One third of Earth’s largest groundwater basins are being rapidly depleted by human consumption
NASA and CalTech report two studies that quantify the depletion rate of major aquifers in the planet. Here are the links to the papers, both open access:
- Quantifying renewable groundwater stress with GRACE
- Uncertainty in global groundwater storage estimates in a Total Groundwater Stress framework
This means that significant segments of Earth’s population are consuming groundwater quickly without knowing when it might run out, the researchers conclude […]
The studies are the first to comprehensively characterize global groundwater losses with data from space, using readings generated by NASA’s twin GRACE satellites. GRACE measures dips and bumps in Earth’s gravity, which are affected by the mass of water. In the first paper, researchers found that 13 of the planet’s 37 largest aquifers studied between 2003 and 2013 were being depleted while receiving little to no recharge.
Eight were classified as “overstressed,” with nearly no natural replenishment to offset usage. Another five were found to be “extremely” or “highly” stressed, depending upon the level of replenishment in each. Those aquifers were still being depleted but had some water flowing back into them.
The most overburdened aquifers are in the world’s driest areas, where populations draw heavily on underground water. Climate change and population growth are expected to intensify the problem.
“What happens when a highly stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?” asked Alexandra Richey, the lead author on both studies, who conducted the research as a UCI doctoral student. “We’re trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods.”
The research team — which included co-authors from NASA, the National Center for Atmospheric Research, National Taiwan University and UC Santa Barbara — found that the Arabian Aquifer System, an important water source for more than 60 million people, is the most overstressed in the world.
The Indus Basin aquifer of northwestern India and Pakistan is the second-most overstressed, and the Murzuk-Djado Basin in northern Africa is third. […]
In a companion paper published today in the same journal, the scientists conclude that the total remaining volume of the world’s usable groundwater is poorly known, with estimates that often vary widely. The total groundwater volume is likely far less than rudimentary estimates made decades ago. By comparing their satellite-derived groundwater loss rates to what little data exist on groundwater availability, the researchers found major discrepancies in projected “time to depletion.” In the overstressed Northwest Sahara Aquifer System, for example, time to depletion estimates varied between 10 years and 21,000 years.
“We don’t actually know how much is stored in each of these aquifers. Estimates of remaining storage might vary from decades to millennia,” said Richey. “In a water-scarce society, we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”
The study notes that the dearth of groundwater is already leading to significant ecological damage, including depleted rivers, declining water quality and subsiding land.
Both papers draw the attention to yet another driver of ecological regime shifts that might be occurring unnoticed by the challenges of data gathering. The recharging of aquifers could be thought of as a regime shift where the dominant feedbacks relate to the recharging rate but also through the coupling of vegetation and rain patterns produced by moisturising recycling. Far fetched idea that worth keep an eye on. For the time being, both papers go to the ‘potential regime shifts’ folder.
Weak monsoons have collapsed entire civilisations
Today NewScientist report yet another study relating changes on the strength of Monsoon systems and the collapse of ancient civilisations. This time is a paper in Geology entitled Abrupt weakening of the summer monsoon in northwest India ~4100 yr ago where the authors found out that the weakening of the monsoon lead to a drought that lasted 200yrs close to the paleo lake Kotla Dahar, which coincide with the abandonment of urban Indu centres. Here some of the relevant text:
Dixit found that Kotla Dahar was a deep freshwater lake between 4500 and 3800 BC. It then started getting shallower, until about 2200 BC, when the summer monsoon suddenly weakened for 200 years.
That would have been bad news for the people living there. The Indus Valley Civilization depended on the monsoons for their crops, says Dixit. “It is inevitable that they were affected by a pronounced drought of this kind.”
The dates of the drought do not match perfectly with the date of the collapse, but Dixit says both figures are quite uncertain.
By itself, the lake is not representative of the entire civilization, says Supriyo Chakraborty of the Indian Institute of Tropical Meteorology in Pune. “But the authors have compared their results with various other observations and found agreement, giving credence to their claim,” he says.
It is not the first time shifts in the monsoon have been linked to the collapse of civilizations.
