Extreme floods on the rise in the Amazon: study

first_imgAdaptation To Climate Change, agribusiness, Amazon Agriculture, Amazon Dams, Amazon Destruction, Amazon Drought, Amazon People, Climate, Climate Change, Climate Change and Dams, Climate Change And Extreme Weather, Climate Science, Crop Yields, Crops, Disasters, Extreme Weather, Flooding, Precipitation, Research, Rivers, Tropical Rivers Popular in the CommunitySponsoredSponsoredOrangutan found tortured and decapitated prompts Indonesia probeEMGIES17 Jan, 2018We will never know the full extent of what this poor Orangutan went through before he died, the same must be done to this evil perpetrator(s) they don’t deserve the air that they breathe this has truly upset me and I wonder for the future for these wonderful creatures. So called ‘Mankind’ has a lot to answer for we are the only ones ruining this world I prefer animals to humans any day of the week.What makes community ecotourism succeed? In Madagascar, location, location, locationScissors1dOther countries should also learn and try to incorporateWhy you should care about the current wave of mass extinctions (commentary)Processor1 DecAfter all, there is no infinite anything in the whole galaxy!Infinite stupidity, right here on earth.The wildlife trade threatens people and animals alike (commentary)Anchor3dUnfortunately I feel The Chinese have no compassion for any living animal. They are a cruel country that as we knowneatbeverything that moves and do not humanily kill these poor animals and insects. They have no health and safety on their markets and they then contract these diseases. Maybe its karma maybe they should look at the way they live and stop using animals for all there so called remedies. DisgustingConservationists welcome China’s wildlife trade banThobolo27 JanChina has consistently been the worlds worst, “ Face of Evil “ in regards our planets flora and fauna survival. In some ways, this is nature trying to fight back. This ban is great, but the rest of the world just cannot allow it to be temporary, because history has demonstrated that once this coronavirus passes, they will in all likelihood, simply revert to been the planets worst Ecco Terrorists. Let’s simply not allow this to happen! How and why they have been able to degrade this planets iconic species, rape the planets rivers, oceans and forests, with apparent impunity, is just mind boggling! Please no more.Probing rural poachers in Africa: Why do they poach?Carrot3dOne day I feel like animals will be more scarce, and I agree with one of my friends, they said that poaching will take over the world, but I also hope notUpset about Amazon fires last year? Focus on deforestation this year (commentary)Bullhorn4dLies and more leisSponsoredSponsoredCoke is again the biggest culprit behind plastic waste in the PhilippinesGrapes7 NovOnce again the article blames companies for the actions of individuals. It is individuals that buy these products, it is individuals that dispose of them improperly. If we want to change it, we have to change, not just create bad guys to blame.Brazilian response to Bolsonaro policies and Amazon fires growsCar4 SepThank you for this excellent report. I feel overwhelmed by the ecocidal intent of the Bolsonaro government in the name of ‘developing’ their ‘God-given’ resources.U.S. allocates first of $30M in grants for forest conservation in SumatraPlanet4dcarrot hella thick ;)Melting Arctic sea ice may be altering winds, weather at equator: studyleftylarry30 JanThe Arctic sea ice seems to be recovering this winter as per the last 10-12 years, good news.Malaysia has the world’s highest deforestation rate, reveals Google forest mapBone27 Sep, 2018Who you’re trying to fool with selective data revelation?You can’t hide the truth if you show historical deforestation for all countries, especially in Europe from 1800s to this day. WorldBank has a good wholesome data on this.Mass tree planting along India’s Cauvery River has scientists worriedSurendra Nekkanti23 JanHi Mongabay. Good effort trying to be objective in this article. I would like to give a constructive feedback which could help in clearing things up.1. It is mentioned that planting trees in village common lands will have negative affects socially and ecologically. There is no need to even have to agree or disagree with it, because, you also mentioned the fact that Cauvery Calling aims to plant trees only in the private lands of the farmers. So, plantation in the common lands doesn’t come into the picture.2.I don’t see that the ecologists are totally against this project, but just they they have some concerns, mainly in terms of what species of trees will be planted. And because there was no direct communication between the ecologists and Isha Foundation, it was not possible for them to address the concerns. As you seem to have spoken with an Isha spokesperson, if you could connect the concerned parties, it would be great, because I see that the ecologists are genuinely interested in making sure things are done the right way.May