HKU Bulletin November 2020 (Vol. 22 No.1)

NOVEMBER 2020 Volume 22 No.1 Tracking the spread of COVID-19 Understanding the pandemic from engineering, data and medical perspectives Digital Divide in Hong Kong COVID-19 prompts major advances in digital competence H THE OT ER LOOMING THREAT

CONTENTS COVER STORY Research COVID-19: Tracking the Pandemic Mind the Gap Easy Warning System Facial Recognition: The Next Phase Sex among the Masses City Squeeze Drawing Rhythm from the Algorithm Feeling Bored? Pay Attention to This Towing the Line 16 20 22 24 26 28 30 32 34 Climate Change: The World’s Other Crisis Carbon Sinks Losing Ground Mysteries of the Deep The Sovereign State Feels the Heat Power Plays Airborne Solution Reasons to Feel Less Helpless 02 04 06 08 10 12 14 PEOPLE Knowledge Exchange Working to His Heart’s Content A Values-Driven Approach Mindful Health The Human Factor Shedding Some Light 46 48 40 42 44 Teaching and Learning Lessons from E-Learning Animal Attractions 36 38 Books Protests Sponsored by the State 50 46 16 50 36 10 44

CLimaTE ChaNgE : ThE wORLd’S OThER CRiSiS Although COVID-19 has understandably captured the world’s full attention this year, the dangers of climate change have not gone away. HKU scholars are applying scientific and legal expertise to assess the ecological and political dimensions of the problem, and the possible solutions. HKU also recently joined the International Universities Climate Alliance, a platform for researchers to exchange information on climate change and join forces in formulating solutions. COVER STORY 03 02 The University of Hong Kong Bulletin | November 2020

Tropical forests and mangroves play an important role in absorbing greenhouse gas emissions, but rising temperatures are putting them at high risk of dying off. CARBON SINKS LOSING GROUND If temperatures increase by two degrees [in the coming decades], we would lose a substantial amount of tropical forest and potential carbon uptake. Dr Alexander Koch Intact tropical forests that are untouched by human activity absorbed 17 per cent of human-made carbon dioxin emissions in the 1990s, or about 46 billion tonnes. But two decades later that has fallen to six per cent, or 25 billion tonnes. The compromised capacity of these forests to literally take some of the heat from rising emissions was the subject of a major international study published on the cover of Nature this year that tracked more than 300,000 trees in the Amazon and Africa over 30 years. The scientists, including earth-systemmodeller Dr Alexander Koch, a Post-doctoral Fellow in HKU’s Department of Earth Sciences, provided hard evidence that these forests are at the brink of a path of diminishing returns. “The tropics are currently a carbon sink because growing trees absorb more carbon than they emit when they die off and decay. But future warming will increase mortality. More trees will die, or they will grow faster and die faster,”he said. The threat to the trees comes from higher temperatures, faster temperature increases and more frequent droughts. While these factors have been known to be affecting forests for some time, they had not been quantified to the same extent as the current study. Scientists from 94 institutions were involved in taking measurements of trees at 565 forest patches every few years over three decades, including diameter and estimated height. They also calculated the carbon stored in both the trees that survived and those that died, to track carbon storage over time. Trees dying off This information was fed into a statistical model that incorporated past and projected emissions of carbon dioxide, temperature and rainfall up to 2040. The data showed the forests’ overall carbon uptake peaked in the 1990s and that the Amazon sink began to weaken first, starting in the mid-1990s. Africa followed about 15 years later. Dr Koch and colleagues have also provided an answer as to when forests will reach a tipping point, in another recent study published in Science that focussed on temperature in tropical forests. They found when the monthly mean rose above 32.2 degrees Celsius, there was a substantial drop in a forest’s carbon uptake. “Above this temperature, especially under dry conditions, tree mortality exceeds tree growth and reduces biomass,” he said. The forests in their study had monthly means ranging from 28 to 34 degrees Celsius, with many approaching 31 degrees. “If temperatures increase by two degrees [in the coming decades], we would lose a substantial amount of tropical forest and potential carbon uptake,” he said. Yet two degrees may be a best-case scenario. Under the 2015 Paris Agreement on reducing greenhouse gas emissions, parties pledged to keep temperature increases ‘well below’ two degrees by 2100 and to aim for 1.5 degrees, but this will require substantial investment in emission reduction. Some projections suggest the world could heat up by more than four degrees Celsius this century if nothing is done to curb emissions. Sea-level rises threaten mangroves Tropical forests are not the only carbon sinks threatened by global warming. A study published in Scienceby another international group of scientists, including Dr Nicole Khan, Assistant Professor of Earth Sciences, found faster rates of sea-level rise associated with higher temperatures also threaten mangroves. Mangroves soak up greenhouse gas emissions at greater densities than other forests, provide protection from storm surges and accommodate nursing grounds for young fish. The researchers used sedimentary archives to examine how mangroves responded to sealevel fluctuations over the past 10,000 years and to estimate the probability of mangrove survival under rates of sea-level rise projected for low and high emissions scenarios. They found mangroves would be unlikely to keep pace with rates projected for 2050 if emissions remain high. A factor in this is that much of their hinterland has been developed. Mangroves typically keep pace with sea-level rises by building up their substrate vertically. When sea levels rise faster than their ability to build vertically, they encroach inland. “If we continue on a high-emissions trajectory, mangroves will face a high risk of loss. We need to adopt coastal management and adaptation measures to give them room to grow,” Dr Khan said. (A separate HKU study has demonstrated that such