More people die in winter than summer, but climate change may see this reverse

Ivan Charles Hanigan, University of Sydney; Alistair Woodward, University of Auckland, and Keith DearClimate change not only poses enormous dangers to the planet, but also harms human health. In our study published today, we show some of the first evidence climate change has had observable impacts on Australians’ health between 1968 and 2018.

We found long-term heating is associated with changed seasonal balance of deaths in Australia, with relatively more deaths in summer months and relatively fewer deaths in winter months over recent decades.

Our findings can be explained by the gradual global warming associated with climate change. Over the 51 years of our study, annual average temperatures increased by more than 1°C in Australia. The last decade (2011 to 2020) was the hottest in the country’s recorded history.

If we continue on this trajectory, we’re likely to see many more climate-related deaths in the years to come.

What we did and found

Using the Australian Institute of Health and Welfare, the Australian Bureau of Statistics and other sources, we gathered mortality data for people aged 55 and over between 1968 and 2018. We then looked at deaths in summer compared to winter in each year.

We found that in 1968 there were approximately 73 deaths in summer for every 100 deaths in winter. By 2018, this had risen to roughly 83 deaths in summer for every 100 deaths in winter.

The same trend, albeit of varying strength, was evident in all states of Australia, among all age groups over 55, in females and males, and in the three broad causes of death we looked at (respiratory, heart and renal diseases).

Elderly woman coughing with blanket over her — Historically, winter death rates have tended to be higher than in summer. But this is changing as our planet warms.
Shutterstock

Hot and cold weather can have a variety of direct and indirect effects on our health. Winter death rates generally exceed those in summer months because infectious diseases, like influenza, tend to circulate more in winter. Meanwhile, heat stress can exacerbate chronic health conditions including heart disease and kidney disease, particularly for older adults.

But the gap between cold-related deaths and heat-related deaths appears to be narrowing. And when we compared deaths in the hottest summers with the coldest winters, we found particularly warm years increase the likelihood of seasonal mortality ratios approaching 1 to 1 (meaning equal deaths in summer and winter).

With summers expected to become hotter, we believe this is an early indication of the effects of climate change in the future.

Our research is unique

Globally, our study is one of very few that directly shows the health impacts of climate change. Most other studies examine the effects of past weather or climate conditions on health and extrapolate these into the future based on projected climate change scenarios, with associated uncertainties. For example, demographic characteristics of the population are likely to change over time.

Climate change occurs slowly, so typically, we need at least 30–50 years of records to accurately show how climate change is affecting health. Suitable health information is seldom available for such periods due to a variety of challenges in collecting electronic health data (especially in low- and middle-income countries).

Further, long-term health trends can be influenced by numerous non-climate related factors, such as improvements in health care.

In our study, we used Australian mortality records that have been collected with remarkable consistency of detail and quality over the last half century. And by focusing on the ratio of summer to winter deaths within each year, we avoid possible confounding associated with, say, improvements to health care.

However, we were unable to consider some issues such as the different climate trends in small areas within each state/territory, or the effects of changing temperatures on different occupation groups, such as construction workers.

Our data also don’t allow us to account for the possible effects of people’s adaptation to warmer temperatures in the future.

Dry, cracked riverbed — Summer deaths will almost certainly increase in the years to come.
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Looking ahead

The changing ratio of summer to winter deaths has previously been identified as a possible warning sign of the impact of climate change on human health.

In one study on the topic, the authors found Australia may initially experience a net reduction in temperature-related deaths. That is, increased deaths from heat during summer would be offset by fewer deaths in winter, as winters become more mild.

However, they predict this pattern would reverse by mid-century under the business-as-usual emissions scenario, with increases in heat-related deaths outweighing decreases in cold-related deaths over the long term.

Our findings support these worrying predictions. If warming trends continue, it’s almost certain summer deaths will increase, and come to dominate the burden of temperature-related deaths in Australia.

