It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, July 14, 2020
Pesticide mixtures a bigger problem than previously thought
UNIVERSITY OF QUEENSLAND
IMAGE: AN AERIAL SHOT OF THE GREAT BARRIER REEF. view more
CREDIT: THE UNIVERSITY OF QUEENSLAND
New research led by The University of Queensland has provided the first comprehensive analysis of pesticide mixtures in creeks and rivers discharging to the Great Barrier Reef.
UQ's School of Earth and Environmental Sciences researcher Associate Professor Michael Warne conducted the study with the Queensland Department of Environment and Science, and analysed 2600 water samples from 15 waterways that discharge into the Great Barrier Reef lagoon over a four-year period.
"While I knew many water samples would contain mixtures, I was shocked to find that essentially every sample contained mixtures of pesticides," Dr Warne said.
"We found 99.8 per cent of the samples contained pesticide mixtures with up to 20 pesticides in any single water sample.
"The issue with having mixtures of pesticides is that as the number of pesticides increases the impact to aquatic ecosystems generally increases.
"This work strongly supports the inclusion of the pesticide reduction target in the Reef 2050 Water Quality Improvement Plan which aims to protect at least 99 per cent of aquatic organisms at the mouths of rivers from the adverse effects of all pesticides."
Dr Warne said the best way to address the problem of pesticides and pesticide mixtures in run-off was to work with land managers, share information and help them to improve their pesticide management practices.
"We are doing just that with other partners including Farmacist, James Cook University and the Department of Environment and Science through Project Bluewater which is funded by the Great Barrier Reef Foundation," he said.
"This project is working with 70 sugar cane farmers in the Barratta Creek and Plane River catchments to improve their pesticide management and application, upgrade equipment, reduce pesticide use and switch to using lower risk pesticides.
"We have found the farmers involved to be very eager to engage with the science - they have embraced the challenge and are making significant steps toward improvement.
"We are looking to expand this project to include considerably more farmers in more catchments and make more rapid progress in reducing pesticide losses to waterways.
"There is always hope, but this study reveals the pesticide situation is more complex than we previously realised."
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The research was published in the journal Environmental Pollution (DOI: 10.1016/j.envpol.2020.114088).
Predation by Caspian terns on young steelhead means fewer return as adults
OREGON STATE UNIVERSITY
IMAGE: CASPIAN TERN WITH SMOLT (PHOTO BY DAN ROBY OSU COLLEGE OF AGRICULTURAL SCIENCES) view more
CREDIT: (PHOTO BY DAN ROBY OSU COLLEGE OF AGRICULTURAL SCIENCES)
CORVALLIS, Ore. - Caspian terns feeding on young fish have a significant impact on runs of steelhead in the Columbia River, research by Oregon State University suggests.
Through detailed analysis of steelhead survival and Caspian tern predation rates, the researchers found that the birds are not only preying on fish that would perish for some other reason, but are adding to the annual death toll by eating steelhead smolts that would have survived without tern pressure.
In scientific terms, the findings indicate that the terns are having an "additive" effect on prey mortality rather than a "compensatory" one.
The study was published in Ecological Applications.
In the Columbia Basin, 13 of 20 populations of anadromous salmon and steelhead are listed as threatened or endangered under the Endangered Species Act. Caspian terns, a protected migratory bird species native to the region, have been the object of predator management in the Columbia Basin in an effort to protect smolts, especially steelhead smolts, from being eaten before they can swim downstream to the ocean.
The largest breeding colony of Caspian terns in the world was formerly on a small island in the lower Columbia River estuary between Oregon and Washington. It hosted more than 10,000 breeding pairs in 2008, just prior to implementation of nonlethal management to reduce colony size to between 3,125 and 4,375 breeding pairs.
"There has been little research, however, into whether reduced predation actually results in greater overall salmonid survival, either at the smolt stage, where the predation is taking place, or across the lifetime of the fish," said Oregon State's Dan Roby, professor emeritus in the Department of Fisheries and Wildlife of the College of Agricultural Sciences. "Without clear evidence that reduced predation means greater survival to adulthood, management to reduce predator impacts would be a waste of time and resources."
To tackle the question, Roby and collaborators at Real Time Research, Inc., of Bend and the University of Washington looked at 11 years' worth of mark-recapture-recovery data for almost 80,000 steelhead trout smolts from the Upper Columbia population that were tagged and released to continue their out-migration to the ocean.
After release, the tagged fish were exposed to predation throughout multiple stretches of river on their journey toward the Pacific. The tag-recovery data made possible estimates of the weekly probability of steelhead survival, mortality from being eaten by birds and death from other causes.
"This approach allowed us to directly measure the connection between smolt survival and tern predation," Roby said.
