Nobel Prize in Economics 2018

Technological Earth concept

The Royal Swedish Academy of Sciences has decided to award the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2018 to William D. Nordhaus, Yale University, New Haven, USA "for integrating climate change into long-run macroeconomic analysis" and Paul M. Romer, NYU Stern School of Business, New York, USA "for integrating technological innovations into long-run macroeconomic analysis."

Integrating innovation and climate with economic growth

William D. Nordhaus and Paul M. Romer have designed methods for addressing some of our time's most basic and pressing questions about how we create long-term sustained and sustainable economic growth.

At its heart, economics deals with the management of scarce resources. Nature dictates the main constraints on economic growth and our knowledge determines how well we deal with these constraints. This year's Laureates William Nordhaus and Paul Romer have significantly broadened the scope of economic analysis by constructing models that explain how the market economy interacts with nature and knowledge.

Technological change

Romer demonstrates how knowledge can function as a driver of long-term economic growth. When annual economic growth of a few per cent accumulates over decades, it transforms people's lives. Previous macroeconomic research had emphasised technological innovation as the primary driver of economic growth, but had not modelled how economic decisions and market conditions determine the creation of new technologies. Paul Romer solved this problem by demonstrating how economic forces govern the willingness of firms to produce new ideas and innovations.

Romer's solution, which was published in 1990, laid the foundation of what is now called endogenous growth theory. The theory is both conceptual and practical, as it explains how ideas are different to other goods and require specific conditions to thrive in a market. Romer's theory has generated vast amounts of new research into the regulations and policies that encourage new ideas and long-term prosperity.

Climate change

Nordhaus' findings deal with interactions between society and nature. Nordhaus decided to work on this topic in the 1970s, as scientists had become increasingly worried about the combustion of fossil fuel resulting in a warmer climate. In the mid-1990s, he became the first person to create an integrated assessment model, i.e. a quantitative model that describes the global interplay between the economy and the climate. His model integrates theories and empirical results from physics, chemistry and economics. Nordhaus' model is now widely spread and is used to simulate how the economy and the climate co-evolve. It is used to examine the consequences of climate policy interventions, for example carbon taxes.

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Land-locked Atlantic salmon also use magnetic field to navigate

Atlantic salmon.

A new study shows that Atlantic salmon use the Earth's magnetic field as a navigational tool -- much like their cousins, Pacific salmon -- and don't lose that ability through several generations of fish even after they have been transplanted into a land-locked lake.

The findings suggest that Atlantic salmon, which are widely used in aquaculture, may have greater potential to navigate and thus invade novel habitats if they escape their pens, researchers say.

Results of the study are being published this week in the journal Proceedings of the National Academy of Sciences.

This is the first time in which scientists have documented that another genus of salmon use the magnetic field as a map for navigation. A landmark 2014 study by Oregon State University researchers show that Chinook salmon use the magnetic field to orient themselves as they migrate over hundreds, even thousands of miles through the Pacific Ocean to target their oceanic foraging grounds.

The researchers constructed a testing apparatus at the Oregon Hatchery Research Center with several "arenas" surrounded by wooden coils wrapped in copper wire to mimic Earth's magnetic field, and tested 1,150 juvenile Atlantic salmon transported from Oregon's Hosmer Lake.

Atlantic salmon had first been brought to the land-locked lake from Maine some 60 years ago, and the researchers were curious to see if they had navigational abilities similar to ocean-going salmon, according to lead author Michelle Scanlan, faculty research assistant in OSU's College of Agricultural Sciences and lead author on the PNAS article.

"We wanted to see how Atlantic salmon would respond if we put them into different magnetic fields at the boundaries of Pacific salmon oceanic range," Scanlan said. "If we put them into an extreme northern field, would they 'course-correct' and align themselves in a southerly direction, and vice-versa? And the answer was yes. They clearly aligned themselves in the tank to adjust to an appropriate magnetic field signal."

This ability to use the magnetic field to navigate by land-locked Atlantic salmon is of particular concern because of an incident in August of 2017, when 200,000 to 300,000 Atlantic salmon escaped an aquaculture pen in Washington's Puget Sound. Eight months later, one of the fish was reportedly caught 40 miles up the Skagit River, raising concerns about the impact on native salmon and the ecosystem.

