Category: Health

Climate change has growing effect on public health

Climate change has growing effect on public health

By Will Bugler

The impacts of climate change and extreme weather on public health is an area of growing concern. Extreme weather has affected human lives and sustainable development on every continent around the globe in 2018, a World Meteorological Organization (WMO) report has found.

U.N. Secretary-General Antonio Guterres called the report a “wake-up call”, during a press conference in New York. Where he implored world leaders to take practical action on climate change saying that they shouldn’t “come with a speech” but instead, “come with a plan.”

“The average number of people exposed to heatwaves has increased by some 125 million since the beginning of the century, with deadly consequences,” Guterres said. “The combination of extreme heat and air pollution is proving increasingly dangerous, especially as heatwaves will become longer, more intense and more frequent.”

Extreme weather and climate events accounted for most of the natural hazards that affected nearly 62 million people during the year, according to the WMO’s annual State of the Climate report. Over 35 million people were affected by flooding, and more than 1,600 deaths were related to heatwaves and wildfires in Europe, Japan and the U.S., the report

showed. WMO Secretary-General, Petteri Taalas, cited the devastation caused by cyclone Idai, which hit Mozambique, Malawi and Zimbabwe in March, as an example of the need for action.

“Idai’s victims personify why we need the global agenda on sustainable development, climate change adaptation and disaster risk reduction,” said Taalas in a statement.

The report includes input from U.N. agencies, national meteorological and hydrological services, and scientific experts.


Cover photo from Wikimedia Commons.
Heat-induced heart attack risk on the rise

Heat-induced heart attack risk on the rise

By Will Bugler

Extreme temperatures can have a significant impact on the risk of developing cardiovascular complications, a new study suggests. Researchers from Ludwig Maximilian University in Munich, Augsburg University Hospital and Nördlingen Hospital, found that high temperatures are a contributing factor to heart attack rates, and suggests climate change may have increased the risk.

It has long been assumed that severe spikes in temperature increase the risk of heart attack. “In the case of very high and very low temperatures in particular, this has been clearly demonstrated. In this latest study, we wanted to see to what extent the heat and cold-related heart attack risk has changed over the years,” explains Dr. Kai Chen, researcher at the Institute of Epidemiology at Helmholtz Zentrum München.

The research team looked at over 27,000 heart attack patients between 1987 and 2014. The individual heart attacks were compared against meteorological data on the day of the attack and adjusted for a range of additional factors, such as the day of the week and socioeconomic status. “Our analysis showed that, over the last few years, the risk of heat-induced heart attack with increasing average daily temperature has risen compared to the previous investigation period,” explains Chen.

Individuals with diabetes or hyperlipidaemia were particularly at risk over the latter period. The researchers suspect that this is partly a result of global warming, but that it is also a consequence of an increase in risk factors such as diabetes and hyperlipidaemia, which have made the population more susceptible to heat.

“Our study suggests that greater consideration should be given to high temperatures as a potential trigger for heart attacks; especially in view of climate change,” explains lead researcher Dr. Alexandra Schneider. “Extreme weather events, like the 2018 heat waves in Europe, could in future result in an increase in cardiovascular disease. At the same time, there is likely to be a decrease in cold-related heart attacks here in Germany. Our analysis suggests a lower risk in the future, but this lower risk was not significant and very cold days will continue to represent a potential trigger for heart attacks.”

Read more:

Kai Chen, Susanne Breitner, Kathrin Wolf, Regina Hampel, Christa Meisinger, Margit Heier, Wolfgang von Scheidt, Bernhard Kuch, Annette Peters, Alexandra Schneider, A Peters, H Schulz, L Schwettmann, R Leidl, M Heier, K Strauch. Temporal variations in the triggering of myocardial infarction by air temperature in Augsburg, Germany, 1987–2014European Heart Journal, 2019; DOI: 10.1093/eurheartj/ehz116


Cover photo by Benjamin Voros on Unsplash.
Experts warn: climate change already a health emergency

Experts warn: climate change already a health emergency

By Elisa Jiménez Alonso

Climate change is already damaging people’s health in a number of ways from deadly heatwaves across the globe to increasing instances of dengue fever in the tropics.