Estimates of tern predation on steelhead were substantial for most of the years studied, he said. And increases in tern predation probabilities were connected with statistically significant decreases in steelhead survival for all of the years evaluated and both of the fish life stages studied: smolt out-migration and smolt-to-adult returns.
"Our results provide the first evidence that predation by Caspian terns may have been a super additive source of mortality during the smolt stage and a partially additive source in the smolt-to-adult life stage," Roby said. "A persistent pattern was clear: For each additional 10 steelhead smolts successfully consumed by Caspian terns, about 14 fewer smolts from each cohort survived out-migration."
Another pattern: On average, for every 10 steelhead smolts eaten by terns, one fewer individual from each cohort returned to the Columbia Basin as an adult.
"Our model shows that mortality from tern predation was primarily additive and therefore has a credible, significant impact on prey survival," Roby said. "Predator-prey models need to consider additive effects of predation across life stages to avoid exaggerating potential benefits from management actions aimed at reducing predator populations to enhance prey populations. The primary value of the study is by analyzing the true effects of natural predators on populations of their prey, and thereby assessing the conservation value to prey of managing predators."
Roby notes that the study by OSU, Real Time Research, and the University of Washington contradicts recently published research by scientists with the U.S. Fish and Wildlife Service and the Fish Passage Center, who found that steelhead mortality due to tern predation is compensatory.
That paper, in the Journal of Wildlife Management, suggests that "management efforts to reduce the abundance of the [tern] colonies are unlikely to improve the survival or conservation status of steelhead."
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Collaborating with Roby were corresponding author Quinn Payton, who has a doctoral degree from OSU, and others from Real Time Research, and Nathan Hostetter of the University of Washington.
The Public Utility District No. 2 of Grant County, Washington, the Bonneville Power Administration and the U.S. Army Corps of Engineers funded the research.
Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news
OUR UBIQUITOUS NATIONAL BIRD
Invasive alien species may soon cause dramatic global biodiversity loss
Experts identify future tipping point due to rapid spread of non-native plants and animals
UK CENTRE FOR ECOLOGY & HYDROLOGY
IMAGE: CANADA GEESE ARE NOW WELL ESTABLISHED IN EUROPE, POSING A SERIOUS THREAT TO BIODIVERSITY. THEY ALSO DAMAGE FARMLAND AND HAVE BEEN INVOLVED IN A NUMBER OF BIRD STRIKES. view more
CREDIT: PHOTO: TOM KOERNER/USFWS (CC BY 2.0) HTTPS://FLIC.KR/P/HRBQXQ
An increase of 20 to 30 per cent of invasive non-native (alien) species would lead to dramatic future biodiversity loss worldwide. This is the conclusion of a study by an international team of researchers led by Franz Essl and Bernd Lenzner from the University of Vienna. It has been published in the journal Global Change Biology.
Human activities intentionally and unintentionally introduce more and more plant and animal species to new regions of the world - for example, via commodity transport or tourism.
Some of these alien species have negative consequences for biodiversity and humans well-being, for example by displacing native species or transmitting diseases. However, while we have relatively good information on the historical spread of alien species, there is still little knowledge about their future development.
"At the moment it is not yet possible to generate precise predictions based on computer models as to how the spread and impact of alien species will change in the future. Therefore, expert assessments via standardised surveys are an important tool to obtain a better understanding of the causes and consequences of the spread and impact of alien species for the coming decades," says Franz Essl.
The study shows that an increase of 20 to 30 per cent in the number of newly introduced alien species is considered sufficient to cause massive global biodiversity loss - a value that is likely to be reached soon, as the number of introduced species is constantly increasing.
Climate change and trade drive increase
Furthermore, humans are the main driver of the future spread of alien species. The experts identify three main reasons, primarily the increasing global transport of goods, followed by climate change and then the impacts of economic development such as energy consumption and land use. The study also shows that the spread of alien species can be greatly slowed down by ambitious countermeasures.
The researchers additionally investigated the influence of the increase of alien species on different regions of the world: For example, tourism is a major driver of biological invasions in tropical and subtropical regions, while climate change favours the survival and establishment of alien species in the future, especially in polar and temperate regions.
"Our study illustrates the option space we currently have to reduce the future impacts of alien species," says Bernd Lenzner.
"The results form an important scientific basis for the further development of international agreements such as the Sustainable Development Goals or the Convention on Biological Diversity. This way we will be able to reduce the negative impacts of alien species on global biodiversity and our society."
The study involved 38 researchers from across Europe, North and South America, New Zealand and South Africa.
Helen Roy of the UK Centre for Ecology & Hydrology, one of the co-authors, says: "There has been a rapid escalation in the number of non-native species being transported and introduced by humans around the world; the adverse effects of some of these so called invasive non-native species on biodiversity and ecosystems has been extensively documented.