We found the speed of change in the ratio of summer to winter deaths was fastest in the hottest years within each decade. This strengthens our conclusion we’re observing an effect of long-term climate change.

Besides helping to answer the question, “does climate change affect human health?”, we believe our findings should inform planning for climate change mitigation and adaptation. The implications are considerable for the planning of hospital services and provision of health care, as well as for emergency services, housing, energy supply, holiday periods and bushfire disaster preparedness.

Ivan Charles Hanigan, Data Scientist (Epidemiology), University of Sydney; Alistair Woodward, Professor, School of Population Health, University of Auckland, and Keith Dear, Adjunct Professor of Public Health

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Car accidents, drownings, violence: hotter temperatures will mean more deaths from injury

New research shows people will be more likely to die from accidents and injuries as the climate gets warmer.
From shutterstock.com

Liz Hanna, Australian National University

What we suspected is now official: 2019 was Australia’s hottest year on record. The country’s average maximum temperature last year (30.69℃) was a scorching 2.09℃ hotter than the 1961-1990 average.

For the whole planet, 2019 is expected to come in second (behind 2016) making the last five years the hottest on record since 1880.

As we brace for increasingly hot summers, we are mindful extreme heat can pose significant health risks for vulnerable groups. But the effects of heat on the incidence of accidents and injury are less clear.

In research published today in Nature Medicine, researchers in the United States looked at the impact warmer temperatures will have on deaths from injury. They found if average temperatures warmed by 1.5℃, we could expect to see 1,600 more deaths each year across the US.

Given Australia is ahead of the global temperature curve, we could see an even greater number of deaths from injury per capita as a result of rising temperatures.

What the study did and found

The researchers analysed death and temperature data collected from 1980 to 2017 across mainland United States (so their results excluded the states of Alaska and Hawaii).

They looked at records from more than five million injury deaths from this 38-year period. They also identified temperature anomalies by county and by month, to understand how these deaths could relate to spikes in the weather.

Using a method called Bayesian Spatio-temporal modelling, the authors combined this information to estimate the rates at which injury deaths would rise with a 1.5℃ temperature increase.

Hotter temperatures have been associated with spikes in domestic and other violence.
From shutterstock.com

They categorised injury deaths as either unintentional (transport, falls and drownings) or intentional (assaults and suicides), and stratified results further by gender and age group.

They found deaths from drownings would increase by as much as 13.7% in men aged 15-24 years, whereas assaults and suicides would increase by less than 3% across all groups. Transport deaths would rise by 2% for men aged 25-34 years and 0.5% for women in the same age group.

Overall, these increased risks would account for 1,601 additional deaths per year from injury across the US, an annual rise of 0.75% in overall deaths from injury in the population. They indicate 84% of these deaths would occur in males.

Although the primary focus was on 1.5℃ warming, the researchers also looked at a rise of 2℃. The found this would result in 2,135 additional deaths from injury (a 1% increase).

Why do deaths from injury increase in hot weather?

Higher temperatures are associated with irritability, and increases in conflict and interpersonal violence.

Research has shown each degree celsius increase in annual temperatures is linked to nearly a 6% average increase in homicides. Another study showed domestic violence rates increased by 40% when the daily maximum temperature exceeded 34℃.

Hyperthermia (abnormally high body temperature) can also lead to symptoms such as loss of concentration and fatigue. These factors can trigger incidents such as car accidents and faults operating mechanical equipment. So we can expect injuries to increase as we face more hot days.

A South Australian study of workers’ compensation claims found for every degree above 14℃, occupational injuries requiring more than three days off work increased modestly (0.2%).

Increases in drowning might occur due the higher proportions of people seeking relief in the water on hot days.

Being too hot can lead to a loss of concentration or fatigue, which can increase the risk of accidents.
From shutterstock.com

Importantly, climate change is heightening anxiety in rural communities, and more broadly throughout the population.

