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WWF works to sustain the natural world for the benefit of people and wildlife, collaborating with partners from local to global levels in nearly 100 countries.
Each year, 41 million people die from noncommunicable diseases. These are noninfectious diseases that cannot be transmitted between people and include cardiovascular diseases, cancers, chronic respiratory diseases, diabetes, and mental health issues. Exposure to forests may reduce some factors that elevate the risks of noncommunicable diseases, and human stress hormones—such as cortisol, progesterone, and adrenaline—respond significantly when a person spends time in a forest.
Nearly one in three outbreaks of new and emerging diseases is linked to land-use change, including deforestation. Infectious diseases are the leading cause of death in low-income countries and the leading cause of death of children aged under five years globally. Intact forest landscapes allow animals the habitat they require to maintain distinct populations and limit the ability of infectious diseases to spread among and between species. Forest loss and degradation concentrates animal populations, which has led to the emergence of novel infectious diseases that can have dramatic impacts on people and society.
In 2015, air pollution (ambient and household) accounted for 6.5 million deaths, with noncommunicable diseases accounting for most of the disease burden. By filtering pollutants from air and water, forests help reduce the threats of pollution-related infectious diseases and noncommunicable diseases, including diarrheal disease, cancers, and respiratory diseases. Diarrheal disease is the second-leading cause of death and the leading cause of malnutrition in children aged under five years worldwide. A 30% increase in upstream tree cover is linked to a 4% reduction in the probability of diarrheal disease—similar to the effects of an improved sanitation facility.
Forests can offer a nutritional safety net. Each year, 3.1 million children worldwide die from undernutrition, while those that survive with poor nutrition during the first 1,000 days of life often suffer lifelong health, social, and financial challenges. Children with adequate nutrition will have improved cognitive and physical development as well as lower risk of morbidity and mortality.
Between 1996 and 2015, 1.3 million deaths were directly attributed to physical hazards such as wildfires, flooding, and extreme heat. Forests can provide protection against physical hazards in a variety of ways that can prevent death and protect human health. For example, as the planet faces a rise in extreme heat—affecting 1.7 billion people between 1983 and 2016—the cooling potential of forests is essential in battling the direct risk of heat-related illnesses such as heatstroke but also the impact that excessive heat has on exacerbating respiratory and chronic cardiovascular conditions.
We know that our exposure to physical hazards like heat and more severe storms and floods will increase and the habitat of common vectors of infectious diseases like mosquitoes and ticks will expand. We also know the nutritional content of staple foods will decrease as CO2 in our atmosphere increases. And we know people are more vulnerable to climate change if their health is compromised. For each of these impacts, forests represent an indispensable solution to mitigating and adapting to climate change while supporting the health and well-being of people.