we all come together and make things happen.Rare Amazon bush dogs caught on camera in BoliviaCarrot1 Feba very good iniciative to be fallowed by the ranchers all overSponsored Article published by Glenn Scherercenter_img Scientists and the media have documented deepening drought in the Amazon basin. But a new study finds that flood events are significantly intensifying too, becoming five times more common over the last century.The effect is caused by a combination of factors, including an increase in strength of the Walker circulation – an ocean-driven pattern of air circulation that carries warm moist air from the tropical Atlantic across South America towards the Pacific, resulting in Amazon precipitation.Human-driven climate change is a major contributing factor to this increased Amazon basin flooding. Intensifying flood events result in lives and property lost, and significant harm to croplands, pastures and livestock.A better understanding of flood and drought dynamics, and better predictability due partly to this study, could help reduce this damage. How escalating changes in precipitation occurrence and intensity might be altering Amazon flora and fauna is uncertain, though new research shows that tree species composition is altering. Flooding in the center of Manaus, Amazonas state, Brazil in 2009. Image by Jochen Schöngart / National Institute for Amazon Research.While deepening droughts have made headlines in recent years, extreme floods have been steadily increasing in frequency and severity in parts of the Amazon basin, putting lives and livelihoods at risk. According to a new study, longer and more extreme floods are becoming increasingly common due to a combination of fluctuations in atmospheric circulation systems and human-driven climate change.Publishing in the Journal Science Advances, Jonathan Barichivich at the Universidad Austral de Chile and colleagues collated daily water level records from the Port of Manaus on the Rio Negro from 1903 to 2015, and from Óbidos on the Amazon mainstem from 1970 to 2015. They found that the frequency of severe floods in both locales has increased steadily since 1970. Together these stations measure flow for the whole of the upstream Amazon.“In the whole 20th Century, there hasn’t been floods as severe or as frequent as in the last decade,” says Barichivich. Meanwhile, droughts have intensified in parts of the Amazon. An increase in intense flooding, alternating with deeper droughts, is a finding in keeping with current global climate change models.River records are useful windows into the dynamics of large regions, as their levels are influenced by the water levels in all tributaries upstream and downstream of the measurement site. They are also among the longest ecological records available.The team identified 14 severe droughts and 14 severe floods in the Amazon since 1903. They used the Geological Survey of Brazil’s official critical water levels to define a severe flood in Manaus as one with levels higher than 29 meters (95 feet), and a severe drought as lower than 15.8 meters.Many people living in the Amazon basin rely on the river’s annual flooding cycle for agricultural crops and livestock grazing. But extreme floods can cause extensive agricultural and infrastructure damage. Image by Jochen Schöngart / National Institute for Amazon Research.The researchers also looked at the severity and duration of floods and found that extreme floods have tended to be higher and longer-lasting, with water levels over 29.7 meters (97.5 feet) for more than 70 days occurring once every 3 years, compared to once every 50 years in the 1900s.Average water levels at Manaus port have increased by 1 meter (3.3 feet) during the 113-year record, a rise caused by increased precipitation during the wet-season.Extreme flood events can have disastrous effects. Traditionally, as the Amazon basin wet season ends, the nutrient rich floodplains offer the perfect conditions for agricultural plantings and grazing livestock. But prolonged, severe flooding destroys these crops and pastures, contaminates water supplies, and cuts people off from their homes for weeks or months at a time. In May 2012, after months of torrential rain, water levels at Manaus port reached 29.7 meters (97.5 feet), their highest level on record, and remained above 29 meters for over 70 days. Large scale floods could potentially pose future threats to the structural integrity of Amazon dams.Flooding also alters sediment transport – an important process for downstream ecosystems, fisheries and farms – and carbon storage in plants, soils and peatlands.Using atmospheric circulation models coupled with real-world data, the team was able to link the increased Amazon precipitation driving these extreme flood events to an increase in the strength of the Walker circulation – an ocean-driven pattern of air circulation that carries warm moist air from the tropical Atlantic across South America towards the Pacific.Since the early 1970s, the Atlantic Ocean has been in a warming phase of a natural cycle called the Atlantic Multidecadal Oscillation (AMO), which has been accelerated by human-caused climate change. However, in 1998 the Pacific Ocean entered a cooling phase of the Pacific Interdecadal Oscillation (PIO), increasing the temperature disparity between the two oceans. This temperature gradient is what drives the Walker Circulation, which supplies rain clouds to the central and northern Amazon basin.A diagram of the Walker circulation, showing the direction of wind circulation over the tropics. Since 1990, sea surface temperatures have warmed in the Atlantic, but cooled in the Pacific, driving warm, moist air from the Atlantic to rain more heavily, and more often, over parts of the Amazon. Image by Jonathan Barichivich.