Around 900 AD one of China’s biggest empires, the Tang dynasty, collapsed. At the same time, halfway across the world, the Mayan civilisation in South America all but disappeared. Records from a lake in China show that stronger winds made the summer monsoon fail, causing widespread drought.
Dixit says the drying events at 900 AD and 2200 BC were both linked to shifts in the position of the Intertropical Convergence Zone, a band of cloud that runs east to west in the tropics and has a big influence on rainfall. “These climate phenomena were not regional but global in nature,” she says.
Life expentancy: demographic drivers
By 2050 the planet is expected to host 9 billion human inhabitants. However, when you think on population growth, it not only means the absolute number of people on the planet. It also accounts for the time that people spend on it, using resources and interacting with nature. In that sense, one has always to be aware that one human being in Canada is not the same as one human being in South Africa. Models usually assume both units to be the same. But, in practice, if a canadian has in average double life expectancy, one could expect that its impact on Earth is approximately twice as the South African. That’s keeping things way too simplistic and assuming lifestyles and consumption patterns are the same (and invariable in time). To make yourself an idea, you can check the photographic work by Peter Menzel, or this short note on Daily Kos. Once the latest assumption is relaxed, the differences between the footprint of say an average European and an Afghani is hardly captured. How many Afghanis are equivalent to one European? How would it be an environmental friendly policy regarding migration and human rights then? How do we do to overcome such limitations when it comes to model and plan our future? Do you think it is even possible? If 9 billion people acquires different meanings when it comes to impacts on the planet, then models we need will have to to include agency, or the particularities of individuals that aggregated at the collective level allow different set of patterns. If you see the paper tackling the issue, please let me know!!
Cascading effects of permafrost melting
EurekAlert reports today the latest findings of Michael Gooseff presented in the annual meeting of the Ecological Society of America. It’s a suggested reading if you are into the impacts of climate change on polar areas. I’ll only highlight some of the links between drivers of regime shifts that potentially cause cascading effects among them.
The increasing melting of polar ice is driven by climate change. Ice is melting faster and it’s expected to “change flow patterns, expand the stream networks, and change both the location of habitats and timing of life cycles” . For example, Gooseff reports “temperatures and snow and rain across the tundra shifts annually and seasonally. We know that fall is beginning later than it once did”.
One of the most common link reported in the literature is that as polar areas warm up, permafrost begins to melt and liberate huge amounts of carbon dioxide and methane that has been stored for centuries. As carbon is released to the atmosphere, climate change is reinforced by the permafrost melting feedback loop.
However, something I haven’t seen is the link between permafrost melting and nutrients runoff. The latest is an important driver of regime shifts like eutrophication, hypoxia and transitions in food webs. Here are some notes:
Extended frost-free time causes soils that do thaw annually to have longer active periods when microbes can mineralize nutrients. While the soils remain frost free longer, plants continue their normal cycle dictated by the length and intensity of daylight, which has not changed. Microbes may continue to create nutrients, but the plants no longer use them, so that when rain or meltwater comes the nutrients leach into the rivers and streams.
“That is exactly what we are seeing,” said Gooseff. “In September and October, we see a substantial increase in nutrients in the water. Concentrations increase many times for nutrients such as nitrate and ammonium.”
I wonder how such linkages will change the map of dead zones, or areas under hypoxia regime around the world. Do you think it will be strong enough to create new dots in polar coasts?
The Dead Zones map was created by EarthObservatory | NASA based on the following paper:
Diaz, R. J., & Rosenberg, R. (2008). Spreading Dead Zones and Consequences for Marine Ecosystems. Science, 321(5891), 926-929.
via: Polar climate change may lead to ecological change. | EurekAlert
War and biodiversity
Today National Geographic reports on how important is to study biodiversity in conflict areas. War and wildlife happen more often than expected to be found in the same places. But it’s also true that violent conflicts usually stop or at least diminish the impacts of the main drivers of biodiversity loss. It’s not a topic that actually attract a lot of scientist. Who would be likely to risk life to study biological diversity? Although I’ve been a bit far away from the related literature, some of my professors studying landscape change in my country, Colombia, have found similar patterns: there is a correlation amongst biodiversity hotspots and violence, conflict or war. I don’t claim war is good for biodiversity; it’s clearly not the case either. Here some lessons from Afghanistan:
Afghanistan Animals Not Out of the Woods
For example, satellite studies show that Nuristan’s forest cover has been greatly reduced during the past two decades, and it’s still disappearing today.
