Climate change poses the biggest global health threat of the 21st century, according to a new report launched jointly by The Lancet and University College London (UCL).

Lead author Anthony Costello of the UCL Institute for Global Health says that failure to act will result in an intergenerational injustice sparking a future level of  moral outrage similar to that we feel today for those did nothing to stop slavery.

“Managing the Health Effects of Climate Change” is the work of UCL academics from many disciplines across the university — including health, anthropology, geography, engineering, economics, law and philosophy. Costello says the effort brought down traditional interdisciplinary barriers common at all universities, and hopes it could act as a model for global governance bodies to work together.

The UCL team focused on six key areas: patterns of disease and mortality, food security, water and sanitation, shelter and human settlements, extreme events and population migration.

“The big message of this report is that climate change is a health issue affecting billions of people, not just an environmental issue about polar bears and deforestation,” Costello says. “The impacts will be felt not just in the UK, but all around the world — and not just in some distant future but in our lifetimes and those of our children.”

The authors of the study consider a wide range of pathways through which climate change could exert its effects on health, some of which may happen before others. Changing patterns of disease and mortality would emerge in a greater rate of transmission and geographic spread of traditionally tropical endemic diseases such as malaria and dengue fever. Heat — the “silent” killer — has a major effect on mortality, with the 2003 heatwave causing up to 70,000 excess deaths in Europe.  While some people believe populations in India and Africa may be more resistant to heatwaves, there is little evidence of this and major heatwaves could increase death rates in these populations more than in high-income countries.

Food and water security will also be a major issue as climate change progresses. Scientists are finding that crops are more sensitive to temperature changes than first thought; for example, a change of  1 degree Celsius can produce a 17 per cent difference in yields.

“If we are going to get early changes in the next 20 or 30 years, falling crop yields could trigger more of an effect through rising food prices,” Costello says. “Look at what happened last year when food prices rose globally. And one billion people currently have calorie-deficient diets — this situation will get worse as demand increases from India, China and other nations with a population boom.”

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