SciDev.Net

This factsheet from The Center for International Forestry Research (CIFOR) aims to answer common questions about the role of reducing forest emissions in tackling climate change.

This includes explaining why reducing emissions from deforestation and forest degradation (REDD) is important and identifying the four key challenges facing REDD projects — measuring carbon, making payments, accountability and funding. The authors summarise ongoing global initiatives to implement REDD, including the UN REDD Programme Fund and the Forest Carbon Partnership Facility.

A glossary of terms used in the debate is included as well as a list of facts and figures on key variables such as forest cover and forest loss. Contact details for some of the key people involved in CIFOR research are provided.

This journal article, written by three researchers in Trinidad and Tobago, looks at malaria in the Caribbean. It asks why there are still outbreaks — including a big one in Jamaica in 2006/2007 — when the disease was allegedly eliminated in the late 1950s. The authors review malaria and vector data from across the Caribbean, summarising the pattern of imported cases as well as indigenous ones.

They identify three essential conditions for malaria transmission: presence of the vector, imported organisms and susceptible human hosts — all of which the authors show still exist across the Caribbean.

The authors suggest specific actions for regional policymakers to combat malaria. These include enhancing vector control skills, strengthening surveillance with new technologies, upgrading malaria therapy, increasing prevention strategies such as bed nets and raising public awareness of malaria. They emphasise that the role of climate change must be considered too, saying that rising temperatures could lead to new malaria vectors entering and colonising Caribbean islands and transmitting malaria on a major scale. But the authors are also careful to point out that the link to climate change is uncertain and remains contested in scientific circles.

This report from the WHO assesses the potential for creating early warning systems for vector-borne disease. It reviews the current state of research for several diseases such as dengue fever, leishmaniasis, malaria and West Nile virus.

The report includes an algorithmic framework for developing early warning systems, outlining data requirements and the different components of the system. It also contains two useful tables: one on the sensitivity of different infectious diseases to climate; and one summarising the existing research, identifying in which region the disease is most common, data availability and proposed actions.

A key problem in developing early warning systems, as highlighted by this report, is that non-climatic risk factors such as population immunity and food security strongly affect the potential for a disease outbreak. Equally challenging is the poor disease surveillance in many developing countries — the authors call on these countries to strengthen these systems, to help in the fight against climate change.

The report concludes that it will be important for researchers not to design these systems in isolation — health policymakers should be included at all stages of the design.

The third IPCC assessment report, Climate Change 2001, includes this section on the links between climate change and health. It offers a detailed look at how variations in climate, such as temperature or rainfall, could affect vector-borne disease. In particular, it evaluates computer models that predict climate impact on dengue fever and malaria. The assessment also looks at specific diseases such as leishmaniasis or schistosomiasis, explaining how the disease is spread and how changes in the environment might alter that spread.

The authors take a holistic look at the various factors involved. For example, in assessing schistosomiasis, they also consider the irrigation systems that will likely be needed to cope with expected water shortages resulting from climate change. The schistosomiasis parasite uses water snails as an intermediate host, so irrigation systems will need to be designed in such a way that they do not cause snail populations to multiply.

An update to the research on climate and vector-borne disease is also included in the fourth IPCC assessment report[796kB] although not in as much detail.

This journal article describes the first climate-based model used to predict outbreaks of dengue fever. Researchers from the University of Miami and the University of Costa Rica used climate data and vegetation indices from Costa Rica to predict disease outbreaks with 83 per cent accuracy.

Globally, there are up to 100 million cases of dengue fever, and its more dangerous form, dengue haemorrhagic fever, every year. The spread of dengue fever is set to rise as the world's climate changes. The importance of this model is that it could be used as the basis for an early warning system to prevent the spread of the disease by warning populations that are at risk.

The indices used in the model include variables such as El Niño Southern Oscillations and sea surface temperature, which affect populations of the Aedes aegypti mosquito that spreads the infection.