The state of Washington has since banned Atlantic salmon farms.

The study also raises some interesting questions about how long fish in general, and salmon in particular, retain skills they no longer need, said Nathan Putman, a senior scientist with LGL Ecological Research Associates in Bryan, Texas, who led the 2014 Pacific salmon navigation study as a post-doctoral scholar at OSU.

"Why didn't the Hosmer Lake fish lose their ability to navigate?" Putman said. "It apparently isn't a 'use it or lose it' skill. It may be possible that they have some finer-scale navigation tools at their disposal to use in a lake. Even at small-scales, fish are confronted by a variety of spatial tasks that might benefit from use of magnetic cues -- from traveling in a straight line to maneuvering through the water column. More research is needed to answer those questions."

A study by the same researchers published in February in Biology Letters found that larval salmon use the magnetic field when emerging from "redds" or nests and into the water column -- suggesting salmon do have some fine-scale magnetic tools that may not have been fully identified.

On a broad scale, however, the use of the magnetic field explains, in part, how salmon can find the way to their river of origin.

"The magnetic field is kind of like having a GPS system in your car," said Amanda Pollock, a graduate student in OSU's Department of Fisheries and Wildlife and co-author on the study. "That gets them close to their river and then their olfactory senses kick in."

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Drier, less predictable environment may have spurred human evolution

During the dry season, evaporating water leaves behind trona crystals growing on the Lake Magadi lakebed. The drilling rig used in this study towers above the dry lakebed in the background.

A progressively drying climate punctuated by variable wetter episodes may have precipitated the transition from our hominin ancestors to anatomically modern humans, according to research published on Oct. 8 in the online edition of the Proceedings of the National Academy of Science (PNAS).

Since the discovery of a rich assemblage of human fossils as well as stone tools and other archeological evidence in the rift valley of East Africa, a region often referred to as the cradle of humanity, scientists have attempted to piece together the complex puzzle that is the history of our human origins, including the environmental context of that history.

The study, based on lake sediment cores, is the first to provide a continuous environmental context for the diverse archeological evidence recovered from nearby localities in the rift valley basins of southern Kenya. The cores were sampled from Lake Magadi as part of the Hominin Sites and Paleolakes Drilling Project, or HSPDP, which is directed by University of Arizona professor Andrew Cohen.

Lake Magadi, a shallow, periodically dry lake, is close to the Olorgesailie basin in Kenya, one of the most productive sites for archaeological evidence of human evolution in Africa. The authors suggest that the profound climatic changes may have been driving forces behind hominin evolution, the origins of modern Homo sapiens and the onset of the Middle Stone Age.

While previous hypotheses have related hominin evolution to climate change, most prior studies lack regional-scale evidence for a link between environment and hominin evolution, the authors write in the paper, "Progressive aridification in East Africa over the last half million years and implications for human evolution." According to the study, a trend toward intense aridification in the area began 575,000 years ago. The change, not previously documented in continuous continental cores from East Africa, corresponds with faunal extinctions and a major transformation in stone tool technology documented in the Olorgesailie region.

"Much evidence for human evolution has been gathered from the area, but linking those records to detailed environmental records was missing until now," said the study's lead author, Richard Owen, of Hong Kong Baptist University. "There is a big gap in the records between the last Early Stone Age tools 500,000 years ago and the appearance of Middle Stone Age tools about 320,000 years ago. Our results plugged that gap with a continuous environmental record."

A critical transition occurred sometime during this gap, a period for which archeologists have unearthed evidence of a leap in early humans' abilities to make, use and trade stone tools.

The cores from Lake Magadi provide the first detailed link between climate change and events known from the region's archeological record.

"We have known for a while that the climate at the time was very varied, but the key here is that the records are in proximity to the archeological evidence for this transition," says Cohen, a professor in the University of Arizona's Department of Geosciences. "The older stone tools found at Olorgesailie did not change much between 1.2 million and a half-million years ago. And suddenly, after 500,000 and before 320,000 years ago -- we don't know exactly when, but in that timespan -- there was a critical transition in archeology when tools became more sophisticated and were transported over longer distances."