The 2018 report of the Lancet Countdown: Tracking Progress on Health and Climate Change, produced by 150 experts from 27 universities and institutions including the World Health Organization (WHO) and the World Bank, also shows climate change can negatively affect nutrition, mental health, and people’s capacity to work outdoors.

During the press conference marking the report’s launch, authors highlighted that the combination of rising temperatures, leading to higher A&E and hospital admissions due to heat-related illness, and extreme weather event, which can damage infrastructure, could overwhelm health services.

WHO director-general Tedros Adhanom Ghebreyesus said about the report “The findings are clear and the stakes could not be higher, we cannot delay action on climate change. We cannot sleepwalk through this health emergency any longer.”

Nick Watt, the executive director of the Lancet Countdown, added “These are not things happening in 2050 but are things we are already seeing today. We think of these as the canary in, ironically, the coalmine.”

According to the report, 153 billion hours of work were lost in 2017 due to extreme heat. 80% of it in agriculture and almost half of the losses happened in India, which is equal to roughly 7% of its whole working population. Compared to the year 2000, 157 million more vulnerable people were exposed to heatwaves in 2017 and 18 million more than in 2016.

The temperature increase is not just dangerous because the heat itself affects human health directly, it also exacerbates urban air pollution. With 97% of cities in low- and middle- income countries not meeting WHO air quality guidelines, this adds even more pressure to health systems.

Prof. Kris Ebi, Professor of global health and of environmental and occupational health science, University of Washington, said “Increased mortality in extreme heatwaves is not something that may happen, it’s happening now and will continue as global temperatures continue to rise. There is abundant evidence that communities are not prepared for the ongoing increases in the frequency, intensity, and duration of heatwaves. Actions are needed right now, matched with investments, such as implementing early warning systems for heatwaves, including mapping vulnerable populations and providing interventions designed to increase resilience during hot weather.”

Of the 478 global cities surveyed in the report, 51% were expecting climate change to seriously compromise their public health infrastructure. 65% said they have either already completed or are currently doing climate change risk assessments but spending on climate adaptation for health is estimated to be just 4·8% (£11·68 billion) of all adaptation spending which is woefully inadequate, the report warns.

Access the report and its accompanying materials by clicking here.

Suicide risk may rise as severe heat grows

Suicide risk may rise as severe heat grows

By Tim Radford

High temperatures do more than raise tempers and stoke conflicts. They are also linked to depression, mental instability and a higher suicide risk.

A new study suggests that hot weather’s adverse effects on some people can include a heightened suicide risk. While the rise is numerically small today, the increase in extreme heat expected later this century could have starker consequences.

Californian scientists have looked at 50 years of records to establish a link between higher-than-usual temperatures and suicide rates in the United States and Mexico.

They found that a 1°C rise above average temperatures could be linked to a tiny increase – just 0.68% – in suicides in the US and by 2.1% south of the border. The rise is small. But it means that if the pattern of heat extremes predicted under all global warming scenarios continues to 2050, then there could be an additional 21,000 acts of suicide.

The same study, in Nature Climate Change, also identified a tendency to respond depressively: in such hot spells, people who used the social media platform Twitter were more likely to employ telltale words such as “lonely” or “trapped” or “suicidal”.

Scientists have already repeatedly established that heat extremes can be lethal,  and will multiply as the world warms, directly as a consequence of profligate human combustion of fossil fuels.

“Suicide is one of the leading causes of death globally, and suicide rates in the US have risen dramatically over the last 15 years”

The Californian scientists looked at official death records county by county in the US from 1968 to 2004, and across municipalities in Mexico from 1990 to 2010. They then matched these with temperature records by day and by month for those locations.

They also checked 600 million Twitter updates that could be identified as coming from a particular place and combed them for evidence of what they call “depressive feelings.” And they found a link between temperature and low spirits, as well as between temperature and suicide rates.