This Nature paper reviews evidence that a changing climate poses significant health risks and that global warming over the past few years has already increased illness and death worldwide.

Infectious diseases are strongly affected by climatic variations because the vectors that carry the bacteria or viruses do not have thermoregulatory mechanisms, say the authors. One of the most important existing sources of climatic variability is El Niño. This weather system has been shown to influence malaria in South America, rift valley fever in east Africa, cholera in Bangladesh and dengue fever in Thailand. If, as some scientists have suggested, climate change alters El Niño, the consequences will be significant.

The authors say there are some promising early warning systems for infectious disease. In Botswana, for example, two-thirds of the inter-annual variability of malaria can be predicted from sea surface temperatures and monthly rainfall.

A population's immunity to disease can greatly affect outbreaks of vector-borne disease, and isolating the influence of climate variability has proven difficult. This research study sets out to evaluate the effect of climate by accounting for population immunity.

The authors collated data on cholera cases from a predominant strain in the rural area of Matlab, Bangladesh, from 1966–2002. They used a model to incorporate immunity from previous infections and also potential cross-immunity from previous infections by other strains. They found that both forms of immunity were long-lasting — over 10 years in some cases. Yet the variation in transmission did not always match variations in immunity; at several points, it coincided with severe weather change such as monsoon rains or river overflow.

The authors suggest that forecasting disease will require considering climate variability alongside population susceptibility.

This extensive report from the Institute of Medicine of the US National Academies takes on the considerable challenge of understanding how, and to what extent, climate change will affect infectious diseases.

The report provides detailed summaries of current knowledge on diseases such as cholera and rift valley fever. Several pages are devoted to reviewing the latest climate science to contextualise the effect on infectious disease; it also includes several maps on climate anomalies to show how they are linked to disease.

One section highlights methods to assess climate change impacts on infectious diseases. These include analyses of historical records; monitoring programs, especially those that track disease in wild animals; and comparisons of satellite-derived environmental measurements with epidemiological data.

The report concludes with an analysis of the challenges facing policymakers. In many cases, it says, the best public health measures against climate change are those that strengthen health systems in general, such as better training for professionals and better disease surveillance. Policymakers will need to move away from the traditional thinking of individual policies for individual diseases, towards a joined-up approach aimed at tackling "systemic, long-term" stresses that cause a range of effects.

Paul Reiter, a researcher on insects and infectious disease at the Institut Pasteur in France, is not convinced that climate change will cause a rise in malaria in tropical regions. In this opinionated review he sets out to dispel widely held "common misconceptions" about the effect of climate variability on future transmission.

To do so, he examines the history of malaria. He finds that in the past, contrary to expectations, climate has often not affected the transmission of the malaria parasite. Researchers claim that the Anopheles mosquito that carries the parasite cannot survive extreme temperatures, yet Reiter cites examples of the mosquito finding ways to adapt. In Sudan, for example, they can survive temperatures of over 55 degrees Celsius by hiding in buildings in daytime and only feeding after midnight.

Reiter's main disagreement with prediction models is that they only look at how one climate variable, temperature, is likely to interact with mosquito populations. Temperature, rainfall and humidity are interconnected and cannot be analysed separately, he says. The ecology of mosquitoes and humans is too complex to predict future malaria prevalence and incidence from temperature alone, he adds.

As global temperatures rise, vector-borne disease is set to increase in the developing world but patterns will vary across countries. This review looks at how the prevalence of vector-borne disease will change in Africa, Asia, Australia, Europe, North America and South America.

As the authors explain, urbanisation levels will determine which diseases are likely to hit hardest. For example, dengue fever is a largely urban disease and will affect South America, where over 70 per cent of the population live in cities, far more than it will Sub-Saharan Africa, where less than 30 per cent of people live in urban areas. Malaria, by contrast, will have a bigger impact in Africa.

As ecosystems change, so will the distribution of vector species. Some will find their habitats expanded. A positive note is that most vectors cannot survive above about 40 degrees Celsius, so regions in which warming tips the temperature over this level could well see a drop in vector-borne disease — this is starting to be seen in Senegal, for example.

