Climate Change

by Jason and Rachel Roach

The evidence for climate change is irrefutable and it is more than 90% certain that most of the warming is due to the observed increase in man-made greenhouse gas emissions. Global warming has serious consequences for health; most are negative, but some are positive because actions that are good for curbing climate change are also good for health. Christians have a special mandate to care. Suggestions are made for tackling the causes and the effects of climate change.

In the year of 2000 alone, climate change is estimated to have caused the loss of over 150,000 lives.(1) Since the industrial revolution began more than 200 years ago, the average global surface temperature has risen by 0,76°C. This warming is leading to disrupted seasonal weather patterns and an increased frequency and severity of extreme events. In different parts of the of the world this means more heatwaves, more floods and droughts, and more intense storms and hurricanes. Each of these consequences increases deaths and the occurrence of various diseases around the globe.

According to the Intergovernmental Panel on Climate Change (IPCC) there is more than 90% certainty that most of the warming is due to the observed increase in man-made greenhouse gas emissions.(2) Many of the national science academies of the world (including in the USA) have publicly pledged their agreement.(3)

Climate science

The ‘greenhouse effect’ has been known for nearly 200 years. Greenhouse gases in the atmosphere (such as water vapour and carbon dioxide) acct as a blanket over the earth’s surface. By absorbing infra-red radiation from the earth’s surface. By absorbing infra-red radiation from the earth’s surface they keep it on average 20-30 degrees Celcius warmer than it would be otherwise. This warming effect, however, is increasing. As a consequence, the global average temperature is projected to rise by between 2-6 degrees Celcius from the pre-industrial level over the 21st century.(4)

It is true that the climate record over the last 1,000 years shows a lot of natural variability; for example, as a result of volcanic activity and changes in the sun. But the rise in global average temperature (and its rate of rise) during the 20th century is well outside the range of known natural variability. The evidence is very strong that most of the warming over the last 50 years is due to the increase of greenhouse gas emissions, especially carbon dioxide. It is therefore labelled as man-made, or anthropogenic.

Two basic observations illustrated the reality of anthropogenic climate change. First, climate scientists are able to compare historic concentrations of atmospheric carbon dioxide with the present day. This is possible using measurement from air bubbles trapped in the ice cores of the Antarctic and Greenland ice caps. From these ice core readings we know that carbon dioxide in the atmosphere has increased by nearly 40% since the beginning of the industrial revolution (around 1750). it is now at a higher concentration than it has probably been for millions of years. This increase is due largely to the burning of fossil fuels – coal, oil, and natural gas.(5) There has been a close correlation between the concentration of greenhouse gases and global temperature over the past 800,000 years.(6) Secondly, computer models of climate (of which there are many) only show good agreement between observed and simulated global average temperatures when both natural and anthropogenic factors are included.(7)

The most reliable source of scientific information about climate change is the Intergovernmental Panel on Climate Change (IPCC). The body was founded in 1988 and has involved scientists from around the world in producing for major reports, the most recent in 2007. It has been a massive undertaking; involving 450 lead authors and 800 contributing authors. During three stages of review, more than 2,500 expert reviewers collectively submitted 90,000 review comments on the various drafts, all of which are on public record. The final report is comprised of three volume volumes, which are one thousand pages each. In a document of this scale and size, it is likely (some would say inevitable) that small mistakes will be made even with a rigorous review system in place. However, the very few errors that have been identified and subsequently rectified cannot legitimately be used to negate the rest of the report.(8)

The precautionary principle

It is difficult to predict with certainty the precise rise in temperature and the precise scale of the effects in such a multifactorial process. But in the face of such uncertainties, the precautionary principle is an important guide. It reminds us that on the one hand scientific conclusions are always made on the basis of the information available at a particular point in time. They are therefore subject to change in the light of further observations. On the other hand, however, inaction in the light of current compelling evidence cannot be justified on this basis. While this principle does not commit us to a particular course of action in the light of the evidence, it does legitimate acting on the present data even while being uncertain about some long term outcomes.(9)

