Category: Health

Health impact of climate change is ‘the major threat of 21st century’

Health impact of climate change is ‘the major threat of 21st century’

By Daisy Dunne

The health of millions of people across the world is already being significantly harmed by climate change, a major new report finds.

From driving up the number of people exposed to heatwaves to increasing the risk of infectious diseases, such as dengue fever, climate change has had far-reaching effects on many aspects of human health in last few decades, the authors say.
In fact, the effect of climate change on human health is now so severe that it should be considered “the major threat of the 21st century”, scientists said at a press briefing held in London.
The report is the first from the Lancet Countdown on Health and Climate Change, a project involving 24 academic institutions and intergovernmental organisations from across the world. The project plans to release a report tracking progress on climate change and global health every year.

Feeling the heat

The report uses a set of 40 indicators to track the effects of climate change on global health. The first of these indicators assesses the “direct impacts” of climate change on human health, including the effects of exposure to extreme heat and natural disasters.

One of the report’s findings is that, from 2000 to 2016, the rise in the average temperatures that humans were exposed to was around three times higher than the rise of average global temperatures worldwide.

This is shown on the graph below, where the rise in the global average surface temperature from 2000 to 2016, when compared to the average from 1986 to 2008 (red), is shown alongside the rise in the temperatures that humans are typically exposed to (blue).

The rise in average global surface temperatures from 2000 to 2016 (red), alongside the rise in the average temperatures that people are exposed to (blue), relative to averages taken from 1986 to 2008. Source: Watts et al. (2017)

The average temperatures that humans are exposed to are significantly higher than the global surface average because most people live on land, where warming happens most quickly, explains Prof Peter Cox, an author of the new report and a climate scientist at the University of Exeter: “Generally speaking, when you look at where people are, the rate of change appears much larger than when we look at global averages. So maybe when we think about global targets, we should be always bearing in mind that the global mean temperature doesn’t really mean much to most people. We don’t live on the ocean, which is two-thirds of the global mean. We live on the land, and on the land that tends to warm fastest.

The report also finds the number of “vulnerable” people exposed to “heatwave” events increased by around 125 million between 2000 and 2016. “Vulnerable” is here defined as being over the age of 65, while a “heatwave” is defined as three consecutive nights where temperatures are in the top 1% of the 1986-2006 average for the region.

In 2015, a record 175 million more people were exposed to heatwaves, when compared to the average for 1986-2008, the report finds. You can see this in the chart below, which shows the change in the number of people exposed to heatwaves from 2000 to 2016, relative to 1986-2008.

The change in the number of people exposed to heatwaves in millions per year from 2010 to 2016 (blue), relative to the 1986-2008 average. Source: Watts et al. (2017)

These spikes in exposure are a result of an increase in heatwave events, as well as other environmental and social factors, including population growth, Cox says.

Heatwave exposure has previously been linked to an increased risk of premature death in many parts of the world, he explains:

“During the 2003 European heatwave, there were 75,000 extra premature deaths in Europe, including 2,000 in the UK. That was mainly because of people not being able to recover, and I guess breathing gets harder when it’s hot too. There is a correlation between these periods of hot nights and mortality. I suspect there must be a correlation with ill health as well.”

Natural disasters

The report finds that the number of weather-related disasters from 2007 to 2016 increased by 46%, when compared with the average for 1990-1999.

Asia is the continent most affected by weather-related disasters, the report says – particularly because of its size and population. Between 1990 and 2016, 2,843 weather-related disasters were recorded in Asia, affecting 4.8 billion people and causing more than 500,000 deaths.

Despite a rise in the number of natural disasters, there has been no discernable rise in the global number of deaths or in the number of people affected by natural disasters, when compared to data from 1990 to 1999, the report finds.

This could indicate that countries are beginning to invest in adaptation strategies to cope with natural disasters, Cox says. However, the mismatch could also reflect a lack of data on deaths from climate-related disasters in the developing world, he adds:

“If you look at what happens when a disaster strikes, if it’s in the rich developed world, it leads to economic damages but we don’t lose people. If it’s in the developing world, then we lose lives.

“It is true that there is a kind of contradiction in that exposure is going up, but actually the number of people affected, at least recorded as affected, is staying flat, which either means we’re building greater resilience [to climate change], which I suspect is not true, or that the data we’re collecting on the amount of money being lost is better than on the amount of people being lost.”

Losses to the global workforce

Another set of indicators explored by the report look at the “human-mediated” impacts of climate change. These are impacts that are intrinsically linked to human society, but often exacerbated by climate change.

The first of these indicators explores how climate change has affected the productivity of the global workforce, particularly in the less economically-developed parts of the world. The report finds that the global productivity in rural labour capacity – defined as those who work in outdoor manual labour in rural areas, but excluding agricultural workers – has fallen by 5.3% from 2000 to 2016.

The chart below shows how this global loss in productivity is spread across the world, with red indicating a percentage loss in productivity and blue showing a percentage gain in labour capacity.

