Impacts of Climate Change


Climate change is likely to have wide ranging and mostly adverse effects on human health with significant loss of life. (WGII SPM).


Global climate change poses substantial risks to human health. Millions of people could be affected and the IPCC anticipates that most of the impacts would be adverse. Increases in mortality from heat waves compounded by more severe urban air pollution are predicted with high confidence. Increases in infectious diseases, such as malaria and schistosomiasis, are also predicted with high confidence, due to the geographical spread of conducive climactic conditions and changes in the lifecycle of disease vectors and infectious organisms. Finally, other impacts of climate change, such as sea-level rise and increases in drought in some places and more intense flooding, would also adversely affect public health by increasing hunger in some areas, by damaging infrastructure and displacing populations.

IPCC Findings

The sustained health of human populations requires the continued integrity of Earth’s natural systems. The disturbance, by climate change, of physical systems and ecosystems would therefore pose risks to human health.

Heat Stress

Extensive research has shown that heat waves cause excess deaths. The IPCC predicts, with high confidence, that climate change will cause additional heat-related deaths and illnesses. Studies in selected cities in North America, North Africa, and East Asia indicate that the number could more than double by the end of the next century, representing several thousand extra deaths annually in number of very large cities. It has been reported that 669 people died prematurely during the American Midwest heat wave during the summer of 1995, providing a picture of what the future will bring. Although cause and effect cannot be established for any single event, this heat wave is consistent with IPCC predictions.

Infectious Diseases

Vector-borne diseases are a major cause of illness and death in tropical countries. Rather than being transmitted directly from human to human, these diseases are transmitted by insects or other vectors. Climate is an important determinant of the spread of vector-borne diseases, affecting the distribution of the disease-carrying insects as well as the infectiousness of the disease itself. The IPCC concluded that “in general, increased warmth and moisture would enhance transmission of these diseases.” One model of malaria transmission indicates that global warming could cause 50-80 million additional cases annually. Although this quantitative result must be viewed cautiously, and does not account for the potential for public health measures to mitigate the impact, it clearly indicates the magnitude of the potential impact of climate change on human health.

 Links and References

The Environmental Protection Agency has a page on the health related impacts of global warming, including further information on infectious diseases, heat exhaustion and respiratory problems associated with a warmer planet.

The Climate Change and Human Health Integrated Assessment Web provides recent and relevant information about the potential impacts of climate change through integrated assessment. This web site aims to appropriately characterize and communicate current scientific research to support policy development and analysis.

World Wildlife Fund has published an incredibly comprehensive and navigable report on human health impacts. The health of multiple communities is discussed based on region: those effected by El Nino, mountainous regions, coastal regions, and much much more.

WWF’s also has a page on human health including reports on malaria, dengue fever, encephalitis, climate variablity, rodents and disease, marine environment, and costs of diseases.

The World Health Organization has a new paper out on the health effects of global warming, entitled “Climate change and Human health: Impact and Adaptation”.

Coastal Zones and Small Islands

Climate change and resulting seal level rise can have a number of negative impacts on energy, industry, and transportation infrastructure; human settlements; the property insurance industry; tourism; and cultural systems and values. (WGII SPM) Sea level rise will continue at a scarcely unabated rate for many centuries after concentration stabilization and/or the stabilization of global mean temperature (WG I SPM Chapter 7).

IPCC Findings

The impact of a higher average sea level on coastal areas may be increased greatly during high tides and storms. Higher average sea level means high tides will be higher and coastal storm flooding and storm surges will cover more area. Larger stretches of coastal lands could potentially be flooded and damaged. Those coastal ecosystems particularly at risk include saltwater marshes, mangrove ecosystems, coastal wetlands, sandy beaches, coral reefs, coral atolls, and river deltas as well as developed coastal cities towns and resort areas.

Changes in these ecosystems would have major negative effects on tourism, freshwater supplies, and biodiversity. (IPCC, SAR, 3.10)

Although adaptation measures may be able to preserve much of the economic value of coastal areas in some countries, sea level rise and increased sea temperature has the potential to destroy unique human, animal, and plant habitats. For example, as sea level rises, wetlands may be able to move inland. However, human infrastructure may block his movement leading to the decline and loss of the wetland. The IPCC estimated that even if wetlands were able to move inland, a sea level rise of 20 inches would result in a loss of 17 to 43 percent of coastal wetlands in the United States. If the wetlands cannot migrate the loss will be much more severe.

Links and References

Coral bleaching events have been increasing in both frequency and extent worldwide in the past 20 years. Global climate change may play a role in the increase in coral bleaching events, and could cause the destruction of major reef tracts and the extinction of many coral species. Find out more at:

The Food and Agriculture Organization of the United Nations addresses issues related to the potential impacts of sea level rise on the world’s coastal populations and agriculture. This is a “global” study mostly based on national data in India.

Ozone Action published a report on the impact of sea level rise, you can find it at

World Wildlife Fund displays its research on the impact of the coral reef system in the face of rising temperatures. The page discusses the unique diversity the coral reef systems hold, the threat climate change poses and solutions to prevent further damage.