mitigation measures can help – see page 14.) Dr Khan was also involved in another study that showed global mean sea levels could rise by more than one metre by 2100 if emissions Measuring trees in Lope National Park, Gabon. (Courtesy of Simon Lewis, University of Leeds) A large tree in Esuboni Forest Reserve, Ghana. (Courtesy of Sophie Fauset, University of Plymouth) Dr Nicole Khan (right) and her colleague investigating the growth of mangroves. are not reduced. By comparison, the level has risen by 0.2 metres since the late 19th century. “Hong Kong and the Greater Bay Area have a large population and extensive infrastructure located in vulnerable, low-lying areas. These will be increasingly exposed to the impacts of sea-level rise and coastal flooding if emissions targets are not met,” she said. Mangroves are amongst the most valuable of natural ecosystems, supporting coastal fisheries and biodiversity. COVER STORY 05 04 The University of Hong Kong Bulletin | November 2020

Abrupt sea-level events caused by ice sheets melting are crucial to our understanding of Earth’s climate system and how it is influenced by glacial conditions. A new discovery that eustatic sea-level rises can be discontinuous and sudden, has big implications, especially for low-elevation cities like Hong Kong. Mysteries of the deep Our study showed that sea-level change and warming are not linear in relationship. Future warming may not mean a gradual global sea-level rise, but may result in some sudden sea-level jumps at unpredictable times. Dr Moriaki Yasuhara A great mystery in palaeoclimatology is the timing and magnitude of the second largest meltwater pulse (MWP-1B). A meltwater pulse is an abrupt rise in sea levels caused by a sudden influx of meltwater. The first MWP, known as 1A, is well documented but until now the exact timing and magnitude of MWP1B have remained under debate. As often happens at such moments, the MWP1B was not actually the subject under study when Ms Skye Tian Yunshu (who was doing a Major in Ecology and Biodiversity at the time, and is now a PhD student) made the discovery. She was focussing on reconstructing past oceanographic change (palaeoceanography) of temperature and salinity using small fossils called Ostracoda as a proxy. Skye led the study under the supervision of Dr Moriaki Yasuhara and Dr Yuanyuan Hong, both from the School of Biological Sciences and Swire Institute of Marine Science, and in collaboration with Professor Tine Rasmussen of UiT The Arctic University of Norway, who is a top specialist of Arctic palaeoceanography. Faunal shift Dr Yasuhara said: “We were not expecting to see a sea-level change recording a meltwater pulse from the data. But during the study, Skye discovered a strong faunal shift and we gradually realised it must reflect the meltwater pulse.” Skye said: “Based on other studies of the last deglacial-Holocene history of the Svalbard region, we initially hypothesised the salinity changes may have contributed to ostracod faunal turnovers in our two cores. Only after we had the ostracod census data and investigated the ecology of every species in the references, did we realise the ostracod faunal turnover at 11,300 years BP [Before Present] reflected the abrupt sea-level changes of the MWP-1B because of the melting of large ice sheets. “The MWP-1B was first discovered from coral cores in low-latitude regions [known as farfield – that is, places far enough from the polar ice sheets, like low latitude areas such as Hong Kong]. But the MWP-1B as an abrupt sea-level event remains controversial because its timing, rate, and magnitude are not well constrained under the background of continuous deglacial sea-level changes. Unlike elusive far-field records, our study indicates abrupt sea-level changes of 40 to 80 metres in approximately 300 years in Svalbard, a high-latitude region near the polar ice sheets and source of meltwater [known as near-field, where ice sheet melt causes large sea-level change]. We think it’s clear evidence of MWP-1B.” The research group used fossil Ostracoda preserved in two marine sediment cores as an indicator to quantitatively reconstruct the water depth changes in Svalbard in the past 13,000 years. More than 5,000 specimens and 50 species were recorded in two sediment cores from Storfjorden in Svalbard. “Ostracods are a group of small (usually <1mm) aquatic crustaceans which are very sensitive to water conditions,” said Dr Yasuhara. “They have calcareous shells that are very well preserved as fossils and their fossil shells have a variety of morphological characters that allow precise species identification of specimens. In addition, they are abundant in a small amount of sediment and so it’s reasonably possible to obtain enough numbers of specimens needed for robust statistical analyses, even from a small amount of sediment typically available from sediment cores that are usually <10cm in diameter. There are very few such organisms and fossils ostracods are an ideal proxy to reconstruct palaeoenvironmental changes.“ Much of the hard work was down to the efforts of Skye, who embarked on this research as her Final Year Project with Dr Yasuhara. Dr Yasuhara said: “Skye did an outstanding job and proved that an undergraduate student can do first-class scientific discovery important for the global research community and publish the result in a very top journal likeQuaternary Science Reviews .” Global sea-level rise While their studies focussed on a period more than 10,000 years ago, the implications of the discovery in connection with today’s rising sea levels are important. Dr Yasuhara said: “Our study showed that sea-level change and warming are not linear in relationship. Future warming may not mean a gradual global sealevel rise, but may result in some sudden sealevel jumps at unpredictable times, which has An international team of marine biologists have been looking at another aspect of temperature change in oceans – the impact of the 2016 heatwave on the Great Barrier Reef in Australia and how it affected five species of reef fishes. The marine heatwave (MHW) was the longest and hottest thermal anomaly on record and killed a third of the reef’s corals. The team, led by Dr Celia Schunter, Assistant Professor in the School of Biological Sciences and Swire Institute of Marine Science, measured RNA in fish livers and discovered