Climate change: The biggest global-health threat of the 21st century

14 May 2009

Grand Challenge of Global Health marque

A major report on managing the health effects of climate change, launched jointly by ‘The Lancet’ and UCL today, says that climate change is the biggest global-health threat of the 21st century.

Lead author Professor Anthony Costello (UCL Institute for Global Health) says that failure to act will result in an intergenerational injustice, with our children and grandchildren scorning our generation for ignoring the climate change threat – with moral outrage similar to how we today look back on those who brought in and did nothing to stop slavery.

‘Managing the Health Effects of Climate Change’ is the work of UCL academics from many disciplines across the university – including health, anthropology, geography, engineering, economics, law and philosophy. Professor Costello says that this climate-change project brought down the traditional interdisciplinary barriers common at all universities, and hopes it could act as a model for global governance bodies to work together.

Professor Anthony Costello

Watch a video featuring members of the UCL–Lancet Commission

The UCL team focused on key areas: patterns of disease and mortality, food security, water and sanitation, shelter and human settlements, extreme events, and population migration.  

Professor Costello says: “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.”

Disease and mortality

The UCL–Lancet Commission discusses the global health implications of the Intergovernmental Panel on Climate Change (IPCC) projections – from the optimistic average global temperature rise of 2 degrees C to the catastrophic 6 degrees C. The authors consider a wide range of pathways through which climate change could exert its effects on health, some of which may happen before others. Changing patterns of disease and mortality would emerge in a greater rate of transmission and geographic spread of traditionally tropical endemic diseases such as malaria and dengue fever. Heat – the ‘silent’ killer – has a major effect on mortality, with the 2003 heatwave causing up to 70,000 excess deaths in Europe.  While some people believe populations in India and Africa may be more resistant to heatwaves, there is little evidence of this and major heatwaves could increase death rates in these populations more than in high-income countries.

Food security, water and sanitation

Food and water security will be a major issue as climate change progresses. Scientists believe that crops are much more sensitive to temperature changes than first thought – a 1 degree C change can make a difference of 17% in yields. Professor Costello says: “If we are going to get early changes in the next 20 or 30 years, falling crop yields could trigger more of an effect through rising food prices. Look at what happened last year when food prices rose globally. And one billion people currently have calorie-deficient diets – this situation will get worse as demand increases from India, China and other nations with a population boom.” Up to 250 million people in Africa will face water shortages by 2020 if no action is taken on adaptation. Water and sanitation are crucial to prevent gastroenteritis and malnutrition. Melting glaciers, and changing river flows and rainfall patterns, are already causing flooding and droughts.

Urbanisation and extreme events

Rapid urbanisation, particularly in developing nations, leads to inadequate housing, particularly slums, which are the most exposed during extreme climatic events. Extreme events, including cyclones and hurricanes, have doubled over the past 20 years, according to the insurance companies who insure against them. But in an event such as a cyclone, a rich nation would normally have relatively few casualties compared to poorer countries. Consider Hurricane Katrina with a loss of 1,850 lives compared with the recent cyclone in Burma which is thought to have claimed 150,000 lives. Of the 20 largest cities in the world, 13 are on a coast. While sea levels have been predicted to rise, from anywhere between 0.5m and 1.2m over the 21st century, some predictions as high as 5m are beginning to emerge. This would be catastrophic.

A tipping point

Professor Costello says: “We might be reaching a tipping point in public opinion. I think the health lobby has come late to this debate and should have been saying more. Young people realise this is the great issue of our age.”

He proposes three action points leading from this report: “First, we have to add the health lobby to the mitigation debate – they must emphasise the threat to our children and grandchildren from greenhouse-gas emissions and deforestation. Second, there must be a focus on health systems – there is massive inequality in health systems throughout the world. Because of this, the loss of healthy life years as a result of global environmental change is predicted to be 500 times higher in Africa than in European nations, despite Africa making a minimal contribution to the causes of climate change. Third, we must develop win–win situations whereby we mitigate and adapt to climate change and at the same time significantly improve human health and wellbeing. There are major health benefits from low-carbon lifestyles, which can reduce obesity, heart and lung disease, diabetes and stress.”

He concludes: “We believe that all the main players – in health, politics, science, technology and civil society – must come together. The UCL–Lancet Commission laid out a framework for action, and we have called for a collation of information on the health effects of climate change leading up to a major international conference in the next two years. We especially want representation from poorer nations. This conference would set out some clear indicators, targets and accountability mechanisms. We need a new 21st-century public-health movement to deal with climate change.”

‘Lancet’ editorial

An accompanying editorial in ‘The Lancet’ states: “UCL is a university that has combined a distinguished history of moral engagement with a more recent revitalised global purpose, expressed through its strengthened commitment to global health in teaching, research and institution building. In preparing to undertake its work for this first Lancet Commission, the UCL team, led by Anthony Costello, reached out beyond health to engineers, political scientists, lawyers, geographers, anthropologists, economists, philosophers, and students, among others. They discovered new ways to review evidence and integrate ideas collaboratively.

“And through these efforts, they identified five critical challenges that scientists, clinicians, and policymakers will have to address if climate change is not to become the biggest catastrophe threatening human survival. First, there is a massive gap in information, an astonishing lack of knowledge about how we should respond to the negative health effects of climate change. Second, since the effects of climate change will hit the poor hardest, we have an immense task before us to address the inadequacies of health systems to protect people in countries most at risk. Third, there is a technology challenge. Technologies do have the potential to help us adapt to changes in climate. But these technologies have to be developed out of greater research investments into climate change science, better understanding about how to deliver those technologies in the field, and a more complete appreciation of the social and cultural dimensions into which those technologies might be implanted. A fourth challenge is political: creating the conditions for low-carbon living. And finally there is the question of how we adapt our institutions to make climate change the priority it needs to be. …

“Our commitment is long term. With UCL and other partners, we plan to convene an international summit in two years’ time to review progress and priorities in our collective responses to the urgent and alarming health effects of climate change.”

The Grand Challenge of Global Health

The cross-fertilisation and application of our expertise is being coordinated through the UCL Institute for Global Health. It is developing an institution-wide agenda leading to strategies, programmes, research and teaching to bring our combined expertise to bear on the Grand Challenge of Global Health.

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