"It is now critical that we work collaboratively to predict future patterns so that we can inform appropriate action going forward - such as improved biosecurity to prevent further introductions of the most damaging invasive non-native species."
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Notes to editors
Essl, F et al. 2020. Drivers of future alien species impacts: An expert-based assessment. Global Change Biology. DOI: 10.1111/gcb.15199
Lead authors: Ass.-Prof Mag Dr Franz Essl Department of Botany and Biodiversity Research, University of Vienna, 1030 Wien, Rennweg 14/1 franz.essl@univie.ac.at
Dr Bernd Lenzner Department of Botany and Biodiversity Research, University of Vienna, 1030 Wien, Rennweg 14/1 bernd.lenzner@univie.ac.at
Disclaimer: AAAS and EurekA
Space to grow, or grow in space -- how vertical farms could be ready to take-off
JOHN INNES CENTRE
IMAGE: VERTICAL FARMING -- ECONOMIC AND ENVIRONMENTAL BENEFITS. view more
CREDIT: LETTUS GROW
Vertical farms with their soil-free, computer-controlled environments may sound like sci-fi. But there is a growing environmental and economic case for them, according to new research laying out radical ways of putting food on our plates.
The interdisciplinary study combining biology and engineering sets down steps towards accelerating the growth of this branch of precision agriculture, including the use of aeroponics which uses nutrient-enriched aerosols in place of soil.
Carried out by the John Innes Centre, the University of Bristol and the aeroponic technology provider LettUs Grow, the study identifies future research areas needed to accelerate the sustainable growth of vertical farming using aeroponic systems.
Dr Antony Dodd, a group leader at the John Innes Centre and senior author of the study, says: "By bringing fundamental biological insights into the context of the physics of growing plants in an aerosol, we can help the vertical farming business become more productive more quickly, while producing healthier food with less environmental impact."
Jack Farmer, Chief Scientific Officer at LettUs Grow and one of the authors of the study, adds: "Climate change is only going to increase the demand for this technology. Projected changes in regional weather patterns and water availability are likely to impact agricultural productivity soon. Vertical farming offers the ability to grow high value nutritious crops in a climate resilient manner all year round, proving a reliable income stream for growers."
Vertical farming is a type of indoor agriculture where crops are cultivated in stacked systems with water, lighting and nutrient sources carefully controlled.
It is part of a rapidly growing sector supported by artificial intelligence in which machines are taught to manage day to day horticultural tasks. The industry is set to grow annually by 21% by 2025 according to one commercial forecast (Grand View Research, 2019).
Green benefits include better use of space because vertical farms can be sited in urban locations, fewer food miles, isolation from pathogens, reduction in soil degradation and nutrient and water recapturing and recycling.
Vertical farms also allow product consistency, price stabilization, and cultivation at latitudes incompatible with certain crops such as the desert or arctic.
"Vertical systems allow us to extend the latitude range on which crops can be grown on the planet, from the deserts of Dubai to the 4-hour winter days of Iceland. In fact, if you were growing crops on Mars you would need to use this kind of technology because there is no soil," says Dr Dodd.
The study, which appears in the journal New Phytologist, lays out seven steps - strategic areas of future research needed to underpin increased productivity and sustainability of aeroponic vertical farms.
These seek to understand:
Why aeroponic cultivation can be more productive than hydroponic or soil cultivation.
The relationship between aeroponic cultivation and 24-hour circadian rhythms of plants.
Root development of a range of crops in aeroponic conditions.
The relationship between aerosol droplet size and deposition and plant performance.
How we can establish frameworks for comparing vertical farming technologies for a range of crops.
How aeroponic methods affect microbial interactions with plant roots.
The nature of recycling of root exudates (fluids secreted by the roots of plants) within the nutrient solutions of closed aeroponic systems.
The report argues that a driver of technological innovation in vertical farms is minimizing operation costs whilst maximizing productivity - and that investment in fundamental biological research has a significant role.
Dr Dodd's research area covers circadian rhythms - biological clocks which align plant physiology and molecular processes to the day to day cycle of light and dark. He recently completed a year-long Royal Society Industry Fellowship with LettUs Grow.
This involved combining Dr Dodd's expertise in circadian rhythms and plant physiology with the work of LettUs Grow's team of biologists and engineers to design optimal aeroponic cultivation regimens. This is a key area of investigation as these molecular internal timers will perform differently in vertical farms.
Aeroponic platforms are often used to grow high value crops such as salads, pak choi, herbs, small brassica crops, pea shoots and bean shoots. LettUs Grow are also working on growth regimens for fruiting and rooting crops such as strawberries and carrots, as well as aeroponic propagation of trees for both fruit and forestry.
