Global distribution of the current likelihood of hydro-political issues among the main transboundary basins (transboundary basin borders in black, non-transboundary areas shaded). Graphic: Farinosi, et al., 2018 / Global Environmental Change

By George Dvorsky
17 October 2018

(Gizmodo) – A United Nations report published last week said we have about a decade to get climate change under control, which—let’s be honest—isn’t likely to happen. So break out your goalie masks and harpoon guns, a Mad Max future awaits! Now, as new research points out, we even know where on Earth the inevitable water wars are most likely to take place.

Sarcasm aside, this report is actually quite serious.

Published today in Global Environmental Change, the paper identifies several hotspots around the globe where “hydro-political issues,” in the parlance of the researchers, are likely to give rise to geopolitical tensions, and possibly even conflict. The authors of the new report, a team from the European Commission’s Joint Research Centre (JRC), say the escalating effects of climate change, in conjunction with ongoing trends in population growth, could trigger regional instability and social unrest in regions where freshwater is scarce, and where bordering nations have to manage and share this increasingly scarce commodity.

Obviously, the causes of geopolitical tension and conflict are complex, but as the new report makes clear, we shouldn’t underestimate the role that water is going to play in the future. Competition for dwindling water resources, the authors say, will exacerbate tensions on a global scale in the coming decades, with certain regions more vulnerable than others. But how are the various factors that influence water demand and availability likely to affect populations around the world?

The new study, led by JRC scientist Fabio Farinosi, was an attempt to answer this critical question, and to also create a model that can predict where and when future water wars might arise. […]

Farinosi’s team used a machine learning-driven approach to investigate the various factors that have traditionally given rise to water-related tensions. An algorithm studied previous episodes of conflict over water resources, of which there is no shortage (check out this impressive database of water-related conflicts to get a sense of how common water wars are in our history). The algorithm considered access to freshwater, climate stress (two greenhouse gas emission scenarios were considered, one moderate and one extreme), population trends, human pressures on the water supply, socio-economic conditions, and more. [more]

Here’s Where the Post-Apocalyptic Water Wars Will Be Fought


Likelihood of the occurrence of hydro-political interactions in the main transboundary river basins (from the top-left [normalized likelihood of hydro-political issues, min = 0 and max = 1]: Ganges-Brahmaputra [1.000], Nile [0.761], Indus [0.675], Euphrates-Tigris [0.592], Danube [0.499], Mekong [0.492], Aral Sea [0.455], Niger [0.447], Congo [0.432], Zambezi [0.431], Senegal [0.372]). In the radar chart the normalized score of the main factors determining the likelihood in the specific river basins. Not all the variables explicitly used for the model are represented in the radar chart: the non-included factors, however, are derived from the climatic variables displayed. Graphic: Farinosi, et al., 2018 / Global Environmental Change

(JRC) – JRC scientists have identified the hotspots where competition over the use of shared water resources could lead to disagreements between countries.

The new study aims to facilitate the implementation of strategies to encourage cooperation between countries.

  • The combination of climate change and demographic growth is likely to exacerbate hydro-political issues.
  • Water conflicts are more likely to occur in areas that are already under water stress.
  • The most vulnerable areas are around the Nile, Ganges-Brahmaputra, Indus, Tigris-Euphrates, and Colorado rivers.

Competition for limited water resources will be one of the main concerns in the coming decades.

Scarce water resources can generate or exacerbate political tensions, regional instability and social unrest.

New scientific methods for early identification of risk areas

JRC scientists used a new machine-learning approach to investigate the pre-conditions and factors that are likely to lead to water management issues in shared water bodies.

They carried out an innovative analysis of past episodes of conflict and cooperation over transboundary water resources, and studied the links with freshwater availability, climate stress, human pressure on water resources and socio-economic conditions.

"The scope of our study is two-fold. First, we wanted to highlight the factors which lead to either political cooperation or tensions in transboundary river basins. And second, we wanted to map and monitor the likelihood of these kinds of interactions over space and time and under changing socio-economic conditions", explains JRC researcher and lead author of the study, Fabio Farinosi.

Determining factors

Scarcity of water, high population density, power imbalances and climatic stressors are the main factors which push countries towards either political cooperation or tensions in transboundary river basins.

The Nile, Ganges-Brahmaputra, Indus, Tigris-Euphrates, and Colorado rivers are "water hotspots", where "hydro-political interactions" are most likely to occur.

These areas are already under water stress, and future demographic and climatic conditions are expected to exert further pressure on scarce water resources.

The changing socio-economic and climatic factors will increase the pressure on water resources worldwide.

This is likely to increase competition between countries for water.

Globally, the combined effect of climate change and population growth can increase the likelihood of water-related interactions in transboundary river basins by between 74.9% and 95%.