many genes changed expression levels across different time points of the MHW, revealing important functions such as cellular stress response and changes in metabolic function. Given similar heatwaves in recent years in the South China Sea, Dr Schunter is calling for more research to be done on the marine waters of Hong Kong. Dr Yasuhara (right) and Professor Tine Rasmussen of UiT The Arctic University of Norway (left). Scanning Electron Microscopy image of typical shallow-marine (neritic) ostracod species from the study sites. With elevated temperatures during a marine heatwave this cardinalfish species (Cheilodipterus quinquelineatus) shows the least changes in gene expression and appears to be more tolerant. huge implications for our society, especially cities on coastal plains of low elevation, like Hong Kong.” The Yasuhara Lab broadly works on past ecosystems, biodiversity, environments, and their interactions mainly via ostracod micropalaeontology. “We continue our research in the Svalbard region with Tine,” said Dr Yasuhara. “We are studying methane seep activity and ecosystem changes using sediment cores in the region. “Closer to home, we are also working on reconstructing Holocene sea-level change and historical anthropogenic impacts [for example, pollution and eutrophication] on marine ecosystems in Hong Kong using sediment cores and other samples. The result will give a nice far field sea-level record and a robust reconstruction of the history of human-induced marine ecosystem degradation.” FEELING THE HEAT COVER STORY 07 06 The University of Hong Kong Bulletin | November 2020

However you look at it, the modern state is ill-equipped to deal with the challenges of climate change. THE SOVEREIGN STATE FEELS THE HEAT Dr Daniel Matthews of the Faculty of Law is an admirer of English philosopher Thomas Hobbes, who defined sovereignty as it is commonly understood: escaping nature under the security and protection of the state through a social contract. Hobbes was writing 400 years ago and today, the cracks are showing. “Hobbes was extraordinarily creative in rethinking how we define political authority,” Dr Matthews said. “But even though sovereignty is back big time, with Brexit and the rise of populism being examples, I see that as a real dead end for dealing with the challenges of climate change. “Climate change does not respect state borders and many of its effects are nonanthropocentric, impacting on a range of non-human forces and relations described by geology and ecology. Modern politics is really bad at being sensitive to these forces.” Dr Matthews has been tracking these shortfalls as a scholar of the history and theory of sovereignty and sees problems in all three components that define sovereignty: territorial, populational and institutional. In terms of territory, climate change is altering the geophysical environment, including boundaries, which had largely been considered immobile and fixed. In Canada, for example, melting ice has transformed sections of the Northwest Passage from land into sea, raising questions over whether it is still part of the Canadian landmass or could now be considered open ocean. “These kinds of challenges are only going to become more significant in the coming years,” Dr Matthews said. Non-human actors ignored The focus on humans as the only population considered worthy of political attention in sovereign states also raises concerns. “It’s becoming clear that the security of a nation depends on all sorts of non-human animals which are constitutively ignored in the classic definition of sovereignty, such as the biodiversity of insects for the pollination of crops, animals that are farmed for protein and so forth,” he said. Institutionally, instruments such as parliaments and courts have been designed to consider human rights and interests, not those of nature. Some places have experimented with addressing this issue – in Ecuador, for instance, the constitution recognises the Rights of Nature and in New Zealand the Whanganui River has recently been granted legal personality. Other institutional experiments include cities linking up through global networks to develop and implement climate policies. But it is still far from adequate. “Sadly, we are only at the beginning of this process. We need a radical re-thinking of some of the things we take for granted,” he said. “The novelist Amitav Ghosh has said that climate change is more a crisis of the imagination than a crisis of policymaking. We need new ways to imagine the meaning and scope of the political.” Maps and other limitations Dr Matthews is contributing to that discussion with a forthcoming book, The Aesthetics of Sovereignty in the Anthropocene , that looks at how maps, rituals, symbols, fictions, narratives and other aesthetic elements are mobilised to legitimise a state and how these practices interfere with our ability to address the unprecedented and disturbing planetary changes wrought by human activity over the past 200 years. “The aesthetic dimension of sovereignty constructs how sovereignty and our political identities appear in the world and allow us to imagine the world in a particular way; but they also have limitations,” he said. “Maps, for example, are wonderful devices for doing all sorts of things, particularly in representing the scope of territorial authority, but they only depict empty, homogenous space. They are not sensitive to all sorts of forces that are increasingly relevant in the current moment, such as biodiversity, risks associated with rising sea levels, or the nature and composition of the soil. Maps, and the cartographic imaginary they engender, inure us to the changing geophysical environment and the non-human actors we depend on for our survival. And they limit our ability to think creatively about these challenges.” Radical changes needed Getting people to see the world differently, both in the visual and contemplative sense, will not be easy. The COVID-19 pandemic offers a glimpse of the challenges. “We’ve seen a reassertion of national borders, concentration of power in the hands of the executive, greater emphasis on who gets the privilege of citizenship and who doesn’t. I fear we will see repeats of this in future climatic crises,” he said. Dr Matthews hearkens back to Hobbes, who was also exploring how politics could be reorganised in a changing world.