Climate change and human health?
This was posted by on the doc2doc website (http://doc2doc.bmj.com/forums/off-duty_climate-change_much-effects-of-climate-change-health-2_.0 by skyesteve in response to the BMJ’s Climate change conference on 17th October 2011: I responsed in red below.
In November 2010 I saw something in the medical literature that I had never seen before. An editorial was published simultaneously in the British Medical Journal and The Lancet (1), (2). It was written by Ian Roberts, Professor of epidemiology and public health at the London School of Hygiene and Tropical Medicine and Robin Stott, Co-chair of Climate and Health Group and it sought to address the issue of climate change from the perspective of its impact on the medical profession and our role in addressing the issue. In doing so Roberts and Stott attempted to use what were, effectively, news headlines to try and demonstrate some “cause-and-effect” proof of climate change. I felt that this was a risky strategy as such headlines seldom allude to the multi-factorial nature of the underlying stories. As a consequence, when these headlines are dissected and the underlying complexity is revealed, there is the very real prospect that the argument that you wish to present becomes diminished and devalued, perhaps to the extent that the very people you most need to convince choose instead to ignore your point of view.
Roberts and Stott used three such headlines from 2010 as their opening gambit – the devastating floods in Pakistan; the wildfires in Russia; and the food riots in Mozambique. So how do these stories stand up to dissection? Are they, as Roberts and Stott might claim, mainly “climatic events…the main cause of which is the increase in anthropogenic greenhouse gas emissions”?
The floods earlier this year in Pakistan were, without doubt, catastrophic in their impact. But were these floods and their devastating consequences simply the result of climate change? The Indus is a vast river which, according to the geological evidence, has been prone to flooding for millenia. Over 6000 years ago the river was actually more voluminous and more prone to flooding than it is today. Millions of people now make their homes on the flood plain of the Indus and, consequently, as this population has increased so too has the impact of any flooding that occurs. The population of what we now refer to as Pakistan has increased from 34 million in 1951 to over 170 million today. It’s hardly surprising therefore that, in terms of the number of people affected, any current natural disaster is going to have an impact of historical proportions. As highlighted by Scientific American (3), the causes and consequences of these floods are not simply down to climate change – there is “evidence that points to a calamity caused by man, the cumulative effect of erratic weather, forecast by climate change models; massive deforestation; and lax attention to infrastructure maintenance and engineering standards”. In particular, a western-style levee system that does not seem to cope well with the silt-laden floods waters of the Indus, causing the river channels to silt up. This is fine so long as the levees hold but when they break the consequence can be far more devastating. In addition, mass deforestation has taken place in Pakistan which makes catastrophic flash floods much more likely.
So what of the wild fires in Russia? Certainly they were (as with the Pakistan floods), at least in part, the result of climatic conditions. Russia had its warmest summer since records began – but they only began in 1890. A record temperature of 44C was reached – but this was only 0.2C higher than the previous record set in 1940. The wildfires were not simply the result of extremely high temperatures. Again, other man-made factors may also have been at play. Russia has approximately 25% of the world’s forests. Wildfires are a natural consequence of such arboreal landscapes and existing Russian forests contain evidence of fires going back hundreds of years. Despite this the vast majority of forest fires in modern Russia are down to deliberate fire-raising or wilful neglect of things such as agricultural burning. Catastrophic wildfires in Russia are nothing new. In 1915, a particularly dry year, 12.5 million hectares of Russian forest was destroyed by fire whilst in 1921, wildfires in the Mari region extended to over 2600 square kilometres. During the 1950s soviet authorities displaced thousands of people to remote forest areas to exploit the local natural resources. This too resulted in the burning (deliberate or otherwise) of tens of millions of hectares of forest. During the 1960s Russia’s extensive peat lands were drained drying out the peat and making it much more susceptible to persisting (and difficult to deal with) deep, underground fires. Major fires erupted in 2002 causing widespread damage and pollution. The 2010 wildfires destroyed over 1 million hectares of forest in western Russia. But there were 1.3 million hectares destroyed in 2002, 2.3 million hectares in 1998 and 2.4 million hectares in 2003. In other words, such catastrophic losses are not that unusual in Russia (4).