"This does not mean that each case will result in a conflict. It depends on how well prepared and equipped the countries are to cooperate. This is where we hope our research can help, by raising awareness of the risks so that solutions can be sought early on", Farinosi says.

New tools for monitoring hydro-political dynamics

Based on this research, JRC scientists developed an index and a model which help detect areas in the world that are at high risk of hydro-political conflicts.

These tools can prompt policymakers to design and implement strategies that encourage cooperation between countries before conflicts occur.

The tools also provide an additional method for monitoring the hydro-political dynamics under Target 6.5 of the Sustainable Development Goals (SDGs), which aims to enhance Water Resources Management and transboundary cooperation.

The index and model complement the SDG indicator "6.5.2 Proportion of transboundary basin area with an operational arrangement for water cooperation", by providing additional intelligence on important contributing factors that are not yet included in the current SDG monitoring framework.

The JRC is in the process of developing a more detailed analysis of the largest river basins in Africa in collaboration with the local institutions.

EU action

This study, which builds on the 2013 Council Conclusions on EU water diplomacy, will further inform the EU's work on water diplomacy and transboundary water management.

The EU is engaged in contributing to peace and security in priority regions such as the Nile basin, the Central Asia region and the Mekrou River Basin, with a number of projects aimed at developing mechanisms for cooperative and knowledge based water management in order to avoid conflicts, and to sustain common water resources for sustainable development.

In 2018, the EU worked to promote global membership to the UNECE Water Convention.

The aim was to underscore the EU's belief in the shared value of international agreements on global water cooperation in order to foster development and peace in a context of increasing tensions over water.

Chad has been the first non UNECE country to join the UNECE Water Convention, and Senegal has followed.

Other African countries are also taking steps towards accession to this international legal instrument which promotes international water governance.

The EU is ready to support interested countries in the accession process.

Read the full study: An innovative approach to the assessment of hydro-political risk: A spatially explicit, data driven indicator of hydro-political issues.

Global hotspots for potential water disputes


Change in the likelihood of hydro-political issues considering four future climate change and population scenarios. Graphic: Farinosi, et al., 2018 / Global Environmental Change

ABSTRACT: Competition over limited water resources is one of the main concerns for the coming decades. Although water issues alone have not been the sole trigger for warfare in the past, tensions over freshwater management and use represent one of the main concerns in political relations between riparian states and may exacerbate existing tensions, increase regional instability and social unrest. Previous studies made great efforts to understand how international water management problems were addressed by actors in a more cooperative or confrontational way. In this study, we analyze what are the pre-conditions favoring the insurgence of water management issues in shared water bodies, rather than focusing on the way water issues are then managed among actors. We do so by proposing an innovative analysis of past episodes of conflict and cooperation over transboundary water resources (jointly defined as “hydro-political interactions”). On the one hand, we aim at highlighting the factors that are more relevant in determining water interactions across political boundaries. On the other hand, our objective is to map and monitor the evolution of the likelihood of experiencing hydro-political interactions over space and time, under changing socioeconomic and biophysical scenarios, through a spatially explicit data driven index. Historical cross-border water interactions were used as indicators of the magnitude of corresponding water joint-management issues. These were correlated with information about river basin freshwater availability, climate stress, human pressure on water resources, socioeconomic conditions (including institutional development and power imbalances), and topographic characteristics. This analysis allows for identification of the main factors that determine water interactions, such as water availability, population density, power imbalances, and climatic stressors. The proposed model was used to map at high spatial resolution the probability of experiencing hydro-political interactions worldwide. This baseline outline is then compared to four distinct climate and population density projections aimed to estimate trends for hydro-political interactions under future conditions (2050 and 2100), while considering two greenhouse gases emission scenarios (moderate and extreme climate change). The combination of climate and population growth dynamics is expected to impact negatively on the overall hydro-political risk by increasing the likelihood of water interactions in the transboundary river basins, with an average increase ranging between 74.9% (2050 – population and moderate climate change) to 95% (2100 - population and extreme climate change). Future demographic and climatic conditions are expected to exert particular pressure on already water stressed basins such as the Nile, the Ganges/Brahmaputra, the Indus, the Tigris/Euphrates, and the Colorado. The results of this work allow us to identify current and future areas where water issues are more likely to arise, and where cooperation over water should be actively pursued to avoid possible tensions especially under changing environmental conditions. From a policy perspective, the index presented in this study can be used to provide a sound quantitative basis to the assessment of the Sustainable Development Goal 6, Target 6.5 “Water resources management”, and in particular to indicator 6.5.2 “Transboundary cooperation”.