“This idea that we have to deny our attachments to the natural world in order to create a distinct political sphere is precisely what needs to be reversed. But the way things are going at the moment doesn’t make me massively hopeful,”he said. “Radical changes need to take place. It can’t be business as usual. Exactly how these This idea that we have to deny our attachments to the natural world in order to create a distinct political sphere is precisely what needs to be reversed. Dr Daniel Matthews The Whanganui River in New Zealand has been granted legal personality, meaning it has been awarded the same legal rights as a living entity. Melting ice has transformed sections of the Northwest Passage from land into sea – is it still part of the Canadian landmass? Could it be considered open ocean? changes will be instituted, no one knows. In my own work, I’m hoping to point out the limitations of the existing coordinates that define modern sovereignty and encourage critical and creative thinking about the changing nature of political authority in the context of climatic transformation.” The Aesthetics of Sovereignty in the Anthropocenewill be published by Edinburgh University Press in 2021. COVER STORY 09 08 The University of Hong Kong Bulletin | November 2020

For all the publicity and enthusiasm generated around renewable energies such as solar, wind and biomass, their actual adoption has not been so remarkable. Although their usage in electricity generation has increased from 0.6 per cent of the global total in 1973 to eight per cent in 2016, they are still a small portion of all energy sources. Moreover, in terms of quantities, we use twice as much fossil fuel today to generate energy as we did in the 1970s, even when renewables are accounted for. While there are technical stumbling blocks to renewables, such as the need for better batteries to store solar energy, there are also political blocks. Dr Kim Jung Eun of the Department of Politics and Public Administration has spent the past decade investigating the problem of how to effectively transfer renewable energy technology from the developed countries where it is created, to developing countries. “Developed countries have the capacity to innovate and implement new technologies and policies, but developing countries are still more focussed on economic development. Even if they have the capacity to implement a policy, there is not much motivation to do it or to implement it fully,” she said. Good policy designs are important because otherwise it is difficult to persuade private businesses anywhere to change their behaviour or adopt new technology. The most innovative policies tend to come from developed countries, such as the Renewable Portfolio Standard (RPS) in the United States, a regulatory policy that sets quantitative targets for renewables and lets utilities trade credits, and the Feed-in Tariff (FiT), an incentive scheme used in places like Germany that lets people sell energy generated through renewable means to the electricity grid. Regulation better than incentives To date, FiT has made more inroads in developing countries, but Dr Kim’s research suggests this might not be the most effective approach. “My research has found that in developing countries, regulation works better than incentives in promoting renewable energy use,” she said. Developing countries also need support beyond simply adopting a technology or policy from abroad. Dr Kim looked at transfers of non-hydro renewable energy technology to developing countries and found the transfer alone did not really increase recipients’ capacity. “You need a maintenance programme to go with it. In the past, this kind of knowledge exchange tended to happen without consideration of the local context, although this is changing. My hypothesis is that that approach can affect recipient countries’ motivation, which in turn can affect the success of these transfers,” she said. Consideration also needs to be given to the kinds of renewable energies that are being used. Dr Kim has recently been looking at how policy design affects the technology adopted, initially focussing on developed countries where the policies originate (she plans to extend this to developing countries later). “There are two kinds of policies regarding technology diffusion. One is tech-neutral, the other is tech-specific. If the policy specifies the technology to be used, then that technology will grow its share in the market. But if the technology is not specified, then the market will choose the most cost-effective option,” she said. Market gets locked in Wind is usually the cheaper option and the one utilities tend to opt for when faced with a policy that requires them to derive a certain percentage of energy from unspecified renewables. However, this approach may stunt the development of other technologies, such as solar and biomass. On the other hand, if a policy stipulates that, say, two per cent of renewable energy must be solar energy, it leaves the door open for future expansion of this technology. There is a great deal of effort going into renewable energy and a lot of motivations. It’s all a bit messy. Its use will definitely grow, but I don’t see there being a complete transition to renewables in the short term. Dr Kim Jung Eun Number of countries with different renewable energy policy instruments Renewable energy should be a solution for reducing our impact on the climate. But politics and market considerations are complicating its development and spread. POWER PLAYS “Once a technology is dominant in the market, a political economy develops around it. The market gets locked in. But solar and other technologies that are now less cost-effective might become more efficient with future innovation, so you want to keep those technologies for now that may have future potential,” she said. Dr Kim cautions against raising hopes too high over renewable energy because of other limits to its growth. Renewable energy tends to be more intermittent than coal, gas, hydro or nuclear power. Moreover, wind farms require large areas of land and tend to be located far from population sources, and solar relies on batteries to store electricity for use at night. These batteries contain materials with ethical issues, such as cobalt which is toxic and mined in places like the Democratic Republic of the Congo where child labour may be used. “There is a great deal of effort going into renewable energy and a lot of motivations. It’s all a bit messy. Its use will definitely grow, but I don’t see there being a complete transition to renewables in the short term,” she said. COVER STORY 10 The University of Hong Kong Bulletin | November 2020 11