Global changes to labour capacity from 2000 to 2016 as a result of rising global temperatures, relative to average levels from 1986 to 2008. Red shows areas of loss, while blue shows areas of gain. Source: Watts et al. (2017)

In 2016, this drop in productivity effectively took more than 920,000 people globally out of the workforce, the report finds, with 418,000 of these workers being “lost” from India.

One way that higher temperatures threaten labour capacity is by making manual work more physically challenging, the report finds:

“Higher temperatures pose profound threats to occupational health and labour productivity, particularly for people undertaking manual, outdoor labour in hot areas. Loss of labour capacity has important implications for the livelihoods of individuals, families, and communities, especially those relying on subsistence farming.”

An additional “human-mediated” impact of climate change is undernutrition, the report finds. It reports that the number of undernourished people in the top 30 undernourished countries of the world has increased from 398 million in 1990 to 422 million in 2016.

This is at least in part driven by the effect of climate change of yields of staple crops such as wheat, rice and maize, the report says. Climate change affects crop yields through increasing local temperatures, changes to rainfall patterns and more cases of drought. The report says:

“Increasing temperatures have been shown to reduce global wheat production by 6% for each 1C increase. Rice yields are sensitive to increases in night temperatures, with each 1C increase in growing-season minimum temperature in the dry season resulting in a 10% decrease in rice grain yield. Higher temperatures have been demonstrated rigorously to have a negative impact on crop yields in countries in lower latitudes. Moreover, agriculture in lower latitudes tends to be more marginal, and more people are food insecure.”

Infectious diseases

The report also investigates the “environment-mediated” impacts of climate change. These are impacts on human health that are caused by environmental factors but can be worsened by climate change.

One such impact is the spread of infectious diseases around the globe. Rising temperatures can increase the spread of infectious diseases by allowing pests to conquer new parts of the world, as well as by creating ideal conditions for reproduction and virus replication.

Climate change has affected the prevalence of many infectious diseases, the report notes. However, as an example, the report focuses on how climate change has impacted the spread of dengue fever, a disease spread by mosquitoes native to much of southeast Asia, central and south America, and Africa.

The research shows that the rate of the spread of dengue fever has increased from between 3% and 5.9% globally, when compared to levels from 1990.

The chart below shows how the rate of the spread of dengue fever (vectorial capacity) has increased in the world’s most affected countries from 1950 to 2015. The chart shows results from two species of mosquito, including yellow fever mosquito (Aedes aegypti; left) and Asian tiger mosquito (Aedes albopictus; right).

On the heat map, each block represents one year, with red showing an increase in spread and blue showing a decrease in spread. The chart shows that, since 1995, the vast majority of countries have experienced an increase in the rate of the spread of dengue fever.

Change in the rate of the spread of dengue fever (vectorial capacity) in the countries most affected by the disease from 1950 to 2015. The chart shows results from two species of mosquito: the yellow fever mosquito (Aedes aegypti; left) and Asian tiger mosquito (Aedes albopictus; right). On the heat map, each block represents one year, with red showing an increase in spread and blue showing a decrease in spread. Source: Watts et al. (2017)

The increase in the rate of the spread of dengue fever could be driven by changes in environmental conditions as a result of climate change, says Prof Hugh Montgomery, co-chair of The Lancet Countdown and a professor at University College London. He told the press conference:

“It’s essentially because of the transmissibility, the ability of the virus to be spread by mosquito vector. As you get areas that get wetter, the mosquito has a habitat it can live in; populations go up as it gets warmer, they breed more frequently, they feed faster. So it gets easier to spread the bug, and that’s really why we’re seeing a doubling in the spread rate of dengue cases.”


Looking to the future, the report also explores how climate change could bring new health-related woes, including an increase in the displacement of people as a result of sea level rise.

It is clear that both the current and potential future impacts of climate change on health demand immediate action on tackling fossil fuel use, says Cox, adding that it is not too late to stem some of the effects of climate change on human health. He tells Carbon Brief:

“The co-benefits of action on climate are so huge, I think, well, maybe we present this the wrong way. Rather than saying ‘we should tackle climate change and there’s a co-benefit for health’, it should be ‘we need to do this for our health, and there’s a co-benefit on climate’.”

Montgomery echoed the call for immediate action to tackle climate change for the good of human health. He told the press conference:

“It is too late to avoid impacts, they’re here and if we all die tomorrow and stop producing any CO2, we’re still locked in for a temperature rise. There is a lag between CO2 emissions and the warming that will come. It’s like sticking an extra duvet on, the temperature will slowly rise to a new equilibrium. So we’re locked in for change for a long time to come and those harmful effects we’re seeing already from perhaps little around 1C of temperature rise, we’ve got another half degree as a minimum yet to come.”

However, there are reasons to be hopeful, he adds, pointing to progress on climate action within the last decade, including a shift away from electricity produced from coal and an increase in the investment into electric cars. He adds:

“Climate change can be fixed right now, there isn’t a problem with the technology, it’s readily available and deployable. The money is available for it, the only thing that’s lacking is the political will to connect the money to the infrastructure.”