At the same time the lake core records point to the climate becoming drier and more variable, there is evidence elsewhere in Africa of the appearance of modern Homo sapiens, prompting much speculation whether the two are connected, Cohen said.

"Whether the evolution of bigger brains goes hand in hand with new toolkits is not entirely clear," he said. "But the earliest modern Homo sapiens fossils from Morocco date back 325,000 years, the same time we see this transition of tools. And both happened around the same time that our core record indicates severe drying very close to the archeological sites."

The deepest core drilled at Lake Magadi reached 200 meters (650 feet), penetrating all sedimentary layers down to the volcanic bedrock of the lake. The core samples, each about 10 feet long and 2 1/2 inches in diameter, are cut into manageable 5-foot segments, packaged and air-freighted to the National Lake Core Facility at the University of Minnesota for curation, analysis and storage.

According to the hypothesis of variability selection, a rapidly changing environment creates selective pressure that forces species to adapt to rapid change, Owen said. Under that scenario, the larger brains of anatomically modern humans would have allowed our ancestors to adapt quickly to an increasingly less predictable world.

"Now we have evidence that at the same time the toolkits were changing, the mammal fauna changed and the climate became more arid," Owen said. "So you have a series of coincidences that makes you think, 'This could be real.' Now we can say when the environment changed and then compare that to the archeological evidence of the region."

Drilling at other nearby sites by HSPDP has been completed as researchers gather more of the region's climate data to continue studying the importance of environmental variability in the course of human evolution.

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Out like a light: Researchers ID brain's 'sleep switch'

Two decades ago, Clifford B. Saper, MD/PhD, Chairman of the Department of Neurology at Beth Israel Deaconess Medical Center (BIDMC), and colleagues discovered a set of nerve cells they thought might be the switch that turns the brain off, allowing it to sleep. In a new study published in Nature Communications today, Saper and colleagues demonstrate in mice that that these cells -- located in a region of the hypothalamus called the ventrolateral preoptic nucleus (VLPO) -- are in fact essential to normal sleep.

"Our paper is the first test of what happens when you activate the VLPO neurons," said Saper, who is also James Jackson Putnam Professor of Neurology and Neuroscience at Harvard Medical School. "The findings support our original observation that the VLPO cells are essential to normal sleep."

Working with genetically engineered mice, Saper's team artificially activated the VLPO neurons using several different tools. In one set of experiments, the scientists activated the neuron cells using a laser light beam to make them fire, a process called optogentics. In another test, the team used a chemical to selectively activate the VLPO neurons. In both cases, activating these cells profoundly drove sleep.

The results confirmed Saper and colleagues' earlier findings that these neurons are active during sleep and that damage to them causes insomnia -- as seen in Saper's subsequent work with laboratory animals and, in 2014, in older people who have lost cells of the VLPO as part of the natural aging process.

Based on that previous body of work, it came as a surprise when another team of researchers reported just the opposite. In a 2017 publication, experiments stimulating the VLPO neurons woke laboratory animals up. In their current paper, Saper's team cleared up the seeming contradiction.

"We found that when the VLPO cells are stimulated one to four times per second, they fire each time they are stimulated, resulting in sleep," Saper said. "But if you stimulate them faster than that, they begin to fail to fire and eventually stop firing altogether. We learned our colleagues in the other lab were stimulating the cells 10 times per second, which was actually shutting them off."

Additionally, Saper's team also found that activating the VLPO cells caused a fall in body temperature. Scientists already knew that warm temperatures activate VLPO cells, and that body temperature dips slightly during sleep, when the VLPO neurons are firing.

"We thought that this is why people need to curl up under a warm blanket to get to sleep," Saper added.

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When is a nova not a nova? When a white dwarf and a brown dwarf collide

This object is possibly the oldest of its kind ever catalogued: the hourglass-shaped remnant named CK Vulpeculae.

Researchers from Keele University have worked with an international team of astronomers to find for the first time that a white dwarf and a brown dwarf collided in a 'blaze of glory' that was witnessed on Earth in 1670.

