Climate Change and its Impact on Health (JPCFM, Feb. 16, 2010)

Ghaiath HusseinMBBS, MHSc. (Bioethics)

Overview

• Climate Change, Greenhouse Effect, and Global Warming Defined

• Greenhouse gases• Evidence of global warming• Impact(s) of climate change• Impact on health

Climate change

• refers to any distinct change in measures of climate lasting for a long period of time, including major changes in temperature, rainfall, snow, or wind patterns lasting for decades or longer. Climate change may result from:

• natural factors, such as changes in the Sun’s energy or slow changes in the Earth’s orbit around the Sun;

• natural processes within the climate system (e.g., changes in ocean circulation);

• human activities that change the atmosphere’s make-up (e.g, burning fossil fuels) and the land surface (e.g., cutting down forests, planting trees, building developments in cities and suburbs, etc.).

Global warming

• is an average increase in temperatures near the Earth’s surface and in the lowest layer of the atmosphere.

• Increases in temperatures in our Earth’s atmosphere can contribute to changes in global climate patterns.

• Global warming can be considered part of climate change along with changes in precipitation, sea level, etc.

Greenhouse Effect

• The greenhouse effect is a natural process that sees the Earth's atmosphere insulate the Earth. 

• Incoming solar radiation (short-wave radiation) is absorbed at the Earth's surface.  The Earth's climatic system then redistributes this energy around the globe, through atmospheric and oceanic circulation patterns.  Energy is then radiated back from the Earth's surface into the atmosphere as long-wave radiation

• Over time there is an approximate balance in this incoming (short-wave) and outgoing (long-wave) radiation.  Changes to this balance, such as changes in the amount of radiation received or lost by the system, or changes to the distribution cycles within the system, can affect climate.

Greenhouse gases

• water vapor and carbon dioxide (CO2), occur naturally. human activities are adding large amounts of:

• carbon dioxide, methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6).

• Since 1750, atmospheric concentrations of CO2, CH4 and N2O have increased by over 36 percent, 148 percent and 18 percent, respectively. Scientists have concluded

Global warmth…so what?

• The heating of the Earth's surface and atmosphere affects these climate variables to produce extreme weather and climate events. 

• Climate change is already being observed in a range of climate variables, such as: temperature, rainfall, atmospheric moisture, snow cover, land and sea ice, sea level, wind patterns and ocean circulation patterns. 

Major global killers are affected by climate

Each year:• Weather– related disasters kill over 60,000• Undernutrition kills 3.5 million • Diarrhoea kills 2.2 million• Malaria kills 900,000

(WHO, 2003, 2008)

Global warming increases the likelihood it will be hot or very hot and decreases, but does not eliminate, the likelihood it will be cold or very cold. Source: IPCC, 2007

Past and projected global average sea level. The gray shaded area shows the estimates of sea level change from 1800 to 1870 when measurements were not available. The red line is a reconstruction of sea level change measured by tide gauges with the surrounding shaded area depicting the uncertainty. The green line shows sea level change as measured by satellite. The purple shaded area represents the range of model projections for a medium growth emissions scenario (IPCC SRES A1B). For reference 100mm is about 4 inches. Source: IPCC, 2007

Agriculture and Forestry

• The supply and cost of food may change as farmers and the food industry adapt to new climate patterns. A small amount of warming coupled with increasing CO2 may benefit certain crops, plants and forests, although the impacts of vegetation depend also on the availability of water and nutrients. For warming of more than a few degrees, the effects are expected to become increasingly negative, especially for vegetation near the warm end of its suitable range.

Water Resources

• In a warming climate, extreme events like floods and droughts are likely to become more frequent.

• More frequent floods and droughts will affect water quality and availability.

• increases in drought in some areas may increase the frequency of water shortages and lead to more restrictions on water usage.

• An overall increase in precipitation may increase water availability in some regions, but also create greater flood potential.

