Albeit on a much larger scale, climate change reminds me of how I felt in March 2014 when I heard about the first case of Ebola virus disease (EVD) in Guinea. Having spent many years in West Africa, I could only begin to imagine the breadth of destruction it would have on the lives of thousands. At the early stage of the EVD outbreak, the world struggled to respond appropriately because we had never experienced such a large outbreak of this disease. Climate change feels the same way, except that we have much better advance knowledge that if the world does not make drastic changes immediately, climate change will have a devastating health effect on countries across the globe.For more than seven decades, Catholic Relief Services (CRS) has responded to both sudden-onset or short-term and slow-onset or long-term emergencies, as a result of both natural disasters and conflict. In 2015, we worked in 101 countries and reached more than 100 million people. Our programing in agriculture, health, and emergency response-our three main areas of intervention-engages a wide range of partners, from civil society and governments to private companies and universities, working with community health workers as well as local health facility and district hospital staff and Ministry of Health representatives. While climate change has an impact on many areas of human health, this commentary is grounded in my expertise in mosquito-borne diseases.The Problem or Challenge From a Public Health Point of ViewFrom a public health perspective, change in the climate means changes in precipitation levels, which may cause flooding and impact health and nonhealth sectors alike. For instance, flooded lands make it difficult or impossible for farmers to cultivate their land, which in turn means reduced nutritious foods for families, affecting the health of pregnant women and children, among others. Flooding also means an upsurge in water-borne diseases and an increase in standing water, which forms a perfect breeding ground for mosquitos, thereby increasing vector-borne diseases such as malaria and Zika.Rising temperatures also means the (re)introduction of malaria in what are currently malaria-free areas. Conversely, this could also mean that there might no longer be malaria in current areas. However, the likelihood of the former could have a dramatic negative effect on the loss of human life and the health burden to humans. This would lead to a rise in malaria epidemics, since such communities would not have acquired natural immunity from the ongoing presence of the malaria parasite (and perhaps would not have the knowledge to prevent malaria) and would be hit with the disease just as hard as foreigners traveling to malaria-endemic countries. In countries with less developed health systems than those in Europe or the United States, this could unfortunately mean many lives lost.In CRS, we see climate change as undermining our investment in supporting national malaria control programs in developing countries to prevent and control malaria activities, such as seasonal malaria chemoprevention, which aims to eliminate malaria from a specific geographic area by providing prophylactic drugs to children 3 to 59 months of age. In addition, in the last few months of 2015, areas as diverse as India and Zimbabwe have struggled with sudden outbreaks of dengue fever, a disease also transmitted by a mosquito. This might forecast the rise of a broad spectrum of vector-borne diseases in the near future, just like we have recently seen with the Zika virus.The Solution From an International Nongovernmental Organization Point of ViewClimate change jeopardizes health for millions, and in turn will affect the way international agencies such as CRS respond to its effects. Since CRS works across sectors that include health and water management, we can contribute to reducing the negative health impacts caused by climate change and in mitigating the impact of climate change on the environment and agriculture and therefore livelihoods. …