Finally we come to Mozambique’s food riots. Once again Roberts and Stott seem happy to use them as evidence of the consequences of climate change but is that the full picture? The riots in Mozambique were brought about when the government of that country decided to raise wheat prices in response to rising world prices and in the face of what they regarded as unsustainable subsidies (they later recanted that decision). Mozambique grows only 30% of the wheat it needs and is therefore heavily dependent on imports. Yet reports suggest nearly 90% of the potential agricultural land in Mozambique remains poorly cultivated or even uncultivated due to a combination of factors including poor infrastructure and a lack of sufficient investment. The cost of wheat did go up in 2010. At least in part this was the consequence of flame-ravaged Russia halting exports (Russia accounts for 8 to 10% of the world’s wheat production). In addition, the switching of agricultural land elsewhere to other activities such as bio-fuels production has helped to fuel a perception of shortage. Yet in reality the world is not short of wheat. As pointed out by the BBC (5) there is no shortage of agricultural land in the world as a whole and higher wheat prices may actually boost production (which has already risen by 10% in the last 4 years). Production in 2009-10 was about 5% higher than consumption and significant reserves of wheat existed. Indeed, the price of wheat at the time of the Mozambique riots was 40% less than it was at its peak in 2008. In addition, the increased cost of imported wheat for Mozambique was due in no small part to the loss of value of the Mozambique currency against the South African rand.
I now want to address some of the concerns Roberts and Stott raised around climate change and disease as this clearly has potential impacts on us as doctors. Do the worries they express stand up to scrutiny and, if climate change is playing a role, is that what we should be really worried about when it comes to public health and disease?
I will leave aside their justified remarks about the obesity epidemic in Mexico where, I would suggest, the approximately 30,000 deaths from homicide in 2010 is probably the most pressing current public health issue.
Instead I would like to look at the 5 health areas they highlight – malnutrition, diarrhoea, deaths from floods, malaria and temperature-related deaths from cardio-vascular disease. I have already alluded to the issue of flooding but what of the other four areas that they highlight?
Malaria has been with us since the dawn of human history. It has been recorded in China as far back as 2700 BCE and a study of Egyptian mummies from the time of the New Kingdom (1550 – 1069 BCE) has found that they were universally infected with malaria. Some historians have even suggested that malaria may have contributed significantly to the fall of the Roman Empire. The so-called Little Ice Age in Europe lasted from the 16th to the 19th centuries with particularly cold dips around 1650, 1770 and 1850. Yet throughout that time malaria was endemic in much of Europe and the USA. It was still present as far north as the Arctic Circle as late as 1950. In the 1880s over 5000 labourers died from malaria whilst working on the Panama Canal. At this time malaria was still endemic in the USA, England, Italy, Holland, Russia and elsewhere in Europe. In 1918 in Italy there were 2 million cases per annum. In 1924 Soviet authorities admitted to 5.5 million cases annually in Russia (and the real figure was perhaps twice as high).
In all these areas malaria was tackled successfully by simple measures – treating or draining breeding grounds (marshes and swamps) and using insecticides and anti-malarial drugs. By 1945 malaria had effectively been eliminated form the USA and most of Europe. But the worldwide incidence was still 300 million cases per annum.
But eradication and therapeutic measures were also used effectively in other parts of the world. This had a dramatic initial impact. India, for example, saw the number of cases reduced to about 100,000 by 1961. Sadly the good news was relatively short-lived. Resistance to (and, in the case of DDT, withdrawal of) pesticides and drugs has seen malaria fight back. By 1977 cases in India were up to 6 million a year and between the 1960s and 1990s the global number of cases of malaria has increased 3 fold.
In 2008 WHO estimated 247 million cases worldwide of which 1 million died. (6) But all these statistics have to be seen in context. In 1945 there were an estimated 300 million cases – but the world’s population was only 2.1 billion. In 2008 there were 247 million cases – but the world’s population had almost tripled to 6.1 billion. So the incidence of malaria in 1945 was around 13% of the world’s population – by 2008 it had fallen to 4%. Even if the worst-case scenario is realised – a doubling of current cases of malaria by 2050 due to climate change – this will be against a rise in the total world population to over 9 billion people such that the incidence will still only be 6.6% – half of what it was in 1945.
I am not trying to downplay the serious impact of malaria. One million deaths is no laughing matter and nor is the undoubted negative economic impact of malaria on the developing world. But I do dispute that climate change is the main issue here. It’s not. The main issue is the need to invest in simple measures which have been shown to be effective time and again – improving health care generally; tackling the breeding areas; using physical and chemical barriers (e.g. net impregnated with pesticide); and judiciously using drug therapy (and, hopefully, the development of new therapies). WHO estimates that for an investment of just US$1 billion they could half the number of cases of malaria – that’s the same amount of money that Pfizer made from the sales of Viagra in 1999 (7).
