Climate change is one of the biggest challenges facing mankind. Always has been, always will be, and that means that big changes lie ahead.

Many of those changes will impact on the work of scientists as they seek to find solutions to the predicted increase in illness caused as the planet warms and its weather becomes more unpredictable.

Numerous pieces of research suggest that warmer average temperatures are likely to lead to effects including hotter days and more frequent and longer heatwaves, which could in turn increase the number of heat-related illnesses and deaths.

According to the World Health Organization (WHO), climate change is expected to cause 250, 000 additional deaths per year from malnutrition, malaria, diarrhoea and heat stress between 2030 and 2050.

Research by the US Global Change Research Program suggests that the impact of heatwaves could be especially severe in large metropolitan areas. For example, it says that in Los Angeles, annual heat-related deaths are projected to increase two-to seven-fold by the end of the 21st Century, depending on the growth of greenhouse gas emissions.

Although its studies concentrate on America, they are just as applicable worldwide. Indeed, the study says that the increase in heatwaves is actually more likely to affect northern latitudes more seriously because people are less prepared to cope with excessive temperatures.

Heatwaves, which lead to heat stroke and dehydration, are one of the biggest concerns because they are the most common cause of weather-related deaths, often accompanied by periods of stagnant air, leading to increases in air pollution and the associated health effects.

For example, ground-level ozone can damage lung tissue, reduce lung function and inflame airways, a particular problem for children, older adults and those with asthma and other chronic lung diseases.

According to the WHO: “Extreme high air temperatures contribute directly to deaths from cardiovascular and respiratory disease, particularly among elderly people. In the heatwave of summer 2003 in Europe, for example, more than 70,000 excess deaths were recorded.”

The US Global Change Research Program and WHO say that changes in climate may have other effects, including:

•Higher air temperatures can increase cases of salmonella and other bacteria-related food poisoning because bacteria grow more rapidly in warm environments

•Heavy rainfall or flooding can increase water-borne parasites such as Cryptosporidium and Giardia that are sometimes found in drinking water. The parasites can cause gastrointestinal illnesses

•Heavy rainfall events cause stormwater runoff that may contaminate water bodies used for recreation such as lakes and beaches with other bacteria. The most common illness contracted from contamination at beaches is gastroenteritis, an inflammation of the stomach and the intestines that can cause symptoms such as vomiting, headaches, and fever. Other illnesses include ear, eye, nose, and throat infections

•Climate is one of the factors that influence the distribution of diseases borne by vectors (such as fleas, ticks, and mosquitoes), which spread pathogens that cause illness. Vector-borne diseases include Lyme Disease, dengue fever, West Nile virus,Rocky Mountain spotted fever and plague. Mosquitoes, carriers of malaria, favour warm, wet climates. Studies suggest that climate change could expose an additional two billion people to the illness by the 2080s.

•Climate change could be bad news for hayfever and allergy sufferers because it results in more frost-free days and warmer seasonal air temperatures, contributing to shifts in flowering time and the emergence of pollen

•Climate change is expected to have global impacts on food production. The WHO said: “Rising temperatures and variable precipitation are likely to decrease the production of staple foods in many of the poorest regions – by up to 50% by 2020 in some African countries. This will increase the prevalence of malnutrition and under-nutrition, which currently cause 3.1 million deaths every year.”

For Janet McCabe, acting assistant administrator for the US Environmental Protection Agency’s Office of Air and Radiation on climate change, the warnings are there for all to see.

She said: “The science is clear and getting clearer: climate change threatens our health, our economy, our environment and our way of life in dangerous and costly ways – from superstorms and heatwaves to devastating droughts, floods and wildfires.

“The more we learn about climate change’s impacts on our health, the more urgent the need for action becomes.

“We know that impacts related to climate change are already evident and are expected to become increasingly disruptive across the nation throughout this century and beyond.

“The number of extremely hot days is already increasing, and severe heatwaves are projected to intensify, increasing heat-related mortality and sickness.”

Her concerns were echoed by the American Thoracic Society, which found that the majority of its members who responded to a survey believed that climate change has a negative impact on the health of their patients.

Sixty five per cent of respondents said that effects included more cases of acute and chronic lung conditions due to exposure to ozone or other pollutants and longer and more severe allergy seasons

John R. Balmes, MD, Chair of the ATS Environmental Health Policy Committee, one of the survey’s authors, said: “Our physician members are seeing the effects that climate change is having on the well-being of their patients. These results talk to the importance of groups involved in healthcare taking a stand on this issue and educating their members and the patients that they serve that climate change is a healthcare issue.”

‘The time for action has arrived’

However, it is not a totally gloomy picture and action is already being taken in many countries with the central themes of tackling the long-term causes of warming while also doing more to mitigate its effects.

Janet McCabe in the US said: “Our most vulnerable populations – like children, minorities, communities already overburdened with pollution or poverty, and older Americans – are at greater risk from these impacts.  That’s why, under the American President’s Climate Action Plan, we are taking action now to reduce greenhouse gases such as carbon dioxide, methane, and hydrofluorocarbons.”

There is also action which can have a shorter term effect and among regions responding to the concerns is South Asia, which saw the expansion in April of the Heat Action Plan first introduced in Ahmedabad, the sixth biggest city in India.

The move was timely because within weeks, India was hit by a major heatwave which claimed many lives, more than a thousand in the first week alone.