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the international team of astronomers, including workers from the Universities of Keele, Manchester, South Wales, Arizona State, Minnesota, Ohio State, Warmia & Mazury, and the South African Astronomical Observatory, found evidence that a white dwarf (the remains of a star like the Sun at the end of its life) and a brown dwarf (a 'failed' star without sufficient mass to sustain thermonuclear fusion) collided in a short-lived blaze of glory that was witnessed on Earth in 1670 as Nova Cygni -- 'a new star below the head of the Swan.' The brown dwarf star was 'shredded' and dumped on the surface of a white dwarf star, leading to the 1670 eruption and the hourglass we see today.

In July of 1670, observers on Earth witnessed a 'new star', or nova, in the constellation Cygnus -- the Swan. Where previously there was no obvious star, there abruptly appeared a star as bright as those in the Plough, that gradually faded, reappeared, and finally disappeared from view.

Modern astronomers studying the remains of this cosmic event initially thought it was triggered by the merging of two main-sequence stars -- stars on the same evolutionary path as our Sun. This so-called 'new star' was long referred to as 'Nova Vulpeculae 1670', and later became known as CK Vulpeculae.

However, we now know that CK Vulpeculae was not what we would today describe as a 'nova', but is in fact the merger of two stars -- a white dwarf and a brown dwarf.

By studying the debris from this explosion -- which takes the form of dual rings of dust and gas, resembling an hourglass with a compact central object -- the research team concluded that a brown dwarf, a so-called failed star without the mass to sustain nuclear fusion, had merged with a white dwarf.

Professor Nye Evans, Professor of Astrophysics at Keele University and co-author on the paper appearing in the Monthly Notices of the Royal Astronomical Society explains:

"CK Vulpeculae has in the past been regarded as the oldest 'old nova'. However, the observations of CK Vulpeculae I have made over the years, using telescopes on the ground and in space, convinced me more and more that this was no nova. Everyone knew what it wasn't -- but nobody knew what it was! But a stellar merger of some sort seemed the best bet. With our ALMA observations of the exquisite dusty hourglass and the warped disc, plus the presence of lithium and peculiar isotope abundances, the jig-saw all fitted together: in 1670 a brown dwarf star was 'shredded' and dumped on the surface of a white dwarf star, leading to the 1670 eruption and the hourglass we see today."

The team of European, American and South African astronomers used the Atacama Large Millimeter/submillimeter Array to examine the remains of the merger, with some interesting findings. By studying the light from two, more distant, stars as they shine through the dusty remains of the merger, the researchers were able to detect the tell-tale signature of the element lithium, which is easily destroyed in stellar interiors.

Dr Stewart Eyres, Deputy Dean of the Faculty of Computing, Engineering and Science at the University of South Wales and lead author on the paper explains:

"The material in the hourglass contains the element lithium, normally easily destroyed in stellar interiors. The presence of lithium, together with unusual isotopic ratios of the elements C, N, O, indicate that an (astronomically!) small amount of material, in the form of a brown dwarf star, crashed onto the surface of a white dwarf in 1670, leading to thermonuclear 'burning', an eruption that led to the brightening seen by the Carthusian monk Anthelme and the astronomer Hevelius, and in the hourglass we see today."

Professor Albert Zijlstra, from The University of Manchester's School of Physics & Astronomy, co-author of the study, says:

"Stellar collisions are the most violent events in the Universe. Most attention is given to collisions between neutrons stars, between two white dwarfs -- which can give a supernova -- and star-planet collisions.

"But it is very rare to actually see a collision, and where we believe one occurred, it is difficult to know what kind of stars collided. The type we believe that happened here is a new one, not previously considered or ever seen before. This is an extremely exciting discovery."

Professor Sumner Starrfield, Regents' Professor of Astrophysics at Arizona State University comments:

"The white dwarf would have been about 10 times more massive than the brown dwarf, so as the brown dwarf spiralled into the white dwarf it would have been ripped apart by the intense tidal forces exerted by the white dwarf. When these two objects collided, they spilled out a cocktail of molecules and unusual element isotopes.