In Australia, heat is commonly associated with drought. Long droughts are known to be linked to spikes in suicide rates, especially among rural males.

We also know suicide rates rise in affected communities following bushfires, in the face of grief and trauma.

The reason for the gender disparity was not tested, but likely relates to the higher prevalence of risk-taking behaviour among males.

So what does this mean for Australia?

With global temperatures on course for a 3-5°C rise this century, limiting warming to 1.5℃ is optimistic. The effects are likely to be even greater than what is forecasted in this study.

This study assessed excess injury deaths with a level of warming Australia witnessed in 2019 alone.

Rising heat is possibly Australia’s number one threat from climate change. It leads to the catastrophic bushfires we’re seeing this summer, and pushes us beyond the temperatures our bodies can withstand.

When looking at deaths caused by heat, we need to look beyond those caused by heat-induced illness, and separate the many caused by injury.

We must strengthen the nation’s climate change and human health research to provide specific details on when, where and how we can best ameliorate heat harm.

We need to ramp up our prevention efforts in this space. All Australians should be made aware of the dangers of a hotter world through a federally funded public education strategy, akin to the successful “Life. Be in it” campaign, which successfully promoted the importance of being active.

Most urgently, we must focus on prevention through climate change mitigation, which will be the best and most far-reaching prevention strategy we can deliver.

Liz Hanna, Honorary Senior Fellow, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We wrote the report for the minister on fish deaths in the lower Darling – here’s why it could happen again

Robert Vertessy, University of Melbourne; Fran Sheldon, Griffith University; Lee Baumgartner, Charles Sturt University; Nick Bond, La Trobe University, and Simon Mitrovic, University of Technology Sydney

Over the recent summer, three significant fish death events occurred in the lower Darling River near Menindee, New South Wales. Species involved included Murray Cod, Silver Perch, Golden Perch and Bony Herring, with deaths estimated to be in the range of hundreds of thousands to over a million fish. These events were a serious ecological shock to the lower Darling region.

Our report for the Minister for Agriculture and Water Resources examines the causes of these events and recommend actions to mitigate the potential for repeat events in the future.

The final report has just been released, summarising what we found and what we recommend.

Causes of the fish deaths

High-flow events in the Darling River in 2012 and 2016 filled the Menindee Lakes and offered opportunities for substantial fish breeding, further aided by the targeted use of environmental water.

The result was very large numbers of fish in the lakes, river channels and weir pools around Menindee. After the lake-filling rains of late 2016, two very dry years ensued, resulting in very low inflows into the Barwon-Darling river.

As the supply of water dried up, the river became a series of disconnected and shrinking pools. As the extremely hot and dry conditions in late 2018 took hold, the large population of fish around Menindee became concentrated within weir pools.

Hot weather, low rainfall and low flows provided ideal conditions for algal blooms and thermal stratification in the weir pools, resulting in very low oxygen concentrations within the bottom waters.

With the large fish population now isolated to the oxygenated surface waters of the pools, all that was needed for the fatal blow was a trigger for the water profile to mix. Such a trigger arrived on three separate occasions, with changes in the weather that brought sudden drops in temperature and increased wind that caused sudden turnover of the low-oxygen bottom waters.

Summary of the multiple causes of the 2018-19 fish death events in the lower Darling river.

With the fish already stressed by high temperatures, they were now unable to gain enough oxygen from the water to breathe, and a very large number of them died. As we write, the situation in the lower Darling remains dire, and there is a risk of further fish deaths if there are no significant inflows to the river.

Fish deaths caused by these sorts of turnover events are not uncommon, but the conditions outlined above made these events unusually dramatic.

So, how did such adverse conditions arise in the lower Darling river and how might we avoid their reoccurrence? We’ve examined four influencing factors: climate, water management, lake operations, and fish mobility.

Key influencing factors

We found that the fish death events in the lower Darling were preceded and affected by exceptional climatic conditions.