This article first appeared on the CarbonBrief website and has been republished here with permission. To view the article in its natural habitat please click here.
Image: Workers at a construction site in Ethiopia. Outdoor workers are particularly exposed to high temperatures can suffer health consequences from a warming climate. Credit: Dfid. CC by 2.0
A deadly combination: Extreme heat and U.S. prisons

A deadly combination: Extreme heat and U.S. prisons

By Gracie Pearsall

In mid-July, a United States federal judge sided with a group of Texas inmates who sued the Texas Department of Criminal Justice (TDCJ) over summer heat conditions at the Wallace Pack Unit near Houston. The groundbreaking decision deemed that exposure to extreme heat was cruel and unusual punishment. The decision also referenced the impact of climate change. This ruling has brought attention to a demographic often excluded from the climate change narrative: Prisoners. Despite the correctional sector’s distinct risks to climate change, officials have taken very little action to adapt their systems and facilities. Climate change is causing average temperatures to rise and making heatwaves more intense, leaving prisoners highly at risk to the deadly effects of extreme heat, especially in the Southern United States.

Dangerous and deadly heat

While extreme heat is a pervasive phenomenon that will affect every American, prisoners are particularly vulnerable. Heat-risk multipliers, such as old age, poor mental or physical health, and use of medications are very common in prisons. These factors limit the body’s ability to acclimate to heat, which often leads to heat cramps, dehydration, and heat stroke. When these factors combine with the institutionalized negligence that permeates through the correction sector, the outcome is often deadly. Since 1998, 23 prisoners in Texas prisons have died from heat-related illnesses, many of whom had pre-existing conditions.

Prisoners have no reprieve from the heat. Officials often house them in close-quarter facilities that are overcrowded. Since the human body generates heat and humidity, the number of bodies in a prison directly influences the thermal environment. Excessive body heat combines with ambient heat to create an unbearably hot environment. Prisoners sometimes endure weeks of temperatures close to and over 40 °C (104 °F), and these heat spells will only get longer as climate change intensifies and extends heatwaves.

Existing regulations and practices fail to keep Texas prisons cool enough. The prisons are constructed from brick, metal, and glass, which absorb heat. Seventy percent of Texas prisons do not have air-conditioning, and temperatures can reach up to 43 °C (109 °F). Moreover, many prisons lack adequate ventilation, making the hot air humid and stagnant. The high humidity prevents sweat from evaporating, greatly increasing the risk of heatstroke. Fans offer no relief because once temperatures surpass 32 degrees Celsius (90 °F), fans only circulate, rather than cool the air.

To add to the temperature problem, officials are denying prisoners the appropriate amount of water. At the Price Daniel Unit near Dallas, inmates only receive a 240ml cup of water every four hours. This is two times lower than the amount that the National Academy of Medicine recommended. Inmates can go weeks without a cool drink, and ice is so limited that prisoners will buy ice from each other.

A lethal mix of all these problems caused the death of a prisoner, Larry McCollum.  McCollum  was transferred to a facility with no air conditioning in July, and assigned a cell with no fan and a non-opening window. Although inmates were supposed to receive regular refills of ice water, McCollum did not own a cup because prison policy forbade him from purchases at the commissary until after 30 days. However, after a week, McCollum was found dead in his bunk. He suffered a heat-stroke in the middle of the night after the heat index (apparent temperature) reached 65 degrees Celsius (150 °F).

Adaptating the correctional sector

The Eighth Amendment of the U.S. Constitution, the only federal standard for prisons, prohibits cruel and unusual punishment and guarantees humane conditions for prisoners. It was under this amendment that the federal judge issued an injunction ordering TDCJ to reduce temperatures to 31 °C (88 °F) where heat-sensitive residents reside, and give inmates regular access to air-conditioned areas.

Although the court did not mandate any specific methods for heat reduction, plenty of options exist. The primary long-term solution should be reducing the prison population. Efforts to move away from mass incarceration, to more effective strategies for reducing crime, pair perfectly with the correction sector’s need to adapt to climate change and provide better conditions for inmates. A smaller inmate population would mean less body heat, and more funds to allocate to heat-reduction and adaptation measures. Freeing up the budget would hopefully allow the TDJC to phase out heat-sensitive prisons, and ensure that new facilities include climate-resiliency measurers.

The installation of air-conditioning in prisons seems an obvious short-term solution. However, air conditioning is often a point of contention between officials. Some officials view air-conditioning as a luxury that criminals do not deserve, and have fought against inmate advocacy groups. Others believe that installation costs and use of air-conditioning is too high. Because of this bureaucratic gridlock, Texas prisons will most likely not expand air-conditioning to the rest of the inmates.

Luckily, other options exist. Retrofitting facilities with passive cooling measurers is effective, easy to implement, and most importantly, inexpensive. For example, installing awnings over windows could reduce inside temperatures by 65% on south-facing windows, and by 77% on west-facing windows. Reflective roofs could greatly reduce the indoor heat index by reflecting solar radiation. Installing a reflective roof is as easy as painting it white.

