Column: Assessing the health costs of global climate change

The threat to human health from climate change could undermine the last 50 years of gains in development and global health.

The threat to human health from climate change is so great that it could undermine the last 50 years of gains in development and global health. This statement headlines a landmark report by a new Commission at the University College London Institute for Global Health. The report was published last month in the prestigious journal The Lancet.

“Climate change has the potential to reverse the health gains from economic development that have been made in recent decades, not just through the direct effects on health from a changing and more unstable climate but through indirect means such as increased migration and reduced social stability,” said Commission co-Chair Professor Anthony Costello. “However, our analysis clearly shows that by tackling climate change we can also benefit health, and tackling climate change in fact represents one of the greatest opportunities to benefit human health for generations to come.”

The report outlined the direct health impacts of climate change which come from the increasing frequency and intensity of extreme weather events, especially heat waves, floods, droughts and storms. Indirect impacts come from changes in infectious disease patterns, air pollution, food insecurity and malnutrition, involuntary migration, displacement and conflicts.

According to the World Health Organization, the health effects of climate change will be felt in air quality, sufficient availability of safe drinking water, enough food, and secure shelter. WHO estimates that between 2030 and 2050, climate change could cause approximately 250,000 additional deaths per year from malnutrition, malaria, diarrhea, and heat stress.

A dollar figure on health costs is around $2 billion to $4 billion a year by 2030 and those with the least ability to cope (largely in developing countries) will need the greatest help to respond to their health challenges.

Extreme high temperatures contribute directly to deaths from cardiovascular and respiratory disease, particularly among elderly people. High temperatures like those seen recently also raise the levels of ozone and other air pollutants especially from wildfires that exacerbate cardiovascular and respiratory disease. Pollen and other allergen levels are also higher in extreme heat and can trigger asthma which affects some 300 million people a year.

The report’s authors and WHO independently agree that reduction of greenhouse gas emissions through lowering pollution and choosing sustainable energy give us at least a shot at protecting health and maintaining the status quo.

“Climate Change is a medical emergency,” said co-Chair Professor Hugh Montgomery at the UCL Institute for Human Health and Performance. “It thus demands an emergency response, using the technologies available right now. Under such circumstances, no doctor would consider a series of annual case discussions and aspirations adequate, yet this is exactly how the global response to climate change is proceeding.”

The authors said that ways to generate health gains include burning fewer fossil fuels to reduce respiratory diseases, encouraging activities like walking and cycling, and reducing pollution.

There may be health benefits from dietary changes as a result of a concerted effort to tackle climate change through less livestock production therefore less red meat consumption and development of a wider variety of drought and pest resistant crops.

The Commission also predicted that a strong international consensus will be essential to move the world to a low-carbon global economy and harness an opportunity to protect human health.

The Commission represents a collaboration between European and Chinese climate scientists and geographers, social and environmental scientists, biodiversity experts, engineers and energy policy experts, economists, political scientists, public policy experts, and health professionals.

“The health community has responded to many grave threats in the past,” said Commission co-Chair Professor Peng Gong, Tsinghua University, Beijing, China. “It took on entrenched interests such as the tobacco industry, and led the fight against HIV/AIDS.”