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.

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 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.

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.