“If this continues, I think we’ll see the last of the larger animals disappear from the area,” Zahler said. “We were delighted that there is wildlife here, but its long-term survival is still very much in question.”
Some deforestation is the result of people cutting trees for fuel or building materials, but the bulk of forest loss is driven by timber industries, which are able to operate with little oversight or regulation in the politically unstable region, Zahler said. The violence has “created a lack of management,” he said. “It’s not complete lawlessness, but a lot of cultural institutions have been degraded to the point where it’s more of a free-for-all—which I think has greatly accelerated the drain on natural resources.”
And when local people sell timber rights for a pittance, Zahler added, it’s not only animals that suffer—people also lose precious resources.
“With the forest clear-cut, they lose the ability to build houses and find firewood in the winter. They lose mushrooms and pine nuts and everything that they depend on for local sale and for food,” he explained.
War and Conservation: Unlikely Partners
In places like Afghanistan, where human misery is a major concern, the environment often takes a backseat. But conservation biologist and author Thor Hanson, who was not involved in the recent study, said conservationists need to work in conflict zones, because these regions harbor some of the planet’s most important habitats. For example, Hanson has co-authored a study showing how wars are usually located in species-rich areas.
“If you look at the overlap between biological diversity and the locations of wars in the second half of the 20th century, we found that 80 percent of those major armed conflicts occurred within recognized global biodiversity hot spots,” he said.
Hanson added that this correlation means some of the world’s most important conservation work is based in dangerous areas, where most people don’t—or can’t—give environmental concerns top priority.
“The practical reality for conservation groups is that we pull out of areas when things get hot. But where groups have tried to stay engaged by supporting local people, we find that it can actually make a real difference in biodiversity outcomes over the course of a conflict,” he said.
The Wildlife Conservation Society’s Zahler agreed that keeping Afghanistan’s wildlife safe is an important way to help keep the peace.
“It’s not just about bears and leopards—it’s about natural resources that people depend on, and wildlife is just an example. Losing those resources means that communities are going to fall apart, because they won’t be able to support themselves.
“So helping them manage those resources is an important part of maintaining stability and security in a country like Afghanistan.”
It worth to follow up on Hanson work. For the interested reader, here is a couple of his papers that just got into my summer-to-read list:
Hanson et a. 2009. Warfare in Biodiversity Hotspots. Coservation Biology 23 (3):578-587
Machlis & Hanson. 2008. Warfare Ecology. BioScience 58 (8):729-736
Floods frequency: New regime shift coming soon
Floods frequency is tricky example of a regime shift. I have not idea yet whether it can be considered one. However, it seems so; and it seems to be driven by deforestation. The more deforested and fragmented a landscape is, the less likely it is to retain water coming from strong rainfall events. Vegetation speed down water drops, and root-rich soils with high porosity retain more humidity. When soils are clean or barely vegetated, one would expect water to run down faster.
On the top of this idea, it seems that climate change and green house gas emissions are playing an important role. NewScientist recently reports a study by Pal and colleagues titled “Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000“. They comment:
This week, a study has shown that the devastating floods which damaged nearly 10,000 properties in England and Wales in 2000, and cost £1.3 billion in insurance losses, were made significantly more likely by climate change caused by humans.
It is the first study to quantitatively link a severe rainfall event and climate change. The team that carried out the work, led by Myles Allen of the University of Oxford, had earlier linked the 2003 European heatwave to climate change.
The bottom line of all this? Allen and his team found that human greenhouse gas emissions “significantly increased” the likelihood of the 2000 floods. They can say, with a 66 per cent confidence level, that emissions nearly doubled the risk of the 2000 floods.
Conversely, says Allen, there is only a 10 per cent chance that the increase in flood risk rose by just 20 per cent as a result of human contributions to climate.