Now what of thermal deaths? WHO suggested in 2003 that the rise in global temperatures between 1970 and 2000 had resulted in an additional 130,000 heat-related deaths – I will come back to that shortly.
In 2001 the UK Climate Impact Programme looked at thermal-related deaths (8). They projected into the future to look at deaths in 2080 based on a worst-case scenario of a 3.47 degrees Celsius temperature rise from the 1960s baseline. They estimated that such a temperature rise would result in the number of heat-related deaths in the UK rising from just 798 in the 1990s to 3519 by 2080 – but, at the same time, the number of cold-related deaths would fall from 80,300 in the 1990s to 51,200 in 2080 such that the overall number of lives saved in the UK from prospected global warming would be around 28,000 per annum by 2080! Similar pictures are likely to be seen in other temperate climates. In hotter climates where cold-related deaths are seldom an issue such a trade off will not exist and heat-related deaths may rise (though presumably people will adapt to hotter climates to some extent).
If we return to the WHO figure of an extra 130,000 heat related deaths between 1970 and 2000 how does that stand in relation to the number of cold-related deaths? Well, looking at the WHO figures it seems that whilst there were 130,000 more heat-related deaths there were perhaps as many as 620,000 avoided cold deaths meaning a total number of lives saved of 490,000 (10). Similar analysis can also be made of the other three areas that Roberts and Stott highlight as health-related impacts of climate change.
At present there are an estimated 950 million malnourished people in the world despite the fact that the world already produces enough food to feed its 6 billion residents. Climate change may have a role in terms of food security but it is not the major concerns. Almost every country with malnutrition problems is crippled by poverty, corruption, and violence. Couple this with a lack of investment in infrastructure and agricultural developments and it’s not hard to see what the real cause of malnutrition is. But the reality overall is that, according to the United Nations, global malnutrition rates fell between 1970 and 2010 (despite rising global temperatures) from 37% of the developing world’s population in 1970 to 16% in 2010 (11).
And what of diarrhoea – is climate change the main culprit here? Not according to a WHO news release from 2009 (10) which states that: Inexpensive and effective treatments for diarrhoea exist, but in developing countries only 39 per cent of children with diarrhoea receive the recommended treatment…despite the known benefits of improving water supply and sanitation, some 88 per cent of diarrhoeal diseases worldwide are attributable to unsafe water, inadequate sanitation and poor hygiene. As of 2006, an estimated 2.5 billion people were not using improved sanitation facilities, and nearly 1 in every 4 people in developing countries was practicing open defecation.
Perhaps before using diarrhoea as an example of the horrors of climate change we should tackle the basic problems and cheap solutions first. (agree).I feel that the whole climate change debate has become increasingly sterile and it seems to be caught in a perpetual loop of claim and counter-claim. No-one seems to baulk from the idea that the planet may be warming but they argue about how much warming there will be (but the range is not disputed) and what will be the impact on mankind (the exact nature of the impact has much room for debate but there is agreement that it will significantly impact)and how much are anthropogenic greenhouse gases to blame (there is very broad agreement among scientists that CO2e’s are too blame), and so on.
I am not trying to down play the importance of climate change – I think that it is happening and I think that it may be, at least in part, anthropomorphic in origin. I am also open-minded about what the possible consequences of this change might be for us as doctors. But I am concerned that the inappropriate use of “headline stories” can reduce the impact of the argument and actually works against that which we are trying to achieve. (Agree, this is about how we communicate not what the message actually is)
It seems to me that everyone is ignoring the two (three)big “elephants” in the room – population growth and dwindling natural resources related to the sustainability agenda, and neoliberal capitalism.The world’s population is far too big – we currently have over 6 billion people on a planet that perhaps is only geared to cope with about a third of that number. And this population pressure is often worst in those regions that are least equipped to cope with it. Yet little is being done on a global scale to tackle this issue. It’s also a “no-brainer” that most of our essential natural resources are finite in nature and that we need to plan ahead for a world without them. Oil is the obvious example yet, despite only an estimated 30 or 40 years of oil remaining there is no concerted world effort to plan for a future without oil. We need to take drastic measures now to reduce our consumption of resources but again we see almost nothing happening. Until and unless we are prepared to tackle the issues of population and resources then there seems to be little point in arguing about the finer nuances of climate change.
Thank you for a considered well argued and thoughtful piece. I cannot disagree with many of your points. However, climate change and carbon reduction are still immediate issues along with your population growth and resource use points. They are all linked.