“The wet season was getting wetter in this period, while the Pacific was cool and the Atlantic was warming very fast,” says Barichivich. This pattern is mirrored in the Manuas port river records, he says, with more frequent extreme floods during the wet season and deeper droughts during the dry season. “The amplitude of this natural water level fluctuation started to increase… due to a combination of both anthropogenic climate change and natural variability.”Zed Zulkafli, a hydrologist at Universiti Putra Malaysia in Selangor, who was not involved in the study, praised the rigor of the data analysis based on the length of the river records, saying, “the novelty [of the study] is in … using long term records at Manaus that reveal the severity of recent floods… as well as in linking the Walker circulation to the increasing flood severity.”In addition to the AMOC and PIO, the Amazon flood cycle is subject to natural fluctuations caused by the osccilation between El Niño and La Niña extremes in the Pacific ­– linked to Amazon droughts and floods respectively, which explains why the devastating drought of 2010, which began as an El Niño year, happened despite a general trend towards higher precipitation..“The perception for most people is that droughts are the most important thing in the Amazon,” says Barichivich, but the century-long records at Manuas port show that “floods are outstanding in meteorological change” the Amazon has experienced.“Until the 1960s we had one [extreme] flood every 20 years more or less,” says Barichivich, but the average number has increased to one every four years since the early 2000s. Interestingly, the team failed to find a long-term trend in the frequency of droughts in the Amazon, with their average occurrence once every 5 to 12 years remaining relatively static throughout the record.Flooded suburb of the city of Itacoatiara in the Central Amazon in 2009. Image by Jochen Schöngart / National Institute for Amazon ResearchAs the Atlantic continues to warm faster than the Pacific, extreme floods look set to be a recurring feature of the Amazon basin. A 2016 study led by Zulkafli predicted a larger increase in wet-season rainfall compared to dry-season drought for the Peruvian Amazon basin by the end of the 21st Century. However, “the degree to which extreme flooding will become more frequent is more challenging to quantify,” she says.Within a decade or so, the study authors predict that the Pacific will move into a warming phase of the PIO, reducing the disparity in sea temperature between the Atlantic and Pacific and thus weakening the Walker circulation that carries rainfall to the Amazon Basin. This, Barichivich says, could slow the acceleration of extreme weather events over the Amazon. However, this effect will not be enough to reduce the frequency and intensity of extreme flooding to pre-1990 levels. “We think that [extreme] floods should still be a problem in the next coming decades,” Zulkafli says.“The biodiversity as well as the riverine communities along the Amazon and its tributaries have developed as a result of [the] Amazon flooding regime. And so they will be impacted by more frequent and prolonged flooding,” Zulkafli concludes.The authors hope their models will allow for more accurate predictions of annual Amazon flooding, allowing seasonal forecasts to take Walker circulation strength, and Atlantic / Pacific ocean conditions into consideration. This forecasting ability could save lives and property, aiding farmers and ranchers. It remains to be determined how more frequent, extreme flooding will impact plants and wildlife.Citation:Barichivich, E. Gloor, P. Peylin, R. J. W. Brienen, J. Schöngart, J. C. Espinoza, K. C. Pattnayak, Recent intensification of Amazon flooding extremes driven by strengthened Walker circulation. Sci. Adv. 4, eaat8785 (2018). DOI: 10.1126/sciadv.aat8785FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.Many people living in the Amazon basin rely on the annual flooding cycle of the region’s rivers for transport and fishing. However, the increasing instability of precipitation cycles, largely driven by climate change, is making it harder to travel these waterways and utilize them in safety. Image by Jonathan Barichivich.last_img

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