Intergovernmental Panel on Climate Change (IPCC) report: negative health effects outweigh benefits

Climate change will mainly exacerbate existing health problems, at least until the middle of this century, and the risks will be largest for populations already most affected by climate-related diseases. There is evidence that the greatest risks to health are:

  • undernutrition resulting from reductions in food production;
  • injury and disease due to intense heat-waves and fires;
  • shifts in the timing and spatial distribution of food, water and vector-borne diseases; and
  • lost work capacity and reduced labour productivity in vulnerable populations.

These are some of the conclusions of the second instalment of the Intergovernmental Panel on Climate Change’s (IPCC’s) fifth assessment report on climate change and its impact.

IPCC assessments provide a scientific basis on which governments at all levels can develop climate-related policies, and underlie negotiations at the yearly conferences held under the United Nations Framework Convention on Climate Change.

Effects of climate change

The temperatures of global land and ocean surfaces are rising. Changes in extreme weather have been observed since 1950: the number of cold days and nights has decreased and the number of warm ones has increased globally. Frequent heat-waves over large parts of Europe, Asia and Australia, and heavy precipitation in North America and Europe are creating increasingly hazardous living conditions for people living in poverty. Oceans are warming; the Greenland and Antarctic ice sheets have lost mass, and the global mean sea level is rising.

Climate change has contributed to ill health in recent decades. While the current worldwide burden is still relatively low, evidence in the report indicates that taking specific action, such as reducing greenhouse gases, can give an immediate health benefit to everyone. For example, the report explains that reducing emissions of short-lived pollutants, such as methane and black carbon, not only would slow warming but could prevent 2–2.5 million deaths per year globally.

If converted into economic terms, the health gains associated with mitigation could offset much of the early cost of greenhouse-gas mitigation. This supports the conclusion that both climate-sensitive health risks and the health benefits of cutting greenhouse gas emissions should be central to any discussion on climate change, and determine the choices to be made today.

Stronger evidence for high-end climate scenarios

The report also reflects recent research on the significant possibility of high-end climate scenarios, with some projecting warming by 4–7 oC over much of the globe. Under these conditions, the human capacity to deal with heat will be exceeded during the hottest parts of the year in some regions, and unprotected outdoor labour or recreational activity will no longer be possible.

Responding to the effects of climate change often requires making decisions with high levels of uncertainty and having to adapt planning processes. Nevertheless, more needs to be done.

The IPCC fifth assessment report looks specifically at the effects of and vulnerability and adaptation to climate change, and helps policy-makers grapple with the long-term, challenging effects it brings.