Unfortunately, this issue is not isolated to Texas. Last week a video surfaced of Louisiana prisoners screaming for relief from the heat. Extreme heat could become a sector-wide problem, as previously immune facilities become hotter. The case of extreme heat in prisons exposes how climate change will exacerbate certain social justice issues, and how successful adaptation will save lives.

Cover photo by JQPubliq/Flickr (CC BY 2.0): Inmates at the Brooklyn House of Detention playing basketball at sunset.
Extreme heat in South Asia threatens millions of people

Extreme heat in South Asia threatens millions of people

By Gracie Pearsall

Pervasive climate-based heat affects all corners of the globe, even places that normally have hot, tropical climates. One place already experiencing some of the devastating effects of rising temperatures and heatwaves is South Asia. The region’s rapid urbanisation and poverty rates are among the most important factors when it comes to heat, and general climate, vulnerability. However, solutions like green and reflective roofs are emerging as heat adaptation measures.

Heat-related illness

South Asia is already a hot and humid region and it’s getting even hotter. The average temperature there is rapidly approaching 37° C, which is the operating temperature of the human body. When the apparent temperature approaches body temperature, the body’s capacity to function properly is greatly diminished. This type of heat-stress leads to heat-related illnesses such as heat-stroke, exhaustion, and dehydration.

In the Ganga Plains, there are regularly days where the temperature exceeds 37° C, which puts residents highly at risk for heat-related illness. Climate projections for this area suggest that by 2050 there will be 152 out of 200 days between April and October where temperatures exceed 37° C. Because of these extended periods of extreme heat, the residents of the Ganga Plains will experience even more heat-related illnesses.

Heat stress in rural areas

Millions of families in rural South Asia depend on livelihoods that expose them to extreme heat, such as farming. These families are usually low-income and do not have access to cooling systems that offer relief from the heat. Extended periods of manual labor in the heat make farmers and other manual laborers distinctly vulnerable to heat-related illnesses.

The heat also decreases agricultural productivity because the heat harms crops and livestock. For example, Terai, Nepal’s most productive agricultural region, is in jeopardy because projections show temperatures increasing by 2.8° C by 2060. This heat will likely reduce the arability of the land, limit water for irrigation, and pose a deadly threat to the farmers’ health.

Urban heat island effect

The Urban Heat Island effect caused by the rapid urbanization and population growth in South Asia is adding heat to the already warming climate. Urbanization modifies land cover and replaces natural heat sinks, such as trees, lakes, and wetlands, with pavement and buildings that absorb a lot more heat. Because of this phenomenon urban areas in South Asia are significantly warmer than their rural counterparts.

This phenomenon is even present in typically cooler hill cities such as Kathmandu. As of 2016, a study estimated that the Kathmandu’s average heat index per month is 20 percent higher than that of each corresponding month 30 years ago. Currently, Kathmandu’s metropolitan center is 1° C warmer than the outskirts. The increased heat makes city residents vulnerable to heat-related illnesses and exposes them to respiratory harm from the high concentrations of air pollutants that usually accompany urban heat islands.

Beating the heat

To cope with the heat, South Asian communities use a variety of cooling techniques. The most popular technique is to install reflective material or vegetation on roofs to minimize heat absorption. Reflective roofs are especially critical in combating heat in urban areas where roofs make up the majority of surfaces hit by solar radiation. In Pakistan, a National Center for Atmospheric Research and Institute for Social and Environmental Transition study found that at night houses with reflective roofs were 3° C cooler inside than outside. Furthermore, in Bangladesh reflective roofs have been shown to reduce the indoor heat index by 77 percent during peak heat times.

South Asia’s overall ability to limit heat stress depends on reliable delivery of basic services such as clean water, sanitation, healthcare, and energy to run cooling technology. These services will help communities stay cool and treat heat-related illnesses. However, to provide these services, there must be significant investment in infrastructure. South Asian governments must also implement policy measures to preserve natural heat sinks, such as parks and lakes, and limit human activities that contribute to climate change, in order to brace for rising temperatures.

Cover photo by Barun Khanal/Wikimedia (CC BY-SA 3.0): Aerial view of field in the Madhesh region of Nepal.
Iranian city experiences scorching heat close to 54 degrees Celcius

Iranian city experiences scorching heat close to 54 degrees Celcius

By Elisa Jiménez Alonso

In late June the Iranian city of Ahwaz, home to over 1 million people, registered scorching 53.7°C. This falls short of the hottest temperatures to ever be reliably measured by just 0.3°C. Météo France meteorologist Etienne Kapikian reported the temperature on 29 June. However, hours later, the website Weather Underground reported 54°C air temperature, tying it with two heat records measured in Kuwait in 2016 and Death Valley in 2013, if verified.