An innovative approach to the assessment of hydro-political risk: A spatially explicit, data driven indicator of hydro-political issues

A caravan of migrants fleeing Honduras approaches the Mexico-Guatemala border amidst a surge in border crossings on the U.S.-Mexico border, 17 October 2018. The caravan has grown to 4,000 people along the way. Photo: Orlando Estrada / NBC News

By Julia Ainsley and Abigail Williams
17 October 2018

WASHINGTON (NBC News) – A caravan of migrants fleeing Honduras has grown to 4,000 and the Mexican government has sent an additional 500 federal police to its border with Guatemala in anticipation of their arrival, according to U.S. government documents obtained by NBC News.

Part of the caravan, which has split into two groups, is now approaching the Mexico-Guatemala border amidst a surge in border crossings on the U.S.-Mexico border.

In September, U.S. Border Patrol agents apprehended more than 41,400 illegal immigrants, up from 37,544 in August, according to numbers not yet released publicly but obtained by NBC News. The Washington Post reported Wednesday that the numbers of families and children traveling on their own surged to record levels in September.

Shelters and churches along the border have been flooded as a result of the surge as U.S. Immigration and Customs Enforcement agents have been releasing hundreds of migrants from detention at a time.

Many of the Hondurans traveling in the caravan are children, some traveling with their parents and some without their parents, according to the documents. Because children are afforded special protections in the U.S., their arrival is creating anxiety within the Trump administration that has pledged to decrease illegal immigration. President Donald Trump said last week that he would consider separating migrant families at the border once again, after reversing his controversial "zero tolerance" policy in June.

U.S. Customs and Border Protection is tracking the caravan as the Hondurans make their way north towards the U.S. border. Meanwhile, the State Department is attempting to stave off that possibility by compelling the Mexican government to stop them at their border with Guatemala.

Secretary of State Mike Pompeo will travel to Mexico to meet with his counterparts on Friday, where plans to stop the caravan will be a "prominent" topic of discussion, according to a senior State Department official who spoke to reporters on Wednesday.

"I am certain that there will be conversations in Mexico about how we can work together on this issue," the official said about the caravan. "We are certainly looking for concrete results and for solutions that work for both countries." [more]

Honduran migrant caravan grows to 4000 as U.S. border crossings spike

'Only YOU Can Stop Climate Change!' by Matt Lubchansky. Posted 10 October 2018. Graphic: Matt Lubchansky

10 October 2018 (The Nib) – “Only YOU Can Stop Climate Change!”, by Matt Lubchansky.

Only YOU Can Stop Climate Change!

Trend in tornado frequency in the U.S. Over the past few decades tornadoes have been shifting — decreasing in Oklahoma, Texas, and Kansas but spinning up more in states along the Mississippi River and farther east. Data: Victor Gensini / Northern Illinois University. Graphic: Associated Press

By Seth Borenstein
17 October 2018

WASHINGTON (AP) – Over the past few decades tornadoes have been shifting — decreasing in Oklahoma, Texas, and Kansas but spinning up more in states along the Mississippi River and farther east, a new study shows. Scientists aren’t quite certain why.

Tornado activity is increasing most in Mississippi, Arkansas, Tennessee, Louisiana, Alabama, Kentucky, Missouri, Illinois, Indiana, Wisconsin, Iowa, and parts of Ohio and Michigan, according to a study in Wednesday’s journal Climate and Atmospheric Science. There has been a slight decrease in the Great Plains, with the biggest drop in central and eastern Texas. Even with the decline, Texas still gets the most tornadoes of any state.

The shift could be deadly because the area with increasing tornado activity is bigger and home to more people, said study lead author Victor Gensini, a professor of atmospheric sciences at Northern Illinois University. Also more people live in vulnerable mobile homes and tornadoes are more likely to happen at night in those places, he said. […]

Even though Texas, Kansas, and Oklahoma get many more tornadoes, the four deadliest states for tornadoes are Alabama, Missouri, Tennessee, and Arkansas, according to the National Oceanic and Atmospheric Administration.

“More folks are generally at risk because of that eastward shift,” Gensini said. […]

Why is this happening?

“We don’t know,” Gensini said. “This is super consistent with climate change.”

As the Great Plains dry out, there’s less moisture to have the type of storms that spawn tornadoes, Gensini said. Tornadoes form along the “dry line” where there are more thunderstorms because there’s dry air to the west and moist air from the Gulf of Mexico to the east.

That dry line is moving east.