Research by Dr Nam Kyung-Min shows air pollution and climate change policies work best if they go hand in hand. AIRBORNE SOLUTION If you want developing countries to act in favour of global benefits, you need to incentivise them locally. Dr Nam Kyung-Min Governments need an incentive to take the hard decisions necessary to address climate change, but many, particularly in the developing world, tend to put off taking decisive action because the costs of climate mitigation may exceed the payoffs and take decades to be realised. Dr Nam Kyung-Min of the Department of Urban Planning and Design has produced solid evidence that an incentive can be found in the here and now. Dr Nam’s focus is the link between climate change and air pollution, particularly in China which is the world’s largest carbon emitter and suffers from serious air pollution. China’s air pollution is notorious for its magnitude – in 2015, for example, the annual mean concentrations of particulate matter, which can penetrate deep into human respiratory and circulatory systems, exceeded the World Health Organization guideline levels by eight times in Beijing. In response, China has been taking increasingly stringent actions against air pollution. As a result, not only has air pollution abated but so have greenhouse gases, whether China intended so or not. “Air pollutants and greenhouse gases are different and they are often controlled independently of each other in many countries,”Dr Nam said. “But these two gas species are inseparable in both being to a large extent co-generated from fossil fuel combustion. Accordingly, if you abate air pollutant emissions, fossil energy use is constrained, as are greenhouse gas emissions, andvice versa . This linkage is particularly strong in China given its high dependence on coal for domestic energy supply.” This observation is important because around the world, governments have been exhorted to reduce greenhouse gas emissions to save the planet – a goal that is more vague than asking them to reduce air pollution to protect health, which most countries, including China, are keen to do. The global benefit of local action “The Chinese government has become serious about pollution abatement and imposed absolute emissions reduction targets. In contrast, its carbon mitigation goal is relatively moderate and is expressed in terms of ‘intensity’, which is carbon emissions per unit of gross domestic product. China wants to reduce carbon intensity by up to 65 per cent by 2030, using 2005 as the base, but because the economy keeps growing at high rates, absolute carbon emissions in 2030 may still be substantially above the 2005 level,”he said. Yet Dr Nam’s research has shown that China may still achieve much greater carbon reductions than its official targets because of its stringent air-quality control. Using an energy-economic simulation model, he looked at data for both pollution and carbon emissions and found that reducing pollutants such as nitrogen oxides and sulphur dioxide helps reduce absolute carbon emissions, too. This was one of the first studies to explore the potential climate co-benefits of air pollution abatement in China. “Mainstream co-benefit analysis tends to place carbon mitigation policy, rather than air pollution abatement, at the centre. Developing countries like China and India have been urged to join the global effort to mitigate carbon emissions by arguing that this is much less costly if the ancillary air-quality improvement is taken into consideration, too. “My approach champions the reverse logic. If you want developing countries to act in favour of global benefits, you need to incentivise them locally.” Dr Nam has also been looking at market-based instruments for climate mitigation such as an emissions trading scheme (ETS), particularly in Hong Kong’s context. Another solution: carbon trading Hong Kong has imposed a similar carbon emissions reduction target as China but has less room to manoeuvre in achieving that goal. About two-thirds of Hong Kong’s carbon emissions come from thermal power plants operated by two local firms, which are already required to install equipment to reduce emissions and switch from coal to less carbon-intensive natural gas. The transport sector, which accounts for much of the remaining local carbon emissions, faces similar requirements. Given the small number of potential participants and a tiny carbon market, Hong Kong would have difficulty sustaining an ETS on its own. But Dr Nam sees a solution across the border. He believes Hong Kong could achieve its official mitigation goals at lower costs by participating in China’s ETS, which is being trialled in eight Mainland locations. This lets firms in industrialised areas trade ‘carbon credits’with those in less urbanised areas or from more energy-efficient sectors within a given economy-wide emission cap. “If Hong Kong tries to achieve its carbon reduction goals solely through commandand-control regulations, it would be very costly. It is hard to imagine that Hong Kong could develop its own carbon market, but its participation in China’s national ETS seems to be a feasible and realistic option,”he said. Dr Nam has developed a computer simulation model based on microeconomic theory and is starting to estimate the effects of crossborder emissions trading between Hong Kong and Mainland China. “I hypothesise that the policy compliance cost measured in terms of GDP loss will be much lower than if Hong Kong regulated its market separately,”he said. He hopes the results, due next year, will help increase local policymakers’attention on regional emissions trading. Historic and estimated emissions trend in Mainland China, 2010–2030 Primary energy supply in 2017 (Source: Created by the author from the International Energy Agency database) Mainland China Hong Kong Other 7.6% Gas 19.4% Oil 26.8% Coal 46.2% Other 11.0% Gas 6.4% Oil 18.8% Coal 63.8% COVER STORY 12 The University of Hong Kong Bulletin | November 2020 13

