From advocacy to action: Projecting the health impacts of climate change
Authors: Hannah Nissan, Declan Conway
Journal: PLoS Medicine (2018)

Mitigating climate change by reducing greenhouse gas emissions has many health co-benefits and is a top public health priority.Policies to limit emissions are associated with improvements across a wide range of public health outcomes, including, among other impacts, obesity, acute respiratory infections among children, and ischaemic heart disease in adults [1].However, recognition that climate change is already underway has led to an increasing focus on adaptation.Studies projecting the impacts of future climate change on health date back to the late 1980s, and their number has grown substantially in recent years.Climate change impact assessments generally use the output of global climate models (GCMs).Here, we profile, and suggest means for addressing, the challenges associated with the use of GCM projections for impact studies to inform adaptation.GCMs provide projections of the climate at a typical resolution of about 100 km 2 .Such low precision is of limited use to decision-makers trying to determine how climate change might affect their particular district, town, or even country.Often, a regional climate model is employed to 'downscale' the output of the global model to a resolution considered more useful for practical applications.Climate model output can then be used to drive disease models or to investigate the risks of surpassing health-relevant climate thresholds in the future.The outputs of these analyses are often explicitly intended to inform the development of adaptation strategies and plans.However, there is little evidence that climate change projections are used to inform practical adaptation decisions [2][3][4].Climate change projections typically target the future several decades ahead, or even at the end of the century.Yet the most pressing issues faced by people and institutions often necessitate a focus on the present and near-term future, particularly in developing countries where there is less capacity to act [3].Heat waves, for example, are an increasing risk to human health in a warming climate, but many of the most effective strategies to reduce this risk concern the development of seasonal adaptation plans and early warning systems [5].These programs allow a range of preparedness measures to reduce vulnerability and exposure, from training and awareness-raising activities at the start of the summer season to emergency interventions that could include public alerts, opening cooling centres, and distributing drinking water.In India, for example, moving the neonatal ward from the top to the bottom floor of a hospital had a significant protective effect and required no forecast information at all [6].Even when the long term is relevant, as, for example, in the case of large infrastructure developments, the uncertainties involved in climate prediction on local scales are so large that they can exceed the magnitude of the projected change [7].Moreover, with many relevant non-climate factors, it is difficult to disentangle the role that climate change projections may have played in the development of an adaptation plan.