If extended to temperatures likely by 2050, suicide rates could increase in the US by 1.4% and in Mexico by 2.3%. And that could add up to an extra 9,000 deaths at the very least, or as many as 44,000.

“Surprisingly, these effects differ very little based on how rich populations are or if they are used to warm weather,” said Marshall Burke, an economist at Stanford University.

“Suicide is one of the leading causes of death globally, and suicide rates in the US have risen dramatically over the last 15 years. So better understanding of the causes of suicide is a public health priority.”

Human impact

Dr Burke and one of his co-authors, Solomon Hsiang of Berkeley University, have repeatedly focused on the human consequences of climate change. Dr Burke has already established that even small reductions in global warming could deliver huge benefits to society.

Separately, Dr Hsiang has warned that global warming could bring poverty even worse than the 1930s Depression for many in the US, and that politicians were ignoring evidence of the sheer social cost precipitated by climate change, not least because rising temperatures make violence and social conflict ever more likely.

Working together, they have also warned that rising temperatures could be associated with lower incomes and productivity, and that with every shift in temperature, there is a link to levels of violence in conflicts worldwide.

“We’ve been studying the effects of warming on conflict and violence for years, finding that people fight more when it’s hot,” said Dr Hsiang. “Now we see that, in addition to hurting others, some individuals hurt themselves. It appears that heat profoundly affects the human mind and how we decide to inflict harm.”

And Dr Burke said: “Hotter temperatures are clearly not the only, nor the most important, risk factor for suicide. But our findings suggest that warming can have a surprisingly large impact on suicide risk, and this matters for both our understanding of mental health as well as for what we should expect as temperatures continue to warm.”


This article was originally published on Climate News Network, access it by clicking here.

Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.

Photo by Ali Morshedlou on Unsplash.
UK heatwave: NHS records over 2 million people in emergency care in July 2018

UK heatwave: NHS records over 2 million people in emergency care in July 2018

By Elisa Jiménez Alonso

The NHS England reported that during the July 2018 heatwave a total of 2.176 million people visited a hospital A&E unit, walk-in centre, or urgent treatment centre putting emergency departments under lots of pressure to cope with the influx of patients.

The latest NHS monthly performance figures show that July 2018 was exceptionally busy with 27.1% more patients admitted than in July 2017. It is believed that the heatwave led to an increase in admissions, mostly people with breathing conditions, like asthma, or people who had become dehydrated due to the heat.

The heatwave, however, is not solely to blame. Doctors spoke out to say that while the record temperatures were a key factor in the surge of attendances, missed waiting time targets showed the NHS is understaffed and underfunded. Chris Hopson, chief executive of NHS Providers, said the figures showed the health service was “running at boiling point all year round.”

Speaking to The Guardian, Dr Taj Hassan, the president of the Royal College of Emergency Medicine, which represents A&E doctors, said “The recent heatwave will have had an impact, but this should not be used to excuse inappropriate resourcing. It should also not come as a surprise that whatever the weather conditions, working in a continually under-resourced and declining system has consequences – all of which are detrimental to our patients.”

He also pointed out that wards and waiting rooms had gotten unbearably hot during the heatwave making longer waiting times hard to cope with and adding to the pressure on staff to deliver safe and effective care.

NHS England made a statement saying that “thanks to hard work of staff 9 in 10 people were seen, treated and admitted or discharged within four hours.”

However, if this summer is a taste of what is to come, it is clear the UK health system will need take decisive measures to adapt to a changing climate. Excessive heat can be detrimental to human health and as temperatures start to rise, so will the number of people who require medical care.

The NHS will have to provide enough resources and staffing in order to cope with the increased demand, especially in summer. Additionally, NHS facilities will need upgrading so that people who come in with heat-related illnesses don’t have to wait in unbearable heat to be seen.