But the precise extent to which climate variability affects vector-borne disease is yet unknown, say the authors, which hampers evidence-based policy change.

This report provides a policy framework for assessing the impacts of climate change on health, including vector-borne disease, by considering five challenges: informational, poverty and equity-related, technological, sociopolitical and institutional.

It begins with a detailed outline of climate science so far and the financial cost of adaptation. The informational challenges relate to better monitoring and surveillance to gather urgently needed data on disease and mortality in different regions, and early warning systems to predict extreme weather events and associated disease outbreaks. Technological challenges include the development of vaccines for diseases such as malaria and dengue fever.

How do policymakers tackle such challenges? A key move will be for government and non-government agencies, academia and civil society to collaborate internationally. Surveillance and primary health information systems in developing countries must be improved and local communities need to share adaptation strategies.

Adapting to climate change also means investing in food security, clean water supplies and reforestation. Policymakers also need to stimulate industry to develop low-cost methods for recycling wastewater and desalinating sea water. Mitigating and adapting to climate change, say the authors, has become inextricable from policies to eradicate poverty or closing the gap on social inequalities and health.

This guide, published by Tebtebba (Indigenous Peoples' International Centre for Policy Research and Education), outlines the expected impacts of climate change on indigenous peoples around the world, and showcases traditional methods of climate change mitigation and adaption.

Following a basic introduction to climate change and the bodies, mechanisms and processes used for addressing it, the authors outline how climate change is impacting indigenous peoples in diverse ecosystems. For example, food and water insecurity arising from increased flooding or drought, and loss of biodiversity and traditional knowledge from rising temperatures.

The authors discuss the likely impacts of climate change mitigation measures highlighting, for example, the limitations of market-based strategies such as the Clean Development Mechanism. They discuss a range of alternative adaptation measures already being practiced by indigenous people, providing several case studies and examples of innovative strategies used in different regions. For example, African farmers using zero-tillage practices to moderate soil temperatures, Asian farmers growing varieties of crops to minimise the risk of harvest failure, and Honduran farmers using agroforestry and terracing to reduce erosion.

The authors go on to discuss measures for reducing emissions from deforestation and forest degradation (REDD) and emphasise the need for indigenous people to be fully engaged in the debate.

This report, prepared by the World Water Assessment Programme under UNESCO (UN Educational, Scientific and Cultural Organization), assesses global freshwater resources including what drives the pressures facing them, how water is used, climate change's future effects on water supplies and options for improving water management for sustainable development.

The authors highlight the increasing demand for water, outlining the demographic, economic and social factors — such as population growth, international trade and changing lifestyles. They argue that climate change will undoubtedly affect water resources, impacting water quality and the frequency of extreme events such as droughts or flooding.

Investment in the water sector is important, say the authors — to improve access to clean water as well as decrease pollution from untreated sewage discharge. International donors must play a part in improving water infrastructure in the developing world, they add.

But how individual countries respond will depend on their own development objectives, capacity and political framework. The authors outline options for policymakers to increase supply, manage demand, reduce losses and reallocate resources.

This report, jointly published by the Food and Agriculture Organization, the Secretariat of the Pacific Regional Environment Programme and the University of the South Pacific, examines the likely impacts of climate change on Pacific island countries, with a focus on food security threats.

Two reports from international meetings and three case studies — from Vanuatu, the Republic of Marshall Islands and the Cook Islands — highlight small island vulnerability. Each case study includes an overview of the country's socio-economic status, an assessment of its agricultural sector and a list of likely climate change impacts, including ocean warming, frequent tropical cyclones, flash floods and droughts.

The authors include successes in each case and make recommendations for future action. They call for a systematic approach to climate change, using national development plans to implement adaptation programmes.

This report, written by a team of international scientists and published by the UN Environment Programme (UNEP), explores the effects of 'atmospheric brown clouds'(ABCs) on regional climate, agriculture and human health.

