Extreme weather leads to public health crises – so health and climate experts must work together

Aparna Lal, Australian National University and Rebecca Colvin, Australian National University

This year has seen a number of extreme weather events around the globe, from hurricanes in the Americas to devastating flooding in South Asia. The loss of lives, homes and livelihoods are made worse by subsequent disease outbreaks: after the South Asian floods, more than 12,000 cases of watery diarrhoea were reported in Bangladesh. Presumably, many more cases are unreported.

As our climate changes, severe weather events (especially intense rainfall) will become the “new normal”. The connection between climate and disease is well established, even in less extreme situations.

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Read more: Irma and Harvey: very different storms, but both affected by climate change

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This makes it vital that our meteorologists, climate scientists and health systems work closely together. Particularly, health professionals should make better use of weather forecasts to proactively manage disease risk. Climate outlooks – with a longer-term perspective than weather forecasts – can also help with long-range tactical and strategic planning.

The link between climate change and disease

Climate change projections consistently indicate increased climate variability. A more variable climate creates conditions for the spread and control of infectious disease. In particular, changes in the intensity and duration of rain can help spread pathogens through water.

Both floods and droughts can increase waterborne infections, either when clean and dirty water mix during floods, or through inadequate storage and concentration of toxic organisms when water is scarce.

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Read more: Flooding from Hurricane Harvey causes a host of public health concerns

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These risks are not restricted to countries with limited resources. In Australia, fluctuations in the sea surface temperatures in the Indian Ocean (a phenomenon shown by the “Indian Ocean Dipole”) are linked to spikes in rates of waterborne diseases like cryptosporidiosis, which cause gastrointestinal illness.

NSW Health documents, obtained earlier this year by the ABC, reveal that more than 100,000 NSW residents were issued protective boil-water alerts in the past five years. These residents lived in areas where pathogens like cryptosporidium were found in unfiltered drinking water pumped from rivers, lakes and dams. A more variable climate can increase these risks.

Research suggests we can improve public health outcomes by integrating both climate dynamics and the impact on human health into our management of natural water resources.

We need integrated climate and health systems

Traditional disease surveillance systems rely on early detection of illnesses as they occur, not predicting them before they happen. But outbreaks that follow extreme events are already underway before authorities are notified.

The close relationship between climate signals and some waterborne diseases suggest that advances in numerical weather forecasting and climate science present new opportunities for public health officials.

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Read more: How satellites can help control the spread of diseases such as Zika

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Forecasting based on climate variables is well established in crop disease management and ecosystem conservation.

Recent technological advancements, such as real-time predictions of disease outbreaks, highlight great potential for forecasting to be used for human health benefit ahead of extreme weather events.

Collaboration is key

At present, health professionals and climate forecasters generally operate separately from each other, as very distinct professions. This can make it very difficult for researchers, public servants and service providers to work effectively together.

Our experience at the ANU Climate Change Institute has taught us that an important early step to fostering cooperation is helping individuals build relationships.

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Read more: We’ve got to stop meeting like this

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It’s important to create opportunities for people from different sectors to come together so they can exchange knowledge and make personal connections. Emphasising that health and climate experts have many shared goals can help encourage new cross-sector networks and a sense of a shared professional identity. (And realistically, one of the most important things you can do to promote productive exchanges is feed people well.)

There’s a real opportunity to integrate health and climate knowledge bases. This could be what’s known as a “boundary object”: something that can be meaningfully interpreted by people with different training and backgrounds, which helps to span the “boundary” between these sectors or disciplines.

We stand to gain from integration across climate and health

As our understanding of climate patterns grows, there are more opportunities for the health sector to take advantage of sophisticated modelling and prediction.

This is particularly true if disease surveillance and climate and weather forecasting can be combined to assess health risks ahead of extreme weather events, rather than during or after the fact.

By fostering collaboration and the integration of the health and climate sectors, we can improve our capacity to respond to the health risks posed by climate change.

Aparna Lal, Research Fellow, Australian National University and Rebecca Colvin, Knowledge Exchange Specialist, Australian National University

This article was originally published on The Conversation. Read the original article.

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Explainer: hydrofluorocarbons saved the ozone layer, so why are we banning them?

Sunrise over the Earth. Hydrofluorocarbons were created to protect the ozone layer, but their stable nature makes them an extremely potent greenhouse gas.
NASA

Jenny Fisher, University of Wollongong and Stephen Wilson, University of Wollongong

On October 28, Australia ratified the Kigali Amendment to the Montreal Protocol. Australia is the tenth country to ratify, joining others as diverse as Mali, the United Kingdom and Rwanda in a global commitment to dramatically reduce hydrofluorocarbons (HFCs) in the atmosphere. Once 20 countries have ratified the amendment, it will become binding.

