Posts Tagged dengue fever

Changing Planet, Changing Health Bryan Walker May 23

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Interconnectedness is a major theme of Changing Planet, Changing Health: How the Climate Crisis Threatens our Health and What We Can Do about It. Jeffrey Sachs describes the book in his preface as ’a scientific detective story of the first order, told with brilliance and relish by one of the world’s great ecological detectives’. The detective is physician and public health scientist Paul Epstein. He has co-authored the book with science writer Dan Ferber.

I warmed to the humanity of Epstein. He and his wife, a nurse, spent two years in newly independent Mozambique in 1978, part of a wave of cooperantes responding to the call for expert help from the government of a country deserted by its Portuguese professionals and destabilised by the South African apartheid regime’s funding of rightist guerrillas. It was there he experienced his first cholera epidemic and gained a new appreciation of the interwoven environmental and social determinants of health. And it was after that experience that he took up the study of public health at Harvard when he returned to Massachusetts. Throughout the book a decent human concern for the life conditions of poorer populations is evident. Human stories punctuate the narrative.

A later cholera epidemic in Peru in 1991, combined with the ground-breaking research of Rita Colwell pointing to the warm ocean as a source of cholera outbreaks, set Epstein on a new path of investigating the threats posed by global warming to human health. It’s rarely a simple connection as other factors are usually also involved, but he teases out the evidence convincingly. He describes, for instance, the painstaking work of Kenyan scientist Andrew Githenko in establishing that it was a warming temperature which enabled the spread of malaria-transmitting mosquitoes to the East African highlands previously free from them. His case had to be made in the face of strong and bitter opposition from medically well-credentialed deniers who blamed the malaria resurgence not on climate but on diminished efforts to kill mosquitoes and the malaria parasite’s growing resistance to drugs.

The book traces the threads which point to the increase of other diseases like Dengue fever, Rift Valley fever and Lyme disease as in part due to climate change. The narratives of the careful scientific work which underlies the attribution are fascinating reading, the conclusions modest and qualified. It seems highly likely that the climate change combination of warming and greater weather variability means millions face a higher risk of infectious disease.

A chapter on the air we breathe implicates the burning of fossil fuels as a factor in the occurrence of allergies, asthma, and other lung diseases. The confidence of an American senator recently in denying that carbon emissions and climate change are connected to asthma and sick children is not shared by the science Epstein explores. Not that that seems to bother many Republican politicians in their current fever of denial.

The book is not restricted to the effects of climate change on the occurrence of human diseases. It discusses, for example, the effects of raised CO2 levels on crops, among other things cautiously pointing to possible evidence that more CO2 and climate change may tip the plant-insect balance of power in favour of the insects. A plug for sustainable agriculture fits well at this stage of the book. The intricate connections of human health and welfare with the world’s seas and forests are highlighted as the effects of climate change on those vast ecosystems is explored. Some, such as the effects of lower fish takes on the diet of poorer populations, are immediately apparent.  Others, such as our dependence on biodiversity for our pharmaceutical treatments, are easily overlooked. Extreme weather events, especially in poorer parts of the globe, can result in clusters of epidemics on top of their immediate impacts.

The authors are up to date with climate science and fully aware that CO2 levels are going higher than they have been for millions of years. The whole Earth system as we have known it is heading for profound change. Taking a little Gaian licence they consider it fair to say that Earth has fallen ill. From our human point of view it certainly has, and there’s no arguing with the authors that we are in uncharted waters.

However the writers are interested in avoiding disaster and the last third of the book addresses that. Epstein has been involved with the insurance industry and has an interesting story to tell of the engagement of big reinsurers and other businesses with climate change issues, with encouraging evidence of at least some taking positive steps towards sustainability.  Solutions have to be treated with care. He looks at life cycle analyses of alternative energy sources, reporting one by a Stanford professor which came up with the following list in order of merit:  wind, concentrated solar, geothermal, tidal, solar photovoltaics, wave, hydroelectric, and then a last place tie between nuclear and coal with carbon capture and storage. The book notes that coal with CCS emits 60 to 110 times more carbon and air pollution than wind energy. Biofuels are only marginally better than nuclear. The policy favourites are nuclear, clean coal and biofuels, but Epstein regards them as duds, favoured only because of the powerful interests promoting them.

We need some basic changes if we’re to get past the dominance of vested interests. The rules of finance and trade must be rewritten. The rigid international free-market system which has held sway since the 1970s is driving poverty in the developing world. Currency speculation is wreaking havoc for many developing countries. Perverse subsidies are driving deforestation and supporting the production and consumption of fossil fuels. They must be dismantled. A large global environment and development fund, representing perhaps 1% of global GDP, needs to be established to enable poorer countries to protect biodiversity and tackle climate change.

The attention given to the global economic system is not an add-on to the health questions the book addresses. Early in the book Epstein describes himself as guided by systems theory, which means trying to see the whole, not just the component parts. He can’t look at the health problems climate change visits on a developing nation without also considering what the dominant economic order is doing to that nation. Honduras, for example, he describes as a poor country whose plight arises from many disasters, some natural, some the result of climate change, but some the result of global forces beyond their control. Mining, shrimp farming and monocrop agriculture extract resources from the country. Each sector is owned by wealthy foreign countries, each generates products for export, and in each case the profit is shared among a handful of politically connected Hondurans and the North American companies who own the projects.

The book argues for an acknowledgment of the seriousness of the threat to global health presented by climate change. It also argues for changes in the global economic system. To create a truly sustainable future we must accept limits. Boundless resources are not there for the taking. Heaven knows whether such sentiments are likely to prevail against current tides, but a book concerned with climate change and human health is surely right to voice them.