“This is what you would expect in a climate change scenario, we just have no way of confirming it at the moment,” Gensini said. [more]

Tornadoes are spinning up farther east in US, study finds


ABSTRACT: Severe thunderstorms accompanied by tornadoes, hail, and damaging winds cause an average of 5.4 billion dollars of damage each year across the United States, and 10 billion-dollar events are no longer uncommon. This overall economic and casualty risk—with over 600 severe thunderstorm related deaths in 2011—has prompted public and scientific inquiries about the impact of climate change on tornadoes. We show that national annual frequencies of tornado reports have remained relatively constant, but significant spatially-varying temporal trends in tornado frequency have occurred since 1979. Negative tendencies of tornado occurrence have been noted in portions of the central and southern Great Plains, while robust positive trends have been documented in portions of the Midwest and Southeast United States. In addition, the significant tornado parameter is used as an environmental covariate to increase confidence in the tornado report results.

Spatial trends in United States tornado frequency

Recorded climate-related disaster losses per income group compared to GDP losses 1998-2017. While high income  countries reported US$ 1,432 billion in climate-related  disaster losses, or 65 percent of the global total, that only represented 0.41% of their GDP. The US$ 21 billion in climate-related disaster losses recorded by low income countries amounted to an average of 1.8 percent of the GDP, well above the IMF’s threshold for a major economic disaster of 0.5 percent. Graphic: UNISDR

10 October 2018 (UN News) – Climate-related and geophysical disasters such as earthquakes and tsunamis have killed 1.3 million people over the last 20 years and left a further 4.4 billion injured, homeless or in need of emergency assistance, UN experts said on Wednesday.

The findings [pdf], published by the UN Office for Disaster Risk Reduction (UNISDR), also show that people in low- and middle-income countries are seven times more likely to die from natural disasters than those in developed nations.

“This puts a big emphasis on the need to…make sure that we curb greenhouse gas emissions,” said Ricardo Mena, UNISDR chief, in charge of implementing the Sendai Framework.

Failing to do this, risks letting climate-related hazards get out of control, he told journalists in Geneva, before calling for greater investment in disaster risk-reduction measures, “so that we do not allow for countries to create new risk”.

In terms of the impact of disasters on the global economy between 1998 and 2017, affected countries reported direct losses of $2.908 trillion. That’s more than twice what was lost in the previous two decades.

Climate-related disaster deaths in absolute numbers per million population potentially exposed (PPE) 2000-2017 (above), and Climate-related disaster affected totals in absolute numbers and percentage of population potentially exposed (PPE) 2000-2017 (below). Graphic: UNISDR

Illustrating the growing threat from climate change, extreme weather events now account for 77 per cent of total economic losses, $2.245 trillion, the report notes.

This represents a “dramatic rise” of 151 per cent compared with losses reported between 1978 and 1997, which amounted to $895 billion.

Poorer countries most vulnerable, worst-hit

The increased vulnerability of poorer countries to disasters is illustrated by the fact that, in the last 20 years, only one officially high-income territory – the island of Puerto Rico – has featured in a league table of the top 10 economic losses as a percentage of gross domestic product (GDP).

Last September, devastation in the US-dependency caused by Hurricane Maria contributed to overall losses since 1998, of more than $71 billion; the equivalent of 12.2 per cent of Puerto Rico’s GDP.

Apart from Cuba, which is classified as an upper-middle income country in the 20-year review, the other top 10 worst-hit nations, as a percentage of their output, are all lower-income.

Relative  human and economic costs of climate-related disasters on continents, 1998-2017 Graphic: UNISDR

Haiti – where a deadly 5.9 magnitude earthquake struck the north-west of the island just four days ago – recorded the highest losses, at 17.5 per cent of GDP.

In terms of fatalities from disasters, the report indicates that more than 747,000 people – 56 per cent of the total - died in the last two decades during major seismic events, a total of 563 earthquakes and related tsunamis.

Overall, however, more than 90 per cent of all disasters in the last 20 years were in fact floods, storms, droughts and other extreme weather events.

Heatwaves are next climate change “explosion”

Heatwaves are an increasing global threat for which solutions need to be found in the next five to 10 years, warned report co-author Professor Debarati Guha, from the Institute of Health and Society (IRSS), part of the Université Catholique de Louvain (UCL).

Top 10 climate-related disasters for absolute losses 1998-2017 (above), and Top 10 climate-related disasters for losses as a percentage of GDP 1998-2017 (below). Graphic: UNISDR

“The next one that is going to hit us with an explosion is heatwaves,” she said. “It’s going to be both in poor countries, remember, human beings have a limit, a thermal resistance limit … it is also going to be a huge problem in the wealthier countries.”

“We emphasize the need to reduce existing risk to strengthen the resilience of people and nations. Otherwise the success of the Sustainable Development Goals (SDGs) is going to be a very elusive target”, UNISDR’s Ricardo Mena said.