Energy

• : Warmer temperatures may result in higher energy bills for air conditioning in summer, and lower bills for heating in winter. Energy usage is also connected to water needs. Energy is needed for irrigation, which will most likely increase due to climate change. Also, energy is generated by hydropower in some regions, which will also be impacted by changing precipitation patterns.

Coasts

• : If you live along the coast, your home may be impacted by sea level rise and an increase in storm intensity. Rising seas may contribute to enhanced coastal erosion, coastal flooding, loss of coastal wetlands, and increased risk of property loss from storm surges.

Wildlife

• Warmer temperatures and precipitation changes will likely affect the habitats and migratory patterns of many types of wildlife.

• The range and distribution of many species will change, and some species that cannot move or adapt may face extinction.

Anthroponotic Infections

Zoonotic Infections

Direct Exposure

Indirect Exposure

Environmental Exposures

Vehicle

Humans

Source

Stream pollutantsAir ParticulatesLegionella

Humans

Humans STDsMeaslesHepatitis B

Vehicle

Humans

Humans

Vehicle

MalariaDengueRoundworm

Vehicle Vehicle

Animals

AnimalsHumans Lyme Disease

Hantaviral DiseaseMost arboviral diseases

Animals

Animals

HumansAnthraxEbola (?)CJD

Environment and Exposure

Source

Humans Solar UVEM RadiationTetanus

WHO: five major health impacts of climate change

1. Malnutrition2. Deaths and injuries caused by storms and floods.

(Flooding can also be followed by outbreaks of diseases, such as cholera)

3. Water scarcity / contamination (droughts and sudden floods) – increased burden of diarrhoeal disease.

4. Heatwaves – direct increases in morbidity and mortality; indirect effects via increases in ground-level ozone, contributing to asthma attacks.

5. Vector-borne disease – malaria and dengue.

Vulnerable population groups

• Chronic medical conditions including mentally ill, clients with special needs

• Social isolation• Poor & vulnerable communities• Being confined to bed• Certain medical treatments • Some types of occupation, outdoor workers• Very young children• Elderly suffer the greatest effects of heat-waves (impact

on mortality greater in women)

Health impact of climate change

• Air pollution - a reduction in the cold, calm winter weather associated with winter air pollution episodes together with reduced emissions of key pollutants including particles, oxides of nitrogen and sulphurdioxide could lead to a reduction (up to 50%) in the adverse health effects of winter air pollution.

• A small overall increase in the number of summer ozone episodes coupled with a longer-term increase in background levels of ozone could cause a rise in the number of premature deaths.

Air Pollution• Pollution determined by

emissions & weather• Increases in ozone:

o extra deaths & o hospital admissions

• Air quality decline:o severity of asthma

• Ozone levels dependent on pollution control in Europe

• Between 2003 – 2020, increase in ozone levels will result in a 51-53% increase in attributable deaths and hospital admissions for respiratory diseases, threshold assumptions of 35-50ppb (attributable to climate change)

Salmonellosis and temperature rise

Modelled association between temperature and number of reported cases of salmonellosis in England and Wales (adjusted for outbreaks, seasonal factors and holidays)

© S. Kovats (Data supplied by HPA)

Infectious diseases – foodborne and waterborne diseases

Foodborne diseases• Likely increase in cases of food

poisoning• incidence dependent on future food

hygiene behaviour• evidence confirms the effect of

temperature on salmonellosis• role of temperature in Campylobacter

transmission remains uncertain Waterborne diseases• Likely increase in cases of

Cryptosporidiosis• Impact of increased temperature on

water quality & disinfection

Health impact of climate change

• Extremes of temperature - heat-related deaths could increase to around 2,800 cases per year.

• This is likely to be offset by milder winters leading to a fall in cold-related winter deaths of up to 20,000 cases per year.

