Long-term trends in the Australaian gannet (Morus serrator) population in Australia: the effect of climate change and commercial fisheries

The Australasian gannet (Morus serrator) population has increased considerably over the past century, both in New Zealand and Australia. Since 1980, the population in Australian waters has increased threefold, from 6,600 breeding pairs to approximately 20,000 pairs in 1999-2000, a rate of 6% per year. Reasons for the increase in the Australasian gannet population are poorly understood; here we consider the possible effects of recent fluctuations in climatic and oceanographic conditions, and changes in major local commercial fisheries. A significant trend towards more frequent, and stronger, El Niño Southern Oscillation events, warmer summer sea surface temperatures in Bass Strait, increased annual catches and catch per unit effort in the Victorian pilchard (Sardinops sagax) fishery and potential increased discarding of fisheries bycatch may account for at least some of the observed increase in the Australasian gannet population. The potential interactive effects of these factors on prey distribution and abundance and consequently on gannet numbers are discussed.

Too hot to trot? exploring potential links between climate change, physical activity and health

Based on an analysis of existing literature, this paper explores the links between climate change, physical activity and health. It highlights the importance of physical activity for health, explores current understandings of factors influencing participation in sport and physical activity, and develops some hypotheses about the ways in which climate change may impact on the factors influencing physical activity and thereby on the level of participation in physical activity. The paper argues that climate change has the potential to be a barrier to participation in physical activity, particularly in areas where temperatures are already relatively high, and that a reduction in physical activity across the population is likely to have detrimental health impacts. The need for research to clarify the nature and extent of the threat posed to physical activity participation is highlighted, as is the need to take into account the direct and indirect costs of any changes or reductions in physical activity in any assessment of the costs of climate change and/or its mitigation.

Biotic effects of climate change in urban environments: The case of the grey-headed flying-fox (Pteropus poliocephalus) in Melbourne, Australia

Urban climates are known to differ from those of the surrounding rural areas, as human activities in cities lead to changes in temperature, humidity and wind regimes. These changes can in turn affect the geographic distribution of species, the behaviour of animals and the phenology of plants. The grey-headed flying-fox (Pteropus poliocephalus) is a large, nomadic bat from eastern Australia that roosts in large colonies known as camps. Historically a warm temperate to tropical species, P. poliocephalus recently established a year-round camp in the Royal Botanic Gardens Melbourne. Using a bioclimatic analysis, we demonstrated that on the basis of long-term data, Melbourne does not fall within the climatic range of other P. poliocephalus camp sites in Australia. Melbourne is drier than other summer camps, and cooler and drier than other winter camps. The city also receives less radiation, in winter and annually, than the other summer and winter camps of P. poliocephalus. However, we found that temperatures in central Melbourne have been increasing since the 1950s, leading to warmer conditions and a reduction in the number of frosts. In addition, artificial watering of parks and gardens in the city may contribute the equivalent of 590 mm (95% CI: 450–720 mm) of extra rainfall per year. It appears that human activities have increased temperatures and effective precipitation in central Melbourne, creating a more suitable climate for camps of the grey-headed flying-fox. As demonstrated by this example, anthropogenic climate change is likely to complicate further the task of conserving biological diversity in urban environments.

The climate change and development nexus

The rapid economic success achieved by the developing countries in general, and India and China in particular, has brought the issue of climate change, which is a spin-off of development, to the fore. Economic growth is essential for the eradication of poverty and generation of wealth. However, it drives energy consumption and demand for energy which, in turn, produces toxic gases like carbon dioxide (CO2 ). Thus, the price of economic growth is climate change. The paradox lies in the fact that when economic growth is the only solution to poverty, the resultant climate change (characterized by emission of greenhouse gases) also affects the poor greatly. In this context, it is observed that while traditionally the developed countries were charged with polluting the environment globally, now the developing countries have overtaken their counterparts as polluters. The developing countries have emerged, over the years, as the agents responsible for growing pollution in the world, though they are also the victims, as most of the poor people belong to the developing countries. The author explores the nexus between climate change and development in the context of the economic growth of the developing countries and its impact on them.

Climate change and human health: what can GPs do?

In recent months articles in the most respected peer reviewed medical journals in Australia, the USA and Britain have called for urgent action to reduce climate change.1–4 The chief scientist of the United Kingdom has described climate change as ‘the most severe problem that we are facing today – more serious even than the threat of terrorism’.5 Yet, many of you will wonder if this is really such an urgent issue, and – even if it is – what on earth has it got to do with general practice?

Action on climate change : the health risks of procrastinating

Objective: The world's climate will continue to change because of human influence. This is expected to affect health, mostly adversely. We need to compare the projected health effects in Australia arising from differing climate change scenarios to inform greenhouse gas emission (mitigation) policy.

Methods: We estimated health effects in Australia (heatwave mortality, dengue transmission regions) around 2100 under various greenhouse gas scenarios: "strong policy action" (efforts made now to reduce emissions) and "no policy action" (emissions continue at present high levels with no climate change-specific policies).

Results: Compared with no policy action, mitigation could reduce the number of deaths caused by hot temperatures among older Australians by 4,000–7,000 a year (range reflects likely population size at 2100). Under a scenario of "no action", the zone of potential transmission of dengue fever expands 1,800 kilometres (km) south, as far as Sydney. In contrast, by markedly constraining greenhouse gas emissions now, this southward extension could be limited to 600 km (to Rockhampton). The number of displaced people within the Asia-Pacific region could increase (by orders of magnitude) under the "no action" scenario because of adverse socioecological circumstances aggravated by climate change.

Conclusions: Additional health effects will accrue as a result of the projected climate change throughout this century, and individuals and health systems should be prepared for some level of adaptation. However, timely and strong policy action to reduce greenhouse gas emissions would diminish the extent and severity of estimated future health effects.