Jane O'Sullivan

The University of Queensland | UQ · School of Agriculture and Food Sciences

Climate change is one of the greatest self-inflicted threats that human civilisation has ever faced. An unprecedented global effort is under way to change course to avert catastrophic outcomes – but doubts remain whether enough is being done, and quickly enough. In the flurry of activity and proposals, the role of human population size and growth i...

‘We have kicked the can down the road once again – but we are running out of road.’ – Rachel Kyte, Dean of Fletcher School at Tufts University. We, in our capacities as scientists, economists, governance and policy specialists, are shifting from warnings to guidance for action before there is no more ‘road.’ The science is clear and irrefutable; hu...

For leaders, planners and people around the world facing uncertainty about actions to resolve our planetary crises, we offer a concrete framework for action. We take the six core areas identified for urgent action by humanity from our 2019 paper in BioScience, World Scientists Warning of a Climate Emergency, and convert these into a framework for c...

(Replaces preprint) We have kicked the can down the road once again-but we are running out of road.'-Rachel Kyte, Dean of Fletcher School at Tufts University. We, in our capacities as scientists, economists, governance and policy specialists, are shifting from warnings to guidance for action before there is no more 'road.' The science is clear and...

Climate change is unlikely to impact the size and distribution of populations markedly unless system collapse causes mortalities on an unprecedented scale. Population growth, however, will greatly exacerbate the impacts of climate change on communities in high-fertility countries, and particularly those located in the humid tropics where heat stres...

Ecological economists accept that the global population cannot grow forever. But papers discussing the relevance of population growth and the prospects for minimising it are rare in the literature on ecological economics. Even these papers treat population almost exclusively as an issue relating to the scale of human activity. The many ways in whic...

SDG3, Health and Wellbeing for All, depends on many other SDGs but there are also potential conflicts and trade-offs. In this chapter, ee stress the importance of forests to global health and well-being as well as for Indigenous and local populations. In contrast, short-term economic and human health gains from further forest conversion (e.g. defor...

Respect for nature demands sharing landscapes and resources fairly with other species, which cannot be achieved without limiting human populations. So ecological citizens should support measures to decrease fertility rates and limit immigration, both of which are necessary to reduce currently excessive populations. Global population growth will onl...

Global, national and regional population projections are embedded in projections of future greenhouse gas emissions and in the anticipated impacts of climate change on food and water security. However, few studies acknowledge population growth as a variable affecting outcomes. Neither the uncertainty around population projections nor the scope for...

As the nations of the world grapple with the task of creating sustainable societies, ending and in some cases reversing population growth will be necessary to succeed. Yet stable or declining populations are typically reported in the media as a problem, or even a crisis, due to demographic aging. This is misguided, as economic analyses show that th...

Journal of Population and Sustainability Vol 1 No 1 Debut issue. Papers by: STEVEN W. SINDING - Reflections on the Changing Nature of the Population Movement. AUBREY MANNING - Population and Sustainability: the Most Inconvenient Truth. SARAH CONLY - One Child: Do We Have a Right to More? COLIN KELLEY - On Sustainability, Vulnerability, Climate and...

Population growth path is a major determinant of both future emissions and climate risk exposure. But the IPCC’s models assume population is dependent on economic development and education level. Historical evidence belies this assumption, showing population path has been governed most strongly by voluntary family planning effort, irrespective of p...

Projections should arm us to prepare for the future and take pre-emptive action to avoid threats. Recent population projections have had the opposite effect. By failing to acknowledge the impact of choices, they have undermined pre-emptive action. This fatalistic approach has probably already contributed to a global slow-down in fertility decline o...

Bradshaw and Brook’s report “Human population reduction is not a quick fix for environmental problems” (1) argues that plausible efforts to reduce birth rates will make little difference to the course of human population this century. Although they emphasize that population reduction is highly desirable from an environmental perspective, and that g...

While most analyses of economic impacts of population growth have been equivocal, this article describes a new perspective from which the effects are strongly negative. The economies and diseconomies of population size are largely circumstantial and empirically inconsistent, but those of growth rate are intrinsic and consistent. These impacts are n...

Submission to the Energy White Paper process This submission is made on behalf of the national executive of Sustainable Population Australia (SPA). SPA is an environmental advocacy organization, which recognizes that population is a key factor in all human impacts on the environment. While energy intensity of lifestyles is also an important source...

Strontium was used as a tracer to detect root activity of yam (Dioscorea alata) at distances from 0.5 to 5.5 m from the plant's crown, and at depths of 7, 15, 25 and 40 cm, in field plantings separated by plastic root barriers. Tracer bands were installed at planting, and leaves were sampled at intervals throughout the growing season. Background Sr...

A growth analysis study involving monthly excavation of Dioscorea esculenta plants revealed that the root system developed fully in the period before tuber initiation, and extended radially for a distance between 2.3 and 4.3 m. Primary roots initially remained in the top 10 cm of the soil profile, but descended to approximately 30 cm near their ful...