I agree that the three flood, fires ad food riot events are mutlifactoral and are not evidence of climate change. They merely illustrate how increasing temperatures may interact with the social, political, historical and environmental factors that currently exist. The complex nature of climate change is such that we can only suggest ways in which this extra factor (rise in global mean temperatures) will impact on such pre existing factors in the future, pointing out that it may be a either a tipping point factor in among many, or that it may introduce such a dramatic change that the ecosystems that support health collapses relatively suddenly. The claim (if made) that these events are a result of climate change is therefore nor helpful. However they may illustrate the type of event that could in future be a result of global mean temperatures rise.
The issues outlined (malaria etc) are occurring in the current temperature range and are affected by various factors and many have solutions that could be put in place reasonably easily. Climate change has little to do with them right now. The argument is that when we reach global mean temperatures of over 2 degrees or up to 4 or more, then the ecosystem feedback loops that kick in (12, 13) will have potentially devastating health impacts. It is accepted that the current 387 ppm (14) of CO2 in the atmosphere (2008 figure) is linked to the rise in temperatures and that even if we reduced carbon emissions to zero today, the ppm will continue to rise for many, many years (the lag effect of CO2). Therefore climate change should concern us now not because the events you describe are results of climate change but because in the future human populations may experience rapid changes in their ecosystems that they may have extreme difficulties dealing with.
You argue “Perhaps before using diarrhoea as an example of the horrors of climate change we should tackle the basic problems and cheap solutions first. (I agree). I feel that the whole climate change debate has become increasingly sterile and it seems to be caught in a perpetual loop of claim and counter-claim (often though due to the ill informed and vested interested oil lobby). No-one seems to baulk from the idea that the planet may be warming but they argue about how much warming there will be (but the range is not disputed) and what will be the impact on mankind (the exact nature of the impact has much room for debate but there is agreement that it will significantly impact) and how much are anthropogenic greenhouse gases to blame (but there is very broad agreement among scientists that CO2e’s are too blame), and so on”.
The measures that will reduce emissions produce co benefits now. In addition, your emphasis on population growth is a key issue linked to development (populations stabilise as they get affluent), but the natural resource issue is equally important and will be harder to crack in the context of current economic orthodoxy (neoliberal and other forms of capitalism) that requires growth. I agree, we need to take drastic action now to curb population growth as soon as possible and to restructure our economies to address resource use, that way we will also address carbon emissions. The transition town movement is one such attempt, it may not be enough. The BMJ conference focused on climate change, but there is the need to link sustainability and political economy to understand the whole picture. Anyone who uses only the current health impacts of climate events as an argument has partial view.
1. Roberts, I. Stott, R. Doctors and Climate Change, BMJ 2010; 341:c6357
2. Roberts, I. Stott, R. Doctors and Climate Change, Lancet 2010; 376: 1801 – 1802
3. Gronewold, N. Scientific American (on-line) October 12, 2010 http://www.scientificamerican.com/article.cfm?id=what-caused-the-massive-flooding-in-pakistan
4. Taiga Rescue Network: Fires in the Russian Taiga: Natural Disaster or Poor Management? December 2004 http://www.taigarescue.org/_v3/files/pdf/99.pdf
5. BBC News (on-line) September 3, 2010 http://www.bbc.co.uk/news/business-11177214
6. World Health Organisation Media Centre Fact Sheet Number 94 Malaria: New York: April 2010 http://www.who.int/mediacentre/factsheets/fs094/en/
7. World Watch Magazine May/June 2000 http://www.worldwatch.org/node/754
8. Department of Health Expert Group on Climate Change and Health in the UK: Health Effects of Climate Change in the UK: London: April 2001 http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4007935
9. Lomborg, B. Cool It: The Skeptical Environmentalist’s Guide To Global Warming, P.126 – 127. London: Marshall Cavandish Ltd 2007 (ISBN 978-0-462-09912-5)
10. Food and Agriculture Organisation of the United Nations: The State of Food Insecurity in the World, Italy: 2008 http://www.fao.org/docrep/011/i0291e/i0291e00.htm
11. World Health Organisation Media Centre News Release: Reducing Childhood Deaths from Diarrhoea; New York: October 14 2009 http://www.who.int/mediacentre/news/releases/2009/childhood_deaths_diarrhoea_20091014/en/
12. Lynas, M. (2007) Six degrees. Our future on a hotter planet. Fourth Estate.
13. Hamilton, C. (2010) Requiem for a species. Earthscan. London.
14. ‘World CO2 levels at record high warn scientists’ http://www.guardian.co.uk/environment/2008/may/12/climatechange.carbonemissions