Photo by rawpixel on Unsplash.
In a warming world, access to cooling is an everyday essential

In a warming world, access to cooling is an everyday essential

By Elisa Jiménez Alonso

A recently released report by Sustainable Energy for All finds that 1.1 billion people around the world face immediate risks from insufficient access to cooling. According to the report, access to cooling is an important emerging opportunity in climate adaptation innovation.

Rachel Kyte, CEO and Special Representative to the United Nations Secretary-General for Sustainable Energy for All, said “In a world facing continuously rising temperatures, access to cooling is not a luxury – it’s essential for everyday life. It guarantees safe cold supply chains for fresh produce, safe storage of life-saving vaccines, and safe work and housing conditions.”

The study shows that access to cooling is very much tied to wealth. Of the 1.1 billion people at immediate risk, 470 million are in poor rural areas and 630 are in hotter, poor urban slums. These people are also concentrated in nine countries across Asia, Africa and Latin America: India, Bangladesh, Brazil, Pakistan, Nigeria, Indonesia, China, Mozambique and Sudan.

Cities, communities, and country leaders are asked to consider cooling action plans in order to close the access to cooling gap. Additionally, the Kyte points out that for companies that produce HFC-free, affordable air conditioning devices there is an enormous market opportunity out there.

In addition to the 1.1 billion rural and urban poor at immediate risk, the report identifies 2.3 billion people from the increasingly affluent lower-middle class, on the brink of being able to afford air conditioning, and 1.1 billion belonging to the established middle class, many of whom own air conditioning units but may able to upgrade them to more efficient ones.

This also ties into findings recently presented in a report completed by Acclimatise with UNEP FI and sixteen leading international banks. The report focuses on climate-related physical risks and opportunities to the banking sector. One of the examples named is an increased demand for loans for home improvements in order to cool houses where it was previously unnecessary.

While cooling is increasingly becoming a necessity, it is also a very energy-intensive measure. Increased cooling from HFCs and using fossil fuel powered energy can lead to more warming. In Mumbai alone, 40% of power use comes from air conditioning. Thus, phasing out HFCs, for instance through the Kigali Amendment, and the continued investment in renewable energy sources should remain priorities.

At the same time, urban development and real estate have the opportunity to radically rethink how buildings and cities can be designed in order to optimize cooling. In India, for example, 75% of the buildings required by 2030 have yet to be built, offering a massive opportunity to be innovative and provide cooler cities and housing.

Download the report by clicking here.


Cover photo by  PDPics/Pixabay (public domain): Mumbai skyline.
The heat is on: Northern Hemisphere experiences sweltering summer temperatures

The heat is on: Northern Hemisphere experiences sweltering summer temperatures

By Elisa Jiménez Alonso

Large parts of the Northern Hemisphere are currently experiencing unusually high temperatures giving us a taste of what climate change looks like in our day-to-day lives, and highlighting the need for adaptation.

Worldwide heat

Temperature records have been breaking across the United Kingdom, Glasgow for example had its hottest day ever recorded with 31.9C, and Scotland broke its temperature record with 33.2C in Motherwell. While these temperatures are not nearly as bad as elsewhere, they are out of the ordinary and are causing infrastructure problems.

Buckled rails and signal failures have led to widespread cancellations and delays. Additionally, the Met Office has activated a Level 3 – Heatwave Action across southern, central, and western England, encouraging people to check on any elderly family members or friends and other vulnerable persons.

In Canada, where Montreal broke its temperature record with 36.6C, up to 54 deaths have been linked to the heatwave in southern Quebec. Temperatures rose to 35C with high humidity and a smog advisory. Most victims were over 50 years old.

Most frightening of all, however, the temperature in the town of Quriyat in Oman never dropped below 42.6C for a full 24 hours in June.

Trends of the new millennium

The warming trend is clear, according to the US National Oceanic and Atmospheric Administration (NOAA), all 18 years of the 21st century have been among the 19 warmest on record with 2016 being the hottest year ever recorded. The five hottest years ever recorded have occurred since 2010.