Nutritional deficiencies in Dioscorea esculenta (Lour.) Burk were studied using a novel culture system, applying a constant water table in acid-washed sand, and a demand-driven nutrient supply schedule. This system provided a stable growth environment and was highly efficient with respect to resources and labor. Yam plants (cv. Balbal) were propaga...

This paper describes the first systematic study of nutritional deficiencies of greater yam (Dioscorea alata). Yam plants (cv. 'Mahoa'a') were propagated from tuber discs and grown in nutrient solution, with nutrients supplied following a modified programmed nutrient-addition method. After an establishment period of four weeks, deficiencies of nitro...

The potassium (K) nutrition and high K requirement of tropical root crops may be affected by their sodium (Na) status, as has been observed in a number of plant species. Solution culture was used to study the effects of K and Na supplies in tannia [Xanthosoma sagittifolium (L.) Schott.], sweetpotato [Ipomoea batatas (L.) Lam.] and taro [Colocasia e...

An interactive key for diagnosing problems in sweetpotato (Ipomoea batatas) has been developed through an international collaboration between The University of Queensland (UQ), the International Potato Center (CIP) and the Philippines Rootcrops Research Institute (Philrootcrops), with funding from the Australian Centre for International Agricultura...

No information is available on the decomposition and nutrient release pattern of Piper aduncum and Imperata cylindrica despite their importance in shifting cultivation systems of Papua New Guinea and other tropical regions. We conducted a litter bag study (24 weeks) on a Typic Eutropepts in the humid lowlands to assess the rate of decomposition of...

Root crops are an important staple food in the Pacific region. Yields are generally low and inorganic fertilizers are deemed an option to increase root crop production. The effects of inorganic N fertilizers on upland taro (Colocasia esculenta (L.) Schott) and sweet potato (Ipomoea batatas (L.) Lam.) were quantified with the aim to investigate rela...

Sweet potato (Ipomoea batatas (L.) Lam) is the major staple crop in Papua New Guinea and experiments were conducted investigating factors affecting yield decline. Yields of unfertilized plots were related to rainfall and measured changes in soil properties, nematode (Meloidogyne sp., Rotylenchulus reniformis) and sweet potato weevil (Cylas formicar...

Poor crop nutrition contributes to the low yields of root crops in the South Pacific region where symptoms of nutritional disorders are frequently observed. This study was therefore undertaken to assess the effect of inorganic fertilizers on sweetpotato [Ipomoea batatas (L.)] and taro [Colocasia esculenta (L.) Schott] yields. It indicates the impor...

Solution culture was used to characterise deficiencies or toxicities of several essential elements in Ipomoea batatas cv. Wanmun, and to define the critical concentrations of these elements in young mature leaves during vegetative growth. Tentative critical concentrations for deficiency, expressed on the basis of dry weight of leaf blade, were: nit...

The lipid-storing tissues of plants contain many small (0.2–1 μl) lipid (normally triacylglycerol) droplets which are surrounded adn stabilized by a mixed phospholipid and protein annulus. The proteinaceous components of the lipid storage bodies are termed oleosins and are not associated with any other cellular structures. The major oleosins of rap...

This study investigated the physiological effects of a thylakoid-bound galactolipase activity, which may participate in thylakoid catabolism during foliar senescence. Electron transport through photosystem II was completely inhibited in thylakoids after only 30 sec of «galactolipase»activation. The thylakoids were completely uncoupled after 60sec....

Segments of attached primary leaves of wheat were labelled with either [14C]urea or Na[l-14C]acetate, and label was measured in the major classes of membrane lipids over several days. Urea label is rapidly incorporated into soluble sugars, and heavily labels the galactose moiety of the galactolipids, while acetate label is directed predominantly in...

The seeds of oleiferous plants, such as rapeseed, soybean and maize, can contain up to 50% lipid by weight, in the form of triacylglycerols. In mature seeds, the triacylglycerols are contained in oil storage bodies of diameter 0.5–1.5 μm. The mechanism of oil-body formation has been investigated in several oilseed species including rapeseed (Murphy...

When chloroplasts prepared from the primary leaves of wheat are incubated at pH 6.0, a large proportion of the thylakoid galactolipids, particularly monogalactosyl diacylglycerol (MGDG), is rapidly degraded. The hydrolysis is incomplete, producing Iyso-MGDG, together with free fatty acids (predominately linolenic acid, LNA). Initial rates are extre...

Isolated chloroplasts from wheat or barley leaves contain an oxidative chlorophyll-bleaching activity (Chlorophyll oxidase, or CHLOX) which is activated in the presence of free polyunsaturated fatty acids. We have shown that CHLOX can be activated by an endogenous «galactolipase » activity, which releases linolenic acid (LNA) from the abundant thyl...

A comprehensive tool for sweetpotato management, providing information across the disciplines of plant pathology, crop nutrition, entomology and pest management, all integrated in a single expert system