"These organic molecules, which we could not only detect with ALMA, but also measure how they were expanding into the surrounding environment, provide compelling evidence of the true origin of this blast. This is the first time such an event has been conclusively identified.

"Intriguingly, the hourglass is also rich in organic molecules such as formaldehyde (H2CO), methanol (CH3OH) and methanamide (NH2CHO). These molecules would not survive in an environment undergoing nuclear fusion and must have been produced in the debris from the explosion. This lends further support to the conclusion that a brown dwarf met its demise in a star-on-star collision with a white dwarf."

Since most star systems in the Milky Way are binary, stellar collisions are not that rare, the astronomers note.

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Mystery of Saturn's moon Titan's atmospheric haze

The atmospheric haze of Titan, Saturn's largest moon (pictured here along Saturn's midsection), is captured in this natural-color image (box at left). A new study, which involved experiments at Berkeley Lab's Advanced Light Source, has provided new clues about the chemical steps that may have produced this haze.

Saturn's largest moon, Titan, is unique among all moons in our solar system for its dense and nitrogen-rich atmosphere that also contains hydrocarbons and other compounds, and the story behind the formation of this rich chemical mix has been the source of some scientific debate.

Now, a research collaboration involving scientists in the Chemical Sciences Division at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has zeroed in on a low-temperature chemical mechanism that may have driven the formation of multiple-ringed molecules -- the precursors to more complex chemistry now found in the moon's brown-orange haze layer.

The study, co-led by Ralf Kaiser at the University of Hawaii at Manoa and published in the Oct. 8 edition of the journal Nature Astronomy, runs counter to theories that high-temperature reaction mechanisms are required to produce the chemical makeup that satellite missions have observed in Titan's atmosphere.

The team also included other researchers at Berkeley Lab, the University of Hawaii at Manoa, Samara University in Russia, and Florida International University. The team used vacuum ultraviolet light experiments at Berkeley Lab's Advanced Light Source (ALS), together with computer simulations and modeling work to demonstrate the chemical reactions that contribute to Titan's modern-day atmospheric chemistry.

"We provide evidence here for a low-temperature reaction pathway that people have not thought about," said Musahid Ahmed, a scientist in Berkeley Lab's Chemical Sciences Division and co-leader of the study at the ALS. "This gives rise to a missing link in Titan's chemistry."

Titan may yield clues to the development of complex chemistry on other moons and planets, including Earth, he explained. "People use Titan to think about a 'pre-biotic' Earth -- when nitrogen was more prevalent in the early Earth's atmosphere."

Benzene, a simple hydrocarbon with a six-carbon single-ring molecular structure, has been detected on Titan and is believed to be a building block for larger hydrocarbon molecules with two- and three-ring structures that, in turn, formed other hydrocarbons and aerosol particles that now make up Titan's atmosphere. These multiple-ring hydrocarbon molecules are known as polycyclic aromatic hydrocarbons (PAHs).

In the latest study, researchers mixed two gases -- a short-lived two-ring PAH known as a naphthyl radical (C10H7) and a hydrocarbon called vinylacetylene (C4H4) -- at the ALS, and produced three-ring PAHs in the process. Both of the chemicals used to drive the reaction are inferred to exist on Titan based on what is known about the chemical makeup of its atmosphere.

The ALS experiments jetted away the end products of the reactions from a small reaction chamber. Researchers used a detector known as a reflectron time-of-flight mass spectrometer to measure the mass of molecular fragments produced in the reaction of the two gases. Those measurements supplied details about the chemistry of the three-ring PAHs (phenanthrene and anthracene).

While the ALS experiments used a chemical reactor to simulate the chemical reaction and a beam of vacuum ultraviolet light to detect the products of the reaction, supporting calculations and simulations showed how the chemicals formed in the ALS experiments do not require high temperatures.

PAHs like the chemicals studied at the ALS have properties that make them particularly difficult to identify in deep space, Kaiser said. "In fact, not a single, individual PAH has been detected in the gas phase of the interstellar medium," which is the material that fills the space between stars.

He added, "Our study demonstrates that PAHs are more widely spread than anticipated, since they do not require the high temperatures that are present around carbon stars. This mechanism we explored is predicted to be versatile and is expected to lead to the formation of even more complex PAHs."

