Expert Commentary

The current and projected health risks of climate change

Due to food shortages related to climate change, the Earth may experience a net increase of 529,000 adult deaths by 2050.

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Due to food shortages related to climate change, the Earth may experience a net increase of 529,000 adult deaths by 2050, according to a new review article published in the New England Journal of Medicine.

The article highlights the state of the research on climate change, including projected global temperature increases, anticipated health impacts, adaptation strategies and health benefits associated with reductions in greenhouse-gas emissions. It cites 54 sources, including government reports and peer-reviewed academic research, as evidence.

“Climate change is happening, and it’s going to have all sorts of impacts on human society,” said lead author Andy Haines, an epidemiologist and professor of environmental change and public health at the London School of Hygiene and Tropical Medicine, in a call with Journalist’s Resource. To that end, Haines and his co-author Kristie Ebi set out to summarize relevant climate research in four main topic areas.

While the review ends with a call to action for health professionals “to protect the health of current and future generations” against the risks posed by climate change, Haines stressed that journalists can play a role as well.

“I think journalists have an absolutely crucial role, particularly in this era of ‘fake news,’” Haines said. “Journalists have a very important perspective and role in helping the public to distinguish opinions and views that are based on strong evidence from those that are not.”

He added that journalists can help communicate the full extent to which individual actions contribute to climate change.

With Haines’ comments in mind, we’ve pulled together some of the key takeaways from the review that might be helpful for reporters. The takeaways are divided according to the four subheadings used in the paper.

Observed and Projected Climate Change

  • “Almost two thirds of the worldwide effects of changes in atmospheric and near-surface ocean temperatures for the period 1971-2010 were attributed to anthropogenic [human-caused] climate change.”
  • August 2018 marked the 406th month in a row for which average global temperatures exceeded long-term historical averages.
  • “The global mean temperature is currently increasing at a rate of 0.2°C per decade.”
  • Since preindustrial times, the global average surface temperature has increased by about 1°C, which is equal to 1.8°F. The majority of this rise happened from the 1970s onward.
  • Carbon dioxide levels in the atmosphere have risen to about 410 parts per million, up from preindustrial levels of about 280 parts per million. And the greenhouse gas has staying power – 20 percent of the gas remains in the atmosphere for over 1,000 years.
  • Extreme weather events linked to climate change include heat waves, floods and droughts. (For tips on covering these events, and understanding the links to climate change, check out our tip sheet.)
  • Even if every country followed through on the steps they agreed to take to reduce greenhouse gas emissions per the Paris Agreement, the world would still see an increase of approximately 3.2°C (5.76 °F) by the year 2100 compared to preindustrial temperatures. For reference, estimates put an additional 10 million people at risk of exposure to flooding due to sea level rise if the average global temperature increases by 2°C instead of 1.5°C.

Health Risks Associated with a Changing Climate

  • There are a number of health risks that operate through both direct and indirect links to climate change, including malnourishment, diarrheal disease, malaria and heatstroke.
  • An example of a direct health effect of climate change is heat-related death.
  • Other health effects are linked to climate change less directly. For example, rising temperatures can lead to changes in the range and distribution of vector-borne diseases, like malaria, which is transmitted by mosquitoes.
  • Climate change is also linked to health effects that vary by factors such as geography, race and socioeconomic status. For example, the relative socioeconomic status of a country will to some extent determine the ability to cope with or mitigate the effects of climate change. (We’ve featured research that touches on this issue on Journalist’s Resource. Andreas Flouris, professor of exercise science at the University of Thessaly in Greece published a meta-analysis documenting the health impacts of working in a hot environment, and, in an interview, he explained that the effect of heat strain is likely to exacerbate global economic inequalities. Hotter regions of the world tend to be poorer, and these economies will face additional challenges as global temperatures rise. Further, developing economies tend to rely more on manual labor, which also contributes to the risk of occupational heat strain.)
  • An estimate for climate change-associated adult deaths resulting from expected changes to the food supply predicts a net increase of 529,000 deaths worldwide by 2050, which vastly exceed previous estimates by the World Health Organization.
  • “The World Health Organization (WHO) estimated that approximately 250,000 deaths annually between 2030 and 2050 could be due to climate change–related increases in heat exposure in elderly people, as well as increases in diarrheal disease, malaria, dengue, coastal flooding, and childhood stunting. This is a conservative estimate, because it does not include deaths from other climate-sensitive health outcomes and does not include morbidity or the effects associated with the disruption of health services from extreme weather and climate events.”
  • A World Bank estimate suggests that “climate change could force more than 100 million people into extreme poverty by 2030.”

New Policies Needed to Adapt

  • “The current policies and measures for the management of climate-sensitive health outcomes were not developed in light of climate-change considerations, which means that they need modification to be effective over coming decades,” the authors write. They suggest improving systems that monitor environmental data and changing building codes and locations in anticipation of flooding risks.
  • The authors suggest using environmental data to create early warning systems in response to certain climate-related health threats, such as heat waves. For example, research shows heat wave warning systems help to reduce deaths by allowing those in the area to take precautionary measures.

Health Benefits of a “Zero-Carbon” Economy

  • Health benefits associated with reducing global carbon emissions to zero would include less exposure to air pollution (which is estimated to account for 6.5 million premature deaths yearly).
  • Shifting to a more sustainable diet of mainly plant-based foods would reduce greenhouse gas emissions by a median of 20 to 30 percent in high-income areas and improve health outcomes.
  • Similarly, shifting transportation use in cities to favor walking, biking and public transportation over personal motor vehicles would reduce emissions while encouraging health-promoting physical activity.

Story Ideas

  • For journalists looking to expand their coverage of climate change, Haines suggested “shedding light on evolving and unexpected findings” within the field of climate research. Haines offered the example of research he took part in that found a relationship between climate change, increased drinking-water salinity and high blood pressure in inhabitants of coastal Bangladesh as “a potential link between human health and the environment that perhaps a few years ago we might not have thought about.”
  • Haines also stressed the importance of highlighting potential solutions in climate change coverage. “We know presenting people with a doom and gloom scenario is a way to disempower and potentially demotivate people,” Haines said. “I think journalists can have a major role in communicating threats and also opportunities” to adapt and mitigate climate change, he added. For more on this approach, and additional pointers on covering climate change, check out our tip sheet featuring advice from NPR’s Elizabeth Arnold.

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