Many countries have experienced what these trends can lead to. The notorious 2003 European heatwave is estimated to have caused anywhere between 20,000 and 70,000 premature deaths. In 2006, California saw a ten-day heatwave that was linked to 140 deaths. In Canada, the summer heatwave of 2010, one of the hottest on record, killed about 280 people.

A hot new normal without political will to change

The warming trends are clearly linked to increasing greenhouse gas concentrations in the atmosphere. While renewable energy use is growing, 80% of global energy use is from fossil fuels. The transition to a low-carbon economy is proving to be a slow one, thus, adaptation to climate change will be, and already is, essential.

National infrastructure, especially related to water supply, will need a lot of attention, as will housing standards. But, as we are seeing in the UK right now, transportation will need to be updated as well to deal with higher temperatures. There are also considerations for national healthcare and land management – adaptation truly needs to happen across all sectors.

However, as the political climate in the Northern Hemisphere heats up as well, climate change is rarely top of the agenda. This, of course, is a major mistake, as climate change will put even more pressure on any problems we are already facing undermining prosperity, progress, and economic growth.


Photo by Garry Knight/Flickr (CC BY 2.0): Summer in Regent’s Park.
Study counts lives saved with push for 1.5°C climate target

Study counts lives saved with push for 1.5°C climate target

By Inga Vesper

Speeding up progress on reducing carbon emissions would save millions of lives, mostly in metropolitan areas of Africa and Asia.

To keep global warming below 1.5 degrees Celsius, the world would need to cut the majority of fossil-fuel related carbon emissions this century – and because this would also reduce air pollution locally, it would prevent 150 million premature deaths, according to a paper published in Nature Climate Change.

The researchers found that reducing this century’s expected carbon dioxide emissions by 180 gigatonnes – the amount needed to meet the 1.5 degree target, or keep global warming at 2 degrees without negative emissions– would mean moving to a largely renewables-sourced energy system.

Making this shift sooner rather than later would save an estimated 90 million lives by 2100 due to reduced exposure to fine particles, according to the study. Another 60 million deaths could be prevented because of reduced ozone levels.

“The public health benefits of very low carbon policies are enormous.”

“The public health benefits of very low carbon policies are enormous,” says Drew Shindell, a climate researcher at Duke University in North Carolina, United States, and co-author of the paper.

Last year saw the first increase in global CO2 emissions in four years, which puts added pressure on governments to live up to their emission reduction targets. While industrialised countries remain the biggest emitters by far, the researchers point out that developing countries avoid slipping down the fossil fuel pathway.

“Developing countries are largely in control of their own fate when it comes to air pollution,” says Shindell. “They’d have to make big changes to get off fossil fuels but they’d reap enormous benefits locally via air quality if they did so.”

Because their pollution levels are already high, Indonesia, China and Nigeria are likely to benefit the most from speeding up emissions reductions. Large urban centres, such as Cairo in Egypt, would also see significant improvements in death rates from pollution, the researchers found.

The first goalpost for global emission reduction targets, as set by the United Nations Framework Convention on Climate Change, is 2030 – by which time many countries are meant to have significant renewable energy capacity in place.

But with financing falling short, the resulting emission reductions – and drop in deaths from pollution – could fail to happen, says Neill Bird, a senior research fellow at the UK-based Overseas Development Institute. “A lack of investment could result in countries sticking closer to a business as usual pathway,” he says.

Many developing countries find it difficult to finance renewable energy projects. A separate study warns that countries in the Global Green Growth Institute, a club of nations with voluntary renewable energy targets, need at least US$260 billion in additional investment if they are to meet their goals.

Published in Energy Policy, the study found that with the right investment, GGGI countries such as Uganda, Mexico, the Philippines and Senegal could draw up to 30 per cent of their energy needs from renewables by 2030. But the high upfront cost of installing renewables is an obstacle.

Dereje Senshaw, a Korea-based researcher for the GGGI and co-author of the study, says the best way to find the money is a combination of national and international funds. “Developing countries should not just expect international financial assistance,” he told SciDev.Net. “They should develop their own business models for renewable energy and create favorable market conditions in order to attract private investments.”