Here some more comments from NatureNews:
The research directly links rising greenhouse-gas levels with the growing intensity of rain and snow in the Northern Hemisphere, and the increased risk of flooding in the United Kingdom […]
“We can now say with some confidence that the increased rainfall intensity in the latter half of the twentieth century cannot be explained by our estimates of internal climate variability,” she says.
The findings mean that Northern Hemisphere countries need to prepare for more of these events in the future. “What has been considered a 1-in-100-years event in a stationary climate may actually occur twice as often in the future,” says Allen.
“Governments plan to spend some US$100 billion on climate adaptation by 2020, although presently no one has an idea of what is an impact of climate change and what is just bad weather,” says Allen […] “If rich countries are to financially compensate the losers of climate change, as some poorer countries would expect, you’d like to have an objective scientific basis for it.”
For the interested reader:
Cost of natural disasters $109 billion in 2010: U.N. | Reuters
Natural disasters caused $109 billion in economic damage last year, three times more than in 2009, with Chile and China bearing most of the cost, the United Nations said Monday.
Earthquakes, landslides, floods, droughts, are costing a lot of money for different countries, not only in economic losses but also in rebuilding infrastructure or coping with the tragedy after the shock. However, the question is what of these shocks are manageable and what is not. Which ecosystem services are interacting with external shocks. What are the differences between what we can prevent and what we can only resign and manage?
Droughts, floods and landslides quite often pop up in my analysis of regime shifts. They seem to follow threshold like response to ecological processes like plants rooting deep, albedo and evapotranspiration or erosion. It seems to be manageable. It requires a deep understanding of vegetation dynamics, soil properties and climate variability.
There is, however, some social trends that seems to confer resistance to the managerial options. My country, Colombia, presented several floods during the last raining season, particularly strengthen by La Niña phenomenon. Nevertheless, there are floods every year in my country. Some ecosystems are adapted to receive great discharges of water coming from all over the country. Such is the case of wetlands and mangrove forest in the Caribbean plains. Decades of deforestation and land clearing have reduce the ability of soil and plants to retain water and when heavy rains come there is not enough resistance. Poor communities loss homes, cattle, crops; but they also gain the assistance of the state. In a poor country where being a farmer is not rentable enough, a catastrophe may become an opportunity. As stated by the new head of the scientific unit of the von Humbold Institute, Brigitte Baptiste, being “damnificado” becomes a profession.
In the short term, poor families receive an extra income, politicians make sure to assure some votes for the next poles, but the origin of the problem, what is still manageable is never addressed. Land clearing is even encouraged under agricultural development projects. It worth to explore what other social mechanism maintain ecological regimes.
Cost of natural disasters $109 billion in 2010: U.N. | Reuters.
NASA Study Finds Earth’s Lakes are Warming
NASA finds lakes are warming up. This brings unexpected consequences to eutrophic lakes which now have to handle another driver: global warming. NASA reports:
Researchers Philipp Schneider and Simon Hook of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., used satellite data to measure the surface temperatures of 167 large lakes worldwide.
They reported an average warming rate of 0.45 degrees Celsius (0.81 degrees Fahrenheit) per decade, with some lakes warming as much as 1 degree Celsius (1.8 degrees Fahrenheit) per decade. The warming trend was global, and the greatest increases were in the mid- to high-latitudes of the Northern Hemisphere.
Small changes in water temperature can result in algal blooms that can make a lake toxic to fish or result in the introduction of non-native species that change the lake’s natural ecosystem.
A warming Earth could mean stronger toxins : Nature News
Global warming might change the level of toxicity of current toxins by making them more available in nature reports Richard Lovett from Nature News. Here are some of the pathways involved:
… melting sea ice in the Arctic Ocean exposes more seawater to the atmosphere, which may make it easier for toxic chemicals in arctic waters to escape into the air.
…climate change will cause differences in the movement, quality and distribution of water that could affect stream acidity all over the world […] Drugs are designed so that small changes in acidity alter their bioavailability, helping to route them to the bodily tissues where they are needed.