John Innes Centre researchers have bred a line of broccoli adapted to grow indoors for a major supermarket and one of the aims of research will be to test how we can genetically tune more crops to grow in the controlled space of vertical farms.
Bethany Eldridge, a researcher at the University of Bristol studying root-environment interactions and first author of the study adds: "Given that 80% of agricultural land worldwide is reported to have moderate or severe erosion, the ability to grow crops in a soilless system with minimal fertilizers and pesticides is advantageous because it provides an opportunity to grow crops in areas facing soil erosion or other environmental issues such as algal blooms in local water bodies that may have been driven by traditional, soil-based, agriculture."
Lilly Manzoni, Head of Research and Development at LettUs Grow and one the authors of the study says, "This paper is unique because it is broader than a typical plant research paper, it combines the expertise of engineers, aerosol scientists, plant biologists and horticulturalists. The wonderful thing about controlled environment agriculture and aeroponics is that it is truly interdisciplinary"
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The study Getting to the Roots of Aeroponic Indoor Farming appears in the New Phytologist journal.
The Lancet: World population likely to shrink after mid-century, forecasting major shifts in global population and economic power
By 2100, projected fertility rates in 183 of 195 countries will not be high enough to maintain current populations without liberal immigration policies
THE LANCET
IMAGE: TOP TEN COUNTRIES BY POPULATION IN 2017 &2100 view more
CREDIT: THE LANCET
World's population likely to shrink after mid-century, forecasting major shifts in global population and economic power - new analysis, published in The Lancet forecasts global, regional, and national populations, mortality, fertility, and migration for 195 countries worldwide.
The USA is projected to have population growth until just after mid-century (364 million in 2062), followed by a moderate decline of less than 10% to 336 million by 2100--the world's fourth most populous country.
The USA's total fertility rate--which represents the average number of children a woman delivers over her lifetime--is predicted to steadily decline from 1.8 in 2017 to 1.5 in 2100; well below the minimum birth rate (2.1) considered necessary to maintain existing population levels long-term without immigration.
In 2100, the USA is forecasted to have the fourth largest working-age population in the world (around 181 million), after India, Nigeria, and China (figure 8)--with immigration likely sustaining the US workforce, with the largest net immigration in absolute numbers (more than half a million more people are estimated to immigrate to the USA in 2100 than will emigrate out). However, the researchers warn that US liberal immigration policies have faced a political backlash in recent years, threatening the country's potential to sustain population and economic growth.
The forecasting model predicts that while the USA had the largest economy in 2017, China is set to replace it in 2035, but the USA is forecasted to once again become the largest economy in 2098--bolstered by immigration (figure 9). Among the 10 countries with the largest populations in 2017 or 2100, the USA is predicted to have the fifth highest life expectancy in 2100 (82.3 years), up from 78.4 in 2017 (appendix 2, section 3).
Please find below: 1) Media release, 2) Access to the Article + linked Comments 3) Country data 4) Infographics. For further information, please contact The Lancet press office (pressoffice@lancet.com)
By 2100, projected fertility rates in 183 of 195 countries will not be high enough to maintain current populations without liberal immigration policies.
World population forecasted to peak in 2064 at around 9.7 billion people and fall to 8.8 billion by century's end, with 23 countries seeing populations shrink by more than 50%, including Japan, Thailand, Italy, and Spain.
Dramatic declines in working age-populations are predicted in countries such as India and China, which will hamper economic growth and lead to shifts in global powers.
Liberal immigration policies could help maintain population size and economic growth even as fertility falls.
Authors warn response to population decline must not compromise progress on women's freedom and reproductive rights.
Improvements in access to modern contraception and the education of girls and women are generating widespread, sustained declines in fertility, and world population will likely peak in 2064 at around 9.7 billion, and then decline to about 8.8 billion by 2100--about 2 billion lower than some previous estimates [1], according to a new study published in The Lancet.
The modelling research uses data from the Global Burden of Disease Study 2017 to project future global, regional, and national population. Using novel methods for forecasting mortality, fertility, and migration, the researchers from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington's School of Medicine estimate that by 2100, 183 of 195 countries will have total fertility rates (TFR), which represent the average number of children a woman delivers over her lifetime, below replacement level of 2.1 births per woman. This means that in these countries populations will decline unless low fertility is compensated by immigration.
The new population forecasts contrast to projections of 'continuing global growth' by the United Nations Population Division [1], and highlight the huge challenges to economic growth of a shrinking workforce, the high burden on health and social support systems of an ageing population, and the impact on global power linked to shifts in world population.
The new study also predicts huge shifts in the global age structure, with an estimated 2.37 billion individuals over 65 years globally in 2100, compared with 1.7 billion under 20 years, underscoring the need for liberal immigration policies in countries with significantly declining working age populations.