And because PAHs are considered as precursors to forming molecular clouds -- the so-called "molecular factories" of more complex organic molecules that can include the precursors to life as we know it -- "This could open up theories and new models of how carbon-containing material in deep space and in the rich atmospheres of planets and their moons in our solar system evolve and originate," he said.

Alexander M. Mebel, a chemistry professor at Florida International University and co-leader of the study, carried out calculations that showed how the reactants can naturally come together and form new compounds at very low temperatures.

"Our calculations revealed the reaction mechanism," Mebel said. "We showed that you don't need any energy to drive the reaction of naphthyl and vinylacetylene, so the reaction should be efficient even in the low-temperature and low-pressure atmospheric conditions on Titan."

A key to the study was in the detailed modeling of the reactor cell where the gases were mixed.

Mebel noted that modeling of the energies and simulations of the gas-flow dynamics in play within the reactor help to monitor reaction progress inside the reactor, and allowed researchers to tie theoretical results closely with experimental observations.

The modeling work, which helped to predict the chemicals produced in the reactions based on the initial gases and the temperature and pressure of the heated chamber where the gases were mixed and struck with the vacuum ultraviolet beam, was led by the research team at Samara University.

"This verification of the model, by comparing it with experiments, can also be helpful in predicting how the reaction would proceed in different conditions -- from Titan's atmosphere to combustion flames on Earth."

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Rapid response needed to limit global warming

Climate change concept

Limiting global warming to 1.5°C would require rapid, far-reaching and unprecedented changes in all aspects of society, the IPCC said in a new assessment. With clear benefits to people and natural ecosystems, limiting global warming to 1.5°C compared to 2°C could go hand in hand with ensuring a more sustainable and equitable society, the Intergovernmental Panel on Climate Change (IPCC) said on Monday.

The Special Report on Global Warming of 1.5°C was approved by the IPCC on Saturday in Incheon, Republic of Korea. It will be a key scientific input into the Katowice Climate Change Conference in Poland in December, when governments review the Paris Agreement to tackle climate change.

"With more than 6,000 scientific references cited and the dedicated contribution of thousands of expert and government reviewers worldwide, this important report testifies to the breadth and policy relevance of the IPCC," said Hoesung Lee, Chair of the IPCC.

Ninety-one authors and review editors from 40 countries prepared the IPCC report in response to an invitation from the United Nations Framework Convention on Climate Change (UNFCCC) when it adopted the Paris Agreement in 2015.

The report's full name is Global Warming of 1.5°C, an IPCC special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.

"One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes," said Panmao Zhai, Co-Chair of IPCC Working Group I.

The report highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. For instance, by 2100, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C. Coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2°C.

"Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems," said Hans-Otto Pörtner, Co-Chair of IPCC Working Group II.

Limiting global warming would also give people and ecosystems more room to adapt and remain below relevant risk thresholds, added Pörtner. The report also examines pathways available to limit warming to 1.5°C, what it would take to achieve them and what the consequences could be. "The good news is that some of the kinds of actions that would be needed to limit global warming to 1.5°C are already underway around the world, but they would need to accelerate," said Valerie Masson-Delmotte, Co-Chair of Working Group I.

The report finds that limiting global warming to 1.5°C would require "rapid and far-reaching" transitions in land, energy, industry, buildings, transport, and cities. Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching 'net zero' around 2050. This means that any remaining emissions would need to be balanced by removing CO2 from the air.

"Limiting warming to 1.5°C is possible within the laws of chemistry and physics but doing so would require unprecedented changes," said Jim Skea, Co-Chair of IPCC Working Group III.

Allowing the global temperature to temporarily exceed or 'overshoot' 1.5°C would mean a greater reliance on techniques that remove CO2 from the air to return global temperature to below 1.5°C by 2100. The effectiveness of such techniques are unproven at large scale and some may carry significant risks for sustainable development, the report notes.

"Limiting global warming to 1.5°C compared with 2°C would reduce challenging impacts on ecosystems, human health and well-being, making it easier to achieve the United Nations Sustainable Development Goals," said Priyardarshi Shukla, Co-Chair of IPCC Working Group III.