Bird says that middle-income countries should target foreign direct investment for their projects, but points out that the poorest nations will probably have to rely on international public funds, such as aid, to up their renewables capacity.


This article was originally published on SciDev.Net. Read the original article.

Cover photo by Thomas Richter on Unsplash.

The impact of climate change on mental health is impossible to ignore

The impact of climate change on mental health is impossible to ignore

By Prof Helen Berry, inaugural professor of climate change and mental health at the University of Sydney.

It is now widely accepted that climate change is one of the world’s leading health risks. From driving up the number of people exposed to heatwaves to increasing the risk of infectious diseases, such as dengue fever, climate change is already causing significant harm.

Similarly, the body of evidence that climate change is increasing the frequency and ferocity of weather-related extremes is increasing year-on-year. More people are being exposed – or, worse still, the same people are exposed more frequently – to injury, loss of homes and businesses, environmental damage and even loss of lives.

All of these have profound, often long-term effects on mental health. Yet there remains relatively little research on this topic, and even less commitment to doing anything about it.

This is a mistake. Good mental health is essential to our capacity to cope with and make the best of what life throws at us, including climate change. But it is not something we can take for granted.

Neglected research

Each year, hundreds of millions of people around the world experience mental illness. For most people, this is frightening, distressing, confusing and painful – potentially affecting every aspect of life. Work, relationships, finances, community participation and physical health are all touched.

Yet mental illness remains poorly understood, stigmatised and feared, too often experienced in shame and isolation. And the funding needs for mental health services and research are not being adequately addressed the world over.

That same neglect is reflected in the research around mental health and climate change. For example, as I show in a paper published in Nature Climate Change last week, a search on the online research database Scopus for studies concerning climate change and mental health yields just 208 publications between 2007 and 2018. And of these, only 29 critically evaluate mental health.

So, what does the available research tell us about the impacts of climate change on mental health?

Aggravating risk

Overall, the consensus in the scientific literature is that climate change will increase the number of people exposed to extreme events and, therefore, to subsequent psychological problems, such as worry, anxiety, depression, distress, loss, grief, trauma and even suicide.

Heatwaves, for example, are of particular concern. Research across the Australian population shows their impact on mental health is similar to that of unemployment. Night-time heat is associated with reduced sleep – a cause and consequence of poor mental health – and some psychoactive medicines become ineffective during heatwaves.

Research has shown a rise in hospital admissions for mental health issues during heatwaves in the Australian city of Adelaide, and identified a link between extreme heat, reduced crop yields and suicides in Indian farmers.

The impacts of weather-related disasters can be more dramatic and this is where the biggest risks lie. They can create food shortages, destroy public infrastructure and disrupt transport, cut off power and connectivity, damage land used for agriculture and recreation, destroy sacred places and even force people to migrate. Vital medicines and medical aids can be lost fleeing extreme events, interrupting continuity of care.

Reconstruction and recovery from disasters is enormously costly. Pressures quickly escalate on frontline responders, such as emergency services, nurses and pharmacists, and other public health-related resources – including hospitals, care homes and the healthcare workforce.

These pressures create stress on society and the communities which have to absorb impacts and costs. Volunteers and paid service providers burn out, businesses and economic opportunities are damaged, incomes are reduced and productivity falls. Inequality – a key driver of poor health – can also begin to rise.

Pressures on time, money and stress can lead to people spending less time participating in their communities, being with and supporting each other. This can impair social cohesion and positive identities. For some, isolation can result or intensify. When this happens, we lose our most critical sources of mental wellbeing.

The scientific literature shows that severe mental health effects of disasters disproportionately hit vulnerable people – particularly women, young people, migrants, people living with a disability, and ethnic minorities.

Flooding distress

Flooding in the UK offers another example. Research conducted by Public Health England (PHE) shows the floods in 2000 in Lewes, southern England, quadrupled community levels of psychological distress – and that those psychological problems were still identifiable four years after a flood.