Disasters: UN report shows climate change causing ‘dramatic rise’ in economic losses

Idukki Dam, in India's Kerala state. Photo: Sivaram V. / Reuters

By Euan Rocha, Rajendra Jadhav, and Promit Mukherjee; Editing by Alex Richardson
10 October 2018

KOCHI/MUMBAI (Reuters) – Joby Pathrose, a farmer living a kilometre away from the usually languid Periyar river in southern India, was woken in the night by the sound of rushing waters.

Hours later his plantations and everything he owned were completely submerged.

“There was absolutely no warning from the government side,” said Pathrose, describing the devastating flooding that hit his village of Okkal, in Kerala state, on 15 August 2018.

Pathrose says local authorities had advised his fields were safe, despite the incessant rains that battered Kerala at the peak of the monsoon.

More than 5mn people in Kerala were affected and over 200 were killed amid torrential rain and floods in August.

The flooding, dubbed the worst to hit the southern state in nearly a century, caused billions of dollars of damage to fields, homes and other infrastructure.

As the rain intensified in mid-August state authorities were forced to release water from 35 dams to manage rising waters in reservoirs, many of which are used to generate hydroelectricity.

Pathrose and others living near the Periyar say the sudden opening of dam gates without proper warnings to those living downstream was a big factor in the devastation.

More than half a dozen experts whom Reuters consulted were divided on the extent to which dam water spills contributed to the flooding, but almost all, including India’s Central Water Commission (CWC), said reservoirs levels were too high ahead of the disaster.

Water levels for three reservoirs in India's Kerala state in 2017 and 2018. Monsoon rains in 2018 filled the reservoirs to capacity, forcing spillways to be opened and causing massive flooding downstream. Graphic: Reuters

How Kerala’s dams failed to prevent catastrophe

“Because of this carelessness the disaster proportions were multiplied,” said Himanshu Thakkar, co-ordinator of the South Asia Network of Dams, Rivers and People (SANDRP), a non-governmental body that advocates for better water management practices.

The release of dam water, sharply criticised by some water management experts, has put a focus on reservoir operations and the need for better flood mapping and warning systems in India.

State government officials say the severity of the flooding was due to a once-in-a-century storm that could not reasonably have been prepared for, and that the spilling of dam water had little impact.

Reuters has learned the two largest reservoirs in Kerala — Idukki and Idamalayar — have been operating for years without any emergency action plans — a basic requirement for major dams worldwide. […]

“One of the key advantages of a dam is it can help moderate floods,” said SANDRP’s Thakkar, an engineering graduate from the elite Indian Institute of Technology (IIT) Mumbai. “That didn’t happen as Kerala’s dams were already full by end-July. Dams aren’t supposed to be full before the end of the monsoons.”  [more]

Did Kerala’s dams exacerbate India’s once-in-century floods?

A man rescues a drowning man from a flooded area on the outskirts of Kochi, India, on 16 August 2018. Photo: Sivaram V. / Reuters

By Rebecca Solnit
14 October 2018

(The Guardian) – In response to Monday’s release of the IPCC report on the climate crisis – which warned that “unprecedented” changes were needed if global warming increases 1.5C beyond the pre-industrial period – a standup comic I know posted this plaintive request on her Facebook: “Damn this latest report about climate change is just terrifying. People that know a lot about this stuff, is there anything to be potentially optimistic about? I think this week I feel even worse than Nov 2016 and I’m really trying to find some hope here.”

A bunch of her friends posted variations on “we’re doomed” and “it’s hopeless”, which perhaps made them feel that they were in charge of one thing in this overwhelming situation, the facts. They weren’t, of course. They were letting understandable grief at the news morph into an assumption that they know just how the future is going to turn out. They don’t.

The future hasn’t already been decided. That is, climate change is an inescapable present and future reality, but the point of the IPCC report is that there is still a chance to seize the best-case scenario rather than surrender to the worst. Natan Sharansky, who spent nine years in a gulag for his work with Soviet dissident Andrei Sakharov, recalls his mentor saying: “They want us to believe there’s no chance of success. But whether or not there’s hope for change is not the question. If you want to be a free person, you don’t stand up for human rights because it will work, but because it is right. We must continue living as decent people.” Right now living as decent people means every one of us with resources taking serious climate action, or stepping up what we’re already doing.

Climate action is human rights, because climate change affects the most vulnerable first and hardest – it already has, with droughts, fires, floods, crop failures. It affects the myriad species and habitats that make this earth such an intricately beautiful place, from the coral reefs to the caribou herds. What we’re deciding now is what life will be like for the kids born this year who will be 82 in 2100, and their grandchildren, and their grandchildren’s grandchildren. They will curse the era that devastated the planet, and perhaps they’ll bless the memory of those who tried to limit this destruction. The report says we need to drop fossil fuel consumption by 45% by 2030, when these kids will be 12. That’s a difficult but not impossible proposition.

