Climate change driving flooding, heatwaves and infectious diseases

China is one of the most exposed countries to the health impacts of global warming, finds health study. Catherine Early reports

China urgently needs to make public health a higher priority when designing policies to tackle climate change, according to a report published in medical journal The Lancet.

Doctors, academics and policy makers from 26 global health institutions including the World Bank, World Health Organisation and Tsinghua University collaborated on the report under the Lancet Countdown project, which aims to ensure that the case for action on health and climate change is better understood.

The research finds that climate change is already affecting the health of all populations worldwide, with impacts including flooding, heatwaves, increased spread of infectious disease, growing rates of undernourishment and malnutrition, and sickness caused by air pollution. It also highlights broader economic impacts such as reduced labour capacity, population displacement and involuntary migration.

Looking at China, the authors note that it has developed many policies to address climate change, including making changes to industrial and energy systems, such as improving energy efficiency.

Policies to phase out coal have also reduced exposure to air pollution, for example, the population-weighted annual mean PM2.5 concentrations decreased by 21.5% throughout China from 60.5 micrograms per cubic metre (μg/m3) in 2013, to 47.5 μg/m3 in 2015. Deaths attributed to PM2.5 pollution decreased by 9.1% over the same period, according to the report.

PM2.5 concentrations decreased by 21.5% throughout China

However, the authors state that health should be as high a priority as the other considerations of policymakers, which are typically reducing greenhouse gas emissions reduction, technical and economic costs and social acceptability. This will maximise the health benefits of climate change mitigation and adaptation, they say.

The report gives the example of road transport, which contributes more than 20% of total air pollution from particulate matter in Shanghai and Guangzhou, more than 30% in Beijing and more than 40% in Shenzhen. More policies are needed to constrain vehicles in urban areas, it states.

Further research is also needed to better understand how policies to address climate change can reduce disease, according to the report. For example, the mean surface temperature in China has risen by 0.9°C to 1.5°C since 1909, which may have increased the range mosquitos.

There is “clear and consistent” evidence that the rate at which two types of mosquito have spread diseases such as dengue, Yellow Fever and Zika in China has increased since 1950, and the authors predict that the rate of disease spread by these two mosquitoes could rise by a further 1.5% and 1.7% between 2015 and 2030.

Although China has set up a good response system to health emergencies, further analysis and better understanding of the causes are needed, especially the role of climate change, the report states. This will enable more prevention-oriented and cost-effective strategies to deal with it, the experts said.

The report highlights many other impacts of climate change on human health worldwide. Between 2000 and 2016, the number of people exposed to heatwaves increased by approximately 125 million, with a record 175 million exposed in 2015.

Productivity of rural labour has fallen by an average of 5.3% since 2000 as a result of rising temperatures. In 2016, this effectively took more than 920,000 people out of the workforce globally, with 418,000 of them in India alone.

Up to one billion people globally will need to leave their homes by 2050

The biggest health impact of climate change identified by the report was undernutrition. Each 1°C rise in global temperature has caused a 6% decline in global wheat yields and a 10% fall in rice yields. The regions with the highest vulnerability to undernutrition are also areas where yield losses due to climate warming are predicted to be relatively high, the authors noted.

Climate change is already forcing people to migrate, and is the sole contributing factor for at least 4,400 people who have already moved. Rising sea levels, coastal erosion and changes in rainfall and temperature will mean that between 25 million and one billion people globally will need to leave their homes by 2050. Such migration has potentially severe impacts on mental and physical health, both directly and by disrupting essential health and social services, the report found.

However, the authors stress that though the outlook is challenging, there is an opportunity to turn a looming medical emergency into “the most significant advance for public health this century”.

Mitigating climate change effectively will bring benefits including reducing illness caused by air pollution; delivering more nutritious diets; ensuring energy, food and water security; and alleviating poverty, the authors believe.

Christiana Figueres, chair of the Lancet Countdown’s high-level advisory board and former executive secretary of the UN Framework Convention on Climate Change, said that the report shows that tackling climate change “directly, unequivocally and immediately” improves global health.

“Most countries did not embrace these opportunities when they developed their climate plans for the Paris Agreement. We must do better. When a doctor tells us we need to take better care of our health we pay attention and it’s important that governments do the same,” she said.