"Continued global population growth through the century is no longer the most likely trajectory for the world's population", says IHME Director Dr. Christopher Murray, who led the research. "This study provides governments of all countries an opportunity to start rethinking their policies on migration, workforces and economic development to address the challenges presented by demographic change." [2]
IHME Professor Stein Emil Vollset, first author of the paper, continues, "The societal, economic, and geopolitical power implications of our predictions are substantial. In particular, our findings suggest that the decline in the numbers of working-age adults alone will reduce GDP growth rates that could result in major shifts in global economic power by the century's end. Responding to population decline is likely to become an overriding policy concern in many nations, but must not compromise efforts to enhance women's reproductive health or progress on women's rights." [2]
Dr Richard Horton, Editor-in-Chief, The Lancet, adds: "This important research charts a future we need to be planning for urgently. It offers a vision for radical shifts in geopolitical power, challenges myths about immigration, and underlines the importance of protecting and strengthening the sexual and reproductive rights of women. The 21st century will see a revolution in the story of our human civilisation. Africa and the Arab World will shape our future, while Europe and Asia will recede in their influence. By the end of the century, the world will be multipolar, with India, Nigeria, China, and the US the dominant powers. This will truly be a new world, one we should be preparing for today." [2]
Accelerating decline in fertility worldwide
The global TFR is predicted to steadily decline, from 2.37 in 2017 to 1.66 in 2100--well below the minimum rate (2.1) considered necessary to maintain population numbers (replacement level)-- with rates falling to around 1.2 in Italy and Spain, and as low as 1.17 in Poland.
Even slight changes in TFR translate into large differences in population size in countries below the replacement level--increasing TFR by as little as 0.1 births per woman is equivalent to around 500 million more individuals on the planet in 2100.
Much of the anticipated fertility decline is predicted in high-fertility countries, particularly those in sub-Saharan Africa where rates are expected to fall below the replacement level for the first time--from an average 4.6 births per woman in 2017 to just 1.7 by 2100. In Niger, where the fertility rate was the highest in the world in 2017--with women giving birth to an average of seven children--the rate is projected to decline to around 1.8 by 2100.
Nevertheless, the population of sub-Saharan Africa is forecast to triple over the course of the century, from an estimated 1.03 billion in 2017 to 3.07 billion in 2100--as death rates decline and an increasing number of women enter reproductive age. North Africa and the Middle East is the only other region predicted to have a larger population in 2100 (978 million) than in 2017 (600 million).
Many of the fastest-shrinking populations will be in Asia and central and eastern Europe. Populations are expected to more than halve in 23 countries and territories, including Japan (from around 128 million people in 2017 to 60 million in 2100), Thailand (71 to 35 million), Spain (46 to 23 million), Italy (61 to 31 million), Portugal (11 to 5 million), and South Korea (53 to 27 million). An additional 34 countries are expected to have population declines of 25 to 50%, including China (1.4 billion in 2017 to 732 million in 2100; see table).
Huge shifts in global age structure - with over 80s outnumbering under 5s two to one
As fertility falls and life expectancy increases worldwide, the number of children under 5 years old is forecasted to decline by 41% from 681 million in 2017 to 401 million in 2100, whilst the number of individuals older than 80 years is projected to increase six fold, from 141 million to 866 million. Similarly, the global ratio of adults over 80 years to each person aged 15 years or younger is projected to rise from 0.16 in 2017 to 1.50 in 2100, in countries with a population decline of more than 25%.
Furthermore, the global ratio of non-working adults to workers was around 0.8 in 2017, but is projected to increase to 1.16 in 2100 if labour force participation by age and sex does not change.
"While population decline is potentially good news for reducing carbon emissions and stress on food systems, with more old people and fewer young people, economic challenges will arise as societies struggle to grow with fewer workers and taxpayers, and countries' abilities to generate the wealth needed to fund social support and health care for the elderly are reduced", says Vollset. [2]
Declining working-age populations could see major shifts in size of economies
The study also examined the economic impact of fewer working-age adults for all countries in 2017. While China is set to replace the USA in 2035 with the largest total gross domestic product (GDP) globally, rapid population decline from 2050 onward will curtail economic growth. As a result, the USA is expected to reclaim the top spot by 2098, if immigration continues to sustain the US workforce (figure 9).
Although numbers of working-age adults in India are projected to fall from 762 million in 2017 to around 578 million in 2100, it is expected to be one of the few - if only - major power in Asia to protect its working-age population over the century. It is expected to surpass China's workforce population in the mid-2020s (where numbers of workers are estimated to decline from 950 million in 2017 to 357 million in 2100)--rising up the GDP rankings from 7th to 3rd (figure 8).