Taking action is the best way to live in conditions of crisis and violation, for your spirit and your conscience as well as for society. It’s entirely compatible with grief and horror; you can work to elect climate heroes while being sad. There are no guarantees – but just as Sakharov and Sharansky probably didn’t imagine that the Soviet Union would dissolve itself in the early 1990s, so we can anticipate that we don’t exactly know what will happen and how our actions will help shape the future.

The histories of change that have made me hopeful are often about small groups that seem at the outset unrealistic in their ambition. Whether they were taking on slavery in antebellum USA or human rights in the Soviet bloc, these movements grew exponentially and changed consciousness and then toppled institutions or regimes. We also don’t know what technological breakthroughs, large-scale social changes, or catastrophic ecological feedback loops will shape the next 20 years. Knowing that we don’t know isn’t grounds for confidence, but it is fuel against despair, which is a form of certainty. This future is as uncertain as it’s ever been. [more]

Don't despair: the climate fight is only over if you think it is

Mean dry-weight arthropod biomass per 100 sweeps taken in the same sample area in the Luquillo rainforest in Puerto Rico during July 1976, January 1977, July 2011, and January 2013. One SE around the mean biomass is shown for each bar. Total sweeps taken in each period was 800, except for July 1976, when 700 sweeps were taken. Data for 1976 and 1977 are from Lister, 1981 / Ecology. Graphic: Lister and Garcia, 2018 / PNAS

By Ben Guarino
15 October 2018

(The Washington Post) – Insects around the world are in a crisis, according to a small but growing number of long-term studies showing dramatic declines in invertebrate populations. A new report suggests that the problem is more widespread than scientists realized. Huge numbers of bugs have been lost in a pristine national forest in Puerto Rico, the study found, and the forest’s insect-eating animals have gone missing, too.

In 2014, an international team of biologists estimated that, in the past 35 years, the abundance of invertebrates such as beetles and bees had decreased by 45 percent. In places where long-term insect data are available, mainly in Europe, insect numbers are plummeting. A study last year showed a 76 percent decrease in flying insects in the past few decades in German nature preserves.

The latest report, published Monday in the Proceedings of the National Academy of Sciences, shows that this startling loss of insect abundance extends to the Americas. The study’s authors implicate climate change in the loss of tropical invertebrates.

“This study in PNAS is a real wake-up call — a clarion call — that the phenomenon could be much, much bigger, and across many more ecosystems,” said David Wagner, an expert in invertebrate conservation at the University of Connecticut who was not involved with this research. He added: “This is one of the most disturbing articles I have ever read.”

Bradford Lister, a biologist at Rensselaer Polytechnic Institute in New York, has been studying rain forest insects in Puerto Rico since the 1970s. If Puerto Rico is the island of enchantment — “la isla del encanto” — then its rain forest is “the enchanted forest on the enchanted isle,” he said. Birds and coqui frogs trill beneath a 50-foot-tall emerald canopy. The forest, named El Yunque, is well-protected. Spanish King Alfonso XII claimed the jungle as a 19th-century royal preserve. Decades later, Theodore Roosevelt made it a national reserve, and El Yunque remains the only tropical rain forest in the National Forest system.

“We went down in ’76, ’77 expressly to measure the resources: the insects and the insectivores in the rain forest, the birds, the frogs, the lizards,” Lister said.

He came back nearly 40 years later, with his colleague Andrés García, an ecologist at the National Autonomous University of Mexico. What the scientists did not see on their return troubled them. “Boy, it was immediately obvious when we went into that forest,” Lister said. Fewer birds flitted overhead. The butterflies, once abundant, had all but vanished.

García and Lister once again measured the forest’s insects and other invertebrates, a group called arthropods that includes spiders and centipedes. The researchers trapped arthropods on the ground in plates covered in a sticky glue, and raised several more plates about three feet into the canopy. The researchers also swept nets over the brush hundreds of times, collecting the critters that crawled through the vegetation.

Each technique revealed the biomass (the dry weight of all the captured invertebrates) had significantly decreased from 1976 to the present day. The sweep sample biomass decreased to a fourth or an eighth of what it had been. Between January 1977 and January 2013, the catch rate in the sticky ground traps fell 60-fold.

“Everything is dropping,” Lister said. The most common invertebrates in the rain forest — the moths, the butterflies, the grasshoppers, the spiders, and others — are all far less abundant.

“Holy crap,” Wagner said of the 60-fold loss.