PHE researchers have begun a programme of investigations to find out more about this and are looking at physical as well as mental impacts and “secondary stressors” – such as flood-related money pressures, problems with insurance claims and relationship stress.

The first year of the research has found elevated depression, anxiety and post-traumatic stress disorder in flooded areas, even among those who were not personally flooded. Rates of problems were much higher in flooded households, especially when the flooding disrupted domestic utilities or healthcare, or forced residents out of their homes for a time.

In good news, being forewarned of flooding protected people against mental health impacts – an important lesson to take from the research so far.

Way forward

The research undertaken so far has provided a solid base for understanding how climate change affects mental health. But connections still need to be analysed, theories tested and further evidence gathered.

In its Comprehensive Mental Health Action Plan 2013-2020, the World Health Organisation drew attention to the huge unmet global need for more and better, research-informed, mental health support.

The complexity of both mental health and climate change means that tackling the two together requires a “systems thinking” approach. This describes the big picture as well as the detail, taking in complex set of interacting factors – geopolitical, socio-economic, ecological and environmental – to best identify policy solutions.

Like all systems, the climate change-mental health system has power, resilience and momentum. As a result, there will be some aspects of mental health impacts – within a certain range of tolerance – that are unavoidable.

Working within an understanding the system will usefully influence policy thinking and the research needed to inform it. It is time to talk about climate change and mental health in our local, national and international communities, about harmful and adaptive pathways identifiable in the system – and about what we can do together to inhibit the former and promote the latter.

Fortuitously, people seem to worry about climate change collectively rather than personally, and this form of worry might be harnessed to motivate action on climate change and drive improvements in mental health. Both are greatly needed.


This article originally appeared on Carbon Brief and can be accessed here. It is shared under a Creative Commons license.

Berry, H. L. et al. (2018) The case for systems thinking about climate change and mental health, Nature Climate Change, doi:10.1038/s41558-018-0102-4.

Cover photo by Lieut. Commander Mark Moran, NOAA Corps, NMAO/AOC (CC BY 2.0): Total devastation following Hurricane Katrina. Waveland, Mississippi. September 13, 2005.
Heart attacks can rise during extremes of heat

Heart attacks can rise during extremes of heat

By Tim Radford

Extremes of heat are dangerous. Just how dangerous is still being established. But since heat waves are on the way, city-dwellers need to know.

Extremes of heat can break your heart. Climate change can kill. The risk of heart attack increases by every 5°C leap in temperature differential, according to new research.

That is: on a baking summer day there could be nearly twice as many heart attacks on those days when the temperature swings by 35° to 40°C than on days when there is no such wild fluctuation.

Studies of the link between heat and health matter, because the past decade in North America has now been confirmed as the hottest for 11,000 years.

Climate scientists have repeatedly warned of the dangers of ever more intense and frequent heat extremes as the global average temperatures creep up, and two new studies have identified different ways in which cities themselves can become danger zones for vulnerable people.

One is that, as regional climates change in response to ever-increasing combustion of fossil fuels, which then intensify the greenhouse gas ratios in the global atmosphere, cities in now-arid regions will suffer ever more severe heatwaves, even though their rural hinterlands may enjoy higher rainfall.

And the second is that, in some cities, urban planning may have already provided ways to intensify or mitigate the impact of summer heat waves. It’s a simple but unexpected outcome of atomic physics.

Increasing fluctuation

All four studies are evidence of the subtle and often intricate connections between human civilisation and climate, and of the consequences of the simple question: what happens to communities and landscapes as average temperatures go up?

“Global warming is expected to cause extreme weather events, which may, in turn, result in large day-to-day fluctuations in temperature,” said Hedvig Andersson, a cardiology researcher at the University of Michigan.

“Our study suggests that such fluctuations in outdoor temperature could potentially lead to an increased number of heart attacks and affect global cardiac health in the future.”