Air temperature vs Heat Index

Verified or not, we can probably all agree that temperatures above 40 and, even worse, 50 degrees are unbearable. However, air temperature, which is what thermometers usually measure, is only one part of the equation. In order to calculate the “felt air temperature” or Heat Index, relative humidity needs to be considered as well. Taking into account the 17% relative humidity measured in Ahwaz on 29 June, the “felt air temperature” that day was a staggering 61°C. To put that into perspective: Egg whites cook at 65°C.

The heat index was developed because relative humidity affects how the body cools itself. The human body cools down by sweating. As the sweat evaporates, heat is removed from our bodies. If there is high relative humidity, however, the sweat cannot evaporate anymore leading to a sense of overheating. The degree to which this affects people often depends on their physical disposition like e.g. being pregnant or having metabolic differences. Thus, the index contains many assumptions that might not apply to everyone. Most importantly, however, the Heat Index is based on temperatures in the shade, meaning that actual conditions, especially when being exposed to direct sunlight can be even worse than the index states. One can only guess what this meant for the people of Ahwaz in late June this year.

Temperature records in line with scientists’ expectations

The high temperatures of Ahwaz come just a month after several places in the Middle East experienced their highest temperatures ever recorded. A bit further, the Pakistani town of Turbat recorded 53.5°C on 28 May, a world record for the month.

All of these readings are consistent with scientists’ expectations of extreme temperatures in a warming world. A 2016 report by the National Academy of Sciences stated that hotter and more frequent heatwaves are among the weather events that are most easily connected to human-made climate change. A study published in late 2015 found that future heatwaves in the Gulf might push the region’s temperatures beyond anything humans can adapt to or endure. They likened the future climate of certain Middle Eastern regions to that current one of Northern Afar, Africa, which has no human settlements and an average annual temperature of 34.4°C.

Tackling extreme heat

Apart from reducing carbon emissions in order to avoid even worse climate impacts, it is hard to imagine adaptation strategies that would effectively protect people in such extreme heatwaves. While wealthier states might be able to afford protecting people indoors with air conditioning, countries like Yemen, which relies heavily on aid from multilateral agencies, would surely suffer. Especially children and the elderly would disproportionately be affected by premature deaths due to heat. Since extremely dangerous temperatures are already being observed, it will be of utmost importance for affected countries and the international community to work on solutions that will protect at risk populations.

Cover photo from Pixabay (public domain).
Early weather forecasts are key to saving lives during droughts

Early weather forecasts are key to saving lives during droughts

By Umberto Bacchi

With droughts set to become more frequent due to global warming, delivering timely, long-term weather forecasts to farmers in the developing world will be key to limiting damage and saving lives, the head of the U.N. food agency said on Monday.

Droughts have killed more than 11 million people worldwide since 1900 and now affect double the land area than in 1970, according to the U.N. Food and Agriculture Organization (FAO). Developing countries are the most exposed, with their agricultural sectors shouldering 80 percent of all damage caused by drought, FAO says.

Better access to reliable weather data and early warning systems could help farmers in rural areas get ready to endure long spells of no rain, said FAO director-general Jose Graziano da Silva. “Most of the times poor rural communities in developing countries don’t even know that a drought is about to strike,” he told a conference at the FAO headquarters in Rome. Measures such as planting resistant crops and building water reservoirs can greatly reduce the impact of droughts, but international responses too often focus on emergency relief, said Graziano da Silva. “People die because they are not prepared to face the impacts of the drought – because their livelihoods are not resilient enough,” he said.

In Rome, FAO and the World Meteorological Organization (WMO) signed an accord to increase cooperation in the face of climate change, improving agro-meteorological services to help small farmers prepare for droughts. WMO secretary general Petteri Taalas said weather forecast accuracy had greatly increased in recent years thanks developments in satellite, computing and scientific research. “Weather forecasts are not anymore a joke, they are something you can very much rely on,” he told the conference.

Know-how related to long-term forecasts and prediction of major climate events like El Niño had to be shared between rich and poor countries, he added. The last El Niño, a warming of ocean surface temperatures in the eastern and central Pacific that typically occurs every few years, subsided in 2016 and was linked to crop damage, fires, and flash floods.

Reporting by Umberto Bacchi @UmbertoBacchi, Editing by Ros Russell. Article originally posted on Credit: Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women’s rights, trafficking, property rights, climate change and resilience. Visit
Cover photo by Faxial/Pixabay (Public Domain)
Deadly heat stress could threaten hundreds of millions even if climate targets are reached

Deadly heat stress could threaten hundreds of millions even if climate targets are reached

By Tom MatthewsLiverpool John Moores University

Deadly heat stress is projected to affect hundreds of millions more people each year under relatively little additional climate warming. The Paris Agreement commits the international community to limit global warming to no more than 2℃ above pre-industrial (late 19th century) air temperatures, with an aspirational target of 1.5℃. In our latest research, which looked at the impact of global temperature rises on megacities, we found that even if 1.5℃ is achieved, large increases in the frequency of deadly heat are expected.

By 2050 about 350m more people living in megacities could be exposed to deadly heat each year.