Sub-Saharan Africa is likely to become an increasingly powerful continent on the geopolitical stage as its population rises. Nigeria is projected to be the only country among the world's 10 most populated nations to see its working-age population grow over the course of the century (from 86 million in 2017 to 458 million in 2100), supporting rapid economic growth and its rise in GDP rankings from 23rd place in 2017 to 9th place in 2100 (figure 8).
While the UK, Germany, and France are expected to remain in the top 10 for largest GDP worldwide at the turn of the century, Italy (from rank 9th in 2017 to 25th in 2100) and Spain (from 13th to 28th) are projected to fall down the rankings, reflecting much greater population decline (figure 9).
Liberal immigration could help sustain population size and economic growth
The study also suggests that population decline could be offset by immigration, with countries that promote liberal immigration better able to maintain their population size and support economic growth, even in the face of declining fertility rates.
The model predicts that some countries with fertility lower than replacement level, such as the USA, Australia, and Canada, will probably maintain their working-age populations through net immigration (see appendix 2 section 4). Although the authors note that there is considerable uncertainty about these future trends.
"For high-income countries with below-replacement fertility rates, the best solutions for sustaining current population levels, economic growth, and geopolitical security are open immigration policies and social policies supportive of families having their desired number of children", Murray says. "However, a very real danger exists that, in the face of declining population, some countries might consider policies that restrict access to reproductive health services, with potentially devastating consequences. It is imperative that women's freedom and rights are at the top of every government's development agenda." [2]
The authors note some important limitations, including that while the study uses the best available data, predictions are constrained by the quantity and quality of past data. They also note that past trends are not always predictive of what will happen in the future, and that some factors not included in the model could change the pace of fertility, mortality, or migration. For example, the COVID-19 pandemic has affected local and national health systems throughout the world, and caused over half a million deaths. However, the authors believe the excess deaths caused by the pandemic are unlikely to significantly alter longer term forecasting trends of global population.
Writing in a linked Comment, Professor Ibrahim Abubakar, University College London (UCL), UK, and Chair of Lancet Migration (who was not involved in the study) [3], says:"Migration can be a potential solution to the predicted shortage of working-age populations. While demographers continue to debate the long-term implications of migration as a remedy for declining TFR, for it to be successful, we need a fundamental rethink of global politics. Greater multilateralism and a new global leadership should enable both migrant sending and migrant-receiving countries to benefit, while protecting the rights of individuals. Nations would need to cooperate at levels that have eluded us to date to strategically support and fund the development of excess skilled human capital in countries that are a source of migrants. An equitable change in global migration policy will need the voice of rich and poor countries. The projected changes in the sizes of national economies and the consequent change in military power might force these discussions."
He adds: "Ultimately, if Murray and colleagues' predictions are even half accurate, migration will become a necessity for all nations and not an option. The positive impacts of migration on health and economies are known globally. The choice that we face is whether we improve health and wealth by allowing planned population movement or if we end up with an underclass of imported labour and unstable societies. The Anthropocene has created many challenges such as climate change and greater global migration. The distribution of working-age populations will be crucial to whether humanity prospers or withers."
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Peer-reviewed / Modelling study / People
NOTES TO EDITORS
The study was in part funded by the Bill & Melinda Gates Foundation. It was conducted by researchers at the University of Washington, Seattle, USA.
[1] The latest (2019) UN Population Division report estimates that world population is likely to reach 10.88 billion by 2100 (https://population.un.org/wpp/Publications/Files/WPP2019_Volume-I_Comprehensive-Tables.pdf) The difference between the new GBD projections and UN Population Division forecasts can largely be explained by the unprecedented pace of fertility decline predicted in sub-Saharan Africa (resulting in 702 million fewer people by 2100 than UN Population Division forecasts), and sustained declines in fertility lower than the population replacement level (2.1 births per woman) in many countries--resulting in estimates of 584 million fewer people in south Asia and 447 million less in southeast Asia, east Asia, and Oceania by the century's end than UN Population Division forecasts.
Population forecasts from UN Population Division use just past time trends as the determinant of future trajectories for fertility and mortality. Such an approach does not allow for alternative scenarios linked to policies or other drivers of fertility and mortality. In the new study by IHME, researchers developed a statistical modelling strategy that use past and forecasted trends in drivers of fertility (education and met need for modern contraceptives), mortality (sociodemographic variables and more than 70 risk factors for disease) and migration (sociodemographic variables, deaths due to conflict and natural disasters, and the difference between birth and death rates). Also, their model incorporates uncertainty about migration and accounts for women delaying childbirth as they become more educated. They used the model to develop a reference scenario and four alternative scenarios to show the demographic implications of policies which impact the scale-up of educational attainment and access to reproductive health services, including a scenario in which the Sustainable Development Goals (SDGs) on universal access to secondary education and contraception by 2030 are met (figure 2). They also assessed potential economic and geopolitical effects of demographic change this century.