Inflows to the water storages in the northern Basin over 2017-18 were the second lowest for any two-year period on record. Most of the Murray-Darling Basin experienced its hottest summer on record, exemplified by the town of Bourke breaking a new heatwave record for NSW, with 21 consecutive days with a maximum temperature above 40℃.

We concluded that climate change amplified these conditions and will likely result in more severe droughts in the future.

Changes in the water access arrangements in the Barwon–Darling River, made just prior to the commencement of the Basin Plan in 2012, exacerbated the effects of the drought. These changes enhanced the ability of irrigators to access water during low flow periods, meaning fewer flow pulses make it down the river to periodically reconnect and replenish isolated waterholes that provide permanent refuge habitats for fish during drought.

We conclude that the Lake Menindee scheme had been operated according to established protocols, and was appropriately conservative given the emerging drought conditions. But low connectivity in the lower Darling resulted in poor water quality and restricted mobility for fish.

Recommended policy and management actions

Given the right mix of policy and management actions, Basin governments can significantly reduce the risks of further fish death events and promote the recovery of affected fish populations.

The Basin Plan is delivering positive environmental outcomes and more benefits will accrue once the plan is fully implemented. But more needs to be done to enhance river connectivity and protect low flows, first flushes and environmental flow releases in the Barwon-Darling river.

Drought resilience in the lower Darling can be enhanced by reconfiguring the Lake Menindee Water Savings Project, modifying the current Menindee Lakes operating rules and purchasing high security water entitlements from horticultural enterprises in the region.

In Australia, water entitlements are the rights to a share of the available water resource in any season. Irrigators get less (or no) water in dry (or extremely dry) years.

A high-security water entitlement is one with a high chance of receiving the full water allocation. In some systems, although not all, this is expected to happen 95 per cent of the time. And these high-security entitlements are the most valuable and sought after.

Fish mobility can be enhanced by removing barriers to movement and adding fish passageways.

It would be beneficial for environmental water holders to place more of their focus on sustaining fish populations through drought sequences.

The river models that governments use to plan water sharing need to be updated more regularly to accurately represent the state of Basin development, configured to run on a whole-of-basin basis, and improved to more faithfully represent low flow conditions.

There are large gaps in water quality monitoring, metering of water extractions and basic hydro-ecologic knowledge that should be filled.

Risk assessments need to be undertaken to identify likely fish death event hot spots and inform future emergency response plans.

All of these initiatives need to be complemented by more sophisticated and reliable assessments of the impacts of climate change on water security across the Basin.

Governments must accelerate action

Responding to the lower Darling fish deaths in a prompt and substantial manner provides governments an opportunity to redress some of the broader concerns around the management of the Basin.

To do so, Basin governments must increase their political, bureaucratic and budgetary support for high value reforms and programs, particularly in the northern Basin.

All of our recommendations can be implemented within the current macro-settings of the Basin Plan and do not require a revisiting of the challenging socio-political process required to define Sustainable Diversion Limits (SDLs).

Successful implementation will require a commitment to authentic collaboration between governments, traditional owners, local communities, and sustained input from the science community.

The authors would like to acknowledge the contribution of Daren Barma, Director of Barma Water Consulting, to this article.

A version of this article has been published in Pursuit.

Robert Vertessy, Enterprise Professor, University of Melbourne; Fran Sheldon, Professor, Australian Rivers Institute, Griffith University, Griffith University; Lee Baumgartner, Associate Research Professor (Fisheries and River Management), Institute for Land, Water, and Society, Charles Sturt University; Nick Bond, Professor of Freshwater Ecology and Director of the Centre for Freshwater Ecosystems, La Trobe University, and Simon Mitrovic, Associate Professor, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate change set to increase air pollution deaths by hundreds of thousands by 2100

Guang Zeng, National Institute of Water and Atmospheric Research and Jason West, University of North Carolina – Chapel Hill

Climate change is set to increase the amount of ground-level ozone and fine particle pollution we breathe, which leads to lung disease, heart conditions, and stroke. Less rain and more heat means this pollution will stay in the air for longer, creating more health problems.