The decisions we make today are critical in ensuring a safe and sustainable world for everyone, both now and in the future, said Debra Roberts, Co-Chair of IPCC Working Group II.

"This report gives policymakers and practitioners the information they need to make decisions that tackle climate change while considering local context and people's needs. The next few years are probably the most important in our history," she said.

The IPCC is the leading world body for assessing the science related to climate change, its impacts and potential future risks, and possible response options.

The report was prepared under the scientific leadership of all three IPCC working groups. Working Group I assesses the physical science basis of climate change; Working Group II addresses impacts, adaptation and vulnerability; and Working Group III deals with the mitigation of climate change.

The Paris Agreement adopted by 195 nations at the 21st Conference of the Parties to the UNFCCC in December 2015 included the aim of strengthening the global response to the threat of climate change by "holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels."

As part of the decision to adopt the Paris Agreement, the IPCC was invited to produce, in 2018, a Special Report on global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways. The IPCC accepted the invitation, adding that the Special Report would look at these issues in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.

Global Warming of 1.5°C is the first in a series of Special Reports to be produced in the IPCC's Sixth Assessment Cycle. Next year the IPCC will release the Special Report on the Ocean and Cryosphere in a Changing Climate, and Climate Change and Land, which looks at how climate change affects land use.

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Consumers willing to pay more for sustainably brewed beer

More and more breweries are investing in practices to save energy and reduce greenhouse gases. Will it pay off? A study by Indiana University researchers suggests it may.

Drawing on survey research, they find that a majority of U.S. beer drinkers would be willing to pay more for beer produced with sustainable practices. On average, they would pay about $1.30 more per six-pack.

"The takeaway for the brewing industry is that it is financially feasible to introduce energy-saving practices into the brewing process," said Sanya Carley, associate professor in the IU Bloomington School of Public and Environmental Affairs and the first author of the paper. "Even if it ends up adding costs, more than half of all beer consumers are willing to absorb those extra costs."

The study, "Willingness-to-pay for Sustainable Beer," was published by the journal PLOS ONE. Lilian Yahng, director of research and development for IU's Center for Survey Research, is a co-author.

The research highlights potential for energy savings and sustainability in an energy-intensive industry that is growing rapidly, especially in the craft-beer segment. The number of craft breweries grew by over 200 percent between 2005 and 2015, and their production increased by over 12 percent each year.

The industry has considerable potential for reducing energy use and mitigating its impact on climate change. Some breweries have already added solar panels, installed onsite wastewater treatment plants, insulated brewing vessels and recaptured steam from the brewing process.

But those kinds of measures require upfront investments that are likely to increase prices. To determine whether consumers would be willing to pay more for sustainably brewed beer, the researchers drew on a survey of over 1,000 self-reported beer drinkers, all over age 21. They found that 59 percent said they would pay more.

Consumers who already pay more for their beer were most likely to be willing to pay a premium for sustainability. Also, those who said they would pay more for sustainable beer were likely to report lifestyle activities associated with the common good. For example, they spent time in volunteer work or engaged in recycling, composting, and buying locally produced food and products.

Surprisingly, however, there was no significant correlation between the type of beer that consumers preferred and their willingness to pay more for sustainability, after controlling for differences in price. Consumers of traditional American lagers -- think Budweiser and Coors -- were as likely to be willing to pay more as those who prefer craft beers, a category that includes such exotic brews as avocado honey ale and a wild ale brewed with yeast cultured from the brewmaster's beard hairs.

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Lunar craters named in honor of Apollo 8

The Earthrise color photograph taken by astronaut William Anders. It depicts the moment that our shiny blue Earth came back into view as the spacecraft emerged out of the dark from behind the grey and barren Moon. This is arguably the most famous picture taken by Apollo 8. It became iconic and has been credited with starting the environmental movement. Two of the crates seen in this photo have just been named by the Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union.

The newly named craters are visible in the foreground of the iconic Earthrise colour photograph taken by astronaut William Anders. It depicts the moment that our shiny blue Earth came back into view as the spacecraft emerged out of the dark from behind the grey and barren Moon. This is arguably the most famous picture taken by Apollo 8. It became iconic and has been credited with starting the environmental movement.