[2] Quotes direct from authors and cannot be found in the text of the Article.
[3] Lancet Migration is a global collaboration between The Lancet and researchers, implementers, and others in the field of migration and health that aims to address evidence gaps and drive policy change building on the recommendations of the UCL-Lancet Commission on Migration and Health published in December 2018. http://www.migrationandhealth.org
Evolution after Chicxulub asteroid impact: Rapid response of life to end-cretaceous mass
New study published in Geology
GEOLOGICAL SOCIETY OF AMERICA
IMAGE: LEAD AUTHOR FRANCISCO J. RODRÍGUEZ-TOVAR IN BREMEN, GERMANY, WORKING WITH THE K-PG CORE FROM IODP EXPEDITION 364. view more
CREDIT: GEOLOGY AND FRANCISCO J. RODRÍGUEZ-TOVAR
Boulder, Colo., USA: The impact event that formed the Chicxulub crater (Yucatán Peninsula, México) caused the extinction of 75% of species on Earth 66 million years ago, including non-avian dinosaurs. One place that did not experience much extinction was the deep, as organisms living in the abyss made it through the mass extinction event with just some changes to community structure.
New evidence from International Ocean Discovery Program (IODP) Expedition 364 of trace fossils of burrowing organisms that lived in the seafloor of the Chicxulub Crater beginning a few years after the impact shows just how quick the recovery of the seafloor ecosystem was, with the establishment of a well-developed tiered community within ?700,000 years after the event.
In April and May 2016, a team of international scientists drilled into the Chicxulub impact crater. This joint expedition, organized by the International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Program (ICDP) recovered an extended syn- and post-impact set of rock cores, allowing study of the effects of the impact on life and its recovery after the mass extinction event. The end Cretaceous (K-Pg) event has been profusely studied and its effect on biota are relatively well-known. However, the effect of these changes on the macrobenthic community, the community of organisms living on and in the seafloor that do not leave body fossils, is poorly known.
The investigators concluded that the diversity and abundance of trace fossils responded primarily to variations in the flux of organic matter (i.e., food) sinking to the seafloor during the early Paleocene. Local and regional-scale effects of the K-Pg impact included earthquakes of magnitude 10-11, causing continental and marine landslides, tsunamis hundreds of meters in height that swept more than 300 km onshore, shock waves and air blasts, and the ignition of wildfires. Global phenomena included acid rain, injection of aerosols, dust, and soot into the atmosphere, brief intense cooling followed by slight warming, and destruction of the stratospheric ozone layer, followed by a longer-term greenhouse effect.
Mass extinction events have punctuated the past 500 million years of Earth's history, and studying them helps geoscientists understand how organisms respond to stress in their environment and how ecosystems recover from the loss of biodiversity. Although the K-Pg mass extinction was caused by an asteroid impact, previous ones were caused by slower processes, like massive volcanism, which caused ocean acidification and deoxygenation and had environmental effects that lasted millions of years.
By comparing the K-Pg record to earlier events like the end Permian mass extinction (the so-called "Great Dying" when 90% of life on Earth went extinct), geoscientists can determine how different environmental changes affect life. There are similar overall patterns of recovery after both events with distinct phases of stabilization and diversification, but with very different time frames. The initial recovery after the K-Pg, even at ground zero of the impact, lasted just a few years; this same phase lasted tens of thousands of years after the end Permian mass extinction. The overall recovery of seafloor burrowing organisms after the K-Pg took ~700,000 years, but it took several million years after the end Permian.
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Customizable smart window technology could improve energy efficiency of buildings
DOE/ARGONNE NATIONAL LABORATORY
IMAGE: SCIENTISTS DEVELOPED A SMART WINDOW DEVICE FOR CONCURRENTLY HARVESTING AND REGULATING SOLAR ENERGY. view more
CREDIT: (IMAGE BY PETER ALLEN / UNIVERSITY OF CHICAGO.)
A customizable smart window harnesses and manipulates solar power to save energy and cut costs.
Windows play multiple crucial roles in our homes. They illuminate, insulate and ventilate our spaces while providing views of -- and protection from -- the outdoors. Smart windows, or windows that use solar cell technology to convert sunlight into electricity, present the additional opportunity to leverage windows as energy sources.
However, incorporating solar cells into windows while balancing the other complex, and often conflicting, roles of windows proves challenging. For example, juggling luminosity preferences and energy harvesting goals throughout changing seasons requires complex and strategic approaches to material design.