Our research, published in Nature Climate Change, found that if climate change continues unabated, it will cause about 60,000 extra deaths globally each year by 2030, and 260,000 deaths annually by 2100, as a result of the impact of these changes on pollution.

This is the most comprehensive study to date on the effects of climate change on global air quality and health. Researchers from the United States, the United Kingdom, France, Japan and New Zealand between them used nine different global chemistry-climate models.

Most models showed an increase in likely deaths – the clearest signal yet of the harm climate change will do to air quality and human health, adding to the millions of people who die from air pollution every year.

Stagnant air

Climate change fundamentally alters the air currents that move pollution across continents and between the lower and higher layers of the atmosphere. This means that where air becomes more stagnant in a future climate, pollution stays near the ground in higher concentrations.

Ground-level ozone is created when chemical pollution (such as emissions from cars or manufacturing plants) reacts in the presence of sunlight. As climate change makes an area warmer and drier, it will produce more ozone.

Fine particles are a mixture of small solids and liquid droplets suspended in air. Examples include black carbon, organic carbon, soot, smoke and dust. These fine particles, which are known to cause lung diseases, are emitted from industry, transport and residential sources. Less rain means that fine particles stay in the air for longer.

While fine particles and ozone both occur naturally, human activity has increased them substantially.

The Intergovernmental Panel on Climate Change has used four different future climate scenarios, representing optimistic to pessimistic levels of emissions reduction.

In a previous study, we modelled air pollution-related deaths between 2000 and 2100 based on the most pessimistic of these scenarios. This assumes large population growth, modest improvements in emissions-reducing technology, and ineffectual climate change policy.

That earlier study found that while global deaths related to ozone increase in the future, those related to fine particles decrease markedly under this scenario.

Emissions will likely lead to deaths

In our new study, we isolated the effects of climate change on global air pollution, by using emissions from the year 2000 together with simulations of climate for 2030 and 2100.

The projected air pollutant changes due to climate change were then used in a health risk assessment model. That model takes into account population growth, how susceptible a population is to health issues and how that might change over time, and the mortality risk from respiratory and heart diseases and lung cancer.

In simulations with our nine chemistry-climate models, we found that climate change caused 14% of the projected increase in ozone-related mortality by 2100, and offset the projected decrease in deaths related to fine particles by 16%.

Our models show that premature deaths increase in all regions due to climate change, except in Africa, and are greatest in India and East Asia.

Using multiple models makes the results more robust than using a single model. There is some spread of results amongst the nine models used here, with a few models estimating that climate change may decrease air pollution-related deaths. This highlights that results from any study using a single model should be interpreted with caution.

Australia and New Zealand are both relatively unpolluted compared with countries in the Northern Hemisphere. Therefore, both ozone and fine particle pollution currently cause relatively few deaths in both countries. However, we found that under climate change the risk will likely increase.

This paper highlights that climate change will increase human mortality through changes in air pollution. These health impacts add to others that climate change will also cause, including from heat stress, severe storms and the spread of infectious diseases. By impacting air quality, climate change will likely offset the benefits of other measures to improve air quality.

Guang Zeng, Atmospheric Scientist, National Institute of Water and Atmospheric Research and Jason West, Associate Professor, Department of Environmental Sciences and Engineering , University of North Carolina – Chapel Hill

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

USA: Yosemite National Park Update

The links below are to articles reporting on recent terrible news from Yosemite National Park in the USA, the discovery of The Plague and the death of campers.

For more visit:
– http://www.dailymail.co.uk/news/article-3198822/Yosemite-campground-closing-squirrels-plague.html
– http://www.dailymail.co.uk/news/article-3198847/Two-children-killed-Yosemite-tree-limb-fell-tent-sleeping-in.html