Since the Moon is tidally locked to the Earth -- it always has the same side facing the Earth -- the Earth will never appear to rise above the surface to someone standing on the lunar farside. Orbiting around the Moon, however, gave the Apollo 8 astronauts, Frank Borman, James Lovell, and William Anders this stunning view, before they safely returned home to Earth.

The Apollo 8 mission took place from 21 to 27 December 1968. After completing 10 orbits around the Moon on Christmas Eve, broadcasting images back to Earth and giving live television transmissions, the crew returned to Earth and landed in the Pacific Ocean.

The Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union, who named the craters, is the authority responsible for the naming of planetary features in our Solar System. The two named craters were previously designated by letters.

From Science Daily

Underestimating combined threats of deforestation and wildlife trade will push Southeast Asian birds

The combined impact of deforestation and wildlife exploitation on bird numbers is severely underestimated and could lead to some species becoming extinct, a joint study by the University of Sheffield and National University of Singapore has found.

Scientists focused on Sundaland -- a hotspot of biodiversity in Southeast Asia, spanning Borneo, Sumatra, Java and Peninsular Malaysia -- where habitat loss, and hunting and wildlife trades are particularly intense.

Looking at 308 forest-dependent bird species, they found that when the loss of forest habitat and bird trapping in the area was examined together it resulted in a much higher average population loss than when accounted for separately.

The study calls for the threats to biodiversity to be considered in totality in order for effective measures to be implemented.

The research, which was conducted between October 2016 and July 2017, also suggests that about 50 to 90 of forest-dependent species in the region, such as the ruby-throated bulbul and white-crowned hornbill will be extinct by 2100.

Tropical forests are the most biodiverse ecosystem globally, however, extensive loss of tropical forests driven primarily by the expansion of agricultural land threatens the survival of forest species. Coupled with other anthropogenic disturbance such as logging, hunting and fires, the threat to biodiversity in these forests is amplified.

While the International Union for Conservation of Nature (IUCN) has been tracking the different forms of threats to wildlife, the assessments tend to look at each form of threat separately. These threats, are however, interconnected and the combined impact could be more severe than currently estimated.

The researchers focused their study on quantifying the combined threats of deforestation and wildlife exploitation in Sundaland.

"Recent extinctions like the passenger pigeon and the dodo present common traits like the simultaneous combination of habitat loss and active hunting," said Dr William Symes, from the National University of Singapore.

"This fatal combination of ingredients is present for dozens of unique bird species in Sundaland. At current rates, vanishing forests and enormous trapping pressures are likely to drive many of them to extinction in the near future."

Their evaluation revealed that 89 per cent of the 308 forest-dependent bird species studied had experienced an average habitat loss of 16 per cent due to deforestation, and they also estimated that wildlife exploitation had led to a 37 per cent decline in mean population on average.

Among the bird species studied, the researchers also identified 77 'commercially traded' species that are more commonly exploited. They found that the estimated average decline for these exploited species was 15.3 per cent from deforestation alone, but when combined with the effects of exploitation, the estimated average decline was drastically increased to 51.9 per cent.

In addition, the assessment of the combined impact of deforestation and exploitation in the study suggests that a total of 51 species should be listed as critically endangered, endangered or vulnerable -- nearly doubling the number currently listed by IUCN.

Dr David Edwards, from the Department of Animal and Plant Sciences at the University of Sheffield, said: "Our study highlights the importance of considering the impact of major conservation threats in combination.

"Recent habitat loss and exploitation combine to drive dramatic extinction risks to the forest specialist species of Sundaland. Without urgent policy intervention to curb deforestation and slow the quantities of birds entering the cage bird trade, many species are likely to be lost.

"Failing to account for these combined threats can lead to a major underestimation of threats in the IUCN Red List assessments."

The combined impacts of deforestation, forest fragmentation and commercial exploitation are not unique to Southeast Asia. Rampant land-use change and wildlife trade drive the decline in parrots from Latin America, Africa and Asia.

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