Louisiana State University entomologist Timothy Schowalter, who is not an author of the recent report, has studied this forest since the 1990s. The new research is consistent with his data, as well as the European biomass studies. “It takes these long-term sites, with consistent sampling across a long period of time, to document these trends,” he said. “I find their data pretty compelling.” [more]

‘Hyperalarming’ study shows massive insect loss


Comparison of total dry-weight biomass for the major arthropod taxa captured in sweep samples taken during the summer (A, C, and E) and winter (B, D, and F) seasons 1976–1977 and 2011–2013, within the same Luquillo forest study area in Puerto Rico. Arn, Areneida; Col, Coleoptera; Dip, Diptera; For, Formicidae; Hem, Hemiptera; Hom, Homoptera; Hym, other Hymenoptera; La, Lepidoptera adults; LI, Lepidoptera larvae; Ort, Orthoptera. Graphic: Lister and Garcia, 2018 / PNAS

By Mary L. Martialay
15 October 2018

(RPI) – While temperatures in the tropical forests of northeastern Puerto Rico have climbed two degrees Celsius since the mid-1970s, the biomass of arthropods – invertebrate animals such as insects, millipedes, and sowbugs – has declined by as much as 60-fold, according to new findings published today in the Proceedings of the National Academy of Sciences.

The finding supports the recent United Nations Intergovernmental Panel on Climate Change warnings of severe environmental threats given a 2.0 degree Celsius elevation in global temperature. Like some other tropical locations, the study area in the Luquillo rainforest has already reached or exceeded a 2.0 degree Celsius rise in average temperature, and the study finds that the consequences are potentially catastrophic. 

“Our results suggest that the effects of climate warming in tropical forests may be even greater than anticipated,” said Brad Lister, lead author of the study and a faculty member in the Department of Biological Sciences at Rensselaer Polytechnic Institute. “The insect populations in the Luquillo forest are crashing, and once that begins, the animals that eat the insects have insufficient food, which results in decreased reproduction and survivorship and consequent declines in abundance.”

Climate Driven Declines in Arthropod Abundance Restructure a Rainforest Food Web” is based on data collected between 1976 and 2013 by the authors and the Luquillo Long Term Ecological Research program at three mid-elevation habitats in Puerto Rico’s protected Luquillo rainforest. During this time, mean maximum temperatures have risen by 2.0 degrees Celsius.

Major findings include:

  • Sticky traps used to sample arthropods on the ground and in the forest canopy were indicative of a collapse in forest arthropods, with biomass catch rates falling up to 60-fold between 1976 and 2013.
  • The biomass of arthropods collected by ground-level sweep netting also declined as much as eightfold from 1976 to 2013.
  • As arthropods declined, simultaneous decreases occurred in Luquillo’s insectivorous lizards, frogs, and birds.
  • The authors also compared estimates of arthropod abundance they made in the 1980s in the Chamela-Cuixmala Biosphere Reserve in western Mexico with estimates from 2014. Over this time period, mean temperature increased 2.4 Celsius and arthropod biomass declined eightfold.

Cold-blooded animals living in tropical climates are particularly vulnerable to climate warming since they are adapted to relatively stable year-round temperatures. Given their analyses of the data, which included new techniques to assess causality, the authors conclude that climate warming is the major driver of reductions in arthropod abundance in the Luquillo forest. These reductions have precipitated a major bottom-up trophic cascade and consequent collapse of the forest food web.

Comparison of the average dry-weight biomass of arthropods caught per 12-h day in 10 ground (A) and canopy (B) traps within the same sampling area in the Luquillo rainforest in Puerto Rico. Numbers above the bars give the mean daily catch rate in dry weight of arthropods per day for the respective dates. Data for 1976 and 1977 are from Lister, 1981 / Ecology. Graphic: Lister and Garcia, 2018 / PNAS

Given that tropical forests harbor two thirds of the Earth’s species, these results have profound implications for the future stability and biodiversity of rainforest ecosystems, as well as conservation efforts aimed at mitigating the effects of climate forcing.

Andres Garcia, of the Universidad Nacional Autónoma de México, was co-author on the study, which was funded by the National Science Foundation.

Research into the effects of climate change is an exciting aspect of The New Polytechnic, an emerging paradigm for teaching, learning, and research at Rensselaer. The foundation for this vision is the recognition that global challenges and opportunities are so great they cannot be adequately addressed by even the most talented person working alone. The New Polytechnic is transformative in the global impact of research, in its innovative pedagogy, and in the lives of students at Rensselaer.