ABCs are large plumes of pollutant gases that result from burning fossil fuels and biomass. The authors of the UNEP report examine the spread of ABCs — particularly in Asia — and discuss their likely impacts, including decreases in the Indian summer monsoon rainfall, accelerated glacial retreat and increases in surface ozone.

They suggest that ABCs threaten water and food security in Asia, impact human health and may mask the warming effects of climate change by 20 – 80 per cent. The authors recommend an international response to tackle the twin effects of ABCs and greenhouse gases, and the unsustainable development that underpins them.

The authors of this article analysed simulation results from a regional climate model for the northern Indian Ocean to predict likely changes in the strength and frequency of tropical cyclones in the Bay of Bengal from 2041–2060.

They find that rising concentrations of greenhouse gases will lead to more frequent cyclones in the region, particularly during the post-monsoon period. In addition, the number of intense cyclones and storm surges will increase. These results are consistent with other trend analyses that show intensification of cyclones in the bay during the last century.

But the research described in this paper only deals with simulations from one future climate scenario. To obtain better regional climate projections, the authors suggest it is necessary to examine simulations from more scenarios.

This report by the Institute for Development Studies details the results of a pilot project in Bangladesh aimed at developing a screening process for the UK Department for International Development (DFID) to identify and manage climate change impacts on development investments.

The authors highlight predictions that climate change in Bangladesh may lead to stronger cyclones, increased flooding during the monsoon rains and exacerbated drought in the dry season.

They suggest that raising roads and improving drainage could be a cost-efficient way to reduce the impact. Other options recommended for managing risks include paying greater attention to infrastructure design in health, education and private sector development programmes; and to non-structural measures such as livelihood diversification, education and training about disaster risks and adaptation, and improved research and monitoring.

The authors conclude that DFID should support dialogue on disaster risk reduction and climate change adaptation, integrate priorities identified by the Bangladeshi government, increase emphasis for assistance on urban areas, and stimulate a multi-donor dialogue about water issues.

This paper discusses likely future changes in tropical cyclones, questioning whether they will become more intense following higher sea surface temperatures. The author outlines the different approaches currently taken to climate modelling and discusses the results of characterising current and future climate using the Max Planck Institute for Meteorology in Hamburg model, comparing them to observations.

Most climate models predict stronger tropical cyclones in a warmer climate, as an increase in latent heat provides more energy for the storms. But the author claims there is less evidence for a reduction in the frequency of storms in a warmer climate. Still, such a reduction could result from a general weakening of large-scale atmospheric circulation (which reduces the number of cyclones) caused by the rapid increase in water vapour that would follow a rise in global temperatures.

This book-length report details a study by the International Livestock Research Institute (ILRI) and the African Centre for Technology Studies (ACTS) that aimed to map vulnerability to the impacts of climate change in Africa. 

Climate change models of four different future scenarios were used and the impacts on agriculture assessed. Biophysical and social vulnerability were also analysed, using indicators developed specifically for this research.

The outcomes suggest, if tentatively, that many already vulnerable systems may be adversely affected by climate impacts, including the mixed arid-semiarid systems in the Sahel and rangelands in eastern Africa, the Great Lakes region, the coastal regions of eastern Africa and the drier zones of southern Africa.

The report concludes that adaptation is best researched at national or regional levels, not the macro level, due to local variability, and that communities themselves need to become much more involved in adaptation strategies.

This report published by the IUCN (The World Conservation Union) is based on participatory consultations with stakeholders and provides a comprehensive and in-depth account of West Africa's vulnerability to climate impacts on water resources, wetlands and desertification. 

The report contains two parts; the first section details the regional context, climate impacts on water resources and West Africa's preparedness at present. This is followed by an outline of a potential regional adaptation strategy, its methods and its implementation. 

This report offers recommendations on how African water resources specifically may be affected by climate change, but also ways collaboration for adaptation can be strategic and useful.