"This design framework is customizable and can be applied to virtually any building around the world." -- Junhong Chen, scientist at Argonne and professor at the University of Chicago's Pritzker School of Molecular Engineering
Scientists from the U.S. Department of Energy's (DOE) Argonne National Laboratory, Northwestern University, the University of Chicago and University of Wisconsin-Milwaukee recently combined solar cell technology with a novel optimization approach to develop a smart window prototype that maximizes design across a wide range of criteria.
The optimization algorithm uses comprehensive physical models and advanced computational techniques to maximize overall energy usage while balancing building temperature demands and lighting requirements across locations and throughout changing seasons.
"This design framework is customizable and can be applied to virtually any building around the world," said Junhong Chen, a scientist at Argonne and the Crown Family Professor of Molecular Engineering at the Pritzker School of Molecular Engineering at the University of Chicago. "Whether you want to maximize the amount of sunlight in a room or minimize heating or cooling efforts, this powerful optimization algorithm produces window designs that align with user needs and preferences."
Advanced approach to optimization
The scientists demonstrated a wholistic approach to window design to maximize the overall energy efficiency of buildings while considering lighting and temperature preferences.
"We can regulate the sunlight in a room to ensure the desired luminosity while managing the amount of energy the building uses for heating and cooling," said Wei Chen, the Wilson-Cook Professor in Engineering Design at Northwestern Engineering whose research group led the development of the optimization approach. "Additionally, the sunlight that doesn't pass through is captured by the solar cell in the smart window and converted into electricity."
The approach, called multicriteria optimization, adjusts thicknesses of solar cell layers in window design to meet the needs of the user. For example, to reduce the energy required to cool a building in the summer, the optimal window design might minimize the amount and type of light passing through while maintaining the desired luminosity inside. On the other hand, when winter savings are a priority, the design might maximize the amount of sunlight that passes through, thereby reducing the energy required for heating the building.
"Rather than focusing only on the amount of electricity produced by the solar cell, we consider the entire building's energy consumption to see how we can best use solar energy to minimize it," said Wei Chen.
In some scenarios, for example, it might be more energy efficient to allow a greater amount of light to pass through the window, instead of being converted into electricity by the solar cell, in order to decrease the electricity required for lighting and heating the building.
To determine the optimal design, the algorithm incorporates comprehensive physics-based models of the interactions between light and the materials in the smart window, as well as how the processes affect energy conversion and light transmission. The algorithm also takes into account the varying angles at which the sun hits the window throughout the day -- and year -- in different geographical locations.
"The model we created allows for exploration of millions of unique designs by an algorithm that mimics biological evolution," said Wei Chen. "On top of the physics-based models, the algorithm uses computational mechanisms that resemble reproduction and genetic mutation to determine the optimal combination of each design parameter for a certain scenario."
Promising prototype
To demonstrate the feasibility of a smart window capable of this level of customization, the scientists produced a small prototype of the window with an area of a few square centimeters.
The prototype consists of dozens of layers of varying materials that control the amount and frequency of light passing through, as well as the amount of solar energy converted into electricity.
One group of layers, made of a type of material called a perovskite, comprises the window's solar cell, which harvests sunlight for energy conversion. The window prototype also includes a set of layers called a nanophotonic coating, developed by associate professor of mechanical engineering Cheng Sun and his research group at Northwestern's McCormick School of Engineering. The coating tunes the frequencies of light that can pass through the window.
Each layer is tens of microns thick -- thinner than the diameter of a grain of sand. The scientists chose an aperiodic design for the layers, meaning each layer varies in thickness. As the angle of the sun's rays against the window changes throughout the day and year, the aperiodic design enables the performance of the window to vary in accordance with the user's preferences.
"The variation in layer thickness is optimized for a wide spectrum of change in the nature of the sunlight that reaches the window," said Sun. "This enables us to systematically allow less infrared transmission in the summertime and more in the wintertime to save energy consumption for temperature regulation, while optimizing the visible transmission for the purpose of indoor lighting and energy harvesting."
The scientists optimized the prototype used in this study for a 2,000 square foot, single-story home in Phoenix. Based on experimental characterization of the window prototype, the scientists calculated significant annual energy savings over leading commercially available window technologies. The calculations used the EnergyPlus building model, a software developed at the National Renewable Energy Laboratory, a DOE Office of Energy Efficiency and Renewable Energy laboratory, that estimates realistic power consumption over time.
The synthesis methods the scientists used to produce the window prototype mimic common industrial-level manufacturing processes, and the scientists believe that these existing commercial processes would allow for successful scaling of the window prototype to full-size.
Future considerations include developing the same technology in a flexible form so that the smart window materials can be retrofitted to cover preexisting windows.
The work was funded in part by the National Science Foundation.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.
The U.S. Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.