She told the American College of Cardiology 67th annual scientific session that she and colleagues looked at data from 30,000 patients treated in 45 Michigan hospitals between 2010 and 2016, and then matched the patients with temperature fluctuations on the day of the attack.

Such a study cannot prove that temperature swings actually cause attacks, but there is what scientists call an association: rapid and extreme fluctuations seem to be accompanied by more cases of myocardial infarction, a serious form of heart attack.

Urban vulnerability

That heat is dangerous is not a surprise: heatwaves in the last 30 years have risen three times faster than average temperatures as a whole, and one study has identified 27 different ways in which heat waves can kill. And the greatest concentrations of potential victims will be in the cities.

The crowded urban spaces of America and Europe spread across landscapes warmer than at any time since the end of the Ice Age. US researchers report in the journal Nature that they collected fossil pollens from 642 ponds and lake beds across Europe and North America, to provide a record of local temperature shifts in the last 11,700 years, to conclude that – without global warming as a consequence of profligate human use of fossil fuels – the world ought to be in a cool phase.

“It does show that what has happened in the last 30 years — a warming trend — puts us outside of all but the most extreme single years every 500 years since the Ice Age. The last 10 years have, on average, been as warm as a normal one year in 500 warm spell,” said Bryan Shuman, an earth scientist at the University of Wyoming, and one of the authors.

Whatever the average regional temperature, it’s hotter in the cities, because concentrations of traffic, business, heating, cooking, lighting and air conditioning generate what has become known as the urban heat island effect: what makes this worse is that the asphalt, tarmacadam, stone, brick, glass and tile of which cities are made absorb radiation but prevent ground evaporation as a natural cooling device.

Researchers from Princeton University report in the journal Environmental Research Letters that they considered how future heat waves will play into the urban heat island effect in 50 US cities.

“Fluctuations in outdoor temperature could potentially lead to an increased number of heart attacks and affect global cardiac health in the future”

For the rest of this century, cities in the east and southeast of the US will be more severely affected: less so the cities in the arid parts of the American west.

But by 2100, this could change dramatically. Rainfall and heat extremes will increase. Cities such as Phoenix, Arizona will continue to face water shortages – once again, all that impermeable concrete and sealed highway – but climate change could make the surrounding countryside somewhat moister.

The message, once again, is that what keeps a city cool is moisture: the vapour evaporated from canals and rivers or transpired through green parks and treelined boulevards.

“Given that 50% of the world’s population currently lives in cities, and that percentage is projected to increase to 70% by year 2050, there is a pressing need to understand how cities and landscapes are affected by heat waves,” said Lei Zhao of Princeton’s Woodrow Wilson School of Public and International Affairs.

“Our study explains why cities suffer even more during extreme heat events and highlights the heat risks that urban residents face now and in the projected future.”

Seeking mitigation

The researchers say the hunt should be on for heat mitigation strategies. But a surprising study in the journal Physical Review Letters suggests that some of the problems – and the solution – may have already been built into the fabric of the modern metropolis.

A team of materials scientists and engineers simply considered the city as crystalline or glass-like: that is, was the city laid out on a planned, orderly grid system? Or did it just grow up, in an organic, disorderly fashion?

They applied the tools of classical physics normally used to analyse atomic structures. They looked at satellite images of 47 cities in the US and beyond, and graded them according to their order, or disorder. Grid cities absorbed heat compared to their surroundings far faster than the so-called glass-like cities.

Since urban populations are growing, and new cities springing up everywhere, classical physics can help in unexpected ways. “If you’re planning a new section of Phoenix,” said Roland Pellenq of the Massachusetts Institute of Technology, “you don’t want to build on a grid, since it’s already a very hot place. But somewhere in Canada, a mayor may say no, we’ll choose to use the grid, to keep the city warmer.”

The effects are significant. He and colleagues found, for example, that in the state of Florida alone urban heat island effects cause an estimated $400 million in excess costs for air conditioning. “This gives a strategy for urban planners,” he says.


This article was originally published on Climate News Network, access it by clicking here.