fifth assessment report, disagrees. The IPCC process “continues to provide an essential common ground for negotiations”, he said at an EGU press conference. Many of working group 1’s headline statements made it directly into the documents for negotiation, for example.
That said, Stocker believes that scientists have “experienced the limits of the task, what they can bear”. The process could become “unmanageable if significant assistance is not offered to scientists”.
Jochem Marotzke of the Max Planck Institute of Meteorology, meanwhile, took a middle view. He is “convinced the process is effective…and it delivers comprehensive and reliable information” but doesn’t think that it’s efficient in terms of either time or cost. “You ask yourself, why are we doing this comprehensive assessment when we know much of it won’t make it into the summary for policymakers (SPM),” he said. Lots of the detail and “whole large blocks of topics” don’t make it into the summary. “Climate scientists have to support this assessment but we need to find a way to make it more efficient,” he concluded.
Allen agreed. “If a topic doesn’t need to be in the SPM, perhaps it should be assessed regionally,” he said. “We need a balance.”
- Allen has also responded to (non-climate) feedback by animating his 3-D plot of observed, natural and human-induced climate change so that it’s easier to visualize.
by Liz Kalaugher
What do you do if you discover that your data aren’t very good? When Steffen Fritz of the International Institute for Applied Systems Analysis (IIASA), Austria, wanted more accurate maps of the world’s crop cover, he turned the problem into a game. The researcher recruited members of the public to classify land in return for the chance to help science and perhaps win a prize.
There’s just a week left to join in the fun and play Cropland Capture, which has been running for six months and closes on May 9th. Four thousand players have already classified more than 4 million square km of land – roughly the size of India. Ultimately Fritz would like gamers to analyse crop cover for the whole planet – play will continue after May 9th but without prizes.
The resulting data will provide better maps of crop locations, potentially helping the study of food security, yield gaps and the effects of drought, and help train satellite algorithms to recognize crops more accurately.
Serious gaming or “games with a purpose” are on the rise, Fritz explained at a press conference at the EGU meeting. Each week there are 3 billion hours of playtime around the world; Fritz reckons that if we could use all that time for scientific purposes it would provide some serious benefit for the planet.
In Cropland Capture, gamers are shown images from sources such as Google Earth and geolocated photos and asked to say whether they portray a crop or not. There is a leaderboard for the best players and weekly prizes.
Each image is assessed by multiple players, who receive immediate feedback on whether their answer was correct. Once players have shown that their choices are accurate, they begin to receive images that haven’t been checked before, at a rate of one in ten.
Most players learn the game very quickly, Fritz has found, but sometimes their performance dips over time, perhaps when they are tired.
Fritz plans to use this gaming approach for other classification tasks too, for example spotting signs of human impact such as deforestation. In that case the dates of the images will also be important.
by Liz Kalaugher
As we’ve seen with climate and the IPCC assessments, reaching consensus can be a laborious process. Now geologists are finding the same applies to defining the Anthropocene, the new geologic time period popularized by atmospheric chemist Paul Crutzen because of the large impact man has had on the planet.
As Jan Zalasiewicz of the University of Leicester, UK, and Tony Brown of the University of Southampton detailed in a press conference at the EGU meeting, it’s relatively easy to reach a consensus that it’s worth formalizing the definition of the Anthropocene and many agree that it should be an epoch rather than another type of geological time period. But that’s where the agreement stops – defining when the epoch should begin and what should mark the boundary is a much trickier business.
According to one school of thought, Brown explained, the changes in sedimentation resulting from the onset of large-scale agriculture are clearly visible in the geological record and are the most obvious candidate for the start of the Anthropocene. (Humans now move more sediment each year than rivers). What’s more, these sediment changes are likely to be a permanent feature of the record as it would take many thousands of years at current rates to erode them and this is unlikely to happen within one interglacial.
There are a few snags, however. Agriculture took off at different times around the world – around 4000 years ago in Europe, for example, but not until the 19th century in North America. So there’s a roughly 4000-year lack of co-ordination in the onset of sedimentation changes. What’s more, using agriculture as the boundary point could be problematic for the Holocene – it would become around 4000 years shorter and, at 8000 years or so, be “a ridiculously short” epoch. The Holocene might even need to be redefined itself, based as it is on being the warm period over which human civilisation developed.
In part because of this shortening, others see 1945 or 1950 as a more suitable time for the onset of the Anthropocene, according to Zalasiewicz, as after this energy use soared, population boomed, megacities grew, globalization spread, nuclear power took off and new materials such as plastics and aluminium came into use. But others again believe the Anthropocene has yet to start as we haven’t had a global extinction or a major shift in climate.
Brown and Zalasiewicz are on different expert committees that are preparing their recommendations on the formalization and definition of the Anthropocene. Since geological processes work very slowly, Zalasiewicz joked, it normally takes decades for such decisions to be made. His group began work in 2009 and plans to prepare an interim set of statements by 2016 in time for the next International Geological Congress.
by Liz Kalaugher
It sounds like something out of a horror movie but Corrado Cimarelli of LMU, Germany, who has recreated volcanic lightning in the lab, claims that he is not a crazy scientist. In fact, the reconstruction could help develop volcanic lightning monitoring systems that forecast ash emissions and dispersion.