Health implications – negative

Emerging evidence on the effects of climate change shows three major health implications that have been observed.(10) The first is the direct of increased heatwave and coldwave – related deaths (eg 35,000 excess deaths in Europe in 2003).(11) There were eighteen heatwaves reported in India between 1980 and 1998, resulting in 1,300 deaths. However, three heatwaves between 1998 and 2000 caused an estimated 2,200 deaths in India. Coldwaves are also problematic. Extreme cold lasting from hours to weeks tends to affect the socially deprived (the homeless and alcoholics) and the elderly. Even in countries that experience regular cold spells, this increase in adverse weather conditions can be lethal when heating systems either fail or are not affordable.

The poor will die

The second effect is the altered distribution of some infectious disease carriers (vectors). For example, bird migration patterns and the prevalence of insects such as mosquitoes, ticks and blackflies are changing. They are being found in increasing numbers in areas where the temperature would previously have been unfavourable for their flourishing. This raises the possibility that the distribution of diseases which they carry, such as malaria, may well shift and increase over time, with a longer season of transmission. In many cases it is too early to identify changes in disease patterns exclusively with climate change or to know precisely how these might develop, but we would expect the effects to become increasingly marked.

Thirdly, altered seasonal distribution of some allergenic pollen species has been observed. Changes in climate have already caused the spring pollen season in the northern hemisphere to begin earlier. Certain types of pollen have increased, and some animal species are experiencing a longer pollen season already. This naturally has an effect on the distribution and length of duration of pollen-related diseased=s such as allergic rhinitis.

It is also predicted that in time there will be additional health consequences. These are predominantly negative, such as increased:(12)

  • burden from malnutrition (as a result of drought)
  • diarrhoeal disease (as a direct effect and from reduced water availability)
  • cardio-respiratory disease (as a result of changes in light in urban contexts)
  • disability and death as a direct result of heatwaves, floods, and droughts.
  • burden on health services

A number of other indirect effects are also predicted. For example, financial pressures generated by climate change may impact international pledges to respond to other areas of global health development. The huge numbers of environmental ‘refugees’ will worsen issues of rapid urban growth such as pollution. And in addition it is it is feasible that conflict may arise over these population shifts, as well as over the limited resources available to society.(13)

All these health impacts will be greatest in low-income countries. In all countries, those at greater risk include the urban poor, the elderly and children, traditional societies, subsistence farmers, and coastal populations. As one author put it, ‘The rich will find their world to be more expensive, inconvenient, uncomfortable, disrupted and colourless; in general, more unpleasant and unpredictable, perhaps greatly so. The poor will die.'(14)

Read more: Climate Change Part 2


      1. IPCC 2007. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Parry M et al Eds. Cambridge University Press, Cambridge, UK.
      2. IPCC 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Solomon S et al Eds. Cambridge University Press, Cambridge, UK.
      3. Royal Society. Joint science academies’ statement: Global response to climate change. Royal Society Statement 2005.
      4. Stern et al. Stern Review of the Economics of Climate Change. HM Treasury 2006.
      5. Houghton J. Global Warming, Climate Change and Sustainability, John Ray Initiative Briefing Paper 14:3
      6. Le Page M. Why there’s no sign of a climate conspiracy in hacked emails. New Scientist. 4 December 2009
      7. Houghton J. Copenhagen and the Climate Change Crisis. John Ray Initiative Briefing Paper 19:3
      8. Real Climate, IPCC errors: fact and spin. Guardian Online 15 February 2010
      9. Costello A et al. Managing the health effects of Climate Change. Lancet 2009:1698
      10. IPCC 2007. Working Group II
      11. Menne B & Bertolonni R. Health and climate change: a call for action. BMJ 2005;331:1283-1284
      12. IPCC 2007. Working Group II
      13. Costello A et al. Art cit 1701
      14. Smith K. Symposium introduction: Mitigating, adapting, and suffering: how much of each? Ann Rev Public Health 2008:29:11-25

    Christian Medical Fellowship (CMF) Files No. 41, 2010