Likely increases in:• Sunburn• Skin cancer• Possibly cataracts

Exposure to ultra violet radiation

Health impact of climate change

• Flooding – increased frequency of severe coastal and river floods,

• Analysis of more recent river flooding shows that mental health problems are the most important health impact among flood victims due to experience of personal and economic loss and stress.

River, Coastal Flooding & Flash Floods

• Few direct deaths• Full effect in terms of mortality and morbidity not known

o Accidents – drowning, electricalo Contamination of drinking watero Rise in waterborne infectionso Exposure to toxic pollutants o Psychological consequenceso Disruption, injuries & deathso Late effects include stress &

mental health problems • Food and water safety concerns• Effects on health and social service delivery

UK floods of summer 2007

Health impact of climate change

• • UV exposure – levels of UV radiation reaching the earth’s surface may increase due to sunnier summers,

• a decline in cloud cover and ozone depletion (which

• reduces the capacity of the ozone layer to absorb UV).

• predicted an extra 5,000 cases of skin cancer and 2,000 of cataract per year by 2050.

Directly aged standardised registration rates (DSR)

Source: Health & Social Care Information Centre (2006). Compendium of Clinical & Health Indicators / Clinical & Health Outcomes Knowledge Base http://www.nchod.nhs.uk

Note: International Classification of Disease and related health problems (ICD) definition of all skin cancers - ICD9 172-173, ICD10 C43-C44.

Males

Persons

Females

Year1 Exponential projections based on data for the ten years 1993-2002

Incidence of ‘All Skin Cancer’England and Wales 1993-2002, and projections to 20251Males, Females and all persons

Health impact of climate change

• Vector-borne diseases – various diseases transmitted by mosquitoes or ticks are climate-sensitive and can increase or be introduced due to climate change.

• Malaria might be re-established in non-endemic areas.

• Potential emergence of other vector-borne diseases, such as West Nile Fever.

Vector-borne diseases• Outbreaks of malaria likely to be

rare• Tick borne likely to be more

common, but relate to land use/leisure activities rather than climate changeo Lyme disease – no observed

correlation between temperature and incidence

o Tick-borne encephalitis – low chances of occurrence

• Possible increase in flies

(diarrhoeal disease), midges, fleas, stinging insects• Need to be alert to possibility of emerging infections

Health impact of climate change

• Food poisoning - higher temperatures in summer could cause an estimated 10,000 extra cases of salmonella infection per year.

• Storms – any increase in the frequency of severe winter storms could lead to an increase in personal injuries from flying debris and falling trees.

Health impact of climate change

• Water-borne disease – climate change might increase levels of cryptosporidium and campylobacter in water.

• Secure sanitation systems should safeguard supplies of drinking water, but possible contamination of stormwater outflows could carry disease into basements and nearby rivers, affecting the health of residents and river users.

What diseases are the mostclimate sensitive?

• heat stress• effects of storms• air pollution effects• asthma• vector-borne diseases• water-borne diseases• food-borne diseases• sexually-transmitted

diseases

High

Low

Sensitivity

Health impact of extreme events

Lead to:• Social disruption • Homelessness• Injuries, deaths,

disability• Impacts on food and

water supply

Extreme weather-related events (natural disasters)

Health impact of extreme events

Health impact of extreme events

Due to both direct & indirect effects:• Increased physical activity due to

extended warm weather. But, outcomes could be worse due to extreme heat

• Reduced obesity and road traffic injuries through active transport

• Possibly healthy eating through adoption of sustainable farming & food policy and diets containing less animal products

• Reduced respiratory illness by improvements in air quality

• Increased home energy efficiency reducing temperature-related illness

Potential health benefits

Knowing is not enough; we must apply.

Willing is not enough; we must do.(Goethe)

Discussion… From YOUR EXPERIENCES or INTERESTS:• What diseases might have a climate link and what

climate variables might impact on which diseases?

• How would these be investigated/researched?• What additional information would you seek?• How would you integrate this into OTHER

determinants of risk?• What other factors should be considered and

why?

Q & A