Two Degrees Decimated Puerto Rico’s Insect Populations


Trends in the abundance of canopy arthropods and walking sticks in the Luquillo forest El Verde study area in Puerto Rico. (A) Linear regression of the total number of canopy arthropods captured per foliage weight sampled at El Verde against the period when the samples were taken. (B) Cubic regression for the total number of canopy arthropods captured per foliage weight sampled against the MnMaxT during the period when the samples were taken. (C) Quasi-Poisson regression of total number of walking sticks vs. the period when the population was sampled. (D) Quasi-Poisson regression of total number of walking sticks vs. the MnMaxT during the period when the population was sampled. The 95 percent confidence intervals are shown around the best-fit regression lines. Graphic: Lister and Garcia, 2018 / PNAS

ABSTRACT: A number of studies indicate that tropical arthropods should be particularly vulnerable to climate warming. If these predictions are realized, climate warming may have a more profound impact on the functioning and diversity of tropical forests than currently anticipated. Although arthropods comprise over two-thirds of terrestrial species, information on their abundance and extinction rates in tropical habitats is severely limited. Here we analyze data on arthropod and insectivore abundances taken between 1976 and 2012 at two midelevation habitats in Puerto Rico’s Luquillo rainforest. During this time, mean maximum temperatures have risen by 2.0 °C. Using the same study area and methods employed by Lister in the 1970s, we discovered that the dry weight biomass of arthropods captured in sweep samples had declined 4 to 8 times, and 30 to 60 times in sticky traps. Analysis of long-term data on canopy arthropods and walking sticks taken as part of the Luquillo Long-Term Ecological Research program revealed sustained declines in abundance over two decades, as well as negative regressions of abundance on mean maximum temperatures. We also document parallel decreases in Luquillo’s insectivorous lizards, frogs, and birds. While El Niño/Southern Oscillation influences the abundance of forest arthropods, climate warming is the major driver of reductions in arthropod abundance, indirectly precipitating a bottom-up trophic cascade and consequent collapse of the forest food web.

Population trends for E. coqui and birds near the El Verde Field station in Puerto Rico. (A) Quasi-Poisson regression of estimated total number of E. coqui individuals against time from censuses conducted by Stewart (28) in the Activity Transect. (B) Quasi-Poisson regression of the estimated number of E. coqui individuals against MnMaxT during the time periods when Stewart’s censuses were conducted. (C) Quasi-Poisson regression for the total number of birds captured during equal length, 4-d sessions of mist netting (31) near the El Verde Field Station against the period when the mist netting was conducted. (D) Quasi-Poisson regression of the total number of birds captured during Waide’s (31) 4-d sessions vs. MnMaxT during the year of mist netting. The 95 percent confidence intervals are shown around the best-fit regression lines. Graphic: Lister and Garcia, 2018 / PNAS

SIGNIFICANCE: Arthropods, invertebrates including insects that have external skeletons, are declining at an alarming rate. While the tropics harbor the majority of arthropod species, little is known about trends in their abundance. We compared arthropod biomass in Puerto Rico’s Luquillo rainforest with data taken during the 1970s and found that biomass had fallen 10 to 60 times. Our analyses revealed synchronous declines in the lizards, frogs, and birds that eat arthropods. Over the past 30 years, forest temperatures have risen 2.0 °C, and our study indicates that climate warming is the driving force behind the collapse of the forest’s food web. If supported by further research, the impact of climate change on tropical ecosystems may be much greater than currently anticipated.

Climate-driven declines in arthropod abundance restructure a rainforest food web

By Jason Samenow
16 October 2018

(The Washington Post) – As a powerful cold front charged through Texas from Monday into Tuesday, a deluge unfolded in the middle of the state. More than a foot of rain has fallen in some areas, resulting in severe flooding.

In Kingsland, about 60 miles northwest of Austin, a bridge collapsed Tuesday morning as waters rapidly rose to historic levels on the Llano River. Rising as swiftly as seven feet per hour, the river level hit 39.91 feet, the highest in 83 years and second highest on record, only trailing 41.5 feet in 1935.

At least one person has died in the torrents, according to KXAN, the NBC affiliate in Austin. A body was found in the Colorado River south of Kingsland, where the Llano and Colorado rivers converge.

So much water filled the Llano River that it caused the Colorado to flow backward.

“This is a very dangerous situation for people living within vulnerable areas along the Llano River. Seek higher ground immediately,” the National Weather Service said Tuesday morning.

Water levels, both observed and predicted, along the Llano River in Texas, 16 OCtober 2018. Graphic: NOAA

As of Tuesday afternoon, water levels had begun to recede, but the Llano remained well above flood stage and was forecast to stay that way into Thursday.

Numerous areas in central Texas experienced flooding Tuesday, and several other rivers were predicted to reach major flood stage. In Austin, all recreational, commercial and navigational activities were banned on area lakes due to the high water, the Statesman reported. [more]

Severe flooding in central Texas causes bridge to collapse and at least one death

 

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