The world has abundant freshwater but it is unevenly distributed and under increasing pressure, UN agencies say, as highlighted by the severe shortages in Cape Town. WATER, WATER 'EVERYWHERE' More than 97 per cent of the planet's water is salty, most of it in the oceans and seas, but there is also a good supply of freshwater. Every year around 42.8 trillion cubic metres of renewable freshwater circulates as rain, surface water or groundwater, according to the UN's Food and Agriculture Organization (FAO). This equals 16,216 litres per person per day - four times the amount required in the United States, for example, for personal and domestic consumption, industry and agriculture. Depending on diet and lifestyle, a person needs between 2,000 and 5,000 litres of water a day to produce their food and meet their drinking and sanitation requirements, the FAO says. About 60 per cent
Carbon emissions from the Brazilian Amazon are increasingly dominated by forest fires during extreme droughts rather than by emissions from fires directly associated with the deforestation process, according to a study in Nature Communications.
The authors found that despite a 76 percent decline in deforestation rates over the past 13 years, fire incidence increased by 36 percent during the 2015 drought compared to the preceding 12 years.
They estimate that forest fires during drought years alone contribute on average emissions of one billion tonnes of CO2 annually to the atmosphere, which are more than half those from old-growth forest deforestation.
According to Dr. Aragão, this is the first time scientists have clearly demonstrated how forest fires can become widely spread during recent droughts and how much they influence Amazonian carbon emissions in a decadal scale.
Dr. Marengo adds that three "droughts of the century" in 2005, 2010, 2015/2016 have occurred in the region due to a warmer tropical North Atlantic ocean or to El Nino, and the intensification of these phenomena in the future favours more droughts.... Our results emphasize the fact that in a hotter and drier future, large swaths of the Amazon, distant from the main deforestation epicentres, may burn.
... We suggest that the Brazilian Amazon may be entering a new land use and land cover phase change in which a decoupling between fire-related and deforestation carbon emissions, driven by recurrent 21st century droughts, can undermine the Brazilian achievement of reducing emissions from deforestation.
Our analyses confirm the hypothesis that C emissions from the Brazilian Amazon are increasingly dominated by forest fires during extreme droughts, rather than emissions from fires directly associated with the deforestation process.Conceptual model of feedbacks between climate, land use, forests and policies and their expected impacts on fire emissions. The system is divided in two large components: the political sphere (purple box) and the complex environmental system. In the political sphere, the mechanisms for fire emission reduction are divided into three levels of organization from global to local. The complex environmental system is divided in three components: climate (blue box), forests (green box) and land use (light brown box). Positive and negative feedbacks among the components are identified by red and blue arrows, respectively. The resulting effects of these feedbacks are described by coloured diamonds for the expected probability of fire occurrence and circles for the potential fire impact on C emissions. Numbers are displayed to assist with the description of the processes depicted in the main text
Luiz E. O. C. Aragão et al. 21st Century drought-related fires counteract the decline of Amazon deforestation carbon emissions, Nature Communications (2018)
vox_mundi wrote:
Luiz E. O. C. Aragão et al. 21st Century drought-related fires counteract the decline of Amazon deforestation carbon emissions, Nature Communications (2018)
The world has abundant fresh water but it is unevenly distributed and under increasing pressure, United Nations agencies say, as highlighted by the drought in Cape Town. On Tuesday South Africa declared the drought that has hit parts of the country and threatened to leave the Mother City without domestic tap water a national disaster. More than 97% of the planet’s water is salty, most of it in the oceans and seas. But every year about 42.8-trillion cubic metres of renewable fresh water circulates as rain, surface water or groundwater, according to the UN’s Food and Agriculture Organisation (FAO). This equals 16 216 litres a person a day — four times the amount required in the United States, for example, for personal and domestic consumption, industry and agriculture. Depending on diet and lifestyle, a person needs between 2 000 and 5 000 litres of water a day
Population growth and a record drought, perhaps exacerbated by climate change, is sparking one of the world's most dramatic urban water crises, as South African leaders warn that residents are increasingly likely to face "Day Zero." That's the day, previously projected for mid-April but now mid-July, when the city says it will be forced to shut off taps to homes and businesses because reservoirs have gotten perilously low—a possibility officials now consider almost inevitable.
"I'm afraid we're at the 11th hour," says South African resource-management expert Anthony Turton. "There is no more time for solutions. We need an act of God. We need divine intervention."
Much like Cape Town's fiasco, reservoirs in Sao Paulo, Brazil, dropped so low in 2015 that pipes drew in mud, emergency water trucks were looted, and the flow of water to taps in many homes was cut to just a few hours twice a week. Only last-minute rains prevented Brazilian authorities from having to close taps completely.
"Sao Paulo was down to less than 20 days of water supply," says Betsy Otto, director of the global water program at the World Resources Institute. "What we're starting to see are the confluence of a lot of factors that might be underappreciated, ignored, or changing. Brought together, though, they create the perfect storm."
"Residents of Cape Town are very surprised by how dramatically the situation has escalated, says Magalie Bourblanc, a public policy analyst specializing in resource management at South Africa's University of Pretoria. "But I think people are realizing very quickly just how bad the situation could be."
...dramatic swings are becoming more common and will continue to do so in the coming decades thanks to manmade climate change, according to a study published Monday in the journal Nature Climate Change.
These climate extremes have significant impacts on society, and swinging rapidly from one extreme to the other only makes mitigation and adaptation that much harder...
Drastic swings from extremely wet to extremely dry and vice versa will be nearly twice as likely, occuring on average once every 25 years, by 2100.
"In a place like California, we really need to be thinking about both risks [drought and flood] simultaneously," said Daniel Swain, a University of California, Los Angeles climate scientist and lead author of the study...
Weather whiplash from wet to dry can make for explosive fire conditions, as enhanced vegetation from above-average rainfall years becomes parched during an exceedingly dry year. Toss in regular Santa Ana winds to fuel the flames, and the result is devastating wildfires...
Approximately 191 feral horses have been found dead in a stock pond on Navajo land in northern Arizona, according to Navajo leaders, who attributed the death to ongoing drought and famine.
"These animals were searching for water to stay alive. In the process, they unfortunately burrowed themselves into the mud and couldn't escape because they were so weak," Navajo Nation Vice President Jonathan Nez said in a statement on Thursday.
Some of the horses were found thigh- to neck-deep in the mud at the stock pond in Gray Mountain, according to Nina Chester, a staff assistant for the office of the president and vice president.
Russell Begaye, president of the Navajo Nation tribe, said Tuesday via Twitter:"This is only the beginning. The Navajo Nation has over 70,000 feral horses."
vox_mundi wrote:Nearly 200 Wild Horses Dead Amid Southwest DroughtApproximately 191 feral horses have been found dead in a stock pond on Navajo land in northern Arizona, according to Navajo leaders, who attributed the death to ongoing drought and famine.
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