The plan was developed for just such scenarios and seeks to reduce the impact of extreme heat by operating an early warning system, providing training to medical and community workers and building public awareness of heat-related health risks.

It includes mapping high-risk areas, expanding work in vulnerable communities and improving the response of medical professionals and hospitals, including making ice packs more widely available for use during heatwaves.


The plan has been so effective that a wide range of organisations in the region, including governments and universities, are now working to see it implemented on a wider basis.

Anjali Jaiswal, director of the Natural Resources Defense Council’s India Initiative, said: “These heat action plans are a necessary response to climate change. Hundreds of thousands of people are already living on the threshold of what is tolerable heat-wise; even incremental changes in climate can push these temperatures over the line.”

Dr Dileep Mavalankar, Director of the Indian Institute of Public Health, Gandhinagar, said: “Unless we prepare to adapt our cities and rural areas to rising temperatures and heat waves, we may face serious health issues and mortality during future heatwaves.

“Ahmedabad’s Heat Action Plan is tailored to help the most vulnerable city residents cope with rising temperatures. Preliminary results of the Heat Action Plan in 2013 and 2014 showed that it was successful in saving many lives and raising the discourse around extreme heatwaves and health to a larger strata of society.”

“Given the very hot conditions in north and central India, it is imperative to scale up the Ahmedabad Heat Action Plan. We hope that through this renewed expansion, other cities and states can use this innovative model as a foundation to craft their own plans.”

The Ahmedabad experience can be applied worldwide, according to Dr Jeremy Hess, Intergovernmental Panel on Climate Change author and Associate Professor of Emergency Medicine at Emory School of Medicine and of Environmental Health at the Rollins School of Public Health of Emory University in Georgia, USA.

He said: “Local steps being taken by cities, like Ahmedabad’s heat action plan, are crucial in the global fight against climate change. The Ahmedabad Municipal Corporation has shown tremendous leadership, and I hope their experience will help other cities to implement on-the-ground solutions to growing threats such as extreme heat.”

For all the good work being done, though, there remains much cause for concern. And although a recent report published by the US Government emphasised the need for action, it remained cautious.

The report concluded: “Preventive and adaptive actions, such as setting up extreme weather early warning systems and improving water infrastructure, can reduce the severity of these impacts, but there are limits to the effectiveness of such actions in the face of some projected climate change threats. Climate change presents a global public health problem, with serious health impacts predicted to manifest in varying ways in different parts of the world.”

Among other countries working on a similar approach is the United Kingdom, whose Department of Health has just issued its latest issued guidance.

The UK heatwave plan has been published annually since 2004, following the devastating pan-European heatwave in 2003 when, for example, in Northern France unprecedented high day and night-time temperatures for three weeks resulted in 15,000 excess deaths, the vast majority among older people. In England, there were more than 2,000 excess deaths over the ten-day heatwave which lasted from 4 to 13 August, compared to the previous five years over the same period.

The plan outlines the system to alert those working with vulnerable people to an impending heatwave so that potentially life-saving advice can be issued, everything from nursing homes and schools providing cool areas to ways of reducing heat in people’s homes.

In the foreword to the document, Professor Dame Sally C Davies Chief Medical Officer, says: “Although many of us enjoy the sunshine, as a result of climate change we are increasingly likely to experience extreme summer temperatures that may be harmful to health. For example the temperatures reached in 2003 are likely to be a ‘normal’ summer by 2040, and indeed globally, countries have already experienced record temperatures.

“We want to make sure that everyone takes simple precautions to stay healthy during periods of hot weather and when in the sun. The purpose of this heatwave plan is to reduce summer deaths and illness.”

“Although global warming may bring some localised benefits, such as fewer winter deaths in temperate climates and increased food production in certain areas, the overall health effects of a changing climate are likely to be overwhelmingly negative.

“People living in small island developing states and other coastal regions, megacities and mountainous and polar regions are particularly vulnerable. Children – in particular, children living in poor countries – are among the most vulnerable to the resulting health risks and will be exposed longer to the health consequences.

“The health effects are also expected to be more severe for elderly people and people with infirmities or pre-existing medical conditions.”
World Health Organization.

Report urges action on climate change

Concerns about the link between health and climate change were strengthened by a report launched jointly by The Lancet and London university UCL in June.

The report said that climate change is the biggest global health threat of the 21st Century with dangers ranging from heatwaves to food shortages.


Managing the Health Effects of Climate Change was written by UCL academics from disciplines across the university and the UCL–Lancet Commission based its findings on Intergovernmental Panel on Climate Change projections, from the optimistic average global temperature rise of 2 degrees C to the catastrophic 6 degrees C.

Lead author Professor Anthony Costello, of the UCL Institute for Global Health, said: “The big message of this report is that climate change is a health issue affecting billions of people, not just an environmental issue about polar bears and deforestation.

“The impacts will be felt not just in the UK but all around the world – and not just in some distant future but in our lifetimes and those of our children. Young people realise this is the great issue of our age.

“We believe that all the main players in health, politics, science, technology and civil society must come together. We need a new 21st Century public-health movement to deal with climate change.”

“Extreme high air temperatures contribute directly to deaths from cardiovascular and respiratory disease, particularly among elderly people. In the heatwave of summer 2003 in Europe, for example, more than 70,000 excess deaths were recorded.” – WHO World Health Organisation