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When warming burns… Bryan Walker Aug 19

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Severe risks to human health will accompany the disturbed global climate which comes with global warming. We have only to consider the consequences of the heat waves, the flooding, the African droughts, of recent times to be alerted to that. Our experiences of climate change in New Zealand are unlikely to reach such extreme levels, but we would be wise to think and prepare ahead for the kind of human health hazards we may expect to encounter. Chapter 8 in Climate Change Adaptation in New Zealand (pdf download) is an attempt to sketch out measures we might prepare to take. Four of the five writers are from the Department of Public Health at the University of Otago and one from Victoria University.

The paper rehearses some of the widespread major impacts which will affect human health globally. Higher maximum temperature will lead to increased heat-related deaths and illnesses and contribute to an extended range of some pest and disease vectors. Droughts and forest fires will increase in severity and frequency. More intense rainfall will lead to slope instability, flooding and contaminated water supplies. More intense large-scale cyclones increase the risk of infectious disease epidemics (e.g. via damaging water supplies and sewerage systems) and the erosion of low-lying and coastal land through storm surges. Indirect effects include economic instability, loss of livelihoods and forced migrations.

We have early indications of what the changes are likely to be, and it’s important to be ready with a range of policies to address them rather than wait and react as they occur. Prevention is better than cure. New Zealand may not experience the extremes which will be felt in some parts of the world, but there is much that would wisely be given attention.

One eventuality for which we need to be prepared, and which the article highlights, is the possibility of New Zealand becoming a lifeboat to those living in more vulnerable Pacific countries who are displaced by the impacts of climate change. Particularly is this to be expected if a high carbon scenario prevails, as increasingly seems on the cards. Families forced to leave their island homes are likely to form a pattern of chain migration to New Zealand. Unless, under such circumstances, we recognise the need to build extended-family houses or generally increase the supply of low-income family housing to accommodate these immigrants, we are likely to see an increase in overcrowding in state houses and other low-income housing. This could mean a dramatic increase in the risk of a number of infectious diseases.

Infectious diseases are likely to become more prominent with climate change. Warmer temperatures and increased rainfall variability can increase food-borne and water-borne diseases. Vector organisms such as mosquitoes, ticks and sandflies are strongly affected by temperature levels and fluctuations. Hopefully the risk of dengue in New Zealand may remain below the temperature threshold for local transmission, but there is likely to be a potential for outbreaks of Ross River virus infection.

Flooding is another aspect of climate change to which the paper gives some attention. Adaptive responses, such as health and housing protection and provision during and after extreme events, should not increase health inequalities.  The spectre of New Orleans is invoked to illustrate this. The possible need for relocation of towns and even parts of cities looms in some areas of the world. In New Zealand the sustainability of Kaeo, flooded several times in recent years, has been questioned. But given low income levels and less disposable income for private insurance in such towns, government assistance is likely to be needed to facilitate relocation.   

Other possible health impacts in New Zealand are touched on, including the effects of heat stress on outdoor workers, the exacerbation of asthma symptoms from increased amounts of allergen-producing pollens, the possibility of water charging by local authorities depriving lower income households of access sufficient to ensure general cleanliness.

Isolation and poor access to services puts people at increased risk. Severe mental health problems are identified as a likely risk in rural communities suffering the effects of extreme weather events. Such vulnerability extends also to low-income populations living in socio-economically disadvantaged, residentially segregated areas where there is less public transport and fewer people who own or have access to cars. The paper makes a good deal of the need for adaptation policies to be equitable and fair and inclusive.

Individual adaptive action can be hampered by lack of understanding, but may be attractive when there are co-benefits. An example is walking, cycling and taking public transport which can be presented as less a sacrifice of time and convenience and more an opportunity to socialise, keep fit, and do one’s bit towards a smaller carbon footprint.

At the community level the paper points to the critical role of local government. The progressive modification of urban form will be an important part of adaptation. Intensifying housing, for example, can reduce the vulnerability of dispersed communities and at the same time help build social capital that links together different social and ethnic groups, while reducing car dependence and energy use. Health and environmental benefits can flow from this.

New Zealand cities have little high density housing and a good many large sprawling suburbs. Some attention is beginning to be given to climate change adaptation issues. The paper focuses on dealing with storm-water run-off and urban heat island effects. Trees, parks and roof-top gardens and reduction of roads and parking lots are among the measures to reduce heat effects. Passive cooling of buildings through good design and the painting white of some surfaces also works to this end. Measures to slow storm water run-off, such as rooftop collection, replacement of hard surfaces by porous paving and well-vegetated low-lying areas can reduce risks. Steps to prevent the incursion of storm water into sewerage systems are important.  

Enhanced social networks in cities and other local communities will be needed to provide closer monitoring of, and assistance to, vulnerable people and populations. Living behind locked doors with little neighbourhood contact is not a good preparation for the stresses climate change will bring.

Some needed changes require central government involvement. The paper mentions such matters as retrofitting houses to make them more energy efficient, raising standards in the Building Code, providing social housing. But it also notes that the government record to date shows little sign of advance, and that lack of government progress on mitigation makes adaptation more difficult.

Local government in New Zealand is already expected to take climate change into consideration in its planning, and is provided with useful information by the Ministry for the Environment for doing so. The kind of thinking about health impacts expressed in this paper fits well into the overall intention to “avoid or limit adverse consequences and enable future generations to provide for their needs, safety and well-being.”  Some of it overlaps with measures already recommended to councils. All of it is worth taking up in the discussions and reports that mark local government.  Central government seems trickier ground, more subject to the vagaries of ministers and politics, but one hopes that the good sense represented in papers such as this makes its way there too.