Medical Matters: Climate change threatens flood of health consequences

As I write, the clean-up from Storm Desmond has just begun. There is extensive flooding locally. The west of Ireland bore the brunt of the storm, as was clearly demonstrated in Teresa Mannion's epic mid-storm report on the RTÉ Six One News.

Winds were extremely high and frightening in their intensity and I reckon we underestimate the anxiety induced by extreme weather events. Only once have I been asked to see a patient with symptoms directly linked to a weather event. The woman in question requested a house call during a prolonged rolling thunderstorm. When I arrived she was shaking under the bedclothes having a panic attack, convinced she would be struck by lightning and killed.

What was most unusual about Storm Desmond in our area was the intensity and duration of the rainfall. Fields and roads that don’t normally flood remain full of water. Our domestic water supply was stained brown for longer than usual. Notwithstanding the views of sceptics, for me, the storm’s impact was a vivid illustration of the power of climate change.

Over the past 50 years, human activities – particularly the burning of fossil fuels – have released sufficient quantities of carbon dioxide and other greenhouse gases to trap additional heat in the lower atmosphere, thereby affecting the global climate. Each of the past three decades has been successively warmer than any preceding decade since 1850. Sea levels are rising, glaciers are melting and precipitation patterns are changing. Extreme weather events are becoming more intense and frequent.

According to the World Health Organisation (WHO), weather- related natural disasters result in more than 60,000 deaths annually. With more than a half of the world's population living within 60km of the sea, rising sea levels and extreme weather events will have an impact on health.

Air pollution-related diseases

In 2012, WHO estimated 7 million people died from air pollution- related diseases, making it the world’s largest single environmental health risk. It is predicted that climate change will cause an additional 250,000 deaths annually from malaria, diarrhoea, heat stress and undernutrition between 2030 and 2050. Children, women and the poor in lower-income countries will be the most affected.

Increasingly variable rainfall patterns are likely to affect the supply of fresh water. A lack of safe water can compromise hygiene and increase the risk of diarrhoeal disease, which kills about 760,000 children aged under five annually.

Closer to home and our most recent experience it seems floods are increasing in frequency and intensity. This trend is expected to continue throughout the century.

Effects of flooding

The immediate effects of flooding include drownings and physical injuries, infectious disease and exposure to toxic pollutants. Human sewage and animal wastes escape into drinking water, increasing the risk of water-borne diseases.

Homes are damaged and health services disrupted.

And the dislocation caused by flooding leads to an increase in mental disorders and malnutrition in the medium term.

While we are some way away from experiencing severe health effects of flooding in Ireland, we might expect more frequent “boil water” notices in response to climate change events.

In the coming weeks parents, in particular, should watch for low- grade gastrointestinal symptoms that don’t settle in their children. They may have picked up bacteria or a parasite washed into the water supply during the extreme flooding.

At least we avoided the “perfect storm” of floods and low temperature. When temperature is plotted against the number of daily deaths, a typical U-shaped relationship emerges: cold weather causes a rise in deaths from cardiac and respiratory disease in particular.

People aged over 65 are seven times more likely to be hospitalised as a result of frigid temperatures.

So keep an extra eye out for your older neighbours this winter.