HFCs were designed specifically to replace ozone-destroying compounds previously used in air conditioners and refrigerants. Unfortunately, we now know that HFCs are massively potent greenhouse gases – thousands of times more powerful than carbon dioxide (albeit released in far smaller quantities).

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Read more: The 30-year-old ozone layer treaty has a new role: fighting climate change

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If the Kigali Amendment becomes binding, the hunt will begin for a replacement for HFCs and their uses in industry. In a strange twist, the least environmentally harmful option may well be carbon dioxide.

Where do HFCs come from?

HFCs are made of carbon, fluorine and hydrogen. They are exclusively synthetic, meaning they have no known natural sources. To understand why they came into existence requires a quick history lesson.

Throughout the second half of the 20th century, another class of compounds called chlorofluorocarbons (CFCs) were widely used. CFCs are very stable, which made them ideal for many practical uses, including in refrigeration, foam packaging, and even aerosol cans for hair spray.

However, scientists soon discovered that CFCs had a major downside. Because they are so stable, they can survive in the atmosphere long enough to eventually reach the ozone layer. Once there, they break down in sunlight and destroy ozone in the process.

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Read more: Explainer: what is the Antarctic ozone hole and how is it made?

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The Montreal Protocol was a global agreement developed to stop this harmful ozone destruction. The protocol mandated a time frame to completely abolish CFCs. To replace them, new compounds were developed that do not destroy ozone: HFCs.

The usage of CFCs and their replacements, including HFCs, since 1950.
UNEP 2011. HFCs: A Critical Link in Protecting Climate and the Ozone Layer

But the solution to one environmental problem became the cause of another: these replacements are potent contributors to warming the climate.

Why are HFCs so bad?

All greenhouse gases work by absorbing infrared radiation, which would otherwise escape into space. But not all greenhouse gases are created equal. The potency of a greenhouse gas depends on three properties:

• how long it remains in the atmosphere (its “lifetime”)

• how much radiation it absorbs

• whether the specific wavelength of radiation it absorbs would otherwise be absorbed by something else in the atmosphere (like water).

Global warming potentials of five greenhouse gases. The area of each circle represents the global warming potential, calculated for a 100-year time horizon.
Author created/Data from UNEP 2011 report HFCs: A Critical Link in Protecting Climate and the Ozone Layer, Author provided

Combined, these three properties can be used to determine the global warming potential for each greenhouse gas. This is a measure of how potent the gas is relative to carbon dioxide (CO₂). By definition, CO₂ has a global warming potential of 1. Methane, commonly considered the second most important greenhouse gas, has a global warming potential of 34 – meaning that 1 tonne of methane would trap 34 times more heat than 1 tonne of CO₂.

The global warming potentials for the three most abundant HFCs range from 1,370 to 4,180. In other words, these gases trap thousands of times more heat in our atmosphere than an equivalent amount of CO₂.

What will replace HFCs?

The nearly 200 countries that signed the original Montreal Protocol have unanimously agreed that the climate risks posed by HFCs are too significant to ignore. Developed countries will begin phasing out HFCs in 2019. Developing countries will follow suit between 2024 and 2028.

So what will our refrigerators and air conditioners use instead? Several replacements are being considered.

Some groups are promoting another class of fluorine-containing compounds called hydrofluoroolefins (or HFOs). These have a short lifetime in the atmosphere and so pose much less of a climate risk. However, environmental groups have raised concern about the potentially toxic chemicals produced when HFOs break down.

Another option is to use mixtures of hydrocarbons such as butane. Hydrocarbons pose safety risks as they are highly flammable and may also adversely affect air quality. Ammonia is another alternative that has been used as a refrigerant for a long time but is highly toxic.

And, finally, there is the surprise candidate: CO₂. Although using CO₂ as a refrigerant poses technical challenges, it is non-toxic and non-flammable and a much weaker greenhouse gas than the HFCs it would replace. Strangely, from an environmental perspective, CO₂ may actually be the “best” refrigerant available.

A cooler future ahead?

The Montreal Protocol has long been considered one of the greatest environmental success stories of all time. It brought together the world’s governments and chemical industries to protect the ozone layer.

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Read more: After 30 years of the Montreal Protocol, the ozone layer is gradually healing

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The adoption of the Kigali Amendment will be another feather in the cap of this important agreement. HFCs aren’t overly prevalent yet – but without Kigali they are expected to grow rapidly. By banning them now, we will avoid their impacts before it is too late.

Estimates suggest that phasing out HFCs will prevent up to 0.5℃ of future warming. Even if this estimate turns out to be overly optimistic, getting rid of the HFCs will be an important step towards achieving the Paris Agreement goal of limiting warming to well below 2℃.

Jenny Fisher, Senior Lecturer in Atmospheric Chemistry, University of Wollongong and Stephen Wilson, Associate Professor, University of Wollongong

This article was originally published on The Conversation. Read the original article.