Humans become “heat stressed” when the body absorbs more heat than is tolerable. If core body temperature rises just a few degrees above 37℃, deadly heatstroke can result. By using its cooling system – sweating – the human body can maintain a safe temperature even if air temperatures rise above 37℃. This mechanism works better in a drier atmosphere (which is why steam rooms feel hotter than saunas – even at the same air temperature). The heat index is a measure that combines this humidity effect with air temperature to provide a “feels like” temperature. A heat index in excess of about 40.6℃ is considered dangerous to human health.

As global air temperatures rise, observations and experiments with climate models suggest that atmospheric moisture content also climbs. This means that the heat index (and how hot it feels) rises faster than air temperature. Also, because the amount of moisture the atmosphere can hold increases more rapidly at higher temperatures, the heat index rises faster too (a non-linear response).

Strong incentive to limit global warming

This non-linear response carries over to the definition of “global heat stress burden” used in our research, which we define as the average number of days per year over land areas with a daily heat index above 40.6℃. Using a large number of climate model simulations, we found that this quantity increases faster and faster as global average air temperatures rise. This sharp rise in global heat stress burden has important consequences.

First, any increase in global heat stress from climate warming to date will be smaller than that caused by the same additional warming in the future. (We have seen a 0.8℃ rise in global temperature; another 0.8℃ of warming could be expected to lead to a greater increase in heat stress than caused by the first 0.8℃.)

Second, there may be progressively heavier global impacts if the Paris targets are breached. Our analysis suggests that for 1.5℃ warming, the global heat stress burden will be almost six times greater than experienced during 1979-2005. But heat stress is 12 times greater if warming reaches 2℃. With 4℃ warming – which could happen if mitigation efforts fail – our analysis suggests that the global heat stress burden could be more than 75 times larger.

Such large increases in heat stress may be hard to imagine, so we used recent heat waves to help communicate the impacts that may lie ahead.

For example, in 2015, Karachi and Kolkata in India experienced lethal temperatures. Our analysis suggests that in a 2℃-warmer world, both cities could experience these deadly conditions at least once a year. If global warming reaches 4℃, the record heat of 2015 would be commonplace – more than 40 days a year. Other regions would not be immune. With only 1.5℃ of warming, twice as many global megacities (cities with a population greater than 10m, including Lagos, Nigeria, and Shanghai, China) could start to regularly experience heat stress. At 2℃, Tokyo (the world’s most populous city), may be affected. New York City joins the list at 4℃.

If the global population grows as anticipated this century, it could drive up global heat stress even more. The situation in Lagos illustrates this well. If global warming reaches 1.5℃ by the end of the century (at which time the population of Lagos may have increased elevenfold and dangerous heat may be 100 times more common) the heat stress burden could be more than a thousand times greater than the recent past.

Across all megacity regions, if the 1.5℃ limit is breached by the 2050s, as many as 350m people globally could be regularly exposed to dangerous heat stress. This is more than a fourfold increase compared with 1979-2005.

The ConversationHeat stress sensitivity to global temperature rise and the potential human impacts – even at 1.5℃ above pre-industrial levels – provide a strong incentive for limiting global warming. Warming associated with the Paris targets may sound modest enough for the urgency of the situation to be lost. Our analysis shows that even if ambitious mitigation targets are met, the need to adapt to extreme heat will remain. The high concentration of people and heat in urban environments make cities an important focus for these adaptation efforts.


Tom Matthews, Lecturer in Physical Geography, Liverpool John Moores University. This article was originally published on The Conversation. Read the original article.
Cover photo by Jorge Royan (CC BY-SA 3.0 )
Doctors sound the alarm: climate change poses immediate health risks

Doctors sound the alarm: climate change poses immediate health risks

By Gracie Pearsall

While most Americans recognise that climate change is a real threat, the pervasive attitude is that it is a distant problem. Although, people might be concerned for the future of the ice caps and coastal cities, many have not considered the possibility that climate change could affect their lives and health right now. The Medical Society Consortium on Climate and Health (MSCCH) seeks to remedy this and alert Americans that climate change is already harming their health.

Climate related health impacts

In March of 2017, the MSCCH released a report that outlines the ways climate change threatens our health. Through scientific studies, facts, and anecdotes, the physicians expose the health consequences of climate change. They paint a grim picture of a society plagued by climate-related illnesses explaining how the increased frequency of extreme weather events will impact our health. Heat waves will cause more incidents of heat-related illness and stress, which are already the leading cause of climate-related deaths. Severe storms and flooding will cause displacement, injury, death, and even contaminate drinking water and crops with debris and pollutants.

The report also describes how a warmer and wetter climate allows disease vector species such as ticks and mosquitoes to thrive and expand their geographic range, which alters the pattern of infectious diseases. Physicians are already seeing an increase in cases of Lyme Disease and West Nile virus, and fear that malaria might reemerge in the United States. As these carriers spread throughout the United States, they will bring familiar diseases to new places, and allow for the rise of new ones.

