Are extremes more important to health than changes in means

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Are extremes more important to health than
changes in means? R Sari Kovats Centre on
Global Change and Health, London School of
Hygiene and Tropical Medicine National
Symposium Climate Change and Health Research
Methods and Policy Issues Canberra, 29 Sept 2003
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Categories of climate extremes

• extremes based on the simple climate statistics
• Hot day day with temperature gt 95th centile
• complex, event driven extremes
• Droughts
• Floods
• Hurricanes/typhoons/tropical cyclones
• do not necessarily occur every year at a given
  location.

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IPCC WORKING GROUP I Third Assessment Report 2001
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Climate change may entail change in variance, as
well as a change in mean
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1999 Hurricane Mitch in the Honduras
Devastation related to (i) strength of
hurricane and (ii) poor housing and infrastructure
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Health Impacts of Hurricane Mitch

• 9 550 deaths 137 851 homes destroyed or
  affected and affected a population of around
  3 174 700 people.
• increase in vectors leading to increased
  transmission of vector-borne diseases, especially
  malaria and dengue
• increases in communicable diseases such as
  gastrointestinal and respiratory diseases
• damage to infrastructure and services that
  worsened the secondary effects.
• Honduras lost over 70 of banana, coffee and
  pineapple crops

Source PAHO. Disasters preparedness and
mitigation in the Americas (Supplement 1) S1-S4
(1999).
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Hospital flooded in Peru during 1997/98 El Niño
Source PAHO
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The 10 most disastrous floods in Europe , 1990s
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Health impacts of floods

• Immediate deaths and injuries
• Infectious diseases-leptospirosis, diarrhoeal
  diseases, hepatitis, respiratory diseases,
  vector-borne diseases
• Non specific increases in mortality
• UK study
• Exposure to toxic substances
• Long term mental health effects - depression,
  suicide

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Potential health impacts of drought
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Fiji - 1997/98 drought

• severe water shortages in the drier parts of the
  mainland, especially in the Western and Northern
  Divisions.
• Increase in malnutrition and micronutrient
  deficiency reported in children and infants (OCHA
  1998).
• The drought was followed by a very intense
  rainfall event, in January 1999, which caused
  record floods in the vicinity of Nadi.

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Total number affected by weather
disastersEm-dat database
El Niño years
Source Bouma et al. 1997
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ENSO and climate change

• The effect of global climate change on the future
  frequency and/or amplitude of El Niño is
  uncertain .
• Events may become more frequent or more intense.
• However, even with little or no change in
  amplitude, climate change is likely to lead to
  greater extremes of drying and heavy rainfall and
  increase the risk of droughts and floods that
  occur with El Niño
• IPCC 2001.

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Heat wave August 2003

• France 10,000 excess deaths
• Portugal 1,316 excess deaths
• Italy reports 20 more than average in July/Aug
• Spain has reported 100 deaths
• UK report 900 excess deaths
• But
• - No standard method to estimate excess

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Excess mortality by department
Excess mortality
Less than 25 Between 25 and 49 Between 50 and
74 Between 75 and 99 More than 100
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Daily no. of deaths in Paris (InVS, 2003)25 June
to 19 August 2003
Source INVS, 2003
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Vulnerability in heatwaves

• Physiological
• Demographic
• Ageing population
• Social
• Social isolation
• housing

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Impacts in France, extreme summer 2003

• Agriculture Minister Hervé Gaymard estimated the
  damage to French farms was between 1.1 billion
  and 4.4 billion.
• About 4 million chickens died plus 500,000 set
  aside for breeding, a loss likely to lead to
  price hikes,
• The wheat harvest is expected to drop by 15 per
  cent compared to last year and corn production by
  nearly 28 per cent
• Many areas of France have had 20 per cent to 50
  per cent less rain than normal in six months of
  drought

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Kericho, Kenya, 1990 to 1997
Malaria cases
Rainfall
Source Cox et al., 2003, LSHTM
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Climate change impact assessment

• Climate change scenarios describe changes in
  average conditions
• IAM integrated assessment modelling
• Unable to deal with extreme events
• Now thinking of incorporating them..

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Modelling impacts of climate change
Greenhouse gas emissions scenarios Defined by
IPCC
Global climate modelling Generates series of
maps of predicted future distribution of climate
variables 30 year averages

• Impact models
• Estimates of populations at risk
• hunger
• water stress
• coastal flooding
• malaria

2020s
2050s
2080s
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Are changes in extremes more important than
changes in means?

• Wrong question
• Depends on
• Outcome
• Location
• Time point
• Limits to adaptation
• Hazards approach to adaptation
• Learn to deal with uncertainty.

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