HKU researchers have identified areas where local actions may alleviate some of the impact on marine life and shorelines that is typically associated with global climate change. REASONS TO FEEL LESS HELPLESS We found that in the Pearl River Delta, the threat to corals originates fromour inadequate treatment of wastewater. This is interesting because global warming is usually singled out as the cause of coral decline worldwide. Dr David Baker Corals and mangroves are like canaries in the climate change coalmine. Research has shown that these ecosystems are already experiencing harm that may get much worse. But recent work by scholars in HKU’s Swire Institute of Marine Science (SWIMS) and their collaborators has found the situation is a little less hopeless than feared. The coral study showed that water quality may be a more important stressor for coral communities in the Pearl River Delta (PRD) than global warming, while the mangroves study showed it was possible to rehabilitate these ecosystems. Dr David Baker of SWIMS and the School of Biological Sciences was part of a team of scientists from HKU, Princeton University and the Max Planck Institute for Chemistry that conducted the coral study. “We found that in the Pearl River Delta, the threat to corals originates from our inadequate treatment of wastewater. This is interesting because global warming is usually singled out as the cause of coral decline worldwide. We often feel helpless in that scenario because a solution would require everybody on the planet to drastically change their lifestyles. But wastewater treatment is something we can fix more easily,”he said. The study assessed the growth of living coral in the Pearl River Delta over the past two centuries. Corals form bands that are similar to tree bands – during cooler weather they are smaller due to a decrease in calcification and in warmer weather they are larger. This growth is fuelled by resources drawn from seawater, particularly nitrogen which is a key component of protein scaffolding. Nitrogen is prevalent in human sewage and during the period under study, the Pearl River Delta’s population increased from a few thousand to more than 100 million people. Water quality declined in the latter part of the 20th century and the study was able to link that to coral growth through X-rays of the corals and material extracted from their bands. It also showed that Hong Kong’s improved wastewater treatment from the year 2000 had had a positive impact on corals. “Paradoxically, our study is good news because it implies that the solution to coral decline is in our hands. The improvements in Hong Kong indicate that these efforts must be continued if we want corals to come back here,” Dr Baker said. Turning of the tide Another area of cautious hope is mangroves. Experts warned more than a decade ago that they were being lost faster than almost any other ecosystem, including coral reefs and tropical rainforests. Dr Stefano Cannicci of SWIMS and the School of Biological Sciences was among the team that sounded the alarm. Now he is singing a different tune. The rate of mangrove loss has improved dramatically, from about 1–3 per cent per year in the late 1990s to 0.3–0.6 per cent more recently. This is attributed to successful conservation efforts, such as better monitoring, changing industrial practices, rehabilitation, and expanded management and protection, and was reported in a study with researchers from 24 institutes around the world, including Dr Cannicci. “I am very proud to have been among the academics warning about mangrove loss more than a decade ago because I think it helped turn the tide on mangrove degradation. The perception about their importance to humankind and the planet has changed, although there are still dangers. We need to keep up the effort to manage and preserve mangroves worldwide,”he said. Areas of concern include the uneven distribution in mangrove conservation gains across the world and the risk of mangroves being sandwiched between rising sea levels and developed hinterlands that constrict their growth (see also page 4). Reducing greenhouse gas emissions is not just good for the atmosphere and sea levels – it could also improve water quality. A study by SWIMS and the Department of Earth Sciences of the South China, East China, Yellow and Bohai Seas found nitrogen oxides from air pollution affect water quality when they fall into the water because they enhance the production of algae. When the algae die and sink to the bottom, their decomposition decreases dissolved oxygen in the water, which is bad for marine life. However, their model shows that reducing the emission of anthropogenic nitrogen in the atmosphere could lead to an improvement of water quality, notably in the South China Sea. “Our study shows the potential benefit of reducing fossil fuel burning not only on humans and the ecosystem, but also local activities such as fisheries,”said PhD student Miss Yau Yu-yan, who led the research under the supervision of Dr Benoit Thibodeau. BETTER AIR, BETTER WATER Nevertheless, places like Hong Kong have seen improvements. Dr Cannicci recently recorded about 40 mangrove forests here covering about 350 hectares, which is the largest mangrove patch within the PRD. “Although small and limited in size, Hong Kong mangroves contain a magnificent diversity of plant and animal species: eight species of trees, 53 species of crabs and 42 species of snails. This is more than is known for the mangrove forests of the entire African continent,”he said. A crab resting on a mangrove in Ting Kok, Tai Po, Hong Kong. Researchers drilling coral under water. Anthropogenic pollutants can be observed in the atmosphere of many Chinese coastal cities. A team of international mangrove forest experts now find cause for optimism for global mangrove conservation. COVER STORY 14 The University of Hong Kong Bulletin | November 2020 15