The physicians present poor air quality as the most widespread and pressing threat to our health. The emission of greenhouse gasses and particulate matter, combined with frequent wildfires, has significantly reduced air quality. People’s hearts and lungs are most at risk, but poor air quality has also been linked to cancer in other parts of the body. Approximately seven million people worldwide die prematurely every year due to health issues linked to air pollution.

Furthermore, a growing body of research suggests that the physical, social, and economic stresses that climate change creates increase the risk of mental health issues. In the wake of extreme weather events, most survivors report stress, depression, and anxiety. In one case, after record flooding in Louisiana in 2016, teachers reported that some children became so anxious when it rained, that the children needed counseling.

Image: The map shows key impacts of climate change on health in the USA by region. Credit: The Medical Society Consortium on Climate and Health.

Resilience in the health care sector

In the face of these alarming facts, the MSCCH has embraced a central ideal of public health: prevention. These physicians side with climate scientists and conclude that only through swift action can we prevent further harm and protect the health of all Americans. Their proposed means of prevention is to “accelerate the inevitable transition to clean, renewable energy”. This transition would have immediate public health benefits. It would move away from greenhouse gas combustion, and reduce exposure to harmful pollutants, slow warming, and clean up our air and water. Additionally, clean and renewable energy encourage active transportation, such as walking and biking, which help to lower rates of heart disease, respiratory illness, and diabetes.

To achieve this transition and implement preventative and protective measures, the physicians prescribe certain actions to various demographics. First, they recommend doctors treat patients who are affected by climate-related health effects. They also implore doctors to educate their patients and the public on how climate change can affect their health, and what actions we can take to prevent further harm. Next, they advise public health professionals to educate the public on the threat climate change poses, and develop climate risk monitoring and alert systems to keep the public informed in the case of an extreme weather event. Finally, the MSCCH urges business leaders and policymakers to assess this new information and adapt accordingly so that we can build resilience against harmful effects of climate change. The MSCCH’s prioritization of prevention and mitigation reveals that adaptation and resilience carry diverse sets of benefits.


Cover photo by The Medical Society Consortium on Climate and Health
Arctic ice melt uncovering radioactive waste, sewage, and anthrax

Arctic ice melt uncovering radioactive waste, sewage, and anthrax

By Charlotte Strawson

Melting in the Arctic region is uncovering unwelcome waste, pollutants and diseases that were once thought to be ‘preserved for eternity’. Melting of glaciers, tundra and sea ice is taking place at a rate that is uncovering radiological waste, sewage and even Anthrax.

A military camp built beneath the surface of Greenland ice sheet during the Cold War was left abandoned in 1967, leaving behind a heap of waste which included 200,000 litres of diesel fuel, 24 million litres of biological waste in the form of sewage, and radiological waste. The waste was left in the belief the snowfall would continue falling and the waste would be “preserved for eternity”.

However, due to climate change, Greenland has lost 1 trillion tons of ice over the period of four years between 2011 and 2014. There is worry that the melting and the unearthing of this waste has potential to expose great amounts of hazardous materials. Arctic regions experience warming from climate change at almost twice the global average.

In the northern arctic region of Russia in 2016 there was an outbreak of Anthrax, it caused the death of a 12-year-old boy and hospitalised 90 people. This episode is reported to be a result of climate change as the 10°C warmer than average temperature melted the permafrost of a previous burial site for animals that died of anthrax 70 years ago.

If climate change predictions are correct and the melting of permafrost continues, we could see more cases of disease outbreaks. Infections from the 18th and 19th century could re-emerge, especially near the unknown cemeteries and burial sites where victims were buried.

In Russia, the thawing of permafrost and flooding has led to greater erosion of river banks where the dead were once buried. Researchers are worried that the thawing human and animal remains may lead to the re-emergence of diseases such as Spanish flu virus, which have been found in bodies buried in mass graves in Alaska’s tundra, as well as the smallpox virus and bubonic plague buried in Siberia.

Though some researchers argue that the prospect of a killer infection to appear from melting permafrost is unlikely, it does raise troubling questions about what is locked in the vast frozen landscapes of the north.

Cover photo by NASA Earth Observatory (Public Domain)
Air pollution and climate change: a toxic relationship

Air pollution and climate change: a toxic relationship

By Caroline Fouvet

Each year, 600,000 children under five years old die because of air pollution. Central heating boilers, motor vehicles and industrial facilities are all significant contributors to dirty air. The problem is costing money and lives, especially in built up areas, and it may be further compounded by climate change.

Air pollution is often understood as a visible phenomenon – with dense smog engulfing urban centres. However, for the most part air pollutants do not form smog, and the tiny, makes them invisible. Vulnerable citizens, such as older people and children are extremely sensitive to air pollution and are often among its first victims.

The impact of air pollution on health places a substantial economic burden on society. In developing countries, for instance, air pollution results in premature deaths in the young working age population and in Sub-Saharan Africa, annual labour income losses induced by air pollution amount to 0.61% of GDP. In developed countries, the cost of sick days and emergency care caused by air pollution is considerable.