Hawaii will face more frequent cyclones – New Scientist
Tim Li of the University of Hawaii in Honolulu used two climate models to forecast cyclone formation. When he factored in the impact of global warming, he found that by the end of this century, the frequency of tropical cyclones will have fallen by 31 per cent over south-east Asia and grown by 65 per cent over the north central Pacific Geophysical Research Letters, DOI: 10.1029/2010GL045124.
via Hawaii will face more frequent cyclones – environment – 01 October 2010 – New Scientist.
Ecosystem Services: ‘Pollination crisis’ via BBC News
Pollination is another case of ecosystem service where our understanding of its dynamics is poor, but the changes underlying its dynamics are apparently happen fast. Recently BBC News dedicated an article to the pollination crisis in India, a country which produces 7.5 million tonnes of vegetables that account for 14% of the global production. This figure accounts for the 20% of India’s GDP in contrast to 6% average in other countries. Mark Kinver reports that India potentially is facing a decline in natural pollinators given its agricultural practices. He adds:
Globally, pollination is estimated to be worth £141bn ($224bn) each year […] The UN Food and Agriculture Organization (FAO) estimates that of the slightly more than 100 crop species that provide 90% of food supplies for 146 countries, 71 are bee-pollinated, primarily by wild bees, and a number of others are pollinated by other insects.
The misused of pesticides, habitat loss and fragmentation, and spread of parasites and diseases has been suggested causes of the loss of pollination service.
BBC News – ‘Pollination crisis’ hitting India’s vegetable farmers.
Acute eutrophication in China
Jane Qiu from Nature News reports acute eutrophication in China caused by overuse of fertilizers. China faces the challenge of feed 21% of the world’s population with the 9% of the world’s arable land. This situation has encourage policies that facilitate the use of phosphate fertilizers all across China during the last 30 years. She quotes:
As demand for food production rises, so does the global demand for chemical fertilizer, in which phosphorus is a key ingredient, says Luc Maene, director-general of the International Fertilizer Industry Association.
Such policies has allowed China to greatly increase crop production, but with an increasing rate of 5% per year, China has accumulated 85 million tones in its soils. The author adds:
Such heavy fertilizer use has made China one of the biggest consumers of phosphate fertilizer. Last year, it used 11 million tonnes, or about 35% of global consumption, according to Zhang. With ever-increasing food demand, there is no sign that phosphate use in China will dwindle.
As consequence, China suffers today from acute eutrophication. Apparently livestock is the larger contributor, being responsible for 56% of phosphorous discharges through manure. Symptoms observed include algae blooms, killing fish and plant life and release of poisonous toxins to humans and animals. On managerial options the author notes:
According to Zhang, 3.3 million tonnes of phosphate fertilizer — nearly a third of China’s total consumption — could be saved if all the animal manure is used to fertilize cropland. “There is a lot that can be done to save both the environment and the natural resource,” he says.
Rob Dunbar: Discovering ancient climates in oceans and ice | Video on TED.com
Rob Dunbar: Discovering ancient climates in oceans and ice | Video on TED.com.
Oceans are often forgotten in climate negotiations. Ron Dunbar point out why we should be worried about abrupt transitions in the ocean. Acidification, despite to be one of the latest concerns, seems to be our first global regime shift. The reason proposed by Dunbar is that oceanic fauna probably wont have enough time to adapt to the proposed 450 ppm on the global climate agenda.
Climate change and conflict: arguments about causality.
Mark Levy, deputy director of the Center for International Earth Science Information Network (Columbia University), explain the controversy risen by recent studies on the linkages of climate change and conflict. He summarizes challenges for future research:
Here’s how I would characterize what we know and we are trying to learn:
1) Economic deprivation almost certainly heightens the risk of internal war.
2) Economic shocks, as a form of deprivation, almost certainly heighten the risk of internal war.
3) Sharp declines in rainfall, compared to average, almost certainly generate economic shocks and deprivation.
4) Therefore, we are almost certain that sharp declines in rainfall raise the risk of internal war.
To understand how climate change might affect future conflict, we need to know much more. We need to understand how changing climate patterns interact with year-to-year variability to affect deprivation and shocks. We need to construct plausible socioeconomic scenarios of change to enable us to explore how the dynamics of climate, economics, demography, and politics will interact and unfold to shape conflict risk.
via Climate-Security Linkages Lost in Translation – State of the Planet.