Rigorous research is the key to understanding COVID-19 and getting its spread under control. Scholars in the Li Ka Shing Faculty of Medicine (HKUMed) are at the forefront of this research and have rightly received attention from around the world for their significant findings (see recent highlights on page 19). But scholars in other disciplines have also applied their expertise to reveal new characteristics about the pandemic. On these pages, engineering research shows how poor ventilation can increase risk of exposure to the virus, while business research shows how phone data can be used to track COVID-19’s spread in the population. COVID-19 : Tracking the Pandemic POOR VENTILATION HELPS THE VIRUS SPREAD A simple criterion for insufficient ventilation is if you can smell other people’s breath from a distance. Professor Yuguo Li HKU’s Department of Mechanical Engineering has shown that COVID-19 can be transmitted several metres by air when there is poor ventilation – a timely warning as winter approaches and people spend more time indoors. The finding came out of a detailed study of three COVID-19 outbreaks in crowded situations that looked at where infected individuals were located, who they infected and the rate of ventilation. The outbreaks were at a Guangzhou restaurant, two Hunan buses, and the Diamond Princess cruise ship from January to March, and the study was led by Professor Yuguo Li, Chair Professor of Building Environment, who previously played a key part in showing the role of ventilation in two clusters of cases during the 2003 SARS outbreak. At the Guangzhou restaurant, three families who did not know each other were sitting at adjacent tables. An index patient sat at one table and subsequently infected nine people at all three tables, including one person who sat 4.6 metres away. Subsequent measurements by Professor Li and his team showed the ventilation rate was only 1 L/s (one litre per second) per person, against the international standard of 5 L/s. Similarly, the Hunan buses were poorly ventilated. One index patient took a bus ride of three hours and 20 minutes that resulted in seven patients being infected, then took a second one-hour journey on a minibus in which two people were infected. The furthest infected person was 9.5 metres away from the index patient. The bus had a timeaveraged ventilation rate of 1.7 L/s and the minibus 3.2 L/s. Keep the air moving On the Diamond Princess, which had more than 700 confirmed cases, the findings went the other way: the team showed that infection among passengers after the onset of quarantine was limited to those who had stayed in the same stateroom as an infected passenger. This probably meant the central air-conditioning system did not play a role, although the team were unable to get reference measurements. “In a sufficiently ventilated room, droplet concentrations in the exhaled jet of air from an infected person will continually decrease and become indistinguishable from background room air at a distance of about 1.5 metres. Our findings suggest that airborne transmission of the COVID-19 virus Professor Li is an expert in ventilation of indoor environments with a focus on environmental transmission of diseases. The path of airflow between the tables of the three families involved in the Guangzhou restaurant case. indoors is likely when the ventilation rate is less than 3 L/s per person,” Professor Li said. Public places should enhance indoor air ventilation and social gatherings indoors should be avoided if there is not sufficient ventilation, he said. A carbon dioxide sensor could help indicate poor ventilation if the reading is more than 1,000 parts per million. Otherwise, “a simple criterion for insufficient ventilation is if you can smell other people’s breath from a distance,” he added. 17 RESEARCH 16 The University of Hong Kong Bulletin | November 2020

USING PHONE DATA TO TRACK A PANDEMIC A team of business and statistics researchers, with little background in medicine, have developed a model to accurately predict COVID-19’s spread and assess risk using only mobile phone data, and to explore people’s response to the pandemic. The team, led by Dr Jayson Jia Shi of the Faculty of Business and Economics, focussed on Wuhan, the epicentre of the COVID-19. Complex mathematical models had shown, in retrospect, how the virus spread to the rest of the country and the world. But Dr Jia and his colleagues found a simpler, real-time path to the same conclusion with mobile phone data. Phones automatically alert cell towers whenever they are in range, making them useful for showing population movement. Dr Jia and his collaborators had access to anonymised mobile phone data from China’s telecom companies and used it to track COVID-19’s spread. They showed that from January 1 this year to January 24, whenWuhan was quarantined, more than 11 million people travelled through the city on their way to 296 prefectures on the Mainland. This information was fed into a model that also captured the number of COVID-19 cases in each place. The results confirmed what Mobile apps are a way of using digital behaviour to infer what’s on people’s minds, so now we’re using the shock of the pandemic to study lifestyle changes. Dr Jayson Jia Shi these places experienced: the traffic of people fromWuhan predicted how fast their case load grew. The findings were published inNatureat the end of April. “Our model captured 96 per cent of the statistical variance in the growth of COVID-19,” he said. “By establishing this relationship, we could also predict about two weeks into the future with good accuracy.” They received proof of this while still in the midst of the study, when they noticed that Wenzhou in Zhejiang province was reporting far fewer cases than predicted by the number of arrivals fromWuhan. A short time later, the reported cases started rising and Wenzhou imposed quarantine conditions. “Our paper established the basic assumption that you can use movement data to infer that there are going to be more imported cases,”he said. Their efforts resulted in a COVID-19 risk modelling toolkit and other scholars have picked up on the findings to explore the relationship further. Coping behaviour Dr Jia is now looking at another aspect of mobile phones, the use of apps, to explore COVID-19’s impact on people’s behaviour. This follows on from earlier research he did on the 2013 Ya’an earthquake in Sichuan. That study focussed on social networks and used data from family phone plans to see who people called right after the earthquake hit (mainly family members, rather than the people they called most frequently prior to the tremor, who are presumably work colleagues and friends). It then went a step further to look at which apps people used in the wake of the quake. Apps were divided into three categories – information related (such as news and banking apps), communications (such as WeChat) and hedonic (such as games, video and music). The data showed that people who lived closest to where the tremor was strongest increased their use of hedonic apps in the following week. Moreover, the use of hedonic apps was associated with less fear about future earthquakes, as revealed in a survey carried out around the same time. “That was really the surprising finding – the more they engaged in hedonic behaviours, the lower their perceived risk was. The use of these apps was an effective coping behaviour,” Dr Jia said. HKUMed scholars have made world’s-first discoveries on COVID-19 and are forging a path towards deeper understanding and control of the disease. Selected highlights in recent months* include: • Vaccine candidate approved for clinical trial: A flu-based vaccine developed by the State Key Laboratory of Emerging Infectious Diseases in partnership with Xiamen University and Wantai Biopharmaceutical company, was approved for clinical trial in humans in September by China’s National Medical Products Administration. This is the world’s first nasal spray COVID-19 vaccine to be tested in humans. • First proof of reinfection of COVID-19 virus: Scientists in the Department of Microbiology documented the first case in which a recovered patient was re-infected with SARS-CoV-2, the virus that causes COVID-19, a finding that has important implications for understanding immunity and vaccination prospects for the disease. The case involved a young RECENT COVID-19 RESEARCH ADVANCES For comprehensive and regularly updated reports on our substantial body of COVID-19 research, please visit: * From mid-April to mid-September 2020. SeeBulletinVol.21, No.2 for earlier findings. and apparently healthy patient who was diagnosed with the disease for a second time, four and a half months after the first episode. Samples taken from the patient showed the viral genomes in each case belonged to different lineages. • New knowledge about transmission dynamics: HKUMed scholars were involved in studies confirmed that virus shedding could begin several days before the first symptoms appeared. They also showed non-pharmaceutical interventions against COVID-19 and influenza, such as testing, contact tracing and population behavioural changes, could be effective controls with less disruption than a total lockdown. Another study found such interventions could shorten the serial interval of the virus over time, which can reduce the chance of transmission. An international study with HKUMed scholars showed containment measures were nonetheless effective, too, lowering the daily increase of new cases to less than five per cent within one month. • Potential drug targets and candidates identified: An international team identified neutralising monoclonal antibodies as potential therapeutic and prophylactic options against COVID-19. A separate study showed the disease impairs dendritic cell and T cell function, which are involved in human immune defences and could be targets for treatment and vaccine development. An international study of 12,000 known drugs found 13 could be potential candidates for treating COVID-19. Another study identified potential targets for broad-spectrum antiviral drugs to treat COVID-19 and other viral infections (namely, the P9R alkaline peptide and YxxØ-motif ). • Symptoms and effects: The SARSCoV-2 virus was shown to infect neural progenitor cells and brain organoids and intestinal cells. Scholars also found that the eyes may be an important route of human infection. • Animal connections: Research shows SARS-CoV-2 was probably circulating unnoticed in bats for decades, and that it demonstrably infects bat intestinal cells, as well as those of humans. Tests on two dogs diagnosed with COVID-19 suggested they had been infected via humans. There is a high overlap between the geographical distribution of aggregate population outflow from Wuhan until January 24, 2020 (in red) and the number of confirmed cases of COVID-19 in other Chinese prefectures (n = 296 prefectures). (Map source: National Catalogue Service for Geographic Information. Grey areas lack population outflow data.) Geographical distribution of population outflow and confirmed COVID-19 cases as of February 19, 2020 The relationship between the log-transformed aggregate population outflow from Wuhan (up to January 24, 2020) and the log-transformed number of confirmed cases by prefecture on January 26, 2020 (a) and February 19, 2020 (b). Red circles are prefectures in Hubei; light blue circles are four quarantined prefectures in Zhejiang (including Wenzhou); and the six largest prefectures in China are indicated with unique colours. Correlation between population outflow fromWuhan and confirmed COVID-19 cases “Mobile apps are a way of using digital behaviour to infer what’s on people’s minds, so now we’re using the shock of the pandemic to study lifestyle changes.” Applying that approach to COVID-19, Dr Jia and his team have been analysing data from Chinese users and the longerterm consequences of less physical mobility and social mixing. Compared to before the pandemic, people have become more reliant on some apps, for example short form video and food delivery apps (no surprise there), and they have changed the way they look at other apps, for example dating apps which previously were correlated with information apps but are now more associated with entertainment apps. There have also been some positive changes as people make greater use of learning and studying apps, job search apps, and exercise apps (and presumably exercise more). These findings are still in raw form and the implications will need further analysis. Dr Jia is also trying to promote the idea of social networks when considering the risk factors of COVID-19. “Researchers used to study risk from an atomistic perspective, such as focussing on an individual’s fears or what they thought they could do about a situation. But little thought has been given to social networks and how risk is sometimes beyond our personal control. Let’s say you are really careful about going out, but a family member isn’t. That person is exposing you to risk. So conceptually, we are trying to introduce the idea of networks to risk perception,” he said. 18 The University of Hong Kong Bulletin | November 2020 19 RESEARCH