Compounded by climate change

Unless action is taken to reduce air pollution, the health impacts are likely to increase in severity, as the climate warms. Warmer temperatures can lead to an intensification of particulate concentrations at ground level, especially in cities. Heat and sunlight react with chemical particles such as diesel soot and gases such as nitrogen dioxide (NO2), ozone (O3) and sulphur dioxide (SO2) in the air. This leads to the formation of ground-level ozone gas, both a harmful air pollutant and a component of smog.  The expected increased number of warmer and stagnant days will facilitate the phenomenon and worsen its impact on people’s health.

As ground-level ozone damages lungs and inflames airways, asthma and other respiratory diseases will likely increase. The resulting impact on people’s health is likely to be severely detrimental. In the US, it is projected that tens of thousands of additional ozone-related illnesses and premature deaths per year could occur by the 2030s. The US Environmental Protection Agency assessed that such impacts on air quality could reach US$ 13.6 billion.

Low-level ozone, methane, chlorofluorocarbons and sulphur dioxide emissions are also greenhouse gases, contributing to climate change and creating a noxious self-reinforcing cycle. Breaking this cycle will require concerted policy efforts to prevent particulate pollution, especially in built up areas. The resulting health benefits will undoubtedly save lives.

Cover photo by David Leo Veksler (CC BY-SA 2.0)
A climate change healthcheck: Integrating adaptation into health strategies and plans

A climate change healthcheck: Integrating adaptation into health strategies and plans

By Caroline Fouvet

A changing climate not only impacts weather events and infrastructure, but also presents a major public health challenge. Whether direct or indirect, cimate change impacts can have disruptive effects for human health and wellbeing, and as future climatic trends suggest both higher average temperatures and more regular extreme events, the impacts of climate change on human health cannot be ignored.

Direct health risks include weather-related morbidity, increased respiratory illness and infectious diseases, climate change has broader, indirect repercussions for health, including food insecurity and mental health. Adaptation measures must, therefore, encompass a health component; a point gaining recognition as more and more governments include it in their national strategies.

recent study reviewed 10 OECD countries’ policies in that respect and highlights their varied approaches to addressing the issue. By highlighting current gaps and suggesting possible strategies, the study provides useful insights into health adaptation to climate change.

To better evaluate strategies in this area it is important to identify adaptation means for the health sector. This amounts to taking preventive measures that reduce risk exposure, prevent the onset of illnesses, reduce morbidity, and minimise climate impacts. Although adaptation is often referred to as a local strategy, national governments have a role to play through integrating health adaptation into high-level policy frameworks. Their resources and guidance can strengthen and harmonise adaptation planning and generate ripple effects at the subnational level.

The research – focusing on the current health adaptation strategies of Australia, Belgium, Canada, France, Ireland, Luxembourg, New Zealand, Switzerland, the United Kingdom and the United States – examined three main dimensions of national-level health adaptation: cross-sectoral collaboration, vertical coordination, and national health adaptation planning.  These categories are, however, necessarily open to interpretation: vertical coordination can,for instance, be put into place differently across countries, such as through working groups, networks, partnerships, or consultation.

The study presents four main results:

  • National strategies remain broad, with 50% of surveyed countries addressing general health risks, infectious diseases, as well as heat-related risks.  The ‘general’ character of these stategies suggests that national initiatives are intended to set the framework for more specific local actions. Whilst population-level health programmes, such as protecting people from heatwaves, generally emanate from national governments, interventions that address locally manifest issues, such as flood mitigation, are often conducted at a regional level.
  • Almost two thirds (62%) of reviewed initiatives are ‘groundwork actions’, compared to 38% of adaptation actions. Among the latter, a combination of five adaptation types are being implemented, typically in the following order: capacity building, information, management, planning and policy, information, and practice and behaviour.
  • Intersectoral adaptation planning is a common feature across the surveyed countries. Most of the initiatives are designed and implemented by national public health agencies in partnership with other bodies, with some actions co-implemented with organisations outside of health sector.  This is the case in France, where four health agencies and the Research Institute for Exploitation of the Sea monitor vectors and host reservoirs.
  • Whilst health is an integrated part of most countries’ national adaptation frameworks (with the exception of Ireland), they exhibit varying levels of detail.  Whereas Australia’s adaptation plan provides general adaptation objectives, Switzerland’s plan further outlines responsible agencies and financing for each intervention.

The study’s results present a picture of uneven interpretations of – and approaches to – health adaptation across the 10 countries studied.  Their disparate state structures and degrees of centralisation might account for some of these differences, however, rendering it problematic to  identify any single benchmark  approach.

Drawing-out the similarities and differences between OECD countries in health adaptation planning shows that the issue is widely acknowledged by governments, even if they address it in a plurality of ways. Identifying best practices – referenced to climatic contexts and trends, governmental strutures, and risk and vulnerabilities – and bridging gaps are essential for devising coherent and effective health adaptation frameworks.


Read the full study by clicking here.

Cover photo by Jamiesrabbits/Flickr (CC by 2.0)