Scientists used to think volcanic lightning was rare but as Cimarelli explained at this year’s EGU meeting, in the last four years it’s been observed in all the major eruptions, such as Eyjafjallajökull in 2010 and Grimsvötn in 2011. Japan’s Sakurajima volcano produces volcanic lightning pretty much daily. Many now believe lightning is an intrinsic property of volcanic plumes, which they have dubbed “dirty thunderclouds”.
In the lab, Cimarelli has recreated lightning discharges some 5 cm long compared to the 100 km or so in a volcano. To do this, he pressurised volcanic particles from three different volcanoes, including Eyjafjallajökull, and argon gas in a “fragmentation bomb” before letting them escape and recording the process with high-speed video.
The gas left the chamber first, followed by a dense plume of ash particles edged by a more diluted region of turbulent flow. Lightning only developed once the particles appeared – the kit’s antennas initially showed many small discharges that gradually built up into fewer, larger lightning flashes. Another key requirement was for the pressure at the vent to be higher than atmospheric pressure as the particles were released. Smaller particles produced more flashes as they can carry a higher charge, Cimarelli explained.
In a real-life volcano, lightning occurs when ash particles become charged, either as the magma breaks up or as the particles rub against each other in regions of turbulent flow in the plume. Once sufficient voltage builds up between oppositely charged regions in the plume that have become separated by turbulence, lightning can discharge.
Cimarelli reckons his laboratory findings could help us learn more about volcanic plumes from their lightning, for example ash particle size and ash dispersion since charged particles are more likely to stick together and fall out of the sky. Now he’s using high-speed video, acoustic and magneto-telluric equipment to examine thunder and lightning from Sakurajima.
There are other reasons to study volcanic lightning too. For a start, it could have sparked life, Cimarelli explained, by building organic compounds, while volcanic lightning also contributes to the global electrical circuit, enables remote detection of volcanic activity through arrays of antennas, and could provide evidence of volcanic activity on other planets.
by Liz Kalaugher
In contrast to hydrological challenges, water security is “a term politicians generally understand,” said Hubert Savenije of Delft University of Technology at a press conference at the EGU meeting in Vienna. That’s important because water is the only substance that’s crucial for our survival and yet has no alternative. “If there is hunger in the world, you can send milk powder,” Savenije said, “but there is no way to send water powder.”
In many ways, food security is linked to water security, as Gerrit de Rooij of the Helmholtz Centre for Environmental Research, Germany, explained, adding that water security is the main cause of depressed harvests. Only 1% of the world’s water is freshwater, he pointed out, with 98% of that amount beneath the surface. Of the remaining above-ground, freshwater supplies, one-fifth are in Lake Baikal and a further fifth is in the Great Lakes. “There is not much freshwater available and it’s very unevenly distributed,” he said. And while the bulk of the world’s freshwater currently goes to agriculture, demand is increasing because of the rise of megacities and increased use of biofuels.
Talking of agriculture, the world currently irrigates an area of land the size of Argentina. But this isn’t sustainable – it can lead to salinization of the soil. Each year, the world loses 20,000 hectares of land to salinization, about the same amount of land that is brought under irrigation each year.
Savenije stressed that most agriculture is still rainfed. It could be better to invest in the relatively poor people who farm marginal land, he believes, rather than to put funds into irrigation, as such investment could sequester more carbon, help poverty and boost food production. What’s more, it could even be funded through a carbon tax.
An excess of water can be a problem too. Günter Blöschl of the Vienna University of Technology detailed how our approach to flood protection has evolved over the years. Before the 1960s the focus was on building dams and levees or diverting streams but now we have integrated flood risk management, which aims to retain water in the landscape, rearrange settlements further from rivers, employ flood insurance, forecast floods and increase public awareness.
Whilst dams fell out of favour with international funding organizations in the 1980s, there’s a new wave of investment in dams on the horizon by China, Brazil and in developing countries such as Laos. “Large-scale dam building is on the agenda again,” said Savenije, who would like to see it done sustainably.
The last word goes to Savenije: “there is no way we can deal with exponential growth – the resources are finite, the water is finite, the land is finite”.
by Liz Kalaugher
The larger the area of melt ponds on Arctic sea ice in May and early June, the smaller the sea ice coverage will be the following September, Daniella Flocco of Reading University, UK, reported at the European Geosciences Union (EGU) meeting in Vienna. In fact, the relationship is strong enough to make a skilful forecast of September sea ice cover, as Flocco, Reading colleague Daniel Feltham and other team members recently published in Nature Climate Change. It seems that melt ponds reduce the albedo of the ice surface, leading to greater heat absorption and more melting.
Now the team has moved onto the next problem, Flocco explained, namely trapping of melt ponds in the autumn as ice freezes above them. The phenomenon is invisible from the air but the latent heat released as the trapped melt pond freezes delays thickening of the ice layer into the ocean below.
Ignoring trapped melt ponds could cause models to overestimate ice growth in the autumn by around 265 cubic km [figure updated from sq. km, see comments below] over two months, roughly one-quarter of the total ice growth predicted, Flocco has calculated.
From satellite images the researchers estimate that around 20% of melt ponds become trapped as the freeze begins. Ultimately their studies will help them calculate this figure, Flocco and Feltham told environmentalresearchweb at the EGU meeting. Typically ponds remain trapped for a few months under thin lids